I nt roduct ion St reaming video of t en does not like TCP Want s - PowerPoint PPT Presentation

MediaPlayer ™ vs. RealPlayer ™ A Comparison of Network Turbulence Mingzhe Li, Mark Claypool, Robert Kinicki CS Depart ment Worcest er Polyt echnic I nst it ut e Worcest er, MA, USA http://perform.wpi.edu/

I nt roduct ion • St reaming video of t en does not like TCP – Want s smoot h st r eam, so r at e-based – Does not always want r et ransmissions ! Chooses UDP • UDP f lows may be unresponsive t o congest ion ! Handle wit h Act ive Queue Management (AQM) • Typical AQMs model UDP f lows as CBR (“f irehose”) • More realist ic models of st reaming UDP f lows will make AQMs more ef f ect ive • We invest igat e size and dist ribut ion over t ime ! Turbulence • Big 3: RealPlayer, MediaPlayer, QuickTime [J up01] November 2002 SI GCOMM I nt ernet Measurement Workshop

Met hodology • Build aut omat ed video players ( MediaTr acker and RealTr acker [WCZ01] ) – Use commercial cores – Sof t ware Development Kit s (SDKs) – Record applicat ion st at s: f rame rat e… • Select host s wit h bot h RealNet wor ks and Microsof t Media video servers • St ream ident ical cont ent t o players on t he same host • Analyze result s November 2002 SI GCOMM I nt ernet Measurement Workshop

Clip Select ion Real Microsof t Type Bandwidth (Kbps) (Kbps) 1 Sport s High 284 323 3:46 Low 36 50 2 Commercial High 268 307 0:39 Low 84 102 3 Sport s High 284 307 0:60 Low 37 38 4 Music T.V. High 181 309 4:05 Low 26 50 5 News High 218 250 1:47 Low 22 39 6 Movie Clip Very High 637 731 2:27 High 271 347 Low 39 102 November 2002 SI GCOMM I nt ernet Measurement Workshop

Experiment al Set up • Player Plat f orm – Microsof t Windows 2000 PC – P4 1.8 GHz, 512M RAM, AGP 32MB video card – mindspeed.wpi.edu (Worcest er, MA, USA) • Net work – LAN: PCI 10M NI C Win2k prof essional – Campus uplink: ~50 Mbps (Yipes in 15 Mbps) • Sof t ware – Microsof t Media Player version 7.1 – RealNet wor ks RealOne Player build 6.0.10.505 – Et hereal version 0.8.20 November 2002 SI GCOMM I nt ernet Measurement Workshop

I P Packet Arrivals 1760 830 Real Play (217K) 1755 825 Media Packet Number Real Packet Number 1750 820 Windows Media Player (250K) 1745 815 1740 810 1735 805 1730 800 1725 795 1720 790 30 30.2 30.4 30.6 30.8 31 Time (Seconds) • RealPlayer – single packet s • Media Player – groups of packet s (3 in t his example) – 2 at about 1500 byt es (t ypical MTU) – 1 “lef t -over” less t han MTU November 2002 SI GCOMM I nt ernet Measurement Workshop

Media Player I P Packet Fragment at ion 100% I P Packet s w/ out UDP Header 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 0 200 400 600 800 Encoded Bandwidth (Kbits/ s) November 2002 SI GCOMM I nt ernet Measurement Workshop

Normalized UDP Packet Sizes 0.8 0.7 Real Player Probabilit y Densit y 0.6 Windows Media 0.5 0.4 0.3 0.2 0.1 0 0 0.5 1 1.5 2 Normalized Packet size Media Player – More “Const ant Packet Size” RealPlayer – Less “Const ant Packet Size” November 2002 SI GCOMM I nt ernet Measurement Workshop

UDP Packet I nt erarrival Times 1 0.9 0.8 Cumulative Density 0.7 0.6 0.5 0.4 0.3 0.2 Real Player Window Media Player 0.1 0 0 0.5 1 1.5 2 2.5 3 Normalized I nterarrival Time I nterval Media Player – More “Const ant Packet Rat e” RealPlayer – Less “Const ant Packet Rat e” November 2002 SI GCOMM I nt ernet Measurement Workshop

Playout Rat e 700 Real Player (284K) 600 Bandwidth (Kbits/ sec. ) Real Player (36K) 500 Windows Media Player (323K) 400 Windows Media Player (49K) 300 200 100 0 0 50 100 150 200 250 Time (seconds) RealPlayer buffers at a higher rate November 2002 SI GCOMM I nt ernet Measurement Workshop

Frame Rat e 35 30 Frame Rate (f ps) 25 20 15 Real Player 10 Media Player 5 0 200 400 600 800 Average Bandwidth (Kbits/ sec.) RealPlayer signif icant ly higher at low bandwidt h November 2002 SI GCOMM I nt ernet Measurement Workshop

Summary • Microsof t Media Player t ypical CBR – Const ant packet sizes and int erarrivals • RealNet works RealPlayer less CBR – Range of packet sizes and int erarrivals – Buf f ers at up t o 3 t imes playout rat e • Media Player has signif icant I P f r ag. – 3-5 I P f rags / UDP f or broadband+ bwidt h • Result s can be used f or more realist ic st r eaming simulat ions and emulat ions • MediaTracker and RealTr acker online: http://perform.wpi.edu/real-tracer/ November 2002 SI GCOMM I nt ernet Measurement Workshop

Fut ure Work • Build simulat ed st reaming applicat ion – I n NS • Server side cont rol – Clip encoding, Cont ent t ype – (We have server set -up, preliminary result s) • Bandwidt h under congest ion – TCP-Friendly? – (We have result s f or RealPlayer) • More players and prot ocols – QuickTime ( QuickTracker ) November 2002 SI GCOMM I nt ernet Measurement Workshop

MediaPlayer ™ vs. RealPlayer ™ A Comparison of Network Turbulence Mingzhe Li, Mark Claypool, Robert Kinicki CS Depart ment Worcest er Polyt echnic I nst it ut e Worcest er, MA, USA http://perform.wpi.edu/