Multimedia Communications Introduction ECE 591 Pro. Honggang Wang Notes: Some slides including...

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Multimedia CommunicationsIntroduction

ECE 591Pro. Honggang Wang

Notes: Some slides including figures are referred from textbooks and relevant materials

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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

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Multimedia Communications Coding

Compression algorithms for audio, images, and video

Networking Transmission of multimedia over networks

System Integrating audio, video, and other components

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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.

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Coding Image and Video

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Why Compression Color Images of 600*800

– 600*800*24bits/pixel=1.44M bytes– After JPEG compressionOnly 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

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System and Networking Issues Big Picture

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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 …

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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

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A Simple Study (Try) Download Lena filehttp://en.wikipedia.org/wiki/File:Lenna.png

A=imread(‘Lenna.png');

imshow(A)

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Any Questions?