1. Multimedia Communications Introduction ECE 591 Pro. Honggang Wang Notes: Some slides including figures are referred from textbooks and relevant materials 1

2. Multimedia  What is multimedia - Text, speech, music, audio, image, graphics, video, and many more...  Multimedia Research - Compression/Coding (e.g., MPEG, JPEG) - Networking: Streaming, QoS, etc.. - Implementation: architectures, low power - Databases: Retrieval and Indexing - Human-Machine interface 2

3. Multimedia Communications  Coding  Compression algorithms for audio, images, and video  Networking  Transmission of multimedia over networks  System  Integrating audio, video, and other components 3

4. Current Multimedia and Communication Technologies  Well-developed multimedia standards  Source compression has matured: MPEG-1 Layer 3, JPEG-2000, MPEG-4  Mature standards have created many devices and applications: MP3,DVD, Streaming video  Rapid development of communication technologies  Broadband: DSL, Cable Modems, Satellite  HDTV will convey data and media  Wireless for any-where any-time connections: 3G, 802.11A/B  Advances in networking technologies  Promise of ubiquitous, heterogeneous networks. 4

5. Coding  Image and Video 5

6. Why Compression  Color Images of 600*800 – 600*800*24bits/pixel=1.44M bytes – After JPEG compression Only 89kBytes, Compression ratio 16:1  Movie  720x480 per frame, 30 frames/sec, 24 bits/pixel ~ 243M bits/sec  DVD ~ about 5M bits/sec  Compression ratio ~ 48:1 6

7. System and Networking Issues  Big Picture 7

8. Issues in Networked Multimedia  Real time constraints: delay, delay jitter  Bandwidth requirement  Quality of Services: Delay, delay jitter, packet loss, bit- error-rate…  Error Robustness: Error Resilience, Error concealment  Cost  … 8

9. Topics to be Covered...  JPEG (Joint Photographic Experts Group )  H.261, H.263, H.263 Version 2  MPEG (Moving Picture Experts Group)-1,2,4,7  MPEG Audio  Networking Issues  Error control in video communications  Multimedia over IP  RTP, RTCP, RTSP, RSVP  Audio-visual integration, multimedia processing, organization, storage, retrieval  New approaches to service deployment and ensuring consistent Quality of Service  Security issues in multimedia communication  Multi-camera networks 9

10. A Simple Study (Try) 10  Download Lena file http://en.wikipedia.org/wiki/File:Lenna.png  A=imread(‘Lenna.png'); imshow(A)

11. Any Questions? 11