report of the broadcast of the northern lights 2014 - Sky

Transcription

REPORT OF THE BROADCAST OF
THE NORTHERN LIGHTS 2014
CREDITS
The Seventh Framework Programme of the European Union (EU, FP7/2007-2013,
INFRASTRUCTURES-2011-2, INFRA-2011-1.2.1: e-Science environments) has promoted the
broadcast though the GLORIA project – GLObal Robotic telescopes Intelligent Array for
e-science” (Grant Agreement –Number 283783).
In the broadcast has also participated FECYT (Spanish Foundation for Science and Technology,
Ministry of Economy and Competitiveness) under the project "Citizen Astronomy II".
INFRASTRUCTURE
1.- Portal Web Broadcast.
The infrastructure deployed by CanarCloud (www.canarcloud.es) was based on a VMware
vSphere Cluster 5 (www.canarcloud.es/vmware/) on an Intel Nehalem architecture that is
interconnected to a centralized RAID storage system capable of supporting the load of the
several thousands of requests on the website of the broadcast. The infrastructure also deploys
a DNS balancer that allows the interconnection of all web instances, both physical and virtual of
all collaborators, ensuring an equitable load sharing of all website visits among all instances.
Given the high expectations and in order to reduce the time and the transfer rate of the
resources included in the website (logos and static images, javascript and style files, etc ...), a
proxy was implemented to cache the static content in a CDN service by
gloria.cdn.canarcloud.net.
The operation of this architecture was as follows:
●
Requests made by the clients through the web portal of the broadcast should be
minimized. In order to do so, the web portal should be designed to reduce the overall
loading overhead in terms of size (bytes).
● A Load Balancing system to select which server instance will process the client request
within the cluster according to the defined policy.
● The client was served by the server selected by the load balancing system.
TECHNICAL REPORT FOR THE BROADCAST OF NOTHERN LIGHTS OF 2014
Report made by Alejandro Galtier Hernández in the name of CanarCloud (www.canarcloud.es) for GLORIA
Report of the broadcast made by Urko Serrano on behalf of Systemagic (www.systemagic.se) for GLORIA
●
When the client loads the page directly in the browser, the request is handled by
gloria.cdn.canarcloud.net to load static content through the proxy, which provides a
minimum of 3h cache.
Web Collaborators
The project calls for participation of public or private institutions, associations, foundations, etc.
to collaborate in the dissemination via Internet of the broadcasting website (www.sky-live.tv)
in an attempt to prevent technical disruptions in the system due to massive concurrent
requests.
Web Basics Collaborators
In this type of collaboration, the institution, organization, association, etc.. will add at least one
machine to the cluster previously mentioned. This machine (or machines) that are grouped
together will serve the web portal with all the content from the broadcast.
●
●
Consorci de Serveis Universitaris de Catalunya [1 web server] → www.csuc.cat
TOTAL [1 web server]
Advanced Web Collaborators
Collaborating with one or more machines compatible with VMware vSphere 5, with more than
4 GB of RAM, more than 4 cores, 3 or more IPs and a bandwidth of 100 Mbps or more have
collaborated integrating these machines as remote nodes of the cluster.
●
●
●
●
●
CanarCloud [1 cluster vSphere 5 + 2 nodes + 2 VPS] → www.canarcloud.es
Instituto de Astrofísica de Canarias [1 vSphere 5 node + 1 VPS] → www.iac.es
Extremadura Center for Advanced Technologies [10 VPS] → www.ceta-ciemat.es
Galician Center of Supercomputation [2 VPS] → www.cesga.es
TOTAL [15 VPS]
2.- Video streaming.
The live video platform provided by Youtube Live was used for the distribution of the video
signal, generating a live event for each day of the broadcast.
The operation of this architecture was as follows:
Streams Generation
● Greenland - (23 - 25th August 2014) - video stream of the sky (1:00 to 1:30 UT, 23:00
to 23:30 local time from the day before in Greenland, 03: 00-03: 30 CEST , where UT
stands for Universal Time and CEST Central European Summer Time)
o
Every day for an hour, a camera (Canon 5D-MII) is pointed to the sky in order to
transmit a live video sequence of movements of the Northern Lights.
● Iceland - (26 - August 28, 2014) - video stream of the sky (23:30 to 24:00 UT same
local time in Iceland, and 01: 30-02: 00 CEST)
o Every day for an hour, a camera (Canon 5D-MII) is pointed to the sky in order to
transmit a live video sequence of movements of the Northern Lights.
● Timelapse
o Every night during an hour and every minute, the image of the starry sky was
changed to keep the portal of the emission updated. To obtain images, two
Canon 5D Mark II (color) cameras were used with identical lenses (spaced a
minimum of 1 km and up to 50 km).
Live through the portal of the broadcast
● Customers who accessed the portal of the broadcasting (www.sky-live.tv) could find a
playlist with different broadcasts and recordings from previous events as well as the
current live webcast.
STATISTICS
1.- Portal Web broadcast
To obtain statistics of visits of the web portal of the broadcast (www.sky-live.tv), a statistics
collection service of Google Analytics was enabled for global data of the portal. Locally, the
Awstat collector was used to analyze the individual contribution of each collaborator.
The period analyzed includes visits between August 22nd (0h UT) and August 30th (0h UT) in
2014.
Google Analytics
Under this service we can see that in the analyzed period we obtained 32.239 visits and
48.416 page-views, as we can see in the chart below.
Top 10
Country of Origin
Spain
59,45%
Costa Rica
6,63%
Mexico
3,88%
Polonia
3,67%
Russia
2,65%
Turkey
2,58%
Bulgaria
1,71%
Colombia
1,63%
United States
1,59%
Venezuela
1,34%
Browser
Chrome
Safari
Firefox
Android Browser
Internet Explorer
Safari (in-app)
Opera
Opera Mini
YaBrowser
BlackBerry
43,32
%
16,84
%
13,97
%
9,65%
8,08%
5,49%
1,50%
0,29%
0,22%
0,17%
Operating System
Windows
Android
iOS
Macintosh
Linux
Windows Phone
BlackBerry
(not set)
Chrome OS
SymbianOS
47,19
%
23,97
%
19,97
%
5,63%
2,35%
0,54%
0,18%
0,05%
0,02%
0,02%
Analyzing the data from each night of broadcast separately, we obtain the following results:
●
Range between 22(0h UT)-24 (0h UT). Broadcast 23 agosto
A maximum of 488 visits and 667 pages-views.
●
Range between August 23rd (0h UT) and August 25th (0h UT) during the broadcasting.
A maximum of 525 visits and 1.763 pages-views.
●
Range between August 24th (0h UT) and August 26th (0h UT). The live webcast on
August 25th was cancelled due to bad weather.
●
●
Range between August 26th (0h UT) and August 28th (0h UT) during the broadcasting
on August 27th.
A maximum of 385 visits and 575 page views.
●
Range between August 27th (0h UT) and August 29th (0h UT) during the broadcasting
on August 28th.
●
Awstat
According to the statistics collection tool Awstat that was locally installed in most of the web
instances of the partners, we can see the contribution of each partner to the total percentage
of hits, pages and broadcast traffic.
Summarizing the data obtained from those collaborators with Awstat installed, we see that
globally the portal www.sky-live.tv has received 50.294 visits and 82.216 pagesviews,
providing 85,06 GBytes of data.
2.- Video Streaming.
We can observe during the 4 live webcasts that a total of 2.714 user playbacks were made
during the live webcasts whereas 289 visitors were concurrent viewers.
Analyzing the data from each night of broadcast separately, we obtain the following results:
●
●
●
●
23 of August 873 playback and 140 simultaneous visits. Views 18900.
24 of August 1.134 playback and 102 simultaneous visits. Views 4175.
TOTAL and COMPARATIVE.
Figure 1.- Comparison of visits and viewers to the website and video of the broadcast in the various events, TSE-2010
(Total Solar Eclipse, July 11th, 2010, Easter Island), TLE-2010 (Total Lunar Eclipse, December 20th, 2010, Teide),
TLE-2011 (Total Lunar Eclipse, June 15th, 2011, Teide), NL-2011 (Northern Lights, in August 2011, Greenland), VT-2012
(Transit of Venus, June 6th, 2012, Australia / Japan / Norway ), NL-2012 (Northern Lights, in August 2012, Greenland),
TSE-2012 (Total Solar Eclipse, November 13th, 2012, Australia), NL-2013 (Northern Lights, August 2013 Greenland),
TSE-2013 (Total Solar Eclipse, in November 2013, Kenya), TLE-2014 (Total Lunar Eclipse, April 2014, Perú), NL-2014
(Northern Lights in August 2014 from Greenland and Iceland).
TECHNICAL INFRASTRUCTURE
1.- Configuration.
During the expedition, several technical configurations were proposed in order to make the
live webcast of the northern lights. These configurations were selected according to the
geographical location, the type of Internet connection and the chances to see the northern
lights.
Initially, the expedition was divided into two groups located in Greenland and Iceland. The
Greenland team had a Inmarsat satellite terminal to allow Internet access in remote and
isolated places. On the other hand, the Iceland team was using a stable broadband Internet
connection that provided high definition video quality for the live webcasts.
Greenland Team
Iceland Team
August 23rd
Satellite
Broadband
August 24th
Broadband
Broadband
August 27th
x
Broadband
August 28th
x
Broadband
The table shows the different configurations during each day of broadcasting. The first two live
webcasts had a remote audio/video feed from Greenland. On the other hand, the last two
broadcastings were made in the coordination centre located in Iceland when both teams were
merged.
During the first live webcast, the weather conditions along with the geographical location were
not suitable to receive the live feed from Greenland. However, the configuration allowed to
make the live webcast only from Iceland with the available video resources.
In the second broadcasting, the Greenland team had a broadband connection. With this
configuration, the presenter in Greenland could get the audio feedback from the coordination
centre. This configuration helped during all the sections of the live webcast.
Generally speaking, the time delay is an important factor when the presenter and the live
production team are located in different geographical locations, specially using satellite
communications. To mitigate this problem, only audio feedback for the presenter was chosen in
order to minimize the time delay. This feedback allowed the presenter to change the flow of
the live webcast according to possible unexpected events.
2.- Technical Resources.
To mitigate possible technical issues during the live webcast, both teams had two audio/video
streams and prerecorded material.
The first video source was a Canon EOS 5D Mark II camera. This camera was configured to
capture the northern lights and also the presenter. The intention was to be able to watch the
movements of the northern lights behind the presenter. This video source was combined with
an audio source from a wireless microphone to generate the live feed from Greenland.
The second video source was a Mobotix M15D dual day/night vision camera. This fixed camera
was pointing to the sky from Iceland and the surroundings of the Hekla volcano. A second audio
source was used in case of the main audio feed from Greenland would be lost.
Regardless of the audio/video sources, the live production was using also pre recorded
material such as timelapses, educational videos and interviews.
3.- Production.
During the different live webcasts, two different live productions were made:
-
The first two broadcastings with audio/video feed from Greenland had a private live
channel from Youtube Live. This private channel was fetched in the coordination centre
from Iceland in order to generate the final live stream through a public Youtube Live
channel. At the same time, the Greenland team received the audio feedback for the
presenter via Google Hangouts.
-
In the last two broadcastings there was no live feed from Greenland since both teams
were in Iceland. In this case, the presenter’s live feed was fetched locally in the
coordination centre, reducing drastically the time delay.
4.- Encoding.
In order to make the live production, two different audio/video profiles were used to encode
the live feed using Flash Media Live Encoder. The live feed from Greenland had a low profile in
order to reduce the outbound traffic and the latency. This low profile also modified the video
quality in real time depending on the current bandwidth.
The second profile was used for the final live stream. This was a high profile with a high video
quality.
High profile
Low profile
Video Format
H.264 Main level 4.1
H.264 Main level 4.1
Keyframe sequence
1 second
2 seconds
Frame rate
25 fps.
15 fps.
Resolution
1280x720
426x240
Video bitrate
2000 Kbps.
500 Kbps.
Audio format
AAC
AAC
Sample rate
44100 Hz
44100 Hz
Audio bitrate
128 Kbps
128 Kbps
5.- Conclusions.
The live webcasts of the northern lights in 2014 have achieved several improvements
compared to previous broadcastings.
First of all, it was the first time that live webcasts were made from two different geographical
locations in Greenland and Iceland. This allows the expedition to capture the northern lights
from two strategic spots, increasing the chances to observe the phenomenon.
The second improvement was the possibility to broadcast the northern lights in high definition.
This allows the expedition to make a live webcast with clear images of auroras as well as better
video quality without playback issues. This allowed GLORIA users to enjoy the live webcasts of
the northern lights as never seen before.

report of the broadcast of the northern lights 2014 - Sky

Transcription

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