1. CPSC 601.431 Characteristics of Streaming Media Stored on the Web M. Li, M. Claypool, R. Kinicki, and J. Nichols To appear in ACM Transactions on Internet Technology, 2005.

2. CPSC 601.432 Introduction (1/3) r Several factors contribute to the growth of streaming media on the Web m Availability of broadband m Desktop processing capabilities m Compression technology m Commercial interest r E.g., RealNetworks estimated 350,000 hours of streaming media traffic (2001) r E.g., Significant fraction of Internet traffic (CAIDA, 2002)

3. CPSC 601.433 Introduction – Related Work (2/3) r Characterize streaming application performance (e.g., see references [10-16]) r “TCP-friendly” streaming protocols (e.g., [4],[5]) r Queuing disciplines (e.g., [6-9]) r Acharya & Smith [19] studied all video URLs available in Alta Vista in 1997 m Internet can not support real-time streaming

4. CPSC 601.434 Introduction – Research Questions (3/3) r What are the most popular streaming media applications on the Web? m Real, Windows, QuickTime, MPEG r What is the ratio of streaming audio versus streaming video? m Audio requires lower bitrates? r Are media playback durations of stored media long-tailed? r What are typical streaming media bitrates? m Indications of bandwidth requirements r What fraction of streaming media codec's being used? m Compression efficiency

5. CPSC 601.435 Methodology r Develop a specialized Web crawler r Traverse 17 million URLs; m Selected 17 Web pages as starting points m Considered popularity, demography, connectivity r Identified ~ 30,000 media clips m Used protocol information in URLS m E.g., rtsp://, mms:// etc r Individually access media clips using custom built tools m Encoding format, target bitrate, frame size, codec

6. CPSC 601.436 Analysis - Outline r Aggregate analysis (Section III-A) r Commercial product analysis (Section III-B) m Video m Audio r Codec Analysis (Section III-C)

7. CPSC 601.437 Aggregate Analysis r Each spider collected 1 million URLs m Approximately 11 million distinct URLs m About 55,000 streaming media URLs r In 1997, 23,000 streaming media URLs in 25 million Web pages m A five-fold increase in streaming! r Fig 1: ~ 1% of the servers provide 100 or more media URLs per server r Fig 2: Real Media accounts for almost half of all the streaming media URLs m QuickTime, AVI, MPEG were very popular in 1997, not any more!

8. CPSC 601.438 Commercial Product Analysis Media TypeAudioVideoPercentage Real9863850463 Windows2591656732 QuickTime2814745 Total1284216545100 r About 98% of the streaming media URLs are for pre- recorded media r Most audio/video clips are of short duration m Median for audio ~ 4 minutes (a typical song) m Median for video ~ 2 minutes (a typical trailer) m In 1997, 90% of clips lasted 45 seconds or less m Duration still shorter than typical TV programs

9. CPSC 601.439 Video/Audio Clips r Median bitrate ~ 200Kbps r Approximately 70% of video targeted towards broadband connections; only 1% targets T1 m In 1997, 20% videos were targeted at T1 r Scalable streaming – multiple bitrates per stream m About 12% of Windows Media streams use scalable streaming r About 50% of the videos have less than 320x240 resolution – video resolutions are low r About 90% of the streaming audio is targeted for modem users

10. CPSC 601.4310 Media Codecs r RealPlayer and Windows Media Player (latest version) buffer content at rates significantly higher than the playback rates r Raises “fairness” concern

11. CPSC 601.4311 Sampling Issues r How are the results influenced if there are fewer crawler starting points? r How are the results influenced if there are fewer than 1 million URLs per starting point? r How does sampling affect distributions? r How does choice of starting points affect distributions?

12. CPSC 601.4312 Conclusions r Streaming media on the Web increased 600% in the past 5 years r Real Media most popular, followed by Windows Media r Video and Audio are both equally popular r On-demand streaming dominates r Growth potential m Better resolutions m Higher bitrates?