1. Networks & Multimedia Amit Pande, Post-doctoral fellow, Department of Computer Science, University of California Davis www.cs.ucdavis.edu/~amit

2.  Material adapted from Internet sources, CS529 course at WPI

3. Presentation Outline  Evolution of wireless and Cellular Networks, mobile phones, evolution of Multimedia coding  Multimedia services over Internet

4. Going back – 15 years  Landline phones  Analog camcorders  CRT TV

5. Network – the backbone infrastructure Cellular networks EDGE MCS-159.2 Kbps Evolved Edge1000 Kbps HSCPA14 Mbps (download) HSPA+ (release 9) 84 Mbps (download) LTE>100 Mbps (download) >50 Mbps (upload) Low latency LTE advanced1 Gbps

6.  The traditional sense of watching TV channels or playing a video CD are soon disappearing.  GoogleTV has integrated www and search tools to HDTV Pico-projectors can project HD video from mobile devices

7. Frequency Transform Motion compensa -tion Entropy coding

8. Frequency Transform Motion compensa -tion Entropy coding 50 Kbps 50 Mbps

9. Network Traffic Today  Internet dominated by text-based applications  Email, FTP, Web Browsing  Very sensitive to loss  Example: lose a byte in abcd.exe program and it crashes!  Not very sensitive to delay  10’s of seconds ok for Web page download  Minutes for file transfer  Hours for email to delivery

10. Multimedia on the Internet  Multimedia not as sensitive to loss  Words from speech lost still ok  Frames in video missing still ok  Multimedia can be very sensitive to delay  Interactive session needs one-way delays less than ½ second!  New phenomenon is effects of variation in delay, called jitter!

11. Jitter Jitter-Free

12. Video Coding  MPEG -1 352x240 at 30 frames per second (fps)  MPEG -2 1280x720 at 60 fps. CD quality  MPEG -4 objects, low bit-rates

13. H264 SVC  Parts of the video bit stream can be removed so that the remaining substream can still be decoded  Single-layer vs. Base layer + Enhancement layers Benefits in a mobile environment  Heterogeneous clients  Improved error resiliency

14. Classes of Internet Multimedia Apps  Streaming stored media  Streaming live media  Real-time interactive media

15. Streaming Stored Media  Stored on server  1-way communication, unicast  Examples: pre-recorded songs, famous lectures, video-on-demand, YouTube  RealPlayer, Media Player, Quicktime, FLV  Interactivity, includes pause, ff, rewind…  Delays of 1 to 10 seconds or so tolerable  Need reliable estimate of bandwidth  Not very sensitive to jitter

16. Streaming Live Media  “Captured” from live camera, radio, T.V.  1-way communication, maybe multicast  Examples: concerts, radio broadcasts, lectures, IPTV  Can use: RealPlayer, Media Player… but often custom  Limited interactivity…  Limited opportunities for compression, scaling  Delays of 1 to 10 seconds or so tolerable  Need reliable estimate of bandwidth  Not so sensitive to jitter

17. Streaming Interactive Media  “Captured” from live camera, microphone  2-way communication  Examples: VoIP, video conference  Very sensitive to delay < 150 ms one-way delay good < 400 ms ok > 400 ms crappy  Sensitive to jitter

18. TCP or UDP?  Above IP we have UDP and TCP as the de-facto transport protocols. Which to use?

19. TCP or UDP?  TCP + In order, reliable (no need to control loss) - Congestion control (hard to pick encoding level right)  UDP - Unreliable (need to control loss) + Bandwidth control (easier to control sending rate)

20. Thank you Questions? Feedback/Comments: amit@cs.ucdavis.edu