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FINAL_Fathom Cover.indd 2-3
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INLET TECHNOLOGIES, INC.
Fathom Users’ Guide
v 2.5
 2006 Inlet Technologies, Inc.
1121 Situs Court, Suite 330
Raleigh, NC 27606
919.856.1080 phone
919.256.8123 fax
info@inlethd.com
Fathom and Semaphore are registered trademarks of
Inlet Technologies, Inc. All other trademarks used
herein are the properties of their respective owners and
are used for identification purposes only.
Table of Contents
1
INTRODUCTION ....................................................................................................................... 1
About Fathom........................................................................................................................... 1
What’s New in This Release.................................................................................................... 1
Upgrading from version 2.1 ............................................................................................... 2
Uses of VC-1 Encoded Content .............................................................................................. 4
For computer playback ...................................................................................................... 4
For video playback ............................................................................................................. 4
For IPTV ............................................................................................................................... 5
For digital cinema ............................................................................................................... 5
For high definition discs .................................................................................................... 5
About This Manual................................................................................................................... 6
Before You Begin… ................................................................................................................. 7
What is my source? ............................................................................................................ 7
Who is my audience? ......................................................................................................... 7
What are my communication goals? ................................................................................ 8
2
NAVIGATING THE USER INTERFACE.................................................................................... 9
Customizing the Interface ..................................................................................................... 10
Menus...................................................................................................................................... 10
Setting Options ...................................................................................................................... 12
Toolbar.................................................................................................................................... 13
3
CREATING A JOB .................................................................................................................. 15
Session Directory .................................................................................................................. 15
Toolbar ............................................................................................................................... 16
Job status indicators ........................................................................................................ 17
Editing a job’s parameters ............................................................................................... 18
Creating a job from a template ........................................................................................ 18
Creating a job from ALE/FLEX files ................................................................................ 19
Loading saved jobs .......................................................................................................... 20
Displaying job properties ................................................................................................. 20
4
DEFINING JOB PARAMETERS ............................................................................................. 23
General.................................................................................................................................... 24
Input ........................................................................................................................................ 24
Specifying SDI input ......................................................................................................... 26
Specifying file input .......................................................................................................... 32
Output ..................................................................................................................................... 36
Designating the output settings ...................................................................................... 36
Sizing ...................................................................................................................................... 37
Specifying sizing for SDI inputs ...................................................................................... 37
Compression .......................................................................................................................... 39
Processing.............................................................................................................................. 41
Adding Watermarks .......................................................................................................... 43
Applying Job Parameters and Saving a Job ....................................................................... 44
Saving Job Parameters as a Template ................................................................................ 44
5
QUEUE THE JOB AND MONITOR ENCODING .................................................................... 45
Encoding Queue .................................................................................................................... 45
Toolbar ............................................................................................................................... 48
Queuing a job .................................................................................................................... 48
Reordering jobs in the queue .......................................................................................... 48
Manually stopping jobs in the queue .............................................................................. 48
Encoding Monitor .................................................................................................................. 49
Video tab ............................................................................................................................ 49
Audio tab ........................................................................................................................... 51
Hardware tab ..................................................................................................................... 52
Advanced tab .................................................................................................................... 53
Stats tab ............................................................................................................................. 54
Watch Folders ........................................................................................................................ 55
Setting Up Watch Folder Parameters.............................................................................. 55
6
ANALYZE THE JOB OUTPUT................................................................................................ 57
Video Analysis ....................................................................................................................... 58
Analyzing .wmv files ......................................................................................................... 59
Toolbar ............................................................................................................................... 60
Analysis Timeline................................................................................................................... 61
Toolbar ............................................................................................................................... 62
Graphs ............................................................................................................................... 63
Seen by Scene Re-encoding................................................................................................. 66
Creating a scene ............................................................................................................... 68
Adjusting the scene’s bit rate.......................................................................................... 71
Re-encoding a scene ........................................................................................................ 71
Reviewing re-encoded scenes......................................................................................... 72
Merging approved scenes with the original content ..................................................... 72
Batch Job Utility..................................................................................................................... 74
The Source Files panel ..................................................................................................... 75
The Fathom Jobs panel .................................................................................................... 75
The AviSynth Script panel ............................................................................................... 77
Resolution of filename conflicts...................................................................................... 78
Generating trick streams....................................................................................................... 79
7
INLETASFDUMP..................................................................................................................... 83
Usage ................................................................................................................................. 83
8
TROUBLESHOOTING ............................................................................................................ 85
9
RELEASE NOTES................................................................................................................... 89
General Information............................................................................................................... 89
External inputs .................................................................................................................. 89
File-based input ................................................................................................................ 90
Video pre-processing ....................................................................................................... 91
Output ................................................................................................................................ 92
Statistics ............................................................................................................................ 93
Settings .............................................................................................................................. 93
Seen by Scene™ ............................................................................................................... 94
Device control ................................................................................................................... 94
Fathom Pro encoding station .......................................................................................... 94
System requirements ....................................................................................................... 95
Technical Notes ..................................................................................................................... 95
Working with SMPTE-296 (1280x720p) ........................................................................... 95
Audio formats when using embedded audio from SDI ................................................. 96
Video compression quality setting ................................................................................. 96
CBR and VBR (constrained/unconstrained)................................................................... 97
10
APPENDIX A: TECHNICAL GUIDE........................................................................................ 99
Understanding VC-1 and FourCC......................................................................................... 99
VC-1 codec specification ................................................................................................. 99
WMV3 ................................................................................................................................. 99
WVC1................................................................................................................................ 100
WMVA............................................................................................................................... 100
A Note on Terminology ....................................................................................................... 101
USB License Key required .................................................................................................. 101
Some Background on Input ................................................................................................ 102
Files versus tape sources .............................................................................................. 102
Encoding via SDI............................................................................................................. 102
HD tape formats .............................................................................................................. 103
Encoding from live sources........................................................................................... 104
Getting the correct field mode ....................................................................................... 105
Audio ................................................................................................................................ 105
Encoding from files ........................................................................................................ 105
Wild/Crash Encoding........................................................................................................... 107
Aspect Ratio Overview ........................................................................................................ 107
Frame Aspect Ratio (FAR) ............................................................................................. 107
Pixel Aspect Ratio (PAR)................................................................................................ 107
Image Aspect Ratio (IAR) ............................................................................................... 108
Two Primary Reasons to use Cropping............................................................................. 108
Resizing ................................................................................................................................ 109
Some Background on Compression.................................................................................. 109
What makes high quality video encoding .................................................................... 109
Compliance...................................................................................................................... 110
General encoding settings ............................................................................................. 111
Hardware encoding settings.......................................................................................... 112
Audio compression settings.......................................................................................... 113
Video compression settings .......................................................................................... 115
Interlace processing ....................................................................................................... 122
Complexity....................................................................................................................... 123
Advanced Video Processing Filters.............................................................................. 123
Hardware Processing ..................................................................................................... 124
Dithering .......................................................................................................................... 124
Quantization ......................................................................................................................... 126
11
APPENDIX B: DECKCONTROL USER GUIDE ................................................................... 127
Configuring DeckControl .................................................................................................... 127
VTR and port control selection...................................................................................... 128
Time control .................................................................................................................... 129
Timing .............................................................................................................................. 130
12
APPENDIX C: AVISYNTH AND FATHOM .......................................................................... 131
Introduction .......................................................................................................................... 131
Example scripts ................................................................................................................... 132
Using a single AVI file without any preprocessing...................................................... 132
Using an AVI file and applying a contrast/brightness filter:....................................... 132
Using the same AVI file with a fast resizing filter ........................................................ 132
Using the same AVI file with a more advanced resize and crop filter ....................... 132
Joining (concatenating) two AVI files ........................................................................... 133
Using two GXF files (via Inlet’s GXF decoder) ............................................................. 133
Recommended AviSynth filters.......................................................................................... 133
Known issues/caveats with AviSynth and Fathom .......................................................... 134
13
GLOSSARY........................................................................................................................... 137
14
INDEX
............................................................................................................................... 141
FATHOM™
1
Introduction
1
This manual contains information on getting started and getting the best results with
Fathom™ 2.5, a professional VC-1 encoder that delivers high-performance, advanced
compression to the post-production market. Written with the video professional in mind,
it helps to bring you up to speed with today’s world of compression. It assumes a basic
background in professional video technologies and terms.
About Fathom
Inlet’s Fathom 2.5 is a professional grade encoder for Windows Media files and the
SMPTE VC-1 codec. With Fathom, you reap the benefits of a professional encoding
solution: speed, quality and control.
While Fathom’s focus is on HD, it is also an excellent standard definition encoder,
showing substantially better performance than Microsoft’s own codecs at data rates of
1 Mbps and above. Fathom is well suited for a variety of applications, including content
for DVD-ROM, kiosks, IPTV, Dailies, Digital Signage and the next-generation HD disc
formats including HD DVD, Blu-ray, FVD, and WMV HD.
What’s New in This Release
The Watch Folder feature automates the encoding of file-based source content
within Fathom by detecting the presence of new source or job files in a userdesignated directory, or watch folder. This can be a folder on the same
machine where Fathom is installed or a folder on a remote network share. For
more information, see “Watch Folders” on page 55.
Fathom 2.5 recognizes AviSynth scripts (.avs files) to further enhance
Fathom’s capabilities, features and overall value. Such possible
implementations of using AviSynth scripts include Inverse telecine, source file
concatenation, noise reduction, and advanced resizing filters.
For more information, see Appendix C.
The Workspace tab in the Options dialog lets you select a window layout for
your workspace. You can use one of three default layouts (Last Known,
Default Left, Default Right), or you can create up to two custom layouts. For
more information, see “Setting Options” on page 12.
1
Fathom 2.5 supports the overlay of a watermark to your output image. See
page 43 for more information.
The Encoding Monitor Audio tab displays meters to verify correct input while
encoding from SDI input sources.
Input sources now include AviSynth, MPEG-2, GXF (SMPTE-360), raw YUV,
SD interlaced and HD interfaced files.
SDI sources can now be scaled from 720 to 352 or 320 during encoding.
Semaphore can analyze Windows Media Video 9 .wmv files (WMV3 FourCC),
as well as VC-1 .wmv files (WVC1 & WMVA FourCC), created by Fathom and
other applications. See “Understanding VC-1 and FourCC” in Appendix A.
Fathom 2.5 supports a batch job processing application to help in the workflow
of creating VC1 fast forward trick stream files. Tricks streams are streams that
are used traditionally in Video on Demand applications and provide the method
for fast forwarding and rewinding at rates greater than 1x speed.
Upgrading from version 2.1
If you are upgrading a to version 2.5 from version 2.1, the 2.5 installation resets the
default directories that you previously used for input and output of files (video in,
encodes out).
To use a different directory, navigate to it when you create a job within Fathom.
Upgrading to Fathom 2.5 requires a license key update. Contact support
at support@inlethd.com.
NOTE:
2
FATHOM™
Figure 1: Fathom in action, with jobs defined, queued, and in process of encoding and analysis
Processing within Fathom is centered on a Fathom Job. A Job is defined within Fathom
as the entity that contains all the necessary information to perform an encoding session.
For more information on what components make a job, refer to “Defining Job
Parameters” on page 23.
This manual is organized around the basic workflow process you use to create encoded
files in Fathom:
Step 1. Create/edit a job
Step 2. Queue the job for encoding and monitor its progress
Step 3. Analyze the job output
Step 4. Use Fathom’s Seen by Scene to create, edit, re-encode, and analyze
scenes within a Job.
Repeat these steps as needed until the output quality is acceptable.
3
Uses of VC-1 Encoded Content
SMPTE VC-1 is used in many different environments today, with some very exciting
technologies on the horizon.
For computer playback
A built-in audience of millions of computers already exists—deployed with Windows
Media Player 10, which can play back VC-1 Main and Advanced Profile inside a WMV
file. The very widely installed Windows Media Player 9 can play back VC-1 Main Profile
on up to HD resolutions on 3 GHz+ Windows XP systems.
Streaming
A Windows server is resolution/bit rate independent when it comes to video streaming.
However, significant bandwidth end-to-end is required to be able to stream HD
resolution video. HD at 1280x720 requires about 4 to 6 Mbps minimum to support useful
streaming. As the population with 5 Mbps+ connections grows, spurred by aggressive
fiber-to-the-curb efforts of companies like Verizon and SBC, HD streaming can become
viable. And of course, an efficient advanced compression format such as Fathom’s
VC-1 means that lower data rates can be used for HD than ever before.
Progressive download
Progressive download is a method of delivery between real-time streaming and simply
copying a file. Like streaming, you do not have to download the entire file before
playback can start. But like file transfer, there are never visible or audible glitches
caused by dropped packets. In addition, only a Web server is required.
Files
WMV files can be played back directly, either downloaded to a hard drive, or directly
from a DVD-ROM disc. This capability works great for movie and game trailers, kiosks,
and digital signage.
For video playback
Beyond traditional computer playback options, VC-1 is being adopted for many video
industry uses.
Transport streams
VC-1 content is being used today for video transport applications, such as remote
newsgathering and IPTV. It offers quality equivalent to the standard of MPEG-2 at
roughly half the data rate.
4
FATHOM™
Video servers
VC-1’s superior compression efficiency also makes it a compelling choice for video
servers. Use it inside a facility for storing master quality video or for delivery as video on
demand, like in a hotel system.
For IPTV
The combination of fast consumer bandwidth and modern codecs has made the Internet
a viable competitor to proprietary cable and satellite systems for video delivery. With
IPTV (Internet Protocol Television), consumers use their existing broadband service to
watch streaming and on-demand content via a computer, cable box, or hybrid device.
For digital cinema
Windows Media was the first widely deployed digital cinema codec, starting with a
rollout to more than a dozen independent theaters in 2003. Because playback requires
only a commodity PC and a projector with a DVI connection, this is a very cost-effective
deployment strategy. The excellent compression efficiency of VC-1 means that delivery
of high quality HD assets via cable modem or DSL connections is very feasible.
For high definition discs
A high definition replacement for DVD has been in the works for years, and it is highly
anticipated by both content companies and video enthusiasts. The VC-1 codec is part of
both the major proposed HD disc formats, HD DVD and Blu-ray. Fathom has unique
advantages in this capacity compared to the stock Windows Media Encoder. Critically, it
provides much better quality with variable bit rate encoding, required to maximize
quality for feature-length titles.
DVD-ROM
The first HD discs widely distributed were DVD-ROM discs playable in Windows XP
computers, using Windows Media assets. These discs are known as WMV HD titles,
which remain a popular delivery method for “bonus” and “value add” discs normally
associated with a multiple disc feature package. Over 50 of these titles have been
released commercially to date, with more coming. Sonic Solutions has released DVD
Producer HD product, which authors the interactive portion of those discs, using
Fathom-encoded assets.
HD DVD
The HD DVD format comes from the DVD Forum, with Toshiba leading engineering. HD
DVD was designed to support easy conversion of existing DVD facilities to the new
format. While it offers 15 GB per side compared to Blu-ray’s 25 GB, the superior
compression of Fathom’s VC-1 results in a 3+ hour film that easily fits within that
capacity at excellent quality.
5
Blu-ray
Sony designed Blu-ray as a competitor to HD DVD. From a compression perspective,
they are virtually identical—both formats support VC-1 Advanced Profile. Compared to
HD DVD, Blu-ray has a slightly larger capacity—25 GB per side instead of 15 GB. This
allows somewhat higher data rates for very long content.
SIDEBAR: A NOTE ON TERMINOLOGY
In the convergence of the media and computer worlds of the last decade, we have wound up
with a lot of confusion caused by different definitions of what the common units of “K,” “M,” and
“G” are.
For detailed information about the definitions of K, M and G, consult Appendix A: Technical
Guide.
About This Manual
The guide acquaints you with the Fathom user interface, guides you through creating,
defining, and encoding jobs and scenes, provides technical notes and specifications,
and covers the basics on using Semaphore, a stand-alone statistical tool.
As well as explaining how to operate the tool, it also provides the answers of how and
why to choose among the many modes provided by the software.
This background information is introduced throughout the manual in shaded sidebars.
Each sidebar provides a cross-reference leading you to more detailed information
contained in the Technical Guide found in Appendix A.
Additionally, this book uses the following document conventions:
Bold Text is used for the names of buttons and menu options.
Notes are placed throughout the manual to display information that is helpful,
but not crucial to the task at hand. For example:
In future Fathom sessions, you can load the job from in the Session
Directory by clicking the Load Job button.
NOTE:
6
FATHOM™
Tips provide you with useful hints and shortcuts.
In Tools>Options, check the Automatically edit new jobs box. This
opens the Job Parameters window when you create a new job.
TIPS:
SIDEBAR: USB LICENSE KEY REQUIRED
You must have the Fathom USB License Key installed on your system before using Fathom
applications.
For more information on license keys, consult Appendix A: Technical Guide.
Before You Begin…
When you approach any compression project, it is crucial to know the context in which
the content is going to be used. Ask yourself these three questions before you consider
the technical parameters of the project:
What is my source?
HD sources come in many forms, from tape to live video signals to files.
If it is on tape, what is the source tape format?
If it is on file, what file format and codec?
How many channels of audio? Sampling rate? Bit depth?
Who is my audience?
Knowing your audience is critical to any communication medium. Some important
questions include:
What playback system do they want to use, and what formats does it support?
If they are targeting computer playback, what kind of performance does it
have?
Can they use Blue Laser, or just Red Laser?
Do they have a preference between 720 and 1080 content?
Do they have stereo? 5.1? 7.1?
7
What are my communication goals?
It is important to know your target audience and what your communication priorities are.
Who needs to be critically able to play the content back?
Which lower-end playback platforms do I not care about losing?
What is the minimum “good enough” quality for viewing and hearing the
content?
8
FATHOM™
2
Navigating the User Interface
2
When you first open Fathom, the panes and windows are blank.
Session
Directory
Encoding
Queue
Video Analysis
Analysis Timeline
Encoding Monitor
There are five panes in the Fathom interface:
Session Directory –contains information about all jobs: new, queued,
encoding, and completed. Also contains the Properties tab, which displays
read-only information about a selected job or scene.
Encoding Queue – holds the job actively encoding and the jobs to be encoded
Encoding Monitor – calculates and displays stats and information on all
aspects of the source input encoding
Video Analysis – displays finished jobs
Analysis Timeline – shows the encoding information associated with each
frame of the video
9
Use the panes on the right (Session Directory, Encoding Queue, and Encoding Monitor)
to create your jobs and track their progress. On the left, use the Video Analysis and
Analysis Timeline panes to examine the encoded output and determine what if any
changes you should make.
Customizing the Interface
You can view or hide any of the panes on the Fathom interface. Use the toolbar buttons,
or select options from the View menu to change the elements displayed on the
interface. Each pane also has a Close button in the upper-right corner that you can
click to hide the pane.
You can also drag and drop any pane to move it to another location on the interface. To
move a pane, click on its title bar to make it active (the title bar turns blue), then drag it
to the desired location. Hover over the pane borders to activate resizing arrows and
adjust the size of each pane.
All panes (except Video Analysis) are dockable. Click the pushpin icon to dock the pane
to the side of the Fathom window. Hover your mouse over the docked window to briefly
display it; click the pushpin icon on the displayed pane to restore it. You can also move
the Properties tab in the Session Directory out to its own pane.
The Analysis Timeline pane docks to the bottom edge of the window. All other
panes dock to the right side of the window.
NOTE:
Menus
The following tables describe each option in the Fathom menu bar:
File Menu
New
Create a new job from scratch or from an existing template
Save Job
Save the current job
Exit
Exit the Fathom application
10
FATHOM™
Edit Menu
Copy Job
Copy the current job
Paste Job
Paste the copied job
Remove Job
Remove the current job
View Menu
Toolbar
View or hide the Fathom toolbar. See the following section for descriptions
of each toolbar button.
Status Bar
View or hide the Fathom status bar
Session
Directory
View or hide the Session Directory
Properties
View or hide the Properties pane
Encoding
Queue
View or hide the Encoding Queue
Encoding
Monitor
View or hide the Encoding Monitor
Analysis
Timeline
View or hide the Analysis Timeline
Video
Analysis
View or hide the Video Analysis pane
Current
Values
Open the Current Values box and view properties of the current video
source
11
Tools Menu
Watch
Folder
Open the Watch Folder dialog, where you can detect the presence of new
source files in a folder.
Batch Job
Utility
Open the Batch Job Utility window, where you can automate the creation of
Fathom job files and AviSynth scripts for multiple source files
Options
Open the Options dialog, where you can set user preferences and other
application parameters. See the following section for more details.
Help Menu
Fathom Help
Open the online Help file for the application
About
View information about this version of Fathom
Setting Options
The General tab in the Options dialog (see Figure 2) provides several settings that help
you customize the appearance and the actions in Fathom.
Figure 2: Tools>Options dialog
12
FATHOM™
Automatically edit new jobs. (For more information, see page15.)
Prompt before overwriting job’s output file. (For more information see page 46.)
Prompt for tape insertion before VTR job/scene runs in queue. (For more
information, see page 47.)
Default to 8:9 aspect ratio for SD-SDI.
Use exclusive “Mark Out” time codes for new jobs. (For more information, see
page 28.)
Application look-and-feel. Select a color theme from the drop-down box.
The Workspace tab in the Options dialog lets you select a window layout for your
workspace. You can use one of three default layouts (Last Known, Default Left, Default
Right), or you can create up to two custom layouts.
The Last Known layout option refers to Fathom’s window layout when the
Options dialog was opened. If you make a mistake or want to restore
Fathom’s layout, select Last Known and click Load.
NOTE:
To apply a default layout, select it from the Window Layouts group box, and then click
Load.
To create a custom layout, complete these steps:
1. Adjust your window settings to create the desired layout.
2. Open the Options dialog, and click the Workspace tab.
3. In the Window Layouts group box, select Custom Layout 1.
4. Click Save Current.
5. Repeat these steps, selecting Custom Layout, to create a second custom
layout. 0.
Toolbar
The Fathom window contains a toolbar that toggles the display of all the panes in the
user interface. Toolbar buttons are outlined in blue when they are active.
Click this…
To do this…
Show Session Directory pane
13
Click this…
To do this…
Show Properties pane
Show Encoding Queue pane
Show Encoding Monitor pane
Show Timeline
Show Video Analysis
14
FATHOM™
3
Creating a Job
3
Session Directory
To create and define your job(s), begin in the Session Directory. The Session Directory
contains information about all jobs: new, queued, encoding, and completed. You can
define as many jobs as you want.
If you create scenes from an encoded job, then those scenes are displayed under the
job and can be manipulated the same as jobs. (For more information on scenes, refer to
“Seen by Scene” on page 66.)
Figure 3: Session Directory
The following actions are available from either the Fathom File menu, the Session
Directory toolbar, or by right-clicking a job in the Session Directory:
•
Create a new job from scratch, from a template or from an ALE/FLEX file.
Double-click the job to display the Job Parameters window. From the
Tools>Options dialog box, check the Automatically edit new jobs box to open
the Job Parameters window automatically when a new job is created.
•
Load a saved job.
•
Save a job as a Fathom job (*.fj). Fathom jobs are saved in an .XML format.
•
Remove a job from the Session Directory pane. Removing a job does not
delete the job input or output.
15
•
Queue a single job, all jobs, or all marked jobs (you can also drag and drop the
jobs on the Encoding Queue pane).
•
Play back the job’s encoded output via Windows Media Player.
•
Run an analysis on the job’s output in the Video Analysis pane
Jobs are displayed in the order they are created or loaded. You cannot
reorder them.
Windows Media Player 10 is required for Advanced Profile playback.
NOTE:
Toolbar
The Session Directory pane has a toolbar with buttons that provide shortcuts to
common tasks.
Click this…
To do this…
Create a new job or create a job from a template. You can specify the
template name from a list of Fathom job template files.
Load a saved job or a windows media file.
Save a job
Remove a job
Queue a job. Click the drop-down arrow for options to queue all jobs or
queue all marked scenes.
Play back encoded output in Windows Media Player
Run analysis on job output to display graphing information on the
Analysis Timeline. This button is enabled only after a job’s output file has
been created.
Merge Scenes. This button is enabled only when all of a job’s scenes are
queued and completed.
Similarly, if you right-click in the Session Directory, you can select these options from
the pop-up menu.
16
FATHOM™
Job status indicators
Figure 4: Job status indicators
The icon preceding each job in the Session Directory indicates the status of the job.
Figure 4 displays the Session Directory’s job status indicators
This icon…
Represents this status…
Inactive job
Completed job; job’s output file exists
Queued job
In-progress job
Job stopped due to error
Inactive scene
Completed scene
Marked scene
17
Editing a job’s parameters
To edit a job in the Job Parameters window, double-click the job’s icon in the Session
Directory pane. For information on defining a job’s parameters, see “Defining Job
Parameters ” starting on page 20.
Creating a job from a template
New jobs can be based on templates that you create based on the parameters of
previous jobs. (For more information on how to save a job as a template, see page 44.)
To create a new job from a template, complete the following steps:
1. From either the File menu or the Session Directory toolbar, select
New>Create from Template. Select the template you want to use and click
OK.
2. The New Job From Template window opens with sizing, compression, and
processing settings pre-loaded. (See Figure 5.)
3. Edit the parameters for the new job and click OK.0.
Figure 5: New Job From Template
18
FATHOM™
Fathom does not offer default templates. After you have created a template,
the template’s file name is available in the Create from Template option.
NOTE:
In order for Fathom to find them, templates must be saved in the
Program Files>Inlet Technologies>Fathom>Templates directory.
Creating a job from ALE/FLEX files
Creating a job from an ALE/FLEX file requires using a Fathom template that has an
input frame rate that matches the ALE/FLEX file. Refer to “Saving Job Parameters as a
Template” on page 44 for more information. After a template exists, create a new job
from ALE/FLEX files by completing the following steps:
1. Click the Create New Job drop-down button in the Session Directory toolbar,
and select From ALE/FLEX files to open the Import ALE/FLEX File screen
(Figure 6).
2. In the Path box, click Browse to navigate to the location of the ALE/FLEX
file.
Figure 6: Import ALE/FLEX file
3. In the Compression Settings section, click the drop-down box and select the
template that contains the compression settings you want to use. Fathom
19
filters saved templates and displays only templates that match the frame rate
of the imported ALE/FLEX file. If there are no templates in the drop down
box, then no templates exist that match the imported frame rate.
4. In the Output Options section, select whether to output your file into separate
scenes or concatenate all scenes into one file.
If you elect to concatenate all scenes, Fathom creates a single Job for all scenes
in the ALE/FLEX file. Each scene is treated as a video source in the job. Click
Browse to set the name of the single output file.
If you elect not to concatenate scenes, Fathom creates unique Jobs for each
scene in the ALE/FLEX file and creates output filenames based on the scene
names. You must queue and save each separately from one another.
5. When you are finished, click OK. Click Cancel to close the screen without
saving your actions.0.
Loading saved jobs
To load a previously saved job, complete the following steps:
1. In the Session Directory toolbar, click Load Job.
2. Navigate to the job’s location and select the job.
3. Click OK to load the job.0.
Displaying job properties
To display the Properties pane, click the Properties button in the Fathom toolbar, or
click the Properties tab in the Session Directory. The Properties pane displays read-only
information about the selected job or scene. You can view properties alphabetically, or,
for Jobs, according to categories (Audio, General, Hardware, and Video).
You can also complete the following tasks in the Properties pane:
Click the +/- icons beside the category names to collapse or expand that
category.
Click Alphabetize
to view the jobs in alphabetical order.
Click Categorize
to return to the default Categorized view.
Click the Properties drop-down menu to select different jobs.
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Properties drop-down box
Figure 7: Properties, with Categorized view
21
22
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4
Defining Job Parameters
4
To open the Job Parameters window, double-click the job name in the Session
Directory.
Job Parameters are broken out into the following six categories, each with its own
screen:
General
Input
Output
Sizing
Compression
Processing
After you set these parameters, you are prompted to save the job file. You can also
save them as a template to be used for future jobs.
Depending on whether your source is SDI or a file, each screen presents you with
options appropriate to the source. This chapter describes each category in further detail.
In Tools>Options, check the Automatically edit new jobs box (see Figure 2).
This opens the Job Parameters window when you create a new job.
TIPS:
The Job Parameters window is resizable. Also, individual sections within each
job category can be collapsed or expanded as needed.
23
General
Figure 8: Job Parameters>General category
By default, the General screen opens when you open a job. To enter this information,
complete the following steps:
1. Click in the Name field and enter a name for the job. The name you enter
here is the name that appears for the job in the Session Directory after you
save the job.
2. Click in the Notes field and enter any additional details about the job.0.
Input
Click the Input icon to open the Input screen. In this screen, you define the source for
the job. The input can be from any of the following files:
High Definition Serial Digital Interface (HD SDI)
Standard Definition Serial Digital Interface (SD SDI)
SD interlaced
HD interlaced
AVI
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FATHOM™
QuickTime file
AVISynth script
MPEG
GXF
a raw video file (YUV)
If you select a YUV file for input, you will be prompted to specify parameters for width,
height, frame rate and FourCC settings.
Figure 9: Raw Video File (YUV) Format
The hardware board has a single SDI input via BNC connector that serves for both HD
and SD SDI input.
There are several ways to get content into Fathom for encoding. Select the correct
method for your project to ensure output quality.
SOME BACKGROUND ON INPUT
Five years ago, video postproduction was always based around tape. Now a 1 TB portable drive
costs about 1% of the price of a D5-HD 24p compatible deck.
Consult “Some Background on Input” in Appendix A for more information on: File versus tape
sources, encoding via SDI, HD tape formats, encoding from live sources, getting the correct field
mode, and audio input.
25
Specifying SDI input
Selecting a source type
Figure 10: Job Parameter>Input, SDI as Source Type
Real-time encoding is available from SDI inputs up to a 1080p resolution with frame
rates of 23.976, 24, 25 or 30 fps. 720p real-time encoding is available for 23.976, 24,
25, 29.97, 30, 50, 50.94, and 60 fps material. SD-SDI (NTSC 720x480i or PAL
720x576) encoding is also available.
Fathom outputs both progressive and interlaced content, and it accepts 480i, 576i, or
1080i over the SDI input. In these scenarios, de-interlacing is required for optimal
quality except in the case of scaling 1080i to 720p. For more about using de-interlacing,
see “Processing” on page 41.
Using MediaCat to enter video source information
MediaCat, which stands for Media Concatenation, provides easy management of multitape sources and multi-time code content and produces a single output. On the input
tab for SDI source, you can add multiple sources where each source has its own,
possibly unique, time codes and names (Tape IDs). If source Tape IDs differ, Fathom
prompts the user when tape changes are needed. This also works with Fathom’s Seen
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FATHOM™
by Scene. A Scene edit for re-encoding can be within a video source or span two video
sources.
To enter video source information, complete the following steps:
1. Select the input size and input frame rate of the SDI signal you are supplying
to the Fathom hardware (see Figure 11).
For 720p sources, the input rate is typically 60, 59.94 or 50 Hz. Few HD SDI
sources provide native 720p24 output. Fathom handles the conversion from
720p60 to 720p24, for example, when you set the output frame rate to 24 in the
Compression category (see page 39).
Figure 11: Video Sources
2. Click Add Source to add rows to the video sources list box.
By default, the Tape ID is named Tape 1, and the Scene Name is named
Video_1. Double-click either name and enter a meaningful name for the source.
The Tape ID should uniquely identify a tape. Fathom uses this info to determine
when to query the user for a tape change. The Scene Name is not used internally
by Fathom but provides a way for the user to make a note of the mark-in/markout region. For ALE/FLEX import these fields are populated automatically.
If you use multiple sources, each source must have the same size and
frame rate.
NOTE:
27
3. If you know the start and stop times, click in the Mark In and Mark Out
columns to enter them. You can set the hours:minutes:seconds:frame
number time code values to start and/or stop media encoding for SDI. This
supports frame-accurate encoding for a VTR source that supports SMPTE
RP-188 for HD SDI sources or VITC VANC encoding for SD SDI sources.
By default, Fathom treats the output time code as being inclusive,
meaning the end time code value is encoded.
NOTE:
To change the mark out time code to be exclusive, check the box in the
Options dialog. For more information, see “Setting Options” on
page 12.
Using a start time code is required when encoding from sources like a D5 that is
converting 1080p24 material to 720p, because a D5 outputs 720p24 embedded
in a 720p60 signal. In this case, the time code start value should be on frame 0,
5, 10, 15, 20, or 25. This will guarantee that the correct 720p24 frames are
encoded and not redundant frames.
If you do not know the start and stop times, you can use the VTRPreview to
determine the precise start and stop time of a video source. See “VTR Preview –
Controlling Tape Reply” on page 30 for instructions.
Start and stop time codes are required for two-pass encoding. However, for one
pass encoding, you can use wild encoding that does not use start or stop time
codes.
SIDEBAR: WILD/CRASH ENCODING
A wild encode is typically used when someone has a rushed project and wants to
encode what is coming in live without regard to time codes. This is often the only way to
encode from a source like a camera.
For more information about wild/crash encoding, see “Wild/Crash Encoding” on page
107.
4. If the time code on the source tape is Drop Frame, check the Drop Frame
box. In Drop Frame, time code sources the frame count of 0 and 1 are
skipped every minute on the minute except for the tens (0, 10, 20, 30, 40,
50) minutes. For example, time codes hh:0x:00:00 and hh:0x:00:01 do not
exist when x is 1 through 9.
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FATHOM™
When you select Drop Frame, Fathom will not let you enter invalid dropped
time codes.
NOTE:
Fathom treats the Mark Out (stop time code) as either inclusive or
exclusive. If inclusive, Fathom includes the Mark Out time code in its
encoding. If exclusive, Fathom includes time codes up to but not
including the Mark Out time code. Check the box in the Options dialog
to set the default behavior to use exclusive time codes. This default
applies only to new jobs and not to saved jobs.
Fathom treats sources with an input frame rate of 60, 59.94, 30 and
29.97 as having a time code base of 30 (the frame count of the time
codes increment from 0–29).
Fathom treats sources with an input frame rate of 50 and 25 as having
a time code base of 25 (the frame count of the time codes increment
from 0–24).
Fathom treats sources with an input frame rate of 24 and 23.976 as
having a time code base of 24 (the frame count of the time codes
increment from 0–23).
If the Mark Out time code is hh:0x:00:02 (where x is 1–9) the last
encoded time code when exclusive Mark Out time codes are used with
Drop Frame time codes will be hh:0y:59:[29, 24, 23] where y = x-1.
5. Optionally, in the Key Frame File box, enter the name of the file that contains
the time codes where you want I-frames forced. For SDI sources, the input
.txt file should start with the line Version 102 followed by lines with time
codes on them. For example:
Version 102
01:03:18:10
01:03:52:01
01:04:05:00
6. Click the radio button next to the desired Input Scan Type: Progressive,
Interlaced and PsF (Progressive segmented frame).
If your SDI source is set up to output PsF material, you must select the PsF
option for correct encoding. This is typical only of 1920x1080 sources. .
7. Optionally set the pixel aspect ratio. The pixel aspect ratio for HD-SDI is
typically 1:1. For SD-SDI sources (720x480) you may want to treat the pixel
aspect ratio also as 1:1 or you may want to treat it as non-square (8:9) and
then scale horizontal to a square (1:1) pixel aspect ratio on the resize tab.
29
For further information on pixel aspect ratio, refer to the Aspect Ratio section
on page 107. 0.
To set up VTR Control…
If you have connected your VTR to your PC via the supplied VTR cable you can control
your VTR through Fathom. You must use the 9-pin cable provided with Fathom to
control a VTR.
1. Click the VTR Control button
to open the Pipeline DeckControl Setup
dialog box:
Figure 12: Pipeline DeckControl Setup
2. In the VTR and Port Control group box, select the correct COM port in the
Port drop-down box.
3. After setting the COM port choose OK. The defaults for the remaining
settings in this box typically work fine for most VTRs.
If you find that VTR control is not working, review the Pipeline DeckControl
appendix on page 102, make appropriate changes, then click OK.0.
VTRPreview: Viewing video
In the VTRPreview video pane, video is not previewed until you click one of the VTR
buttons. The Fathom hardware provides a ¼-scaled image for preview purposes. Also,
any SDI cropping settings that have been applied in the Sizing section are also reflected
in the preview window.
30
FATHOM™
If you do not see any video or if it looks wrong (stacked images for example), check to
make sure your video input size and scan type are set correctly.
VTRPreview: Seek code
If you know the time code, enter it into the Seek field and click the button to skip ahead
to that location on the tape (see Figure 13). Enter a number followed by a colon and
Fathom automatically adds leading zeros, if needed. (This “auto masking” formatting
also works in the Mark In and Mark Out fields.)
Figure 13: Seek field
Fathom utilizes a serial interface for VTR control. The time codes displayed in the
VTRPreview pane are the time codes read from the VTR over this serial interface. The
Mark In time code will be used by the VTR control interface to pre-roll the VTR prior to
starting an encode. However, the actual start and stop of encoding is subject to
embedded time codes in the SDI signal, not time codes read over the serial interface.
This allows Fathom to be frame accurate with regard to starting and stopping an encode
based on time codes. In some cases, there can be a mismatch between the time codes
read over the serial interface and the time codes your VTR embeds in the SDI signal.
For issues surrounding this refer to the Troubleshooting chapter of this manual.
VTRPreview: Controlling tape replay
1. Use the standard fast forward/rewind buttons to skip through the tape.
2. Click Mark In
click Mark Out
to mark the start time for the section you want to encode;
to mark the endpoint.
3. Click Shuttle and move the slider to do a variable speed fastforward/rewind.
4. Click Jog and move the slider to do a single-step forward and back through
the tape.0.
Setting SDI audio source information
In the Audio Sources section of the Input screen, click the Audio Sources drop-down
menu to select the Use embedded audio option (see Figure 14). By default no audio
source is selected. Fathom supports the selection of 2, 6 or 8 channels of embedded
SDI audio.
31
Figure 14: Audio Sources
When using embedded audio, you must associate or map an SDI audio channel for
each output speaker.
For this…
Map these SDI channels…
2-channel audio
encoding
Front Left and Front Right speakers
6-channel audio
encoding (5.1)
Front Left, Front Right, Center, Low Frequency Effect (LFE), Back Left,
and Back Right speakers
8-channel audio
encoding (7.1)
Front Left, Front Right, Center, Low Frequency Effect, Back Left, Back
Right, Side Left, and Side Right speakers
Click the Channel Shortcut links across the top of the section to quickly populate the
audio fields that specify the audio channel associated with each speaker. Or, click the
drop-down arrow in each row to manually map any of the audio channels for each
speaker.
Specifying file input
As an input source, Fathom can use 8-bit and 10-bit QuickTime, AVI, MPEG-2, GXF,
YUV and AviSynth files (.avs) stored on a hard drive, CD, network, and so on. Users
can also specify SD interlaced and HD interlaced input. Refer to Appendix C for detailed
information on AviSynth.
To enter video source information, complete the following steps:
1. In the Path field, enter the path to the Video Source, or click Browse to
navigate to the source.
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Figure 15: Job Parameters>Input category
If the source file has a FourCC (Four Character Code) then it is displayed here.
All RGB format will simply be shown as "RGB". For sources where the FourCC
does not exist or cannot be determined, a hex value representing the first four
bytes of the format's GUID is displayed.
2. Use the up and down arrows to set the Pixel Aspect Ratio.
NOTE:
This value is not the picture aspect ratio (i.e. the ratio of source width to
the source's height). The pixel aspect ratio is the ratio of the horizontal
distance between pixels to the vertical distance between pixels. For
example, while an HD 1920x1080 source has a 16:9 picture aspect
ratio (its width is 16/9 times the height), the pixel aspect ratio is typically
1:1. If you are not sure what the source content aspect ratio is, set the
pixel aspect ratio to 1:1.
33
SIDEBAR: ASPECT RATIO OVERVIEW
The phrase “aspect ratio” is bandied about throughout video production. However, there are
three different kinds of aspect ratios that apply to a given clip, and it is very useful to be specific
about which is in question.
For more information on Frame Aspect Ratio, Pixel Aspect Ratio and Image Aspect Ratio,
consult the “Aspect Ratio Overview” in Appendix A.
3. In the Key Frame File box, enter the name of the file that contains the time
codes where you want I-frames forced. For file sources the input .txt file
should start with the line Version 101 followed by lines with frame numbers
on them. For example:
Version 101
34
82
102
Setting file audio source information
By default no audio source is selected. To encode audio in addition to video, use the
Audio Sources drop-down menu to select one of the following audio source(s):
If audio is present in the source video file, then the drop-down menu includes
the option Use Embedded Audio. Select this option to use the audio available
in the source video file.
Figure 16: Use Embedded Audio
Select Use multi-channel AVI file to use a single audio-only AVI file source that
contains all the audio channels needed for a stereo or surround encode.
Figure 17: Use multi-channel AVI file
Select Use discrete WAV files to use audio from separate audio files.
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FATHOM™
Figure 18: Use discrete WAV files
When assigning discrete WAV files for each audio source, you must associate or map
an audio file for each output speaker (see Figure 19). You must provide the
pathname(s) for the audio sources. These sources should be mono audio files.
For this…
Map these SDI channels…
2-channel audio
encoding
Front Left and Front Right speakers
6-channel audio
encoding (5.1)
Front Left, Front Right, Center, Low Frequency Effect (LFE), Back Left,
and Back Right speakers
8-channel audio
encoding (7.1)
Front Left, Front Right, Center, Low Frequency Effect, Back Left, Back
Right, Side Left, and Side Right speakers
Figure 19: Specifying WAV files for Audio Sources
Click Browse
use.
at the end of the pathname field to navigate to the files you want to
35
Output
Figure 20: Job Parameters>Output category
Designating the output settings
1. In the Path field, specify the Output File location for the output file, or click
Browse
filename.
to navigate to the file location. You must specify an output
Make sure you designate a unique name for the output file. If two jobs
have the same output filename, the status indicator of a job or its
scenes may not be determined correctly.
NOTE:
2. In the Network Output section, you can configure information to push the
encoded content to a network port on the encoding machine.
36
FATHOM™
3. The Metadata section defines information that is associated with the
encoded media. You can add new attributes, edit the contents of existing
attributes, or delete attributes.0.
•
To add a new attribute, click New Attribute and fill in the Name.
•
To edit an attribute, click in the Value column next to the attribute name. A
cursor appears in the field where you can enter a new value.
•
To remove an attribute, select the attribute name and click Delete Attribute.•
Sizing
As simple as it sounds, it is critical to get your video the correct size and shape to gain
optimum compression and playback. The most important step is ensuring the correct
aspect ratio(s).
Specifying sizing for SDI inputs
Figure 21: Job Parameters>Sizing for SDI input
37
The Sizing category displays information about the current job’s input and output sizes
and pixel aspect ratios. The Input and Output figures are read-only calculations based
on your entries in the Input and Output categories. You can control the Pixel Aspect
Ratio, Cropping, and Resizing parameters. We recommend that you set your video size
options before you adjust the Compression category parameters.
To set the video size options, complete the following steps:
1. In the Pixel Aspect Ratio section, check the Same as input ratio box if you
want the output ratio to be the same as the value from the Input screen.
Disable the Same as input ratio box if you want Fathom to auto-calculate the
ratio given the cropping and custom size settings. Because cropping itself does
not affect the ratio of the horizontal distance between pixels to the vertical
distance between pixels, the output ratio does not change when cropping is
applied without resizing. If an integer output ratio cannot be automatically
determined then the output ratio will be set to 1:1. This condition will be flagged
to the user with the addition of an asterisk after the displayed ratio (for example,
as 1:1*).
If you want to set the output pixel aspect ratio manually, simply set this value on
the Input tab and check the same as input ration on the resizing tab.
2. In the Cropping section, click None if you want to use the whole frame. If the
rectangle is inside the edges, then anything outside the box is excluded.
Click Custom Cropping, then use the up and down arrows to specify the top/left
corner and the bottom/right corner of the cropped image. Cropping values must
be in multiples of 2.
SIDEBAR: TWO PRIMARY REASONS TO USE CROPPING
Cropping defines a rectangle of the source frame that is used to make the output frame,
thus specifying a region of interest within the video frame.
For more information on why to use cropping, see “Two Primary Reasons to use
Cropping” in Appendix A.
For SDI sources, vertical cropping changes can be previewed in the VTR preview
window in the Job’s Input section.
3. In the Resizing section, click None to maintain the source input size.
Click Custom Resizing, then use the up and down arrows to manually adjust the
width and height. The size for encoding must be a multiple of 2 in width and
height.
38
FATHOM™
Click the Preset links across the bottom of the section to quickly adjust the width
and height settings.
With SDI input, you can use only preset scales. The custom resizing
options in the Resizing section will be disabled.
NOTE:
SIDEBAR: RESIZING
Resizing controls scaling, taking the rectangle left after cropping and changing the size
and shape of that rectangle to match the size of the output.
For more information on scaling, consult this section in Appendix A: Technical Guide.
Compression
Use the Compression screen to set the encoding parameters, including the output data
rate. For best results, edit the Compression parameters after specifying the Input and
Sizing parameters.
Figure 22: Job Parameters>Compression category
39
In the Compression pane, complete the following tasks:
1. In the General sections, check the box to enable Two-pass encoding.
Fathom first processes the source content by gathering various forms of
information about the content. On the second pass, it uses that information
to optimize the encoding. Two-pass encoding generally yields betterencoded files. For SDI sources, utilizing start and stop time codes are
required for two-pass encoding.
For more information, see “General encoding settings” on page 111.
2. In the Hardware Acceleration section, check or clear the box to enable or
bypass the hardware accelerator.
Enter the Scene change threshold to specify how much change can be tolerated
between one frame and the next without triggering an I frame. In Figure 22, the
user permits Fathom to accept a continuity of up to 35% between frames. That is,
as long as 35% of the next frame’s content can be predicted from the current
frame, motion vectors handle the changes. If more than 75% of the content
changes, Fathom will produce an Intra-encoded frame (I-Frame). This slider is an
advanced setting and we suggest that you experiment when adjusting this setting
to get the best results
For more information, see “Hardware encoding settings” on page 112.
3. In the Audio Compression section, select the appropriate Codec and
Format from the drop-downs.
If the audio source
contains …
then…
only two channels
both Windows Media Audio 9 and Windows Media Audio
9 Professional are options
more than two
channels
only Windows Media Audio 9 Professional is available
For more information, see “Audio compression settings” on page 113.
4. In the Video Compression section, first select the Codec for video
encoding. Fathom supports VC-1 Main Profile and VC-1 Advanced Profile.
The Quality setting has different implications for hardware encodes versus
software encodes. For more information, see “Video compression quality
setting” on page 96.0.
Fathom supports four Encoding Modes: Constant Bit Rate (CBR), Variable Bit
Rate Quality, Variable Bit Rate Constrained, and Variable Bit Rate
Unconstrained. These modes are available in both single and two-pass encoding
models.
40
FATHOM™
The Frame Rate for file-based sources will be what Fathom determined the
frame rate of the file to be. For SDI sources, the available output frame rates will
be based on the input frame rate. Refer to “Working with SMPTE-296
(1280x720p)” on page 95 for more details on frame rates.
For more information, see “Video compression settings” on page 115.
Depending on the Encoding Mode, various other encoding parameters can be set. For
example, in CBR modes you will need to set a target bit rate, buffer delay, quality level
and the distances between key frames.
SIDEBAR: SOME BACKGROUND ON COMPRESSION
Fathom is all about compression. Understanding some basics of how compression works and
what makes good and bad compression is very useful in planning and troubleshooting your
projects.
For information on compliance, hardware encoding settings, audio and video compression
settings, and encoding parameters, consult “Some Background on Compression” in Appendix A:
Technical Guide.
Processing
The Processing screen contains additional modifications Fathom can make to the video
file as it is generated, controlling some basic ways that Fathom operates outside of the
codec parameters.
41
Figure 23: Job Parameters>Processing
In the Processing screen, you will complete the following tasks:
1. In the Interlace Processing section,you can choose between no interlace
processing (NONE), deinterlace, or maintain interlacing (Field or Frame
mode). Inverse Telecine is available only for software-based encoding. For
more information, see “Interlace processing” on page 122.
2. In the Complexity section, move the slider to trade off between the needs of
Better Encoding Performance versus Better Encoding Quality.
For more information, see “Complexity” on page 123.
3. In the Pre-Processing section, select a Pre-filtering option: None, Normal,
Smooth, or Dynamic.
For more information, see “Hardware Processing” on page 124.
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FATHOM™
4. In the Encode Processing section, check any of the following advanced
video processing filter options:
Adaptive Deadzone – to achieve high quality images at lower bit rates.
Non-Uniform Quantizer – to help eliminate unnecessary bit coefficients to better
target a specific bit rate.
In-loop Deblocking – to enable an adaptive in-loop deblocking filter to help
smoothen the boundaries of encoded macroblocks when using an aggressive bit
rate on complex material.
For more information, see “Advanced Video Processing Filters” on page 123.
5. If Fathom determines that the source file is a 10bit v210 file (that is, 10bits
per component), you can select the optimum Dithering mode to take the 10bit source to 8 bits per component. 0.
For more information, see “Dithering” on page 124.
Adding Watermarks
The last section in the Processing screen lets you add a watermark to your output
image. To add a watermark, do the following:
In the Watermark Directives File section, click Browse to navigate to the location of
the script file that tells the application the name and the placement of the .bmp file you
want to overlay onto the content. 0.
To create watermarks, Fathom uses a user-created text file that contains scripting
commands. Below is an example script that places the file my_bitmap.bmp as a black
and white banner across the output image:
Filename: F:\\my_bitmap.bmp
Location: 100 140
Processing: Banner
Processing: No Chroma
End
SIDEBAR: INTERLACE PROCESSING
Fathom outputs both progressive and interlaced video, and it can accept interlaced content and
deinterlace it with a variety of methods.
Appendix A: Technical Guide contains additional information on interlacing, encoder complexity,
hardware processing, and dithering.
43
Applying Job Parameters and Saving a Job
After you have specified all the parameters for a job, click OK. This applies the
parameters to the current job and the job parameters box will close. Now is typically a
good point to save your job.
1. In the Sessions directory, click the Save button in the toolbar.
2.
Specify a location and file name.
3. Click Save. The job is saved with an *.FJ extension.0.
In later Fathom sessions, you can load the job from the Session Directory by
clicking the Load Job button
NOTE:
Saving Job Parameters as a Template
If you have correctly specified all the parameters for a job, the Save as Template
button is enabled. Job parameters can be saved and applied to future new jobs by
creating jobs from a template.
A template is also required for creating a job from an ALE/FLEX file. Although you will
have the opportunity to change the output filename for jobs created by templates, you
still need to set a default output filename before saving a template. During ALE/FLEX
file import, Fathom filters saved templates and will displays only templates that match
the frame rate of the imported ALE/FLEX file.
When you save a job as a template, the General, Sizing, Compression, and Processing
parameters and most of the input are saved in the template file.
To save the job as a template, complete the following steps:
1. Click Save as Template in the Job Parameters screen to display the Save
as Job Template box.
If the Save as Template button disabled, parameter validation has
failed on some tab. Browse the tabs settings and look for flagged
errors.
NOTE:
2.
Specify a location and file name.
3. Click Save. The job is saved with an *.FJT extension.0.
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FATHOM™
5
Queue the job and monitor
encoding
5
Encoding Queue
The Encoding Queue holds the job that is actively encoding, as well as jobs to be
encoded.
Figure 24: Encoding Queue, with queued jobs
Putting a job in the queue immediately starts the encoding process if the job is the only
item in the queue. When a job has finished encoding, the job is removed from the
queue.
For wild/crash encoding from SDI, the encoding starts immediately. For SDI jobs with a
start time code, Fathom first pre-rolls the VTR to a point just prior to the start time code
and then starts the VTR playing. In this case, encoding starts when the start time code
is seen by the hardware encoder.
Remember that for wild/crash encodes, you must manually remove the job
from the queue to stop the encode.
NOTE:
45
Fathom sees time code from two sources:
•
VTR cable/control
•
Embedded in the SDI signal (Vertical Ancillary VITC for SD sources and
Horizontal Ancillary VITC, SMPTE-RP188, for HD sources).
The second source is used by the encoder for frame-accurate starting and stopping.
Time code read from the VTR via the VTR cable is used for VTR preview control and for
prerolls control prior to encoding.
It is possible that a tape source may have two different sets of time code
where the embedded time code differs from the time code being sent over the
VTR cable. In such cases, it is likely that the job in the queue will not start.
NOTE:
If your job does not start after the VTR has pre-rolled, look at the time code in
the Encoding Monitor. This displays the embedded time code. See if this time
code matches the expected time codes around your start time.
If you attempt to queue a job whose output file already exists, you may get the following
error:
Figure 25: Fathom warns you if the encoding run will overwrite an existing file
You will see this warning only if you have enabled the prompt in the Options dialog. For
more information, see ” Setting Options” on page 12.
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FATHOM™
NOTE:
This overwrite warning may be an indicator that another older job (let’s call
that Job A) had the same output filename as the job being queued (let’s call
that Job B). By continuing with the job B you will be invalidating Job A that
shared the same output filename. However, Fathom will not be able to detect
that this was the case.
If you later load Job A, while its output filename may exist, it will not be from
the encoding done earlier with Job A and Fathom may not behave
appropriately. For this reason, be sure to make output filenames unique. This
is especially true after you use Seen by Scene because intermediate file
names of scene re-encodes are based on a jobs output filename.
Fathom will internally cache the last Tape ID used in the queue. If Fathom senses that a
job or scene re-encode that is about to run in the queue has a different Tape ID than the
cached name, Fathom prompts you to insert the correct tape at the start of the job, as
seen in Figure 26.
Figure 26: Prompt for tape insertion
Even if the cached Tape ID is the same as a Tape ID for job or scene re-encode that is
about to run in the queue, Fathom can prompt you first. To set this prompt, check the
box in the Options dialog. For more information, see “Setting Options” on page 12.
For file-based sources, a job finishes encoding when the file has been completely
processed. For SDI time code based encoding, a job finishes encoding when the end
time code has been encoded.
The job’s status is reflected in the Session Directory panel. (See “Job status indicators”
on page 17 for more information.)
As the job is being encoded, the input is displayed in the Encoding Monitor.
47
Toolbar
The Encoding Queue toolbar contains shortcuts to the following tasks:
Click this…
To do this…
Delete selected job.
Move the selected job up in the queue.
Move the selected job down in the queue.
Queuing a job
To queue a job, do any of the following:
Right-click a job in the Session Directory and select Enqueue.
Select a job in the Session Directory and click Queue
.
With the mouse, drag the job from the Session Directory and drop it onto the
Encoding Queue.
You can queue all jobs or queue all marked jobs by clicking the Queue
button’s drop-down arrow and selecting those options.
NOTE:
Reordering jobs in the queue
To change the order of jobs in the queue, do either of the following:
•
Select and drag the job.
•
Select the job in the queue and press the up and down buttons on the toolbar.
Manually stopping jobs in the queue
Stopping a job removes it from the queue. To stop a job, complete the following steps:
1. Highlight the job to stop.
2. Click Remove from Queue
in the Encoding Queue toolbar.0.
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FATHOM™
Fathom still considers a stopped job as complete so that you can play or analyze the
job. This is also the case with manually stopped non-time code) based SDI jobs
(wild/crash encodes).
For two-pass jobs, an output file is generated only on the second pass.
If a two-pass job is stopped before the second pass, the job is not considered
complete because no output file was generated.
If you stop the job during the second pass, you can play or analyze the job
You cannot pause a job that is in the queue. The only way to stop a job is to
remove it from the queue.
NOTE:
Encoding Monitor
The Encoding Monitor calculates and displays stats and information on all aspects of
the source input encoding. The Encoding Monitor pane has five tabs:
Video tab — lets you view the input and output
Audio — lets you view statistics on the audio output for SDI encodes
Hardware tab — lets you view information on picture type, quantization level
and compressed sizes
Advanced tab — lets you view statistics on the output encoding
Stats tab — lets you view the statistics on the encoding progress
The following sections explain the content of these tabs in further detail.
Video tab
Using the Video tab (Figure 27) you can view the input video, the output video, or some
combination. For hardware- and software-based encodes, Fathom provides a
¼-sized image in width and height for monitoring.
Because the monitored video is reduced in size and represents a scaled
version of the actual source or encoded content, it is not meant to be a tool
for judging output quality.
NOTE:
49
Figure 27: Video tab with drop-down encoding options
For hardware-based encodes, the Video tab includes the following information:
•
Picture type
•
Frame quantization level. Low numbers are good. If the number is consistently
above 8–10, this may mean that you need to adjust the bit rate to a higher
value.
•
Current frame number
•
Current frame size
Select any of the following video display options from the drop-down box:
•
No Video
•
Input—View the source input as it is being encoded.
•
Output—View the encoded output.
•
Split – Horizontal—View input video on the top half of the window, and output
video on the bottom half.
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FATHOM™
•
Split – Vertical—View the left half of the input video on the left of the window
and right half of the output video on the right.
•
Interleave – Horiz, Interleave – Vert.— When selecting one of the Interleave
modes, Fathom will show about 16 lines of the input followed by 16 lines of the
output, followed by 16 lines of the input, and so on. For horizontal interleave,
this is a top-down interleave with the top set of lines belonging to the input. For
vertical interleave, the first set of column lines are the input.
•
Differential—View of the difference between the luminance component of the
current and last input frame. Identical pixels in the input and output will result in
a difference value of 128. Where the input pixel value is greater than the output
pixel value, the difference value will be darker (toward black). Where the input
pixel value is less than the output pixel value, the difference value will be
lighter (toward white).
Audio tab
The Audio tab displays meters to verify correct input while encoding from SDI input
sources.
Figure 28: Audio tab
51
Hardware tab
For hardware-based encodes, the Hardware tab (Figure 29) provides information on the
picture type, quantization level, and compressed sizes.
Figure 29: Hardware tab showing stats on the hardware processors
The Processor bars represent the amount of load on a given processor for the frame
being encoded. The load is a percentage of the average number of cycles available per
frame. The average number of cycles available per frame is the total number of DSP
cycles per second/target frame rate.
NOTE:
If you are encoding from a file, such constraints as disk I/O, PCI bus
throughput, and host-based preprocessing may limit the encoding frame rate.
This limitation is reflected in the encoding frame rate, which may not be at or
above your target output frame rate (see the Advanced tab) and the DSP
loads, which may be under 100%.
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FATHOM™
Advanced tab
The Advanced tab (Figure 30) displays statistics on the audio and video output
encoding.
Figure 30: Advanced tab showing output stats
The video output fps values represent the frames per second that are being encoded
into the output file. The fps values do not represent the rate at which frames are being
sent to the encoder. If, for example, your encode session is disk- or CPU-bound and
thus is not encoding in real time, you may still see that the output-encoded frame rate is
meeting the desired encode frame rate.
If the hardware encode option is disabled when you are using software-encoding
programs to encode Windows Media content, the encoder may drop frames during
encode. Thus, it will not produce a steady output frame rate.
During the first pass of a two-pass encode, Fathom displays 0 for the fps
because Fathom is analyzing, not encoding, the input.
NOTE:
53
Stats tab
Fathom provides real-time statistics on the encoding progress. For a two-pass job, the
tab highlights whichever pass is current.
Information on the Stats tab can be useful to monitor if computer resources (such as
disk space) are at a premium.
The Percent Complete statistic applies to jobs only where the source is a file.
NOTE:
Figure 31: Stats tab showing the job’s progress and system information
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FATHOM™
Watch Folders
The Watch Folder feature automates the encoding of file-based source content within
Fathom by detecting the presence of new source files in a user-designated directory, or
Watch Folder. This can be a folder on the same machine where Fathom is installed or a
folder on a remote network share. You can also build a watch folder to watch for jobs,
for example, in using trick streams.
Fathom's watch folder automatically creates a job with pre-defined characteristics:
•
The job's name is "abc.xyz (watch)" where abc.xyz is the input file name.
•
The job's output file name is the input filename + a ".wmv" extension.
When a file is "found" in the watch folder, a corresponding job is automatically created
and queued within Fathom. A file is considered "found" only when it is completely
copied/moved into the watch folder. Because source files are typically large and require
several seconds to be completely copied (especially over the network), Fathom will not
create a job until that copy operation is deemed complete. Currently, Fathom checks
every 30 seconds to verify if the copy/move operation is complete.
Typically, if an output file is about to be overwritten, the user is notified by a warning
dialog, confirming the overwrite.
NOTE:
However, because the watch folder feature is automated, it is not possible to show
modal dialogs that might interfere with the process (because Fathom would be
stuck waiting for a user to click OK) As a result, if a watch folder job overwrites an
existing output file, there is no warning
Setting Up Watch Folder Parameters
To use Watch Folder for automated encoding, complete the following steps:
1. From the Fathom menu bar, select Tools>Watch Folder to open the Watch
Folder dialog box.
55
Figure 32: Watch Folder dialog box
2. Check the Enable Watch Folder box.
3. Check the Watch for job files only box if you want Fathom to watch only for
job files.
4. In the Folder to Watch field, type the name of the directory folder to watch, or
click Browse to navigate to the location of the folder. The folder you select
here must support read/write access for the current user. For network
shares, use the UNC format (i.e., \\server\share).
5. In the Template to Use field, select the job template that is used to encode
all source files found in the watched folder. The template you use must be
file-based (SDI-based job templates are not listed as options.)
6. In the Destination Folder field, type the location where you want to store the
encoded output. Click Browse to navigate to the location of the destination
folder. The folder you select here must support read/write access for the
current user. For network shares, use the UNC format (i.e., \\server\share).
7. Check the Encode Pre-Existing Source Files in Watch Folder box to
automatically queue pre-existing media files in the watched folder. Use
caution when enabling this option, especially if you have a lot of pre-existing
content in your watched folder.
8. Click OK to begin the watch. 0.
If the OK button is disabled, you did not enter valid parameters in the
Watch Folder fields. Invalid parameters are marked with a red
exclamation point.
NOTE:
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FATHOM™
6
Analyze the Job Output
6
After a job is completed, use the Video Analysis pane and the Analysis Timeline to play
back and scrutinize the encoded output.
Figure 33: Fathom’s analysis panes with all visualization options active
57
Video Analysis
After a job finishes, it is displayed in the Sessions Directory with a green checkmark, as
shown in the following figure.
Figure 34: Completed jobs in the Session Directory
Select a completed job, and then do one of the following:
Click this…
To do this…
Play back the encoded output in the Windows Media Player.
Analyze a job’s encoded output in Fathom. Fathom displays the output in
the Video Analysis pane.
Figure 35: Video Analysis pane with viewing options
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FATHOM™
Analyzing .wmv files
You can open a .wmv file in the Session Directory for analysis. To do this, complete the
following steps:
1. In the Session Directory toolbar, click Load, or right-click and select Load
Job.
2. In the Files of Type drop-down box, select .wmv.
3. Navigate to the location of the file, and click OK to load it in the Session
Directory. You can select it for analysis just like any other encoded job.0.
The following table contains several keyboard shortcuts to help you control video
playback.
Click this key…
To do this…
Left Arrow
Go to the previous frame
Right Arrow
Go to the next frame
CTRL + Left Arrow
Go backward one second
CTRL + Right Arrow
Go forward one second
Home
Go to the start of stream
End
Go to the end of stream
CTRL + G
Go to frame
59
Toolbar
Figure 36: Video Analysis toolbar
The Video Analysis toolbar contains the following buttons:
Click this…
To do this…
Go backward one frame
Play video
Go forward one frame
Pause playback
Stop playback
Toggle audio on or off
The drop-down menu offers options for viewing the video playback after Fathom has
completed a scene re-encode. See the section “Seen by Scene” on page 66 for more
information on segment encoding.
Original—View the original encoded content.
Re-encoded—View the re-encoded content from a scene job.
Split - Horizontal—View Input video on the top half of the window, and output
video on the bottom half.
Split - Vertical—View the left half of the input video on the left of the window,
and the right half of the output video on the right.
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Interleave - Horiz, Interleave - Vert.— When selecting one of the Interleave
modes, Fathom will show about 16 lines of the input followed by 16 lines of the
output, followed by 16 lines of the input, and so on. For horizontal interleave,
this is a top-down interleave with the top set of lines belonging to the input. For
vertical interleave, the first set of column lines are the input.
Analysis Timeline
The Analysis Timeline pane works alongside the Video Analysis pane to show the
encoding information associated with each frame of the video.
Figure 37: Analysis Timeline with all graphing elements active
As the video plays, a blue vertical line indicates the frame location. (You can use the
keyboard to jump in one-second or one-frame increments; see the keyboard shortcuts
on page 59 for more information.)
Click anywhere along the timeline to view that frame in the Video Analysis pane.
From the Fathom menus, select View>Current Values (or press F8) to display the
Current Values window, which displays the numbers that go with the currently selected
frame (see Figure 38). You can move the Current Values window anywhere on the
screen.
61
Figure 38: Press F8 to display the Current Values window
Toolbar
The Analysis Timeline toolbar contains shortcuts to the following functions:
Click this…
To do this…
toggle different elements of the display
active only after a merge with re-encoded scenes has been completed.
enlarge or reduce the timeline; the video in the Video Analysis pane is not
enlarged or reduced
mark scenes for Seen by Scene segment encoding (see “Seen by Scene”
on page 66 for more information)
The following sections explain each of these functions in further detail.
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FATHOM™
Graphs
Click the Graphs drop-down arrow to select one of six different graphs.
Figure 39: Analysis Timeline’s Graphs menu
Frame Size
Which frames take up the most space? The Frame Size view will let you see this
information at a glance.
Figure 40: Frame Size
Average Bit Rate
This view displays the average bit rate. The average bit rate is an average over an
interval including the current frame going back N frames where N is determined by the
buffer size of the encoded content. Inlet’s Semaphore allows you to manually set N. Use
the mouse to move the vertical line on the graph to select the frame of interest.
Figure 41: Average bit rate
63
Quantization
This view displays the quantization level of any frame.
Figure 42: Quantization Level
SIDEBAR: QUANTIZATION
Quantization is a core compression technique. You should be aware that it is a significant factor
that irrecoverably removes information from your source video. Quantization can be effective
because the human visual system is more sensitive to low frequencies than high frequencies.
Thus, you can use quantization to remove information that we may not notice in the first place.
Using quantization, a substantial amount of compression can be applied to most images without
any visible loss. But below a certain point, the compromises start to become visible.
For a more detailed explanation of quantization, consult Appendix A: Technical Guide.
Frame Type
The Frame Type view lets you quickly identify the type of frame encoded. Turning on
the Frame Type adds a blue shaded line to the top of the timeline, punctuated by
orange and gray bands.
•
Blue bands—P frames
•
Orange bands—I frames
•
Gray bands—B frames
•
Black bands – Skip frames
Figure 43: P, I, and B frames are denoted by colors on the graph
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Buffer Fullness
You can also see how much any given frame fills its buffer by selecting the Buffer
Fullness view.
Figure 44: Buffer Fullness
You may see the graph lines displayed with the following colors:
•
Black—Original
•
Red—Estimated Seen by Scene changes
•
Green—Merge file. This color appears after you have created a merge file and
you click Compare. For more information on merging and comparing, see
“Merging approved scenes with the original content” on page 72.
Dropped Frames
Which frames were dropped or skipped? The Dropped Frames view will let you see at a
glance. In the picture below, each line represents a dropped frame. The drop frame
markers show up on all graphs.
Figure 45: Dropped Frames
While the Fathom hardware encoder does not drop frames while encoding, dropped
frames are typical of software Windows Media encoders like the Windows Media
Encoder. When the Dropped Frames option is selected, Fathom will mark places by
light red vertical lines where frames have been dropped by the encoder.
65
NOTE:
The width of each line is equal to the time period of consecutive missing
frames; thus, six consecutive dropped frames will appear as a wider line than
one dropped frame. You can determine the number of consecutive dropped
frames by zooming in and examining the number of minor tick marks on each
red vertical line.
Seen by Scene Re-encoding
You may find that some frames within a job need to be re-encoded. To accomplish this,
you can create Scenes by marking the first and last frames of a sequence on the
timeline.
Seen by Scene™ is one of the hallmark features of Fathom. Seen by Scene (SxS) has
long been the province of high-end standard definition MPEG-2 encoders for A-list DVD
encoding. With Seen by Scene re-encoding, a critical or problematic scene can be reencoded without having to re-encode the entire clip. Fathom lets you change the
encoding parameter for a given section (typically to raise the data rate of that section).
However, do not expect that you will need to use SxS on every project or even on many
projects. SxS is a manually guided VBR mode. Fathom provides an excellent automatic
VBR mode that does an extremely good job of distributing bits to provide the best
possible average quality over the clip. In many or most cases, you can just pick the right
VBR settings and let Fathom do the job. And of course, CBR encoding should not use
scene-by-scene re-encoding as few bits remain in CBR encodes to effectively use for
re-encoding.
Where SxS can really shine is where you do not simply want the same average quality
over the clip. For example, if you were encoding a long movie on a medium where there
really were not enough bits to provide an optimal quality average. By encoding the clip
at 5% lower data rate than target, you could use that 5% of bit rate savings to pick
particularly critical scenes or shots and raise the data rates of those scenes. Thus, you
can gain better quality where you really need it.
The following file types are not supported by Seen by Scene: MPEG2
transport, MPEG2 program, GXF, and advanced .AVS files.
NOTE:
AviSynth encodes may or may not work with Seen by Scene, depending on
the script in use. With simple scripts, AviSynth Seen by Scene will often work.
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FATHOM™
When you adjust the bit rate for marked scenes you may not exceed the buffer
constraints of the job properties. Fathom estimates the effect of bit rate changes to the
buffer utilization and limits bit rate fluctuations based on these estimates. In scenes
where the buffer utilization is already very high or in areas where future utilization is
high you may be limited in bit rate changes.
If you find bit rate adjustments are limited in a scene you want to edit, you
may need to find future areas to reduce the data rate in order to increase it
your scene.
TIPS:
The typical workflow for scene re-encoding is:
1. Create a scene.
2. Adjust the scene’s bit rate.
3. Re-encode the scene.
4. Review the re-encoded scene.
5. Delete, adjust, or approve the scene.
6. Repeat steps 1-5 as needed for additional scenes.
7. Merge all approved scenes with the original content.0.
The Scenes appear beneath the Job in the Session Directory (Figure 46). You can then
edit each scene’s parameters or manipulate the bit rate graph and re-encode the scene.
Figure 46: Scenes in the Session Directory
67
Fathom lets you review the scene via playback in Windows Media Player and by using
the A/B frame compare option (see Figure 47). If the re-encoded scene meets your
requirements Fathom replaces the original scene in the job with the newly encoded
scene using the merge feature.
When allowing you to make scene changes Fathom was estimating resultant changes
to buffer utilization. If this estimate is significantly off and buffer utilization is exceeded
on re-encodes, the merge process may encounter an error or an analysis of merged
content will indicate buffer utilizations peaking at 100%. If this is the case, simply readjust your scene bit rates lower, re-encode the scenes again, and re-merge.
Figure 47: Video Analysis options allowing you to compare encoded files
Fathom considers a scene to start and end based on the nearest I-frame. If
your scene selection falls short of an I-frame, Fathom automatically extends
your selection to the nearest I-frame.
NOTE:
Creating a scene
To create a scene, complete the following steps:
1. If Frame Type is not displayed in the timeline, select it from the toolbar
Graphs menu.
2. On the Timeline toolbar, click Mark. The cursor changes to look like this:
3. In the timeline, position the cursor at the beginning of the scene (Figure 48).
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FATHOM™
Figure 48: Marking the start of a scene
4. Click and drag the mouse to the scene’s endpoint (Figure 49).
Figure 49: Marking the end of a scene
Fathom shades the selection to indicate a scene has been selected. Fathom
ensures that a scene starts on an I-frame and ends on a frame just prior to an Iframe (Figure 50).
69
Figure 50: Scenes extend from I frame to I frame
Note that the cursor has changed to a sizing tool; you can use this to adjust
the Scene’s endpoint.
5. The scene appears nested under the parent job in the Session Directory.
Right-click on the scene and select Rename to edit the default name for the
scene. (Figure 51).0.
Figure 51: Scenes appear under the parent job. Right-click and select Rename to edit the
scene name.
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FATHOM™
Adjusting the scene’s bit rate
After you have created a scene, you can adjust the scene’s target bit rate. Given
various factors of a scene, Fathom will automatically determine the constraints related
to making changes in the bit rate. When a scene is created, a new horizontal blue line
appears in the scene. This line represents the average bit rate for the scene. You can
grab this horizontal bar and move it up to increase the bit rate in the scene or move it
down to decrease the bit rate in the scene.
When a scene is re-encoded, only the scene itself is re-encoded. Therefore, extra bits
used in a scene re-encode are not taken from other locations in the encoded content. A
successful scene re-encode is one where the buffer fullness constraint of the encoded
content is not violated. Because there are typically more bits to utilize in the buffer
modeled by VBR Constrained encoding as compared to CBR encoding, Seen by Scene
works best with VBR Constrained jobs.
Fathom will display estimates to the changes in frame size, quantization level, and
buffer fullness in response to the change in bit rate. Note that buffer fullness changes
can extend beyond a scene and affect future frames and scenes.
A scene is dependent on its parent job’s encode parameters and on the output file of
which it is a part. After you have created scenes, you cannot change the parent Job’s
encode parameters.
If you attempt to queue a job that has defined scenes, Fathom will prompt you to delete
all of the job’s scenes.
Re-encoding a scene
When you have completed bit rate adjustments to a scene, the next step is to queue the
scene just as you would queue a job. Select the scene in the Sessions Directory and
click Queue job.
Figure 51 shows what the Fathom User Interface looks like when a scene has been
defined.
71
Figure 52: Scenes appear in the Analysis Timeline as shaded blocks, in the Session Directory
under the selected Job, in the Encoding Queue, and in the Encoding Monitor
Reviewing re-encoded scenes
After a scene has been encoded, review the scenes using one of the following tools:
Use the Session Directory toolbar’s playback button to play back the scene in
Windows Media Player.
Use the Video Analysis and Analysis Timeline panes to compare on a frameby-frame basis the original output with the re-encoded scene output.
You can re-encode a scene with new parameters, approve, or delete a scene.
Merging approved scenes with the original content
After you have reviewed your scenes and kept the approved scenes, you can merge the
scenes. The Merge function stitches the scenes together into a new file. Merge is
available only after all scenes have been encoded.
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FATHOM™
Figure 53: Saving a merge file
After a Merge is complete, click Compare on the Analysis Timeline to compare the
statistics of the original output file to the merged file. The analysis graphs will display the
two encodes in different colors (Figure 54), based on the following:
•
Black—Original encoding
•
Red—Estimated Seen by Scene changes
•
Green—Merge file. This color appears after you have created a merge file and
you click Compare.”
Figure 54: Compare on encoded files
Press F8 to display the Current Values window that displays the statistics (Figure 55).
73
Also present in the graphs will be Fathom’s estimates made prior to re-encoding the
scene. The Current Values window (press F8 to display) uses a slash “/” to note the
change from the first encode to the second encode.
Figure 55: Press F8 to display the Current Values window
Saving a job with scenes will save all scene information. This allows you to reload a
saved job with scenes and to continue adjustments.
Figure 56: Graphs comparing two video files
Batch Job Utility
The Fathom Batch Job Utility automates the creation of Fathom job files and AviSynth
scripts for multiple source files. For each of the source files you select, the Batch Utility
can create a Fathom job file and associated AviSynth script, a Fathom job file only, or
an AviSynth script only. Multiple source files can also be concatenated together into one
encode using AviSynth's file joining capability.
AviSynth scripts generated by the Batch Utility can be created in a Fathom watch folder
to begin encoding immediately. Fathom job files generated by the Batch Utility can be
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FATHOM™
opened and queued in Fathom in the same manner as job files created with the Fathom
edit job dialog.
The Source Files panel
The Source Files panel is used to select the source files you want to encode.
Figure 57: Batch Job Utility - Source Files Panel
Click Add to select multiple source files. You may add source files from multiple drives
and directories. Click Remove to remove a source file from the list. Click Join to select
multiple files for joining. When joining files, you may choose to use an aligned join, or an
unaligned join. These options correspond to the AlignedSplice and UnalignedSplice
commands in AviSynth. You should use aligned join in most cases; see the AviSynth
help for more details on when to use each type of join.
Click Move Up and Move Down to change the file order in a file join operation. When
selecting multiple files, the Windows File Open dialog may not return files in the order
selected by the user, so you should review the file order after selecting files to make
sure the source files to be joined are listed in the correct order.
The Fathom Jobs panel
Use the Fathom Jobs panel to specify the Fathom job template, encoded output
filenames, and output directories for jobs, scripts, and encoded output files.
Figure 58: Batch Job Utility - Fathom Jobs Panel
75
Because the Batch Job Utility cannot specify job settings, you must select a Fathom Job
template to create a batch of jobs. The job files generated will use the job settings
specified in the job template. The Batch Job Utility automatically detects when new job
templates are saved in Fathom, and reloads the drop-down list of job templates, so you
can switch to the Fathom application, create new job templates, then switch back to the
Batch Utility and select one of the new templates.
Specify the job and script filenames for each job by entering one or more substitution
macros in the Job and script filenames text box. As each job file is generated, the Batch
Job Utility expands the macros using information specific to that job. (The available
macros and their expanded forms are listed in the following table.) Note that when the
jobs and scripts are created, the file extension .FJ is automatically appended to job
filenames, and the file extension .AVS is automatically appended to AviSynth script
filenames.
The encoded output filenames for each job are specified in the same manner as the job
and script filenames. A .WMV file extension is automatically appended to output
filenames when the jobs are created.
Macro
Expanded Form
%SOURCEFILE%
The filename and extension of the source file (example:
City1.gxf)
%SOURCEFILEBASE%
The filename, without the extension, of the source file
(example: City1)
%SOURCEFILEPATH%
The full path, filename, and extension of the source file
(example: E:\Clips\GXF\City1.gxf)
%DATE%
The current date (example: 2006-01-31)
%TIME%
The current hour and minute (example: 21_15)
%JOBNUMBER%
A number starting at 1 that increments as each job is generated
%TRICKNUMBER%
Trick Stream speed value
A source filename of E:\Clips\GXF\City1.gxf and an encoded output filename of
%DATE% %SOURCEFILEBASE% %JOBNUMBER% will expand in the job file to 200601-31 City1 1.wmv. The default entry is %SOURCEFILEBASE% ; this adds the .wmv
extension to the base filename of the source file and may be sufficient for many
encoding jobs.
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FATHOM™
For Trick Stream Generation, the macro %TRICKNUMBER% is useful if multiple trick
speeds have been defined. When you define multiple trick speeds, a job is created for
each trick speed and this macro substitutes the trick speed into filenames.
Specify the directory where the generated Fathom job files and AviSynth scripts are
created by entering it in the Output directory for jobs and scripts text box. The directory
you enter here, along with the macro-expanded encoded output filename, determines
the full path and filename of the encoded files for each job.
If you want to generate only AviSynth scripts, check the Generate AviSynth scripts only
box, then enter the output directory for the generated scripts. You may enter a Fathom
watch folder for this directory, and your scripts will begin encoding immediately using
the job template settings for that watch folder.
To enable Trick Stream job creation, check the Enable box under the Trick Stream
Settings. To add a desired trick stream rate, enter a numeric value into the box next to
the Add Speed button and then click Add Speed. This value is added to the list of
current speeds. For example, to produce a trick stream 30 times faster than the source,
add a trick speed rate of 30. To remove a trick speed, select it in the Current Speeds list
box and click Remove Selected Speed. No jobs will be created if trick streams are
enabled but no speeds have been added.
The AviSynth Script panel
The AviSynth Script panel is used to enter AviSynth script commands you want to apply
to each encoding job.
Figure 59: Batch Job Utility - AviSynth Panel
AviSynth scripts usually contain the filename of a media source file. This filename must
be edited each time you want to process a different source file. By replacing the
filename in your script with the %SOURCEFILEPATH% macro, you can use the Batch
Job Utility to automatically generate an AviSynth script for each of your selected source
files. Other macros in the script will also be expanded, including macros inside
77
comments, but the %SOURCEFILEPATH% macro is required or AviSynth will not be
able to find your source files.
The Batch Job Utility also implements file joining in AviSynth scripts. To successfully
join files, your script must contain one line somewhere in the script with the macro
%SOURCEFILEPATH% and one of the AviSynth commands AVISource,
OpenDMLSource, AVIFileSource, or DirectShowSource. The Batch Job Utility
duplicates this entire line of script one time for each of your joined source files, expands
the %SOURCEFILEPATH% macro to the filenames of the joined files, and then uses
the AlignedSplice or UnalignedSplice command to concatenate these script lines.
Click Open, Save, and Save As to open previously saved scripts, save changes to your
script, or save your script under a new name. Click New to create a new default oneline script.
To generate only Fathom jobs, with no AviSynth script processing, leave the script edit
box empty, or comment out all the script commands. Comments in AviSynth scripts
begin with the '#' character.
Resolution of filename conflicts
When you create a batch of jobs with source files from different directories, the
directories may contain identically named source files. The Batch Job Utility uses the
following logic to resolve filename conflicts between files from different directories, or
conflicts with files already existing on disk:
Filenames of generated Fathom jobs and AviSynth scripts are created by
expanding the macro text entered in the Job and script filenames text box. If
the macro-expanded filename already exists on disk, a unique filename is
created by appending a (1) to the base filename. The number in parenthesis is
incremented until a filename is found which does not exist on disk. The Batch
Job Utility never overwrites existing Fathom job files and AviSynth script files.
As the Batch Job Utility expands the filename of the encoded output file
(WMV) for each job, it verifies that this batch of jobs has already used this
filename. If so, a unique filename is generated in the same manner described
above. The Batch Job Utility never generates a batch of jobs that causes one
job to overwrite the encoded output of another job from the same batch.
When the Batch Job Utility creates the encoded output filenames, it DOES
NOT verify that file already exists on disk. Therefore, it is possible to create a
batch of jobs that will overwrite one or more existing encoded files. To avoid
this, specify an empty directory for the encoded output files, or check the
Prompt before overwriting output files box in the Options dialog box
(Tools>Options).
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Generating trick streams
Tricks streams are streams that are used traditionally in Video on Demand applications
and provide the method for fast forwarding and rewinding at rates greater than 1x
speed. Trick streams are generated from previously encoded files, and therefore the
process to generate trick streams is different than normal encoding.
Fathom 2.5 includes a batch job processing application to help in the workflow of
creating VC1 fast forward trick stream files
To generate a trick stream, complete the following steps:
1. Encode a WMV file with Fathom.
2. Open the job’s settings used for the previously encoded file that will be the
source for the trick stream generation.
3. On the Input screen, adjust the source pixel aspect ratio to the output
aspect ratio of the original encode.
To do this, go to the Sizing screen and note the Pixel Aspect Ratio under the
Output area in the upper right corner.
4. Change the Audio Sources parameter to None.
5. On the Sizing screen, verify that the Cropping and Resizing parameters are
set to None.
6. On the Compression screen, do the following:
•
Disable Two pass encoding if it was previously enabled (It is unnecessary
for generating trick streams.)
•
Change the Scene change threshold to a high value (~75 recommended).
7. On the Processing screen, verify the following:
•
Interlace Processing option is set to None
•
Pre-Processing is set to Smooth
8. Click Save as Template in the job settings window.
9. After you save the template, from the menu bar select Tools>Watch Folder
to open the Watch Folder dialog box.
79
10. In the Watch Folder box, do the following:
•
Check the Enable Watch Folders box.
•
Check the Watch for job files only box.
11. From the menu bar, select Tools>Batch Job Utility (or click CTRL+B) to
open the Batch Job Utility application.
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Figure 60: Batch Job Utility
12. In the Source Files panel, click Add Files to navigate to the location of your
encoded WMV file. Click Add to add it as a source.
13. In the Fathom Jobs panel, click the Job Templates drop-down box and
select the template you saved for trick streams.
14. In the Job and script filename and Encoded output filename fields, Inlet
recommends selecting %SOURCEFILEBASE%_%TRICKSTREAM%.
81
15. Verify that the directory you select as Output directory for jobs and scripts is
set to the same directory as the folder you set to watch in Fathom.
16. Alter any other settings you wish to customize.
17. In the AVISynth Script panel, click Open and navigate to the following file:
“C:\Program Files\Inlet Technologies\Fathom\AVS Examples\”
“trick_template_2997.avs”.
18. If your source WMV’s frame rate is not 29.97, edit the “AssumeFPS(29.97)”
line in the script box to your appropriate frame rate by changing the frame
per second value and choosing to do a “Save As…” for the updated script.
19. After you set the script, return to the Fathom Jobs panel and check the
Enable box under Trick Stream Settings.
20. Enter a number in the Add Speed box and click Add Speed. The trick
stream speed is now entered in the Current Speeds field, and you can view
other speeds that have been entered by scrolling through the values here.
You can also use the AVISynth Script panel to create new or modify existing
AVS files for non-trick stream scripts. If you do make a change to any of the Inletsupplied AVS scripts, we recommend that you should do a “Save As” to the
script, so as to not overwrite the original script.
21. Click Create Jobs to automatically import and queue your jobs for encoding
into Fathom.0.
By integrating the use of AVISynth and Fathom, you can fully extend the power of the
Fathom software and hardware into an efficient encoding workstation, capable of
handling most any thing you want to throw at it.
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7
InletASFDump
7
Inlet Technologies’ InletASFDump is a command-line tool that operates on a WMV file
and can:
•
(-Iframes) List all I frames with time codes
•
(-frames) List all frames with times codes and frame sizes
•
(-attr) List all the attributes of the file
•
(-markers) List all markers found in the file
•
(-scripts) List all script commands found in the file
•
(-profile) List profile information gathered from the file
•
(-dump) Dump all compressed frames to individual files
•
(-elem filename.es) Extract the video elementary stream and save to a single
output file
•
(-segment [start1, end1, start2, end2, ….]) Extract compressed segments to
binary files
Usage
InletASFDump <inputfile> -Iframes -frames -attr -markers script –profile -dump -elem <file> -segment [start1, end1,
start2, end2,...]
The typical use of this application is for taking VC-1 AP .WMV files and extracting the
video elementary stream to an .ES file. For example:
InletASFDump test.wmv -elem test.es
InletASFDump is in Fathom’s program files folder. The default installation location is:
C:\Program Files\Inlet Fathom 2\
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8
Troubleshooting
8
My 1080 HD SDI encodes have stacked images
Fathom does not currently support interlaced based content. Therefore it is assumed
that a 1080-based HD SDI input is Progressive unless the PsF checkbox on the input
tab is checked. If your encoded output looks like it has two images, one stacked on top
of the other, then this is likely because either your 1080 based source is interlaced and
not progressive or the PsF checkbox was not selected on the input tab. Check your HD
SDI source to confirm that it is outputting either progressive or PsF and then check to
ensure you have selected the PsF checkbox appropriately on the input tab.
I cannot get time code start/stop to work with my SD SDI source
By default, Fathom looks for SD VITC time code on line 18. Some VTRs have the ability
to set the line on which VITC time code is output. If so, check to ensure your VTR is
outputting VITC on line 18. If you cannot change the VITC line on the VTR, open the
Fathom Options dialog (Tools>Options) then select the line from the SD NTSC Vict
drop-down box.
Another potential issue with SD time codes is whether a VTR is outputting time codes it
finds in the VAUX (video auxiliary) area or in the SBC (sub code data) area. The SBC
area is separate from the video and audio data on the helix tape track and is where
SMPTE/EBU information such as recording dates and times is stored. Time codes in
the SBC area may be different than the time code stored in the VAUX area. Thus,
depending on how your VTR is configured, the time codes displayed on the VTR may
be coming from the VAUX area, while the time codes being output in VITC could be
coming from the SBC area. If you are finding that time codes are not what you expect,
try looking at how your VTR is configured.
85
My playback from a 720p HD SDI encode appears to run slow
When the input is a 720p60 HD SDI source, for example, and encoding to 720p24,
Fathom uses a fixed cadence removal as described in the section on working with
SMPTE-296 in the technical release notes of this guide. If the start Time Code is not set
correctly, the cadence removal may operate on the wrong frames and you may encode
duplicate/repeated frames such that, in this example, only 12 unique frames of 24 are
encoded. When this played back will appear to run slow. To solve this issue, make sure
you are starting on a Time Code of frame 0, 5, 10, 15, 20 or 25.
My HD SDI encoding appears scrambled or does not start at all
When the input is a HD SDI source, the video signal and format must be stable prior to
starting encoding and during encoding. If the HD SDI format is incorrect for the profile
being selected (for example, the HD SDI input is 1080 but the job is set up as a 720
encode) encoding may never start, or you may get a scrambled image if it does.
The Fathom hardware utilizes time code embedded in the SDI signal. When a job has a
start time code, the Fathom hardware will not start encoding until it sees this time code
in the embedded SDI signal. When a SDI job with time code starts in the encoding
queue, Fathom first pre-rolls the VTR to a point just prior to the start time code. After the
VTR has been pre-rolled and starts playing, the Fathom application tells the Fathom
hardware to start looking for the start time code. At this point the time code displayed in
the encoding monitor window reflects the time code the hardware is seeing embedded
in the SDI signal.
If the time codes displayed here do not roll past your start time code it may be an
indication that you have two sets of time code on the tape. If this is the case, check to
see if you can configure your VTR to output the same time code both embedded and
over the VTR control interface. Otherwise, check for errors in the start time code
entered for each video source in the job. For example, a time code with frame 24 or 25
will not exist on 24 fps tape material (where time codes range from 0 to 23). Finally, if
the time code is not moving at all, for SD sources review the section above SD time
code.
I don’t see any output preview
Fathom utilizes VMR9 (Video Mixer Renderer Version 9) by default for rendering video.
Depending on your host machines graphics card VMR9 may not render some
resolutions (like non-multiples of 16 in width). If you are not getting any input or output
preview, try switching to VMR7. If it does not exist, create and then set the following
registry setting to 1.
HKEY_LOCAL_MACHINE\SOFTWARE\Inlet\FathomAPI\UseVMR7
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When I play back my clip, the audio runs longer than video
When encoding from a file Fathom sends video frames one at a time to the encoder and
sends blocks of audio data. The block size of the audio data is very dependent on how
the file was created and on the various filters needed to extract audio data from the
source file. Fathom internally holds back video frames and audio sample blocks from
being encoded such that one does not get too far ahead of the other.
However, it is possible in certain circumstances—for example, stopping a job before it
has completed—that the audio encoded so far is ahead of the video encoded. In such
cases, you can end up with more audio encoded than video.
Ramifications of changing amount of PC memory
Fathom writes to the registry some information about upper and lower limits of memory
when the driver gets installed. If the amount of memory in the PC is changed after
installing the Fathom drivers these registry entries are incorrect. This may manifest with
symptoms of Fathom never starting to encode (stopping at frame 0, and incompletely
de-queuing jobs). If the amount of memory is changed uninstall the driver and re-
install the driver.
Fathom does not re-encode scenes from SDI sources with a frame rate
>30 fps
Due to repeat time code (0,0,1,1,2,2,3,3,4,4 etc) for sources that have an fps greater
than 30, Fathom does not currently allow SxS control for this type of content from SDI.
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9
Release Notes
9
Fathom™ is a professional VC-1 encoder that delivers high-performance advanced
compression to the post-production market. Fathom provides a comprehensive solution,
combining a hardware encoding engine with workflow and analysis software to make
next-generation distribution methods a reality today, including: HD DVD, Blu-ray, WMV
HD, FVD, video-on-demand, dailies, digital signage and more. Complementing both SD
and HD workflows, Fathom enhances productivity by reducing file sizes for easier
content creation and distribution.
General Information
External inputs
Video
Single Serial Digital Input (BNC)
•
SMPTE-292 (HD)
SMPTE-274: 1920x1080p 23.976, 24, 25, 29.97, 30
1920x1080i 50, 59.94, 60
SMPTE-296: 1280x720p 23.976, 24, 25,
29.97, 30, 50, 59.94, 60
Progressive, PsF and interlaced
•
SMPTE-259M (SD): 720x480i 29.97, 30 and 720x576i 25
Progressive and interlaced
•
MediaCat multi tape source
NOTE:
Fathom supports 1080i60(field rate) and 1080p30(frame rate)as
input rates, but to output these rates two boards are required.
Fathom does support 1080i60 input to 720p30 on a single board.
Please contact support(support@inletHD.com)for further information
about utilizing a two board solution.
89
Audio
•
Embedded in HD SDI (SMPTE-299)
8 channel custom mapping
•
Embedded in SD SDI (SMPTE-272M)
Time code
•
Via SMPTE RP-188 for HD SDI
•
Via Vertical Interval (VITC) for SD SDI
File-based input
Video
•
AVI files
RGB24, RGB32, v210, YUY2, UYVY,
IYUV, I420, YV12, CFHD, CVID and MP4S
•
QuickTime files
v210, 2vuy, 2Vuy, 2VUY
•
Common film, HD and SD resolutions
2048x1080
1920x1080, 1440x1080
1280x720, 960x720
720x480, 540x480
720x576, 540x576
•
Progressive
•
Interlaced
•
AVI Synth (AVS)
•
GXF
•
Raw YUV
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•
MPEG-2 (TS, TRP, MPG)
Fathom uses the MainConcept MPEG-2 decoder, which is installed with
Fathom 2.5.
© 1999/2000-2006 MainConcept AG
Audio
•
AVI file embedded with video
•
WAV files
•
Extensible WAV file
Data
•
I-frame specification file
•
.ALE and .FLEX video log files
Video pre-processing
•
Interlace processing:
Deinterlace
Maintain interlace
Inverse telecine
•
Pre-filtering:
Normal,
Smooth,
Dynamic
•
Black and white filter
•
Watermarking
•
Dithering
•
Scaling
•
Cropping
91
•
10-bit to 8-bit dithering
•
Color-space correction
•
High-frequency noise reduction
Output
Video
•
VC-1 (SMPTE-421M) Progressive
Profiles
–MP@ML
–MP@HL
–AP@L1
–AP@L2
–AP@L3
CBR 1-Pass
CBR two-pass
VBR Fixed Quality 1-pass
VBR Fixed Quality two-pass
VBR Constrained/Unconstrained 1-Pass
VBR Constrained/Unconstrained two-pass
•
MediaCat tape concatenation
Audio
•
Windows Media Audio 9, 9.1
2 channel
•
Windows Media Audio Professional 9, 9.1
2, 6, or 8 channel
•
CBR 1-Pass
Time code
•
SMPTE codes are embedded in output file
SDI source: SMPTE codes pass through
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File source: SMPTE codes created
Statistics
•
Frame number
•
Frame time code
•
SMPTE time code
•
Frame type
•
Frame size
•
Average bit rate
•
Quantization level
•
Buffer fullness
•
Custom buffer fullness
•
Motion vector display
Settings
Video
•
Key frame interval
•
Scene change detection threshold
•
Quality factor
•
Buffer window size
•
B Frames (0, 1, or 2)
•
Frame accurate start encode based on time code
•
Frame accurate stop encode based on time code
•
Custom I-frame specification
Audio
•
Custom channel mapping
93
Seen by Scene™
•
Mark In/Out
•
A/B graphical comparison
•
A/B visual playback comparison
•
Bit rate adjustment
•
QuickStitch™ seamless stitching
Device control
•
RS 422
•
Play, Pause, Stop, Fast Forward, Rewind, Jog, Shuttle, Step back,
Step forward
•
Cable is included
Fathom Pro encoding station
•
HP xw9300
•
Microsoft Windows XP SP2
•
AMD Opteron 252 / 2.6GHz 1GHz HT
•
NVIDIA Quadro FX
•
2GB DDR-400 EEC RAM Memory
•
73GB SCSI U320 10K RPM
•
1.6TB RAID 0 (4 SATA 400GB 7200RPM)
•
16X DVD +/- RW
•
HP PS2 Keyboard
•
HP PS2 Mouse
•
3 year parts/labor/next day business on-site warranty
•
Optional Rack mount kit
Specifications are subject to change
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System requirements
•
64 bit/66 MHz PCI interface; 32 bit/33 MHz compatible
•
PCI 2.2 compliant, full slot required
•
Pentium 4 (3.4 GHz or higher recommended for playback)
•
1GB RAM
•
50 MB hard drive space
•
Windows XP Service Pack 2
•
DirectX 9.0b or later
•
Windows Media 10 Player
•
Windows Media 9 Series Encoder
•
Microsoft .NET 1.1 runtime
Technical Notes
Working with SMPTE-296 (1280x720p)
While it is common for VTRs to output SMPTE-274 (1920x1080) natively in frame rates
such as 23.976 and 24 this is not the case for SMPTE-296 (1280x720). It is often the
case that 720p material is output as 50p, 59.94p or 60p. A D5 VTR, for example, can
convert 1080p24 material to 720p but it does not output 720p24. Instead the D5 outputs
720p60 where progressive frames are repeated in a 3:2 cadence. A D5 outputs frame
“A” on Time Codes frames 0, 5, 10, 15, 20 and 25.
In Fathom, you must specify the actual HD SDI input frame rate. The encoding profile is
used to determine the output frame rate to process. For 720p output frame rates of 50,
59.94 and 60, each input frame from HD SDI is encoded. For all other output frame
rates the Fathom software either decimates or removes a fixed cadence pattern starting
at the first frame encoded.
For 720p30 every other frame is discarded
For 720p24 and 720p23.976, a 3:2 cadence is assumed and the software
removes the redundant replicated frames and only encodes the resultant 24 or
23.976 frames per second. Thus when sourcing from a D5 , you should start
on an “A” frame which is located on Time Code frames 0, 5, 10, 15, 20,
and 25.
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For 720p25, a 3:2:3:2:2 cadence is assumed and the software removes the
redundant replicated frames and only encodes the resultant 25 frames per
second.
Audio formats when using embedded audio from SDI
The hardware acquires 48 KHz audio samples from embedded SDI audio per SMPTE299 in either 16 or 24 bit form. The bit-depth depends on the output profile. For profiles
that are not 48 KHz the Windows Media format SDK will handle re-sampling of the
source 48HKz material to the destination sample rate.
Video compression quality setting
The video quality setting is found in the Job Parameters>Compression window’s
Video Compression section and is labeled as Quality.
For software-based encodes, the video quality setting (termed Video Smoothness) is a
trade off between dropping frames for higher-quality, sharper video versus decreasing
quality for smoother video. The higher the Video Smoothness value, the more likely the
software encoder will drop frames, but video should be sharper and of higher quality.
The lower the Quality value the more likely the software encoder will reduce quality to
try to encode every video frame.
Another aspect of quality is video fluidity, or frame rate. The ideal experience will have
the full image rate of the original source, with one output frame per frame or field of the
source. And it will not have dropped frames. Dropped frames leads to video that
appears to stutter when it is played back. Fathom has substantial advantages over the
encoder that Microsoft provides with the Windows Media Encoder (WME) in regards to
temporal smoothness. Perhaps stemming from its main focus being on video streaming,
WME can trade off between quality and video smoothness. WME can be configured to
provide better quality by dropping frames as necessary to meet a specific bit rate.
Internally this maps to limiting the use of quantization described above. But even at HD
data rates, it is impossible to turn frame dropping off entirely with WME. Fathom,
however, allows the full use of quantization in order to not drop frames. Careful attention
should be applied to the use of Fathom’s Quality setting for hardware encoding
compared to the Video Smoothness Quality setting used for software based encodes.
This topic is discussed later in this guide.
For hardware-based encodes (either from a file or from SDI), the video quality setting
has a different meaning. The hardware does not drop frames like the software encoder
does. Instead, this quality value maps directly to the minimum quantization value
allowed. Thus this method puts an upper bound on quality.
For quality-based VBR, the quality setting maps directly to the single quantization value
used during encoding. This is true for both software and hardware based encoding.
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The following table shows the mapping of Quality to Quantization values. For quality
based VBR this quant will be used for the entire encode. For other hardware based
encodes, the quant value is the minimum value used (that is, the quant will not go below
this value).
Quality
Quant
Quality
Quant
Quality
Quant
Quality
Quant
100
2
>= 72
9
>= 43
17
>= 15
25
>= 97
2
>= 68
10
>= 40
18
>= 11
26
>= 93
3
>= 65
11
>= 36
19
>= 8
27
>= 90
4
>= 61
12
>= 33
20
>= 4
28
>= 86
5
>= 58
13
>= 29
21
>= 1
29
>= 83
6
>= 54
14
>= 25
22
0
30
>= 79
7
>= 50
15
>= 22
23
>= 75
8
>= 47
16
>= 18
24
For hardware based encoding it is recommended that you leave the Quality field value
at 93 or higher.
CBR and VBR (constrained/unconstrained)
Inlet’s hardware CBR encoder does not pad bit streams to produce a constant bit rate
output. Thus CBR-encoded streams may shoot under the target encoded rate if there is
no reason the encoder feels that bits need to be used given the profile’s quality setting.
The generally understood method for VBR constrained and unconstrained encoding is
to use two-passes and target a specific average bit rate over the entire clip. In addition
to two pass encoding, a single pass VBR mode is also provided for hardware encoding.
The single pass VBR constrained mode attempts keep the target bit rate like CBR
encoding but allows for larger variances than CBR. Thus, average bit rate for VBR
constrained will typically be slightly higher than a similar CBR encode.
VBR unconstrained is modeled like VBR constrained except there is no limit on peak bit
rate and currently the internal peak buffer size is set to 90 seconds. Thus, average bit
rate for VBR constrained will typically be slightly higher than a similar VBR constrained
encode.
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10
Appendix A: Technical Guide
A
Understanding VC-1 and FourCC
Fathom 2.5 supports the following video profiles:
•
VC-1 Main Profile (WMV3)
•
VC-1 Advanced Profile (WMVA)
•
VC-1 Advanced Profile (WVC1)
Files encoded according to these profiles are identified by their Four Character Code
(FourCC). The FourCC identifier is located at the beginning of a media file and tells the
system what codec to utilize for decoding the file. The VC-1 video codec specification
(also known as SMPTE 421M), which is being standardized by the Society of Motion
Picture and Television Engineers (SMPTE), utilizes all three of these profiles.
Understanding the differences between these profiles can help you decide which profile
best fits your delivery stream.
VC-1 codec specification
VC-1 (Windows Media Video (WMV) 9 Advanced Profile) is a video codec specification
implemented by Microsoft to define a standardized specification that was transport and
container independent and supported both progressive and interlaced content. This
allows content to be delivered “over MPEG-2 and RTP systems as well as ASF, which
enables device manufacturers and content services to create interoperable solutions.
Windows Media Video 9 Advanced Profile implements these features, making it much
easier to deliver Windows Media content over traditional broadcast and wireless
infrastructures” (Microsoft.
http://www.microsoft.com/windows/windowsmedia/forpros/events/NAB2005/VC-1.aspx).
WMV3
Before Microsoft implemented VC-1, the WMV3 profile was implemented to allow
progressive encoding for computer displays. In WMV3, interlaced video content was
always de-interlaced before encoding with WMV3. The Windows Media Video 9
(WMV3) codec implements the Simple and Main modes of the VC-1 codec standard. “It
provided high-quality video for streaming and downloading. It provides support for a
wide range of bit rates, from high-definition content at one-half to one-third the bit rate of
MPEG-2, to low-bit-rate Internet video delivered over a dial-up modem. This codec also
supports professional-quality downloadable video with two-pass and variable bit rate
99
(VBR) encoding. Windows Media Video 9 is already supported by a wide variety of
players and devices” (Microsoft.
www.microsoft.com/windows/windowsmedia/9series/codecs/video.aspx).
The professional video market, however, needs to support progressive and interlaced
content, as well as being transport independent. The VC-1 spec as implemented in the
WMVA and WVC-1 profiles, provides this support. The VC-1 spec still utilizes the
WMV3 codec.
WVC1
To implement a solution that would support the compression of interlaced content
without first converting it to progressive and allowing the delivery of Windows Media
files over systems that were not Windows Media-based, Microsoft implemented WVC1.
WVC1, also known as Windows Media Video 9 Advanced Profile, “implements the
Advanced mode of the proposed VC-1 codec standard. It offers support for interlaced
content and is transport independent. With the previous version of the Windows Media
Video 9 Series codec, users could deliver progressive content at data rates as low as
one-third that of the MPEG-2 codec and still get the same quality as MPEG-2. The
Windows Media Video 9 Advanced Profile codec also offers this same improvement in
encoding efficiency with interlaced content” (Microsoft.
www.microsoft.com/windows/windowsmedia/9series/codecs/video.aspx)
Progressive
Interlaced
Windows Media 9 Series
WMV3
N/A
VC-1
WMV3
WVC1
WMVA
WMVA is a previous version of WVC1. WMVA was the draft version of WVC1 during the
acceptance of the VC-1 spec. There are some slight bit stream mods between the
WMVA and WVC1. WMVA is handled by a different DirectShow decoder than WVC1.
Additionally, decoders for some 3rd party hardware and software companies (whether
hardware STBs, software STBs, etc) will only decode WMVA based content.
Earlier versions of Fathom supported only WMV3- and WMVA-based content. FATHOM
2.5 supports WMV3, WMVA and WVC1. The continued support for WMVA is because
the decoder solution of some customers may not yet be WVC1 aware and will continue
to encode with WMVA. From the perspective of Fathom, the application supports VC-1
Main Profile (WMV3), VC-1 Advanced Profile (WVC1) and VC-1 Advanced Profile
(WMVA).
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A Note on Terminology
In the convergence of the media and computer worlds of the last decade, we have
wound up with a lot of confusion caused by different definitions of the common units “K,”
“M,” and “G”. The actual metric units are defined as powers of ten. These values are
close, but not identical to power of two numbers typically used in the computer industry.
Thus computer folks started using the terms “K,” “M,” and “G” that have slightly different
values from the true definition, used by the communications engineers who develop
codecs. The differences are shown in the following table:
Unit
Official value
Proposed power
of 2 unit
“Computer” value
Difference
K
103=1000
Kib
210=1024
2.4%
M
106=1,000,000
Mib
220=1,048,576
4.9%
G
109=1,000,000,00
0
Gib
230=1,073,741,824
7.4%
Note that the difference gets bigger as the values get higher. A lot of the confusion here
results from the fact that different parts of the compression process can use different
values. For example, Fathom uses the proper base 10 values. But the operating
systems report drive space remaining in the erroneous base 2 values. Thus, when
calculating the data rate that can be used just to fill up a disc, the GB used by the
operating system and by Fathom will be 7.4% different.
New labels have been proposed for the power of 2 units, called “Kib,” “Mib,” and “Gib.”
This document will use those units as necessary, and when using K, M and G,
specifically means the correct power of 10 units
USB License Key required
You must have the Fathom USB License Key installed on your system before using
Fathom applications. Refer to the Fathom Installation Guide for instructions concerning
software installation for the USB License Key.
If the USB License Key is not installed, has not been detected, or does not contain valid
licenses to run one of the Fathom applications, a dialog box will notify you of a license
error.
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Some Background on Input
Files versus tape sources
Half a decade ago, video postproduction was always based around tape. Now however,
a 1 TB portable drive costs about 1% of the price of a D5-HD 24p compatible deck.
Because of this, we are seeing more content delivered as digital files. The workflow is
simple—instead of printing back to tape, the timeline is exported to a self-contained file.
Even network-based transport of HD content is feasible with today’s fast gigabit
Ethernet and fiber switches.
File transport also avoids the compression introduced by mainstream HD tape formats.
Encoding via SDI
While the file-based workflow is great for many users, tape still makes sense in many
areas. Tape is very compact, and there are no codecs to worry about. It is also
impractical in most facilities to archive hundreds of hours of HD files digitally, while a
tape library of that size is nearly trivial.
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HD tape formats
A number of HD tape formats exist, which offers different advantages and
disadvantages. For many projects, no choice exists. But when you can choose the
format in which content can be produced and provided, different options have a
significant impact on the final result.
D5-HD
Panasonic’s D5-HD has been the format of choice for HD post in Hollywood for several
years. It is unique in that it provides full luma and chroma resolution, up to 1920x1080
with 4:2:2 color. It also supports both 8-bit and 10-bit modes.
One complexity with D5-HD is that not all decks support the 24p mode, which is used
for most film post. Ensure that your deck supports 24p if you expect to get those tapes.
There are no software codecs for D5-HD; working with it requires HD-SDI. This
limitation is less frustrating than with other formats, because it at least uses the full
visual information range of HD-SDI.
DVCPRO-HD
DVCPRO-HD is Panasonic’s other, more compressed HD format. It is commonly used
in cameras and directly competes with HDCAM. Compared to HDCAM, DVCPRO-HD
uses more horizontal compression (a 33% compression to 1280x1080 compared to the
25% to 1440x1080 of HDCAM), but more color detail (4:2:0 color instead of 3:1:1).
Apple’s Final Cut Pro has added great native bit stream support for the DVCPRO-HD
codec (sometimes called DV100). When used with Final Cut, a DVCPRO-HD deck with
a FireWire (1394) interface replicates the simple single-cable workflow of DV. Fathom
does not directly support the DVCPRO-HD codec, so Mac users using that format need
to transcode to a different format.
HDCAM
HDCAM is Sony’s most broadly adopted HD format. HDCAM uses significant image
compression. Instead of the full 1920x1080, for 1080 it uses anamorphically
compressed 1440x1080. HDCAM also uses the unusual 3:1:1 color sampling mode, so
there is only one chroma sample every three pixels horizontally. The net effect of those
is that 1080 HDCAM has only 480 chroma samples per line, compared to the 960 of D5.
While this is not noticeable for many kinds of content, it yields a softness of color detail
with high saturation, especially with rendered graphics. Compared to DVCPRO-HD,
HDCAM is sharper overall, but has a little less color detail.
Sony has not made the HDCAM codec available widely for computers. The only
significant tool with native bitstream support for HDCAM is Sony’s own XPRI.
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HDCAM-SR
While HDCAM is quite compressed; HDCAM-SR is a very different beast. With data well
beyond what D5-HD supports, HDCAM-SR offers full 1920x1080 resolution and works
in either 4:2:2 or RGB 4:4:4, both in 10-bit. This makes HDCAM-SR a real film
replacement option.
Because of its high bandwidth, the RGB 4:4:4 HDCAM-SR signal does not fit over
normal HD-SDI. Instead, it uses dual-channel HD-SDI. Since VC-1 is only an 8-bit 4:2:0
codec, Fathom does not ingest dual-channel HD-SDI. Use the HDCAM-SR in normal
HD-SDI mode and it converts the data into a high quality 4:2:2 10-bit input.
HDV
As its name suggests, the HDV format was designed to fit the role of DV in the HD
market. This required high compression – a 1080i HDV stream runs at only 25 Mbps,
the same as a standard 480i DV stream! It does this by using MPEG-2 with inter-frame
compression. However, this means that the quality of a frame can drop with high
motion. In many cases the HDV compression adds far more compression artifacts than
VC-1 encoding would.
Today there are three main modes of HDV that are used: 480p60, 720p30, and
1080i60. Cameras are coming out soon for 1080p24; highly anticipated for use as a
low-cost film-compatible acquisition format. Also, at only 24 frames second, the 25
Mbps is spread out over fewer frames, helping quality.
While Fathom does not support the HDV codec natively, it certainly does a good job
with HDV content. Watch out for the potentially substantial limitations of the source
footage. If you’re doing a lot of editing of HDV footage, do not export back out of your
NLE as HDV. Instead export to a visually lossless codec like Huff YUV or Motion JPEG.
This way you do not have to put the added effects and motion graphics through another
round of compression artifacts.
Another suggested path is using CineForm’s Aspect HD product. Aspect HD will do this
conversion for you automatically.
Encoding from live sources
It is always possible to encode from a live source, like a camera, VTR or switcher, direct
to Fathom via SDI. For two-pass encoding from a live source, you must have start and
stop time codes identified in the Fathom job. Using 9-pin RS422 control combined with
SMPTE RP-188 or VITC time code Fathom allows for frame-accurate single or two-pass
encoding. With two-pass encoding, Fathom first processes the source content by
gathering various forms of information about the content. On the second pass, it uses
that information to optimize the encoding. Two-pass encoding generally yields betterencoded files.
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FATHOM™
One common use of Fathom with live encoding is using the live HD-SDI output from an
NLE, in order to avoid having to dub to tape.
Getting the correct field mode
HD-SDI sources can be either progressive or interlaced, and you will need to manually
set that correctly in Fathom’s Input pane. One special case to watch out for is PsF, or
Progressive Segmented Frame. This is a video that is laid out as interlaced, but where
both interlace fields are from the same moment, and can be processed as progressive.
Think of this simply as a progressive frame where the odd lines are placed in one field
and the even lines in another. Merging the fields reproduces the progressive frame.
For quality purposes, it is critical to correctly flag the input mode. For example, if the
input is interlaced but you indicate in Fathom that the source is progressive, you will
encode one field on top of the other. Using the video preview window, you can quickly
determine if your settings for the video field mode are correct.
Fathom outputs interlaced content with SD-SDI and SD File interlaced sources
and HD interlaced file sources if you elect to maintain interlacing.
NOTE:
Audio
Fathom receives its external audio via audio embedded in SDI. This audio is
uncompressed 48KHz. Except for HDV, all the HD tape formats use uncompressed
audio, so there is no quality advantage one way or another (and even HDV audio is only
lightly compressed). Most HD formats support at least four channels of audio, and some
do eight. HD-SDI supports up to eight channels, and Fathom can ingest and encode all
eight of those if they exist. HD-SDI goes up to 48 KHz and 24-bit audio. The Windows
Media Audio Professional codec Fathom uses (more on that below) can use up to 96
KHz audio, but you will need to input the audio from a file to use that. Custom channel
mapping of the 8 embedded audio channels is available in the job setup.
Encoding from files
Fathom reads files in a variety of formats, such as High Definition Serial Digital Interface
(HD SDI), Standard Definition Serial Digital Interface (SD SDI), SD interlaced, HD
interlaced, AVI, QuickTime files, AVISynth script , MPEG, GXF, and raw video file
(YUV) . It supports any file and codec that Microsoft’s DirectShow API supports,
including AVI.
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Many codecs give you the option of rendering and exporting in 8-bit or 10-bit. Since the
VC-1 codec is 8-bit only, there’s no advantage to rendering or compressing in more
than 8-bit. It slows down encoding, makes the file a little larger, and requires conversion
within Fathom. Instead, render and compress in 8-bit if you have the option. Since the
native format for Fathom is Y’CbCr (also called YUV) 4:2:0, the most efficient file format
for ingesting into Fathom is an .AVI or .MOV using the uncompressed YV12 or I420
modes. With either of these formats, Fathom will not have to pre-process video prior to
encoding. The best encode speed will also be seen with files in these formats.
TIPS:
If you are planning on encoding the same file multiple times you may want to
consider pre-formatting the file to say YV12. After you do this, you will save
time in Fathom on any future encodes. However, not all NLE’s offer easy
export to these formats.
Getting to Fathom from Windows programs
It is very easy to get to Fathom from most Windows video tools, as nearly all of them
support the DirectShow API for making AVI files, and Fathom can use any DirectShow
codec for decoding AVI files. If you are encoding on a different machine than you
exported from, you will need to make sure you have the same codec available on both
systems. Most NLE vendors provide software-only versions of their codecs that you can
install on your Fathom system to support decode. If not, you can access a variety of free
codecs. One particularly useful choice is the free, open source Huffyuv codec. This is a
mathematically lossless codec that works in the 4:2:2 color space. While it does not
make the smallest files, you can be sure that you are not losing any quality in
transcoding.
Getting to Fathom from Mac programs
Getting from a Mac system to Fathom can be tricky, as most Mac apps support only HD
exports to QuickTime’s .MOV format, and Fathom does not use the QuickTime API to
read files. However, Fathom does have its own .MOV parser that can handle most of
the uncompressed codecs. If you’re using Final Cut Pro, the uncompressed 8-bit and
10-bit 4:2:2 codecs work great in Fathom, and provide perfect quality (although the files
can be huge). Note that while Fathom does not support DVCPRO-HD or HDV codecs
often used with HD on Mac if it does support 8 and 10-bit v210 formats.
When exporting to QuickTime, make sure you are making a self-contained file,
not a reference movie. Fathom supports only self-contained movies.
NOTE:
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FATHOM™
Wild/Crash Encoding
A wild encode is an encode where no time code or stop point is specified. After a wild
code is entered in the queue you must manually remove the job from the queue to stop
the encode. Wild encodes are only available for single pass encode jobs.
Use this method to quickly test and validate your input source.
Aspect Ratio Overview
The phrase “aspect ratio” is bandied about throughout video production. Three different
kinds of aspect ratios apply to a given clip, and it is very useful to specify which type is
in question.
Frame Aspect Ratio (FAR)
The frame aspect ratio (FAR) is the shape of the frame. All HD cameras are natively
16:9, as are consumer HD sets. The only time you would be likely to see any other FAR
is in a file, such as used for a motion picture being produced at a wider aspect ratio like
1.85:1 or 2.35:1
Pixel Aspect Ratio (PAR)
Pixel aspect ratio (PAR) is the shape of the pixels. Most HD delivery uses square pixels.
However, many of the production formats use anamorphic compression, and hence
non-square pixels. For example, Sony’s HDCAM encodes 1080i as 1440x1080i, and
then expands this to 1920x1080 when going out via HD-SDI. 1440 is 0.75 the width of
1920, and so HDCAM is described as having a PAR of 0.75. Only PAR values of 1 or
less are used—the squeeze is always horizontal, never vertical.
Using an anamorphic PAR of 0.75 is also common for many VC-1 projects at 1080
height, hence reducing the width to 1440. This significantly helps playback on older
systems, although today’s fast consumer machines running WMP 10 can handle a full
1920x1080 playback. For a given quality it can also allow a lower data rate to be used.
Inversely, at a given data rate it can be used to provide higher quality. It is certainly a
better choice than encoding at a data rate too low for a full frame of pixels and getting a
lot of compression artifacts. Also, if the source is anamorphic to start with (say
DVCPRO-HD), there is no advantage in using a PAR other than that of your source.
Fathom embeds the PAR information in the bitstreams it produces so that players will
know to automatically adjust the size before display. Thus, a 1920x1080 input can be
encoded as 1440x1080, and then decoded back to 1920x1080 completely transparent
to the end user.
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Using Fathom’s “Enable anamorphic scaling” option on HD-SDI applies a 0.75 PAR.
This turns 1920 wide into 1440 wide and 1280 wide into 960 wide. You can also scale
file-based content and have Fathom automatically compute the PAR for you.
Image Aspect Ratio (IAR)
The image aspect ratio (IAR) is the shape of the active image, excluding letterboxing or
windowboxing. So, a 2.35:1 movie letterboxed into a 16:9 frame has a FAR of 16:9 and
an IAR of 2.35:1. For DVD-ROM playback, WMV files for computer playback should be
encoded with IAR and FAR being identical, with letterboxing removed. However, a
number of video applications require that the FAR be fixed, and so FAR and IAR will be
different.
Two Primary Reasons to use Cropping
Cropping defines a rectangle of the source frame that is used to make the output frame,
thus specifying a region of interest within the video frame.
For more information on why to use cropping, see
The first reason to use cropping is to remove any non-image data. For example,
letterboxing should be removed when encoding WMV for computer playback. Cropping
out the parts of a video frame that do not have image data speeds up encoding and
decoding.
Second, you can crop in order to get the Image aspect ratio to match the Frame Aspect
Ratio. For example, if you want to deliver 16:9 that fills up a 16:9 screen without
letterboxing, you could crop the left and right edges of a 1.85:1 movie slightly in order to
get a 16:9 source frame.
The output of cropping will be your Image Aspect Ratio. It does not affect the pixel
aspect ratio.
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Resizing
The result of any cropping and/or scaling is an output video size that is used for
compression.
Resizing controls scaling, taking the rectangle left after cropping and changing the size
and shape of that rectangle to match the size of the output. When the source and output
are the same size and there is not any cropping, no scaling is required. Scaling is
mainly used for format conversion (for example, downsampling from 1080 to 720) or to
modify the Pixel Aspect Ratio (for example, converting from 1920x1080 to 1440x1080
for easier playback). The section on Pixel Aspect Ratio (on page 107) explains why you
may want to resizing/scale your input video.
While scaling down provides fine quality, scaling up is rarely satisfactory. It is almost
always better to leave the image at its native size and let the video card handle scaling
on playback.
Fathom allows for common scaling conversions from SDI sources and most any scaling
combination for file-based source. In Fathom 2.5, you can scale 720 x 480 and
720 x 576 to 320 x 480 and 320 x 576 during encoding.
Some Background on Compression
Fathom is all about compression. Understanding some basics of how compression
works and what makes good and bad compression is very useful in planning and
troubleshooting your projects.
Compression itself is the act of transforming data to minimize the space required for
storage or transmission. While the word encoding in its generic sense implies simply
“the formatting of data to a specific standard” the word compression is often used
synonymously with encoding.
What makes high quality video encoding
So, what is the difference between good and bad encoding? Compression is
fundamentally about formatting data into another form such that the data takes up less
space. We can reduce the data size to a small fraction of the original—a compressed
file is typically just 1–5% of the size of the uncompressed, original source. Ideally this
process should be done so that later when the video is decompressed (reverting the
process of encoding), the video will be as accurate a version of the original as possible.
Some video compression formats are lossless (the decompressed video is exactly the
same as the original video) but these formats do not offer compression efficiencies that
are viable for transmission or storage on media such as DVDs. Thus, most video
compression formats, such as VC-1 formats are lossy. You lose some information from
109
the original material during compression that is not recoverable. How well the codec
minimizes this loss while achieving high compression ratios differentiates codecs, as
well as implementation of codecs.
Compliance
Compliance is critically important to the encoding setting. Is the bit stream produced
guaranteed to work on the target devices? This is not that big an issue for PC playback,
because so much variability exists in system performance. However, it is vital as we
look towards using VC-1 in consumer electronics, like the next generation HD discs.
NOTE:
By default Fathom will limit compression settings so they conform to VC-1
profiles/levels. This conformity is controlled by the following registry setting,
which you will need to set to 0 if you want to encode outside of the restrictions
of VC-1 (for example, to encode with a larger buffer size than a given VC-1
level allows).
HKEY_LOCAL_MACHINE\SOFTWARE\Inlet\Fathom\VC1Conformity.
The following are examples of some VC-1 profile specifications:
Profile@Level
MB/s
MB/f
Rmax
Bmax
MP@ML
40,500
1,620
10,000
611
MP@HL
245,760
8,192
20,000
2,442
AP@L1
48,600
1,620
10,000
1,250
AP@L2
110,400
3,680
20,000
2,500
AP@L3
245,760
8,192
45,000
5,500
AP@L4
491,520
16,384
135,000
16,500
* Legend
AP = Advanced Profile
Bmax = Max buffer size in units of 16,384 bits
HL = High Level L0 = Level 0 ML = Main Level
MB/f = Max number of macroblocks/frame
MB/s = Max number of macroblocks/sec
MP = Main Profile
Rmax = Max peak transmission bit rate in 1,000 bits/sec
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FATHOM™
General encoding settings
Two-pass encoding
Both CBR and VBR encoding modes support one- and two-pass encoding in Fathom. In
1-pass encoding, the file is read in and compressed in a single stage. In two-pass
encoding, the video is first analyzed to determine the relative complexity of each frame.
Then in the second pass, bits are distributed to each frame in proportion to its
complexity, within the constraints of the encoding mode. The net effect is that two-pass
encoding has a perfect view of what is going to happen in the future, and so does a
better job of optimally distributing the bits when the complexity of the video changes
dramatically.
The advantage of two-pass encoding goes up with longer buffers, and especially with
VBR encoding. Two-pass is also most advantageous, as the average bit rate gets
lower, especially relative to the peak bit rate. For high bit rate video of consistent
complexity, 1-pass CBR and two-pass CBR might well look identical. Two-pass is
generally recommended if your production cycle will allow the extra encoding time. At
aggressive bit rates improvements from a single to two-pass are very obvious with
quantization differences sometimes being greater than 2x improvements from single to
two-pass.
Fathom provides more flexibility in encoding passes than tools based on Microsoft’s
codec. For example, Fathom can do a data-rate limited 1-pass VBR, where the WM
SDK-based tools cannot. Also, the two-pass modes work much better in Fathom at HD
data rates. Microsoft’s SDK cannot produce reliable output frame rates in any mode
other than 1-pass CBR, while Fathom can produce output in any of its supported
modes.
TIPS:
When planning on two-pass file encoding, note that any preprocessing stages
(such as format conversion from 10bit 4:2:2 to 8 bit 4:2:0 or scaling) will be
done on each pass. Thus you may want to consider pre-processing your host
video files once, for example converting the content to YV12, before using the
content in Fathom.
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Hardware encoding settings
Scene change threshold
The scene change threshold parameter determines how much a frame needs to be
changed from the frame that precedes it in order to be automatically turned into a
keyframe. Also called an I-frame (or “Independent” frame) a keyframe is a fully selfcontained frame that makes no reference to any other frame. These are the only frames
that can be accessed directly, and so are critical for random access. It is important to
have keyframes throughout the file in order to provide good random access (like fast
forward and rewinding, and skipping to a particular frame). A keyframe also resets the
video, fixing any playback glitches caused by poor performance or missing bits due to a
dropped packet on the network or a scratched disc.
The sensitivity parameter sets a threshold for how much a frame needs to be different
from the previous frame to be made into an I-frame. This is a very useful feature, since
it tends to make the first frame after any video cut an I-frame. This makes random
access to the beginning of scenes and shots very easy.
For most content, the default setting does a fine job of insertion. However, clips
containing several complex transitions, especially cross-dissolves, may not have
significant enough change between any two frames to trigger an I-frame. In those
cases, increasing the sensitivity (by reducing the threshold of change required) can
help. Conversely, very high motion or action content might wind up triggering keyframes
where they are not needed. Rarely is this a serious problem, because a non-keyframe
of a high motion frame generally will not be much smaller than the keyframe.
This value accounts only for “natural” keyframes. See “Max keyframe distance” on page
118 for the other way keyframes can be inserted into the file.
NOTE:
Fathom’s sensitivity slider moves in a different direction from some other tools.
Lower values (towards 0) decrease the threshold and hence increase
sensitivity, increasing the number of I-frames. Higher values (towards 100)
increase the threshold, decreasing sensitivity, and reducing the number of
I-frames
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FATHOM™
Audio compression settings
Audio codecs
Two audio codecs are available in Fathom—Windows Media Audio 9 (also called
“WMA9 Standard”) and Windows Media Audio 9 Professional (WMA9 Pro).
Fathom exclusively uses the standard one-pass CBR audio encoding mode
for WMA. This is not a significant limitation at the high data rates typical of
Fathom encodes.
NOTE:
The sample rate, bit depth, and data rate options are set as a single value,
constrained by the codec choice and number of input channels.
WMA9 Standard — WMA9 Standard is a modern implementation of the very old
WMA audio codec. The files it creates are backward-compatible to very old
decoders. However, that capability is not a huge concern with Fathom encodes,
since any player that supports WMV9/VC-1 also supports WMA9 Pro.
The bigger reason why WMA9 Standard would be chosen over WMA9 Pro is that it
works at much lower bit rates. While the minimum bit rate for WMA9 Pro is 128
Kbps, WMA9 Standard goes all the way down to 8 Kbps. However, at Fathom data
rates, 128 Kbps for audio is generally acceptable.
Fathom does not make WMA9 Standard an option for encoding when more than
two channels are active in the Input panel.
WMA9 Pro— WMA9 Pro is a newer codec from Microsoft that vastly expands on
what was possible with WMA for “high definition” audio applications. WMA Pro will
be used with a substantial majority of Fathom encodes. It does not have much of a
sweet spot overlap with WMA9, given that its lowest bit rate is 128 Kbps. However,
WMA9 Pro is able to do many things that WMA9 Standard cannot, which makes it
much more of a competitor to home theater codecs like Dolby Digital and DTS.
First, WMA supports higher bit depths, up to 24-bit compared with WMA9
Standard’s 16-bit. While few listeners have the ears and sound systems capable of
really taking advantage of more than 16-bit audio, some feel that 24-bit offers
meaningfully better sound, especially with content with an intense dynamic range.
WMA9 Pro also goes up to 96 KHz for sample rate, letting it reproduce high
overtones much better. Again, most listeners on most sound systems will not be
able to hear the difference.
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Sample rate — Sample rate measures how many thousands of times a second the
audio level is measured, described as KHz. The highest audio frequency that can
be played back is half the sampling rate, so a 20 KHz tone requires a minimum of a
40 KHz sampling rate to be encoded. Audio CD runs at 44.1 KHz, and so 44.1 KHz
or higher is considered CD quality.
WMA9 has a maximum sample rate of 48 KHz. WMA9 Pro has a maximum sample
rate of 96 KHz. At the data rates typical of Fathom use, it is rare to need encoding
at less than 44.1 KHz. While values higher than that generally do not improve
quality, lower sample rates can yield a very noticeable reduction in quality.
Bit depth— Bit depth measures how many bits of precision are used to measure
the audio. Higher bit depths provide better dynamic range, improving the quality of
quiet audio in the middle of a loud piece. Audio CD uses 16-bits, and so 16-bit is
considered CD quality. Higher values generally are not perceptible by most
listeners with most audio equipment. 24-bit is very useful for content being archived
or recorded for later processing. Many audio sources are 16-bit, and no advantage
exists to encoding those in a higher bit depth. However, no disadvantage exists
either, and some combinations make it worthwhile. For example, WMA9 Pro
sounds better at 128 Kbps with 16-bit 44.1 KHz source than WMA9 Standard, even
though WMA9 Pro can only use 24-bits in stereo encoding.
WMA9 Standard is always 16-bit. WMA9 Pro can be either 16-bit or 24-bit (WMA9
Pro in stereo can only be 24-bit).
Channels— Channels refers to the number of independent channels of audio you
use. WMA9 can be either mono or stereo, while WMA9 Pro can be stereo, 5.1, or
7.1. Unlike Dolby Digital, the WMA codecs do not provide any explicit way to
encode Dolby ProLogic surround sound information into stereo audio. ProLogic
appears to survive fairly well in WMA Pro mode, but Inlet does not recommend
using WMA Standard with it.
Fathom requires you to use the number of channels of audio you specified in Input,
so if you have set up eight input channels, your output will be constrained to 7.1
options.
Data rate— Data rate determines how many Kbps are spent on audio. Higher bit
rates generally sound better, up to a certain point. Both WMA codecs constrain the
available data rate options based on the sample rate and number of channels
selected. WMA9 in particular does not give any modes that are likely to sound
bad—even the lowest data rate for any particular combination of channels, bits,
and sample rate will not sound noticeably degraded to the typical casual listener.
In most encodes, audio takes up only a small portion of the total bit rate compared
to video. Because of this, it is rarely useful to try to save bits by reducing audio data
rate to the point where there is an audible degradation in quality.
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Video compression settings
Encoding Mode
Four encoding modes are available in Fathom. They are quite different in practice, so it
is important to pick the right one for the right project.
CBR— CBR is short for “Constant Bit Rate.” In a CBR file, the average data rate
and the peak data rate are identical over the buffer duration. So, with a 5000 ms
buffer, any random five seconds of the file will be at or below the average bit rate.
CBR is required for real-time streaming from a Windows Media server, so the
stream will fit within the allocated bandwidth. Before Fathom, CBR was also used
for most WMV HD DVD-ROM titles, due to weaknesses in Microsoft’s WME at HD
data rates. However, Fathom is able to do studio-grade HD encoding in all the
encoding modes, so CBR is not required anymore. If encoding for a disc where the
capacity relative to media length is so great that the average data rate can be as
high as the peak bit rate, there is little reason to use VBR—just use CBR instead.
The most effective way to use Fathom’s Seen by Scene™ (SxS) tool is
on a VBR Constrained encode.
TIPS:
VBR quality— VBR is short for Variable Bit Rate. In CBR the average and peak bit
rate are identical, but in VBR they are not. Three flavors of VBR are supported in
Fathom, all quite different.
VBR Quality does not offer any data rate control. Instead, the quality control sets
the quantization of each frame, and each frame will use as many or as few bits as
are needed, while adhering to a fixed quantization level. So data rate is largely
unpredictable – easy content might use only 20% of the bits as hard content
encoded at the same quality setting. However, the quality of the resulting
compression is predictable
Quality
Quant
Quality
Quant
Quality
Quant
Quality
Quant
100
2
>= 72
9
>= 43
17
>= 15
25
>= 97
2
>= 68
10
>= 40
18
>= 11
26
>= 93
3
>= 65
11
>= 36
19
>= 8
27
>= 90
4
>= 61
12
>= 33
20
>= 4
28
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Quality
Quant
Quality
Quant
Quality
Quant
Quality
Quant
>= 86
5
>= 58
13
>= 29
21
>= 1
29
>= 83
6
>= 54
14
>= 25
22
0
30
>= 79
7
>= 50
15
>= 22
23
>= 75
8
>= 47
16
>= 18
24
Quality-limited encodes are not appropriate for content to distribute to end-users.
Because neither average nor peak data rate can be controlled, playability cannot
be predicted. However, a quality-limited encode can be a great way to encode a
master file for later video processing. Since quality-limited encode uses the
minimum number of bits required to hit a particular quality level, a quality limited file
can be significantly smaller than a bit rate-limited file encoded at a data rate that is
sufficient to provide similar quality with a variety of content. You can also use a
quality-based encode to determine the worst case files size for a given quality level
or to examine a potential quality setting to be used in a subsequent CBR or VBR
Constrained/Unconstrained encode.
VBR constrained— VBR Constrained is the primary and recommended mode for
most encoding that uses Fathom targeting applications that do not require a fixed,
tight bit rate control, such as live transmission or streaming. In VBR Constrained,
both an average and a peak bit rate are specified. The average data rate
determines how big the file is going to be, and hence how long it will take to
download, or how much disc space it will take up. The peak bit rate determines
how much CPU power and data transfer speed is required to play the file back. The
two parameters are quite different; peak is determined by the playback platform
and average is determined by the media capacity. When encoding different length
content for a fixed-size disc, the average data rate will go down as the media
duration gets longer, but the peak data rate will be fixed.
Note that the peak is a maximum constraint – it is perfectly normal for a file to be
generated where the highest bit rate spike is below the specified peak, especially if
the peak is a lot higher than the average.
VBR unconstrained— VBR Unconstrained is the same as VBR Constrained, but
without any limit on peak bit rate. This is not an appropriate mode for most projects;
for highly variable content it can produce high and unpredictable data rate spikes.
There is no real advantage to this mode, and no particular reason why you should
use it instead of VBR Constrained with a high peak.
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Buffer modeling
Both Fathom and Semaphore display buffer fullness (BF) values. BF is an element
optionally present in simple and main profile VC-1 I-picture headers. However, these
applications ignore that value and automatically compute a BF value for each frame (not
just I frames) based on the bit rate and buffer size of the encoded file. This is also true
for advanced profile VC-1 files. The BF represents the value of buffer fullness (as a
percentage of the buffer size) at the encoder (not decoder), and will be in the range of 0
to 100, inclusive. A value of 100 indicates the encoder buffer is full, and a value of 0
indicates the encoder buffer is empty.
CBR and VBR-Constrained encoding modes both utilize a buffer model to control bit
rate. WME exposes the buffer size through the parameters of buffer duration in
milliseconds. For similar reasons, Fathom does this as well. The actual buffer size in
bits is equal to the buffer size times the bit rate. So a buffer size of 2000msec and a bit
rate of 8 Mb/sec yields a buffer size in bits of 16Mb.
Fathom’s implementation of VBR constrained and CBR are such that they keep this
buffer fullness value under 100%. Thus, when measuring the bit rate produced by
Fathom, it is important to understand that there variances can occur above or below the
target/peak bit rate as long as the buffer fullness being modeled does not exceed 100%.
Codec: main profile versus advanced profile
Two profiles of VC-1 are supported by Fathom. A third profile in the standard, called
Simple Profile is meant for low-bit rate applications outside of Fathom’s target market.
Main profile— The Main Profile is virtually identical to the Windows Media Video 9
“standard” codec. It provides good compression efficiency for typical uses of
progressive scan content. It is considered easier to decode than the Advanced
Profile, and is appropriate for applications targeting playback on today’s computers.
Advanced profile— Fathom is the first professional-grade VC-1 Advanced Profile
encoder. While Microsoft has made available an initial version of the encoder in
their Windows Media SDK 9.5, it is quite limited (for example, it only supports 1pass CBR encoding). Microsoft designed the WMV9/VC-1 Advanced Profile (AP)
codec to provide improved performance in traditional video applications.
The biggest enhancement in Advanced Profile is much more advanced interlaced
encoding. This enhancement is not relevant to Fathom, of course, which supports
only progressive output. Most HD content is originally produced as progressive, so
this is not a significant limitation for most projects.
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Advanced Profile does offer some other tweaks to improve compression efficiency,
especially at lower data rates. However it is quite a lot more complex for CPUs to
decode, and requires the relatively recent Windows Media Player 10 running on
Windows XP. Most HD WMV authoring for computer playback should target Main
Profile for the time being. However, Advanced Profile support is mandated in both
HD disc formats, and so can be used safely there.
The Advanced Profile is also the only VC-1 profile that can be used to create video
elementary streams that can be embedded inside MPEG-2 Transport Streams. The
Fathom software has a utility that can convert VC-1 AP files to video elementary
files. If you are creating content targeted at HD-DVD authoring, you will want to
utilize the Advanced Profile encoding mode.
Frame rate
Typically the output frame rate should be the same as the input frame rate. The only
time Fathom allows you to reduce the input frame rate is with 720p HD-SDI material
(720p50, 720p59.94 and 720p60). The primary purpose of this is to handle 720p24
(p23.976, p25), which is sent over HD-SDI as 720p60. However, you could also use
Fathom to decimate the frame rate of 720p60 down to 720p30 (or p50 down to p25).
Reducing the frame rate can produce a better quality per frame at a given bit rate but at
the expense of less smooth motion. So at a given bit rate, fast sports action will look
smoother at 720p60 than at 720p30 although the quality per frame of 720p30 will be
better than 720p60. The trade off between frame rate and quality can be subjective and
you may wish to experiment with it.
When converting from interlaced video, a frame rate of twice the input frame rate can be
used, to turn each interlaced field into a progressive frame, preserving the full motion of
the source. However, unless you are increasing your source bandwidth this requires a
lower frame size. Thus 1920x1080i30 (30 frames/sec or 60 fields/sec) can become
1280x720p60. The former only has about 12.5% more pixels/sec than the latter. Given
the choice of a higher frame rate or a higher frame size, it is generally better to opt for
higher frame rate. For example, fast sports action will look better at 720p60 than at
1080p30.
Max keyframe distance
The maximum keyframe distance determines the maximum distance between I-frames
(A.K.A. keyframes). When no “natural” keyframes have been inserted because motion
exceeds the threshold set in the scene change threshold for the duration of the Max
keyframe distance value, the next frame will be made a keyframe. Natural keyframes
reset this “counter” so that if natural frames occur every two seconds, a max keyframe
dist of 3000 will never actually come into play. For Fathom data rates, 5000 ms (or at
least one keyframe every 5 seconds) is the maximum value you’d want to use. For HD,
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every 2 seconds is a good option. IPTV often users lower values yet, in order to speed
up channel switching performance and HD DVD using 500ms.
Target bit rate
The target bit rate specifies, of course, the average bit rate of the video. Note that this is
for the video only—for WMV files, you’ll need to add the audio data rate to determine
the total data rate for the file, and hence the total size of the file. The target bit rate and
the buffer size in msec is used to set the encoder’s buffer size in bits for CBR encodes.
Note that these are measured in Kilobits per second. (See “A Note on Terminology” on
page 101 for more information.)
Peak bit rate
The peak bit rate determines compatibility of the compressed content. A too high peak
for too long can overwhelm the processor for decoding, or exceed how fast a disc can
transfer bits. A peak bit rate is always defined with the peak buffer size—one does not
mean much without the other. Thus, like the target bit rate in CBR encodes, the peak bit
rate used in VBR constrained encoding is a factor in setting the peak buffer size in bits.
The following table shows some sample bit rates for typical applications:
Usage
Frame Size
Average Bit rate
Peak bit rate
WMV-HD DVD-ROM 1080p
1440x1080
18 Mbps
30 Mbps
WMV-HD DVD-ROM 720p
1280x720
10 Mbps
18 Mbps
HD-DVD or Blu-ray
1920x1080
12 Mbps
30 Mbps
SD DVD-ROM
640x480
3 Mbps
5 Mbps
SD IPTV
528x480
1.5 Mbps
2.2 Mbps (CBR)
Peak buffer size
One last facet of peak data rates is the peak buffer size, which is the window over which
the average is determined. For example, a peak bit rate of 1000 Kbps with a buffer size
of 5 seconds means that any random 5-second chunk of the file wouldn’t exceed 1000
Kbps.
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Longer buffers give the encoder more flexibility in encoding, since it will be able
to move bits around within the file over a bigger range, helping improve average
quality.
TIPS:
There are drawbacks to longer buffers though. For example, in real-time
streaming, a longer buffer will increase both startup and random access latency,
increasing the worst-case delay after when a user attempts to jump to a
particular point in the file and when video playback starts again. For file-based
playback, a longer buffer can overwhelm the decoder, where a peak at the same
data rate but at a shorter duration would not.
For hardware devices, the maximum buffer size will normally be defined as part of the
specification.
The unconstrained and quality VBR modes do not have a peak buffer size.
Quality
The Quality parameter in Windows Media encoding can be quite confusing. It does
many different things, depending on the encoding mode, and whether hardware or
software encoding is in use.
Quality for software encoding— Quality for software-based CBR is changed by
setting the Video Smoothness parameter. This sets the emphasis between
maintaining the target frame rate and maintaining image quality and is the same
role it performs in Windows Media Encoder. Essentially, the slider sets a maximum
quantization (and hence minimum quality) that will be used for a particular frame. If
the frame needs more than its allocated bits to meet the quantization threshold, it
will use more bits. If this goes on for long enough, frames will be dropped in order
to keep the image quality higher. Of course, this will reduce temporal quality.
Quality in CBR, VBR Constrained/Unconstrained Hardware Encodes— In tools
that use the stock Windows Media codec from Microsoft, the bit rate constrained
VBR modes do not have a quality value at all. In Fathom, quality can be used with
CBR and Constrained and Unconstrained VBR to set a minimum quantization, and
hence maximum quality. This capability is useful when the encoder might give too
many bits to complex portions of the video, saving bits for the easier parts.
In most cases, you will not have to use this setting. Do not use lower values. The
default of 95 is appropriate for most content, and lower values run the risk of
producing an out-of-spec file or undesirable quality.
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NOTE:
Adjusting the quality setting will display the minimum quantization value
that Fathom will attempt to reach while encoding. With quantization a
lower number will produce higher quality encodes in general. However, it
is not a recommended practice to set the quality to 100 resulting in a
minimum quantity of two for lower, or aggressive encoding data rates.
Quality in VBR Quality— Terminology can get a little confusing here—the quality
slider in VBR Quality mode specifies the quantization to be used, and hence
implicitly the quality. This is the only control other than frame rate that VBR Quality
encodes have. The Fathom User’s Guide has a table showing the mapping
between VBR Quality and the internal quantization value used for that setting.
Encoding parameters
Most of this document discusses compression in a general sense. But as we look
toward particular deployment environments, we often get very specific parameters for
encoding.
DVD-ROM — The most common use of VC-1 for discs today is for DVD-ROM titles
designed for computer playback. Since computers vary so widely in performance,
there are not hard and fast rules to define what works—the simpler the encode, the
more machines it will play back on. In general, decoder requirements are
proportional to the pixels per second (so height x width x fps) and to peak data rate.
To play back on a typical high-end system of a few years ago, 1440x1080
maximum resolution at 24 fps with a peak data rate of 10 Mbps is a good start.
Today’s faster computers, especially if they are running Windows Media Player 10
with a video card that supports WMV9 hardware decode, can handle full
1920x1080 and peak bit rates of 15 Mbps.
DVD-ROMs have historically been one-pass CBR encoded, due to the limitations of
WME. With Fathom, two-pass VBR can now be used, allowing higher quality and
much more media on a single disc. Encodes are typically two-pass VBR
constrained, as that mode provides the best control on playback performance and
file size. However, CBR encodes can be used if there is so much capacity on the
disc that the average bit rate wouldn’t be significantly lower than the peak.
Many of the WMV HD DVD-ROM titles released so far include two versions of the
content—one at 720 (really, 1280 width by the correct height for the image aspect
ratio), and the other at anamorphic 1080 (1440 wide by the image aspect ratio
correct height).
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IPTV — IPTV encodes need to use CBR encoding, since they use real-time
streaming. Since IPTV is typically quite bandwidth constrained, two-pass encoding
is always recommended.
Different IPTV installations can use very different options for buffer size and
keyframe distance. For simulated live channels where channel-switching is
important, having a keyframe every half-second, with a one second buffer is typical.
But on-demand content where fast channel switching is not required can have
much more flexible options, up to 10 seconds for each.
HD Discs — VC-1 Advanced Profile is a mandatory codec for both the HD DVD
and the Blu-ray HD formats.
Interlace processing
While Fathom only outputs progressive video, it can accept interlaced content and
deinterlace it via a variety of methods, described in the following paragraphs.
None
Click None if you do not want to deinterlace the video. This setting should be used for
any progressive source, be it true progressive frames or PsF with stacked fields.
Deinterlace
Deinterlace converts two interlaced fields into a single progressive like frame of video.
Inverse telecine
Inverse Telecine will take content encoded to 30i with 3:2 pulldown, and convert it back
to 24p. While most 24p HD is transferred as 24p, this capability is useful when using
Fathom with SD sources that have 3:2 pulldown. Unless you happen to know the field
order of your source, pick Auto mode that will detect it automatically.
NOTE:
Inverse Telecine is available only in Software encoding mode, so you will
need to uncheck the Hardware encoding option in Compression. For
many reasons, it is much more efficient to provide native 24p content to
Fathom.
Maintain interlacing
Maintain Interlacing will pass the interlacing through without modification. This is not a
good choice, since the VC-1 codec does not do well with encoding interlaced content
when in the progressive mode Fathom uses. If for some reason you want to use it, pick
the field order (top or bottom) that matches your source.
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Complexity
Encoder complexity tells the encoder how hard to work to gain maximum compression
efficiency. For complex content, higher encoder complexities will yield better quality at
the same data rate. Simple, static content will not show nearly as much of a difference.
The default of 3 is a good starting point. Slide the bar to 4 when you care about
maximum quality. Depending on your content you may see difference in quality and/or
resultant bit rate at different complexity settings. For example, between complexity level
3 and 4 you may not see a visual impact but you may notice a few percent reduction in
file size.
The complexity control in Fathom determines how hard the encoder works to gain
maximum quality. With the software encoder, within the range of 0–4, there is about a
20% improvement in compression efficiency, and about an 8x difference in speed. The
differences in speed for hardware encoding are much less.
Advanced Video Processing Filters
Adaptive Deadzone
The adaptive deadzone filter in Fathom 2.5 is useful when attempting to achieve nice
looking images at lower bit rates. By selecting the adaptive deadzone filter when
encoding, Fathom 2.5 will selectively attempt to remove coefficients at high frequencies
without the perceivable loss of image quality. The filter essentially keeps all lower
frequency coefficients and places a clamp on the amount of higher frequency
coefficients to be used in an encoded frame. While enabling this filter can especially
help in achieving very low to low bit rates for an encoding with a minimal affect on the
overall quality, scenes with high motion and action may be adversely affected.
Non-uniform Quantizer
Enabling the non-uniform quantizer filter in Fathom 2.5 effects when and where the
quantization level hits zero by pushing all of the quant values down by one. The nonuniform quantizer filter can help in eliminating unnecessary bit coefficients to better
target a specific bit rate. Quality is minimally affected with this filter enabled, and is only
enabled when and where the quantization value level reaches above 9 in an encode.
In-loop Deblocking
Fathom 2.5 can enable an adaptive in-loop deblocking filter to help smoothen the
boundaries of encoded macroblocks when using an aggressive bit rate on complex
material. The in-loop refers to when previously deblocked image data, in addition to
being displayed, is actually used as part of the decoding of future frames. Implementing
the deblocking filter in-loop can increase image quality, especially at low bit rates—but it
also increases computational complexity. This is because the deblocking is not optional
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and is forced upon play back. Thus, a well-equipped system is required for flawless play
back of an encode with in-loop deblocking enabled. In addition, using the in-loop
deblocking filter will slightly soften the overall sharpness of the image.
Deblocking can be very decode intensive, which puts an extra burden on
the decoder's processor requirements.
NOTE:
Hardware Processing
The Hardware Processing mode sets a noise reduction filter.
None leaves the video alone
Normal uses a 3x3 filter
Smooth uses a 5x5 filter
Dynamic enables a 5x5 filter on scenes where Fathom believes dropped
frames could occur if the parameters set for an encode are too aggressive.
Content that is not appreciably noisy should use None. One of the big advantages of
VC-1 over competing codecs is that it can do an excellent job of retaining the texture of
film grain at HD data rates. Do not use this noise reduction option unless you really
want to remove that noise.
That said, reducing noise will make the video easier to encode, reducing artifacts at
moderate and low data rates. If the source is giving distracting artifacts within the target
parameters, using Normal processing can significantly reduce artifacts, with the
sacrifice of some detail. It is a good tradeoff to make in many cases.
The Smooth mode is slower and quite aggressive, especially at SD frame sizes. It
should be used only with really noisy source, like a capture from VHS.
Dithering
When working with 10-bit source files, or with HD-SDI inputs, the Dithering mode will be
available in Fathom. Since Fathom output is always 8-bit, 10-bit sources need to be
converted to 8-bit. Dithering is a general technique to reduce data from one format to
another. It is also called “error diffusion” with the idea that instead of just throwing out
the extra data, it will be spread between adjacent pixels. This approach will produce
higher quality and less banding, especially with smooth gradients.
HD-SDI is natively a 10-bit per channel format. VC-1 is an 8-bit per channel format.
Those extra two bits normally hold visual information, and so you will want to take
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advantage of that data. The process of converting to the lower bit depth is called
“dithering” and consists of optimally spreading the extra data from those bits across
multiple pixels in the output, to preserve as much of the original dynamic range as
possible. Doing this poorly (for example, by just ignoring the two extra bits) can result in
obvious banding where there were gradients in the original. Doing this well will preserve
the smooth look of gradients in the original.
One irony is that most of the HD tape formats are themselves 8-bit. Unfortunately, there
is no way to get the native 8-bit data off some of those formats. Instead, the deck uses
dithering to convert from the native 8-bit to the 10-bit output for HD-SDI, and then you
will need to reverse the conversion on re-encoding.
None
The None option is the same as Truncate, explained in the following paragraph.
Truncate
The truncate mode simply discards the two least significant bits. This capability is
appropriate when 8-bit data is packed into 10-bits, with the extra two bits left blank.
Ideally, this situation will not occur too often. Even though the 8-bit tape formats are
internally 8-bit, they using dithering on output to fill in the extra 2 bits, so truncate is not
appropriate there. And for file-based workflows, if only 8-bits of data are there, it is
better just to use an 8-bit codec.
If you get 8-bit video packed into 10 bits, truncate is the idea mode.
Gaussian
Gaussian, which essentially uses a Gaussian blur to spread the extra 2 bits around
neighboring pixels, is mathematically the best solution when there are 10 real bits of
data. However, it is quite slow, and in extensive testing has not shown any quality
advantage over triangle dithering for real world content.
Triangle
Triangle is the optimum mode in most cases. It is much faster than Gaussian, while
offering effectively identical quality. And even if 8-bit data packed in 10-bit is given to it,
the quality hit is generally miniscule, and never substantial. Triangle is the default mode
for live SDI input.
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Quantization
Quantization is a core compression technique. You should be aware that it is a
significant factor that irrecoverably removes information from your source video.
Quantization can be effective because the human visual system is more sensitive to low
frequencies than high frequencies. Thus, you can use quantization to remove
information that we may not notice in the first place. Using quantization, a substantial
amount of compression can be applied to most images without any visible loss. But
below a certain point, the compromises start to become visible
Each frame in VC-1 has a particular quantization level, ranging from 1-31, with 1 as the
highest quality, and 31 as the lowest. Even within a frame the quantization level can
vary. Typically, a quantization below 8 does not look appreciably compressed, but
values above 8 can look increasingly bad. These compression artifacts caused by high
quantization typically fall into two categories: blocking and ringing.
Blocking is when the underlying 8x8 structure of the codec reveals itself. This can often
been seen in areas of smooth transition, like a sunset.
Ringing is when very high frequency data, like sharp edges, does not have enough bits
to encode it precisely enough, leading to distortions around the edge. Another name for
ringing is mosquito noise, since it looks like buzzing around the edges. This is most
noticeable with text, like white text on a black background.
NOTE:
Post-processing can be applied on decode, which tries to hide the blocking and
ringing. In Windows Media Player, this happens automatically if there is enough
CPU power left after the basic encode (hence rarely or never at HD resolutions,
but often at SD resolutions). Fathom’s preview is without post-processing, so that
is only the worst the video will look— it may turn out much better.
The main Fathom application or the standalone software analysis application
Semaphore™, can analyze your Fathom-encoded WMV files, showing how quantization
changes over the file. One of the biggest uses of this analysis is to find spikes in
quantization, since those are the points in the file most likely to have problems. This
capability allows you to jump to the most potentially problematic parts of the clip for
testing, instead of having to watch the whole thing through after every change in
compression. Coupled with the Seen by Scene re-encoder, Fathom provides very fine
control of quantization, and hence of quality.
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11
Appendix B: DeckControl
User Guide
B
When you use the VTR Control on the Job Parameters Input screen, you are using
DeckControl software from Pipeline Digital. This appendix contains information on
configuring and using DeckControl.
Configuring DeckControl
The Pipeline DeckControl Setup dialog is where you configure Deck Control for your
computer system and videotape machine. If there is a successful connection to the
deck, DeckControl maintains its own preference file called “swimwr.prf” in the Windows
directory.
After a successful connection, the DeckControl Setup dialog opens.
Figure 61: Pipeline DeckControl Setup dialog
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VTR and port control selection
You can select between COM1 through COM9 to communicate with the VTR. Select the
port that you want to use in the popup menu. Make sure that the port you have selected
is not in use or being shared. Most importantly, ensure that the comm port exists in your
system. Please refer to your operating system settings if you are not sure. If you select
a comm port that does not exist, unpredictable results may occur.
Protocol
Supported protocols are:
Sony RS-422 (UVW-1800) and VTRs that emulate this protocol
Sony RS-232 (SV0-2100) and VTRs that emulate this protocol
Sony RS-232 UVW (UVW-1400) and VTRs that emulate this protocol
Sony VISCA (Vdecks, or LANC machines hooked up to a Sony Vbox)
Addenda RS/4L (and LANC decks hooked up to the Addenda RS-422 to LANC
interface)
Panasonic RS-422 (AJ-D750, AG-DS 850)
Panasonic RS-232 (AJ-D230 with AG-AI-232TC adapter) and any VTR that
emulates this protocol
JVC RS-232 (SR-365U) and any VTR that emulates this protocol
Use 19.2k baud for RS-232
This feature lets you select 19.2K Baud for Sony RS-232 decks. This is intended for
VTRs that are capable of high speed communications, and will improve editing accuracy
during print-to-tape. Make sure you set the matching rate at your deck. Most RS-232
VTRs default to 9.6K baud.
Use VTR'S internal cue
Checking this box lets you select the VTR’s internal cueing method. High-end decks
usually do not need to use this mode. It is primarily included for the benefit of those
VISCA and RS-232 decks that sometimes struggle trying to cue to a time code number.
You may see picture during the shuttle to your cue point, but it will take significantly
longer to reach that point. Over a period of time, there is the possibility of excessive
tape and/or head wear. Pipeline recommends using this only if your deck has difficulty
cueing to a time code number.
Enable assemble
Not supported at this time.
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Time control
Time source
LTC—Longitudinal Time Code is recorded on its own track, adjacent to the
video. This is the default time source. Selecting LTC will request interpolated
LTC from the VTR.
LTC + VITC—LTC+VITC will pass a request for both LTC and VITC, letting the
VTR decide which time source it can supply. This is a good choice for the SVHS, RS-422 VTRs that offer VITC.
If the VTR supports VITC, then Corrected LTC (LTC + VITC) will be returned.
Otherwise, LTC corrected by control track will be used. But beware: in some
cases the VITC may be different from the LTC! If you have search problems,
try another time source, like LTC.
Timer—Timer is also known as the Control Track counter. This is used for
VTRs that do not have time code capabilities, or source tapes with no time
code. Control track accuracy varies from deck to deck, and may slip after
prolonged tape shuttling.
Pipeline does not recommend using VISCA decks in timer mode. In Timer
mode, VISCA decks only send hours, minutes, and seconds— no frames are
sent.
DVTime—While Sony DV camcorders have LANC protocol ports, a Sony DV
camcorder's time code is NOT the same as Hi8 "RC" time code: RC time code
is non drop-frame, and DVTime is drop-frame (NTSC-only). Select DVTime
when using Mini DV tapes that originated in Sony (and compatible)
camcorders. DVTime is only available when you select VISCA or ADDENDA
protocol.
Time base
Choose the time base for your device here. Deck Control supports the following time
bases 30 FPS (NTSC Drop Frame and Non-Drop Frame), 25 FPS (PAL / EBU), and 24
FPS. Make sure that the time base you have selected matches your device or the
resultant time code may be incorrect.
Reset timer
If you are in Timer mode and have this box checked, upon starting up Deck Control, this
will reset the VTR’s timer to zero (00:00:00). One reason to do this is to set a reference
for the VTR. By rewinding the tape, then resetting the timer, you have a reference point
that will be accurate to within a few seconds throughout the tape.
129
Timing
Time code offset
Calibrating Time Code Offset—When capturing video to disk with certain video
digitizers, the time code may not be recorded accurately. That is, the time code
numbers in the captured clip might not be correctly aligned with the time code numbers
on the videotape. If you need to correct any time code errors, you may do so in the
DeckControl Options dialog.
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FATHOM™
12
Appendix C: AviSynth and Fathom
c
Introduction
AVISynth is a powerful tool for video post-production. It provides a multitude of methods
for processing videos. AVISynth works as a frameserver, providing instant processing
without the need for temporary files.
AVISynth itself does not provide a graphical user interface (GUI) but instead relies on a
script system that allows advanced video processing. While this may at first seem
tedious and unintuitive, it is remarkably powerful and is a very good way to manage
projects in a precise, consistent, and reproducible manner. Because text-based scripts
are human readable, projects are inherently self-documenting. The scripting language is
simple yet powerful, and complex filters can be created from basic operations to
develop a sophisticated palette of useful and unique effects.
Fathom 2.5 can recognize AVISynth scripts (.avs files) to further enhance Fathom’s
capabilities, features and overall value. Such possible implementations of using
AVISynth scripts include:
•
Inverse telecine
•
Source file concatenation
•
Noise reduction
•
Advanced resizing filters
•
Image color correction
To use AVISynth with Fathom (2.5 required), first install AVISynth and the appropriate
filter(s) to enable within Fathom. AVISynth is available at www.avisynth.org, or from
the Fathom 2.5 or higher installation CD and can be installed at the same time of
Fathom installation. Also included on the Fathom 2.5 CD are a set of filters to enhance
Fathom 2.5’s capabilities.
Fathom will directly recognize and handle most AVISynth .avs scripting files, making the
integration of Fathom and AVISynth as simple as using a file-based asset.
To use Fathom and AVISynth, follow these steps:
1. Install AVISynth either during Fathom installation or from the Fathom CD
(Fathom2.5 CD\Extras\AVISynth [version 2.56 or later required]).
131
2. Write the AVISynth script to use in Fathom. A few example scripts have
been provided on the CD (Fathom2.5 CD\Extras\AVISynth\Scripts).
NOTE:
If you are using an Inlet-provided decoder, such as with QuickTime and
GXF files, you will need to use some special AVISynth commands to get
proper recognition with Fathom. (If you are not using an Inlet decoder,
such as when using a standard uncompressed AVI file, you do not have
to enter a special tag.)
You can write a script by opening a NotePad or WordPad document and
entering the AVISynth commands, then saving it as an .AVS file.
Additionally, Fathom 2.5 includes a new Batch Utility app in which you
can open, edit, write, and save AVISynth scripts. Common scripts can
also be easily found by doing a simple Web search.
3. Select the .AVS file in the Fathom Input pane as you would a file-based
source. 0.
Example scripts
Using a single AVI file without any preprocessing
DirectShowSource("D:\AVI\AVI_Source_File.avi")
Using an AVI file and applying a contrast/brightness filter:
Tweak(cont=1.2,sat=1.0,bright=10,hue=0)
Using the same AVI file with a fast resizing filter
BilinearResize(528,480)
Using the same AVI file with a more advanced resize and crop
filter
Crop(8, 8, -8, -8)
LanczosResize(640, 360, taps=4)
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FATHOM™
Joining (concatenating) two AVI files
clip1=DirectShowSource("D:\AVI\AVI_Source_File.avi")
clip1=DirectShowSource("D:\AVI\AVI_Source_File.avi")
#Do an “aligned” join
clip1 ++ clip22
Using two GXF files (via Inlet’s GXF decoder)
# Test GXF inverse telecine encode, joining files
clip1=DirectShowSource(MakeGXFGraph("D:\GXF\1.gxf"),pixel_type="YUY2")
clip2=DirectShowSource(MakeGXFGraph("D:\GXF\2.GXF"),pixel_type="YUY2")
# Do an "aligned" join
clip1 ++ clip2
AssumeTFF()Telecide(guide=1,post=2,vthresh=30)
Decimate()
Crop(,0,32,0,0)
LanczosResize(528,480)
ConvertToYV12()
This script is performing 4 functions in the following order:
•
It concatenates two 720x512 telecined GXF files
•
It applies an inverse telecine from 29.97fps to 23.98fps
•
It crops the image 32 pixels from the top
•
It scales the output to 528x480
Recommended AviSynth filters
These filters are included with the Fathom install unless otherwise noted.
For this…
Use this filter…
For resizing
BilinearResize(w,h) - for downscaling (fastest)
BicubicResize(w,h) - for upscaling
LanczosResize(w,h, taps=x) – for slower but best downscaling {taps
indicates search distance to be used}
For file joining:
clip1=DirectShowSource(“file1.avi”)
clip2=DirectShowSource(“file2.avi”)
Do an “aligned” join
clip1 ++ clip2
133
For this…
Use this filter…
For Image
adjustments
Tweak(cont=1.0,sat=1.0,bright=0,hue=0) {default, no change settings}
For inversetelecine
Decomb ( http://neuron2.net/decomb/decombnew.html ):
Telecide (guide=1, post=2, vthresh=30) {this may differ depending on
telecine process used in source}
For smoothing
Deen ( http://ziquash.chez-alice.fr/ )
For sharpening
Msharpen ( http://neuron2.net/msharpen/msharpen.html )
For temporal
noise reduction
STMedianFilter ( http://home.comcast.net/~trbarry/ )
For deinterlacing
TomsMoComp ( http://home.comcast.net/~trbarry/ )
For grain
reduction:
Deen ( http://ziquash.chez-alice.fr/ )
For more filters:
http://www.avisynth.org/warpenterprises/
Known issues/caveats with AviSynth and Fathom
It is always best to use the command “DirectShowSource(“”)” for serving files
with AVISynth into Fathom.
The scripting MakeGXFGraph or MakeQTGraph must be used when using
AVISynth to serve Quicktime or General Exchange Format files into Fathom.
This is because these file types are not generally supported by DirectShow
plugins and therefore Inlet’s included decoders for each format are used to link
with DirectShow. Proper usage for a QT file with AVISynth would be:
DirectShowSource(MakeQTGraph(”D:\Sources\example.mov”))
It is always best to use the command “seekzero=true” when serving MPEG-2
files or any other similar format that does not offer proper seeking on the
decoding. An example of this usage would be:
DirectShowSource(“D:\Sources\example.mpg”, seekzero=true)
When using any script that will filter or pre-process the image, it is best to
include the scripting “ConvertToYV12” after the sourcing line.
If you will be using AVISynth to serve a file into Fathom, and you will be
scaling the source to a different output resolution upon the encode, it may be
best to apply the scaling in the AVISynth script. This will allow Fathom to
concentrate only on encoding and therefore no cycles will be taken away for
134
FATHOM™
scaling during encoding. Note however, that scaling with AVISynth may put a
greater hit on your computer’s main processor(s).
A great web site for the explanation and usage of various AVISynth filters is
located at:
http://www.animemusicvideos.org/guides/avtech/avspostqual.html
135
136
FATHOM™
13
Glossary
G
Microsoft Corporation provides an excellent on-line glossary of video processing terms
at:
http://www.microsoft.com/windows/windowsmedia/knowledgecenter/glossary.aspx
The following glossary covers terms mentioned in this manual, and is adapted from
several online sources.
Term
Definition
.avi
The file name extension for a video file in Audio Video Interlaced (AVI)
format.
.avs
The file name extension of an animation file
.gxf
The file name extension of a General CADD Pro Font file
.mp3
The file name extension of an audio file in MPEG format.
.prx
The file name extension of a Windows Media Profile file.
.trp
The file name extension of an mpeg-2 transport stream
.ts
The file name extension of a transport stream MPEG-2 video stream
.wav
The file name extension for a sound file in WAV format..
.wma
The file name extension of an audio file in Windows Media Format.
.wmv
The file name extension of a video file in Windows Media Format.
.yuv
The file name extension of a Color Space Pixel Format file
Audio Video
Interleaved
(AVI)
Digital media file format for storing sound and video.
bit rate
Number of bits transferred per unit of time, typically expressed in bits
per second.
137
Term
Definition
buffer
Area of computer memory that briefly holds data before that data is
used on the receiving computer. Buffering protects against the
interruption of data flow.
caption
This text accompanies images or videos, either as a supplemental
description or a transcript of spoken words.
codec
Abbreviation for compressor/decompressor. Software or hardware
used to compress and decompress digital media.
compression
Process for removing redundant data from a digital media file or
stream to reduce its size or the bandwidth used.
constant bit rate
(CBR)
A data stream whose bit rate remains nearly uniform for the duration of
the stream.
differentials
Indicators of transitions between compressed frames.
encode
Converting audio and video content to a specified digital format.
encoder
Device that converts live or prerecorded audio and video content to a
specified digital format. Content is usually compressed during
encoding. Windows Media Encoder is an example of an encoder.
frame
One of many sequential images that comprise video.
frame rate
Number of video frames displayed per second. Higher frame rates
usually produce smoother movement in the picture.
interlace
To display a video frame in two fields. One field contains the even lines
of the frame; the other field contains the odd lines. During playback,
the lines in one field are displayed first; the lines in the second field are
displayed next.
inverse telecine
Process that removes the frames that were added when 24-fps film
was converted to 30-fps video.
key frame
Video frame containing all the data needed to construct an image
without reference to previous frames. Also known as an I-frame.
metadata
Information about digital media content such as the artist, title, album,
producer, and so forth.
138
FATHOM™
Term
Definition
multi-channel
audio
An audio reproduction system that processes several, typically more
than two, channels of sound. For example, 5.1 multi-channel audio
refers to a surround sound system in which there are five primary
channels and a subwoofer channel
multiple bit rate
(MBR)
Data stream in which the same content is encoded at several different
bit rates to optimize content delivery.
Progressive
Segmented
Frame (PsF)
Standard frame types are p - progressive, i - interlaced, and PsF progressive segmented frame. A PsF frame is a progressive frame that
transmitted as two interlaced fields. This increases slow frame rates,
such as 24fps, above the human flicker perception frequency. 24 fps
becomes 48 fps.
telecine
Film-to-video conversion system that adds frames to video to
compensate for the differences in frame rates between film and video.
timeline
The area of the user interface that shows the timing and arrangement
of frames, files or clips that make up a project.
variable bit rate
(VBR)
Data stream in which the bit rate fluctuates, depending upon the
complexity of the data.
WAV
Digital media file format for storing sound.
Windows Media
Audio (WMA)
Audio file or stream in Windows Media Format. The audio content of
the file or stream is encoded with one of the Windows Media Audio
codecs.
Windows Media
file
A file that contains audio, video, or script data. The content of the file is
encoded with one of the Windows Media codecs.
Windows Media
Format
Format of a digital media file or stream that was encoded with
Windows Media codecs.
Windows Media
Video (WMV)
Video file or stream in Windows Media Format. The video content of
the file or stream is encoded with one of the Windows Media Video
codecs.
Windows Media
Video 9
Advanced
Profile (WVC-1)
A codec that offers support for interlaced content.
139
140
FATHOM™
14
average bit rate, 65
Index
I
automatically display, 13
AVI files, 24
opening, 23
AviSynth, 133
key frame, 140
B frames, 66
keyboard shortcuts
Batch Job Utility, 76
Video Analysis, 60
buffer fullness, 72
layout, 13
Buffer Fullness, 66
merge
CBR, 72
scenes, 74
compare
Metadata, 37
colors, 66
P frames, 66
Complexity, 42
P Type, 65
Current Values window, 75
Pipeline DeckControl, 30
Dithering, 43
PsF, 29, 141
Dropped Frames, 67
quantization level, 51, 65
ES file, 84
queue
FJT files, 44, 45
procedure, 49
frame rate, 96, 140
reorder jobs in, 49
Frame Size, 64
QuickTime files, 25, 32
Hardware Acceleration, 40
scene, 15
HD SDI, 24, 86, 96
creating, 69
I frame, 40, 70, 84, 140
defined by I frame, 71
scene defined by, 71
Scene change threshold, 40
I frames, 66
SD SDI, 24, 86
I-Frame, 40
Session Directory
InletASFDump, 84–85
procedures, 15–16
Interlace Processing, 42
template
job
job parameters saved with, 44
defined, 3
trick stream, 80
queuing, 49
Two-pass encoding, 40, 106
remove from queue, 49
two-pass job, 55
reorder in queue, 49
two-pass jobs
template, parameters saved in,
stopping, 50
44
upgrades from version 2.1, 2
two-pass, 55
VBR Constrained, 72
Job Parameters
Video Analysis
141
keyboard shortcuts, 60
Watch Folder, 56
video compression quality, 97–98
watermark, 43
VITC time code, 86
Windows Media Player, 16, 69, 73
VTR
WMV, 141
controlling through Fathom, 29
workspace, 13
142

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Transcription

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