Low-cost video transcoding at the wireless edge

Low-costvideotranscodingatthe
wirelessedge
JongwonYoon
HanyangUniversity
jongwon@hanyang.ac.kr
1
Mo9va9on
• 
• 
Mobilevideostreamingisakillerapplica9on
Wirelesslinkisdynamic;linkfluctua9on,limitedbandwidth,
longlatency,highjiAer,pronetobeingunstable.
stall
• 
glitch
Hardtoprovidesa9sfactoryvideostreamingqualitytomobile
users.
2
Solu9ons
Adap<vebitratestreaming
-HLS,MPEG-DASH
-Massivestorage
-Coarse-grainedadapta9on
-Notapplicabletolive-stream
VideoTranscoding
-Requirehighcomputa9onal
powerandresources
-Mediaserver,off-line
3
TransPi
client’sprofile
Transcoder
Mediasource
(DATN)
(RaspberryPi)
Internet CNN
(HLS)
ENC
DEC
NBC
(DASH)
CableTVnetwork
29channels
NBC
Queue
NBC
CNN
2.Videotranscoder
1.Raspberrypi
-  -  GStreamerimplementa<on(opensourcemediaframework)
singleboardcomputer,cheap($35)
-  -  pluginbased
includesGPU,HWvideodecoderandencoder
transcodedoutput
videosegments-  providesOpenMAXAPIstoaccessde-/encoder
HLS
HW
HW
TS
-  4<mesfaster,18<meslessCPUu<liza<on
demux
decoder
encoder
muxer
-  transcodingon-the-fly
-  handleslivestreamswithmindelay(<1sec)
4
TransPi
client’sprofile
Transcoder
Mediasource
(DATN)
(RaspberryPi)
Internet CNN
(HLS)
ENC
Queue
DEC
NBC
(DASH)
CableTVnetwork
29channels
3.Channel-awarebitratedecision
NBC
NBC
CNN
-  APpassivelymonitorsdownlinkBW
1.Receivingachannelrequestandtheuserprofile
bi:bitrateforclienti,pi:clienti’s
2.Determiningbitratesbasedontheclient’sinfo
bandwidthfori [1:|I|]do
3.Transcodingoriginalvideowiththedeterminedbitrate
if(pi>bi×(1+α))||(pi<bi×(1−α))then
4.Deliveringtranscodedstreamtotheclients
bi=pi,si=pi
si:selectedbitrateforclienti
4.Clientplayer
-  open-sourceapplica<on(e.g.,ffmpeg,gst-launch)
-  maintainsHLS/DASHformat
5
TransPi
6
TransPidemo
7
PIintheSky
8
SkyPidemo(plane)
9
SkyPidemo(drone)
10