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An Empirical Study of RealVideo Performance Across the Internet. Yubing Wang, Mark Claypool and Zheng Zuo http://perform.wpi.edu/real-tracer. Introduction. Streaming Audio and Video is growing Traditional Internet studies, but …. video is different Bandwidth and response time not enough

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An empirical study of realvideo performance across the internet

An Empirical Study of RealVideo Performance Across the Internet

Yubing Wang, Mark Claypool and Zheng Zuo

http://perform.wpi.edu/real-tracer


Introduction
Introduction Internet

  • Streaming Audio and Video is growing

  • Traditional Internet studies, but …. video is different

    • Bandwidth and response time not enough

      • Care about smooth rate

    • Packet loss rate alone is not enough

      • Often use repair techniques

  • RealVideo is big [Jup01]

    • RealPlayer, MediaPlayer, QuickTime

Measure RealVideo on Internet

SIGCOMM Internet Measurement Workshop


Outline
Outline Internet

  • Introduction

  • RealVideo

  • Methodology

  • Results

  • Analysis

  • Conclusions

SIGCOMM Internet Measurement Workshop


Realvideo network characteristics

RTSP Internet

Server

Data: TCP or UDP

RealVideo Network Characteristics

  • Buffering

  • SureStream

  • Scalable Video Technology

  • Repair

SIGCOMM Internet Measurement Workshop


Outline1
Outline Internet

  • Introduction

  • RealVideo

  • Methodology

  • Results

  • Analysis

  • Conclusions

SIGCOMM Internet Measurement Workshop


Methodology
Methodology Internet

  • Build customized RealVideo player (RealTracer)

    • Uses RealPlayer core

    • Software Development Kit (SDK)

    • Records performance stats: frame rate, jitter ….

  • Select diverse set of RealVideo servers and videos

  • Solicit volunteers to run RealTracer

    • Many users to Many servers

    • Friends, colleagues outside of Mass., U.S.

    • rec.video newsgroup and end2end mailing list

    • 2 weeks in June 2001

  • Analyze results

SIGCOMM Internet Measurement Workshop


Outline2
Outline Internet

  • Introduction

  • RealVideo

  • Methodology

  • Results

  • Analysis

  • Conclusions

SIGCOMM Internet Measurement Workshop


Results
Results Internet

  • 11 servers in 8 countries

  • 63 users in 12 countries

  • 2855 video clips played

  • 388 video clips watched and rated

  • 10% chance clip unavailable

SIGCOMM Internet Measurement Workshop


Geographic location of servers and clients
Geographic Location of Servers and Clients Internet

SIGCOMM Internet Measurement Workshop


Clips played per user
Clips Played per User Internet

SIGCOMM Internet Measurement Workshop


Outline3
Outline Internet

  • Introduction

  • RealVideo

  • Methodology

  • Results

  • Analysis

    • Frame Rate

    • Jitter

    • Perceived Quality

  • Conclusions

SIGCOMM Internet Measurement Workshop


Frame rate
Frame Rate Internet

  • Basic video performance unit

    • frames per second (fps)

  • Guidelines [Rea00a]:

    • 24-30 fps: full-motion video

    • 15 fps: full-motion video approximation

    • 7 fps: choppy

    • 3 fps: very choppy

    • Less than 3 fps: slide show

SIGCOMM Internet Measurement Workshop


Overall frame rate
Overall Frame Rate Internet

SIGCOMM Internet Measurement Workshop


Frame rate vs network configuration
Frame Rate vs. Network Configuration Internet

Modem: 19% (550)

DSL/Cable: 30% (874)

T1/LAN: 51% (1468)

SIGCOMM Internet Measurement Workshop


Bandwidth vs network configuration
Bandwidth vs. Network Configuration Internet

SIGCOMM Internet Measurement Workshop


Outline4
Outline Internet

  • Introduction

  • RealVideo

  • Methodology

  • Results

  • Analysis

    • Frame Rate

    • Jitter

    • Perceived Quality

  • Conclusions

SIGCOMM Internet Measurement Workshop


Jitter
Jitter Internet

  • Frame rate alone not enough

    • Also need smooth playout

    • High frame rate but choppy playout can be as bad as frame loss [CT99]

  • Variation in frame playout interval called jitter

    • Standard deviation

  • Buffering can reduce jitter [RKTS94, SJ95]

    • But can still have residual jitter

  • Quantitative impact of residual jitter on perceived quality scarce

    • 50 ms imperceptible, 300 ms very rough

SIGCOMM Internet Measurement Workshop


Overall jitter
Overall Jitter Internet

SIGCOMM Internet Measurement Workshop


Jitter vs network configuration
Jitter vs. Network Configuration Internet

SIGCOMM Internet Measurement Workshop


Outline5
Outline Internet

  • Introduction

  • RealVideo

  • Methodology

  • Results

  • Analysis

    • Frame Rate

    • Jitter

    • Perceived Quality

  • Conclusions

SIGCOMM Internet Measurement Workshop


Perceived quality
Perceived Quality Internet

  • Frame Rate and Jitter not enough

    • Best frame rate depends upon content [TC01]

      • RealServer varies

    • Effects of jitter depend upon content [CT99]

  • Perceptual Quality

    • Numeric rating, 0-10

SIGCOMM Internet Measurement Workshop


Clips rated per user
Clips Rated per User Internet

(388 video clips rated)

SIGCOMM Internet Measurement Workshop


Quality vs network configuration
Quality vs. Network Configuration Internet

SIGCOMM Internet Measurement Workshop


Conclusions
Conclusions Internet

  • Average RealVideo clip has good quality

    • 10 frames per second

    • Nearly imperceptible jitter

  • Network configuration

    • Modems are a bottleneck

    • DSL/Cable modems pushing bottleneck towards server

SIGCOMM Internet Measurement Workshop


Future work
Future Work Internet

  • RealVideo over UDP

    TCP-Compatible?

  • Perceptual quality of streaming video

  • Other streaming players and protocols

    • MediaPlayer, QuickTime

  • Effects of caching, CDNs

  • Release of customizable RealTracer

  • Download IP addresses, Playlist, RealTracer

    • From Web page

SIGCOMM Internet Measurement Workshop


An empirical study of realvideo performance across the internet1

An Empirical Study of RealVideo Performance Across the Internet

Yubing Wang, Mark Claypool and Zheng Zuo

http://perform.wpi.edu/real-tracer


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