Analysis of FEC Function for Real-Time DV Streaming Kazuhisa Matsuzono, Hitoshi Asaeda, Kazunori Sugiura, Osamu Nakamura, and Jun Murai Keio University Graduate School of Media and Governance

Introduction Due to the widespread dissemination of high speed DSL and FTTH, the demands of transmitting high quality audio and video data have been increased. –DVTS (Digital Video Transmission System) is used in various research communities. International symposium, network collaboration game, etc. HD Camera studio

Digital Video Streaming Simply equipment International symposium, network collaboration game, and so on.. High quality and low delay and low cost –Resolution: 720×480,1280×720, 1440×1080 average consumption bandwidth –About 30Mbps Sender Receiver buffer Internet

The problem of quality reduction According to network condition, pktloss happens –Physical bandwidth or available bandwidth Σ(DVTS traffic + other traffic ) > available bandwidth –Congestion –Quality reducing Sender Receiver Internet DV/RTP packet bursty

Real-Time Streaming Play quality vs Timeliness (interaction) –Packet reachable Dead Line is restricted No utilizing the large amount of buffer –Congestion  reducing play quality Adjusting sender’s transport method to changing network condition is very difficult –Rate control –FEC Sender Receiver buffer

Motivation Providing seamless and high interactive streaming on End-to-End model –taking into account high quality streaming, timeliness and high bandwidth-delay network Supportive packet loss avoidance mechanism for real- time streaming application with minimal quality loss –use the network resource effectively Providing best possible video quality –help reducing quality losses Hopefully collaborate within other Internet Video frame data Internet sender FEC data Changing each rate

The relation between quality and FEC Video quality FEC rate Max Situation B Situation A need Rate Control!! Optimal Point Quality is good?

Related Work Internet Receiver MPEG source MPEG sender Change of FEC encoding rateVideo Frame of pattern 1 Video Frame of pattern 2 FEC data Change of MPEG quality Rate Control –TFRC (TCP Friendly Rate Control) DCCP (Datagram Congestion Control Protocol) QAFEC (quality adjusted FEC)

Design and Implementation of FEC function for DVTS Static FEC using Reed-Solomon Code RTP Header PAD DV data FEC data Receive buffer FEC group ID = X DV part FEC partdiscard Play buffer FEC group ID = X+1FEC group ID = X+2 Packet loss Waiting for FEC data Waiting for DV data and FEC data

Experiments Test bed network SenderReceiver Dummynet DV streaming Sender and ReceiverDummynet CPUIntel Pentium M 1GHzIntel Xeon 3.60GHz Memory512MB3GB OSLinux Kernel FreeBSD 5.4 Release NICRealTech 100Base-TXIntel 1000Base-T Hardware in our experiment

Experimental Analysis Costs of encoding and decoding FEC redundancy 0%1.0 msec.10.2 msec.11.2 msec. 30%11.8 msec.21.9 msec.33.7 msec. 60%27.1 msec.61.4 msec.88.5 msec. 90%39.7 msec.62.9 msec msec. FEC rateencodingdecodingtotal

DV Frame Rate 100%

DV Frame Rate 50%

Conclusion Analyzing FEC function with DV streaming –It is very effective to provide the best possible streaming quality Using the appropriate decided frame rate and FEC encoding rate –The further disruption of video and audio could occurs deciding non-proper FEC encoding rate and frame rate toward the current bandwidth condition

Future Work Verify and define the algorithm –Adaptive rate control and FEC for DVTS Rate Control –Applied only when the network congestion is highly observed FEC –Protect the quality to provide best possible streaming quality –Bandwidth estimation with packet error torelance Probe the best combination between FEC rate and frame rate according to the current network condition –Packet loss rate, non-recovery rate, and the amount of receiver buffer –Evaluate our proposed mechanism on a heterogeneous communication enviroment

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