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Wednesday, 5 December 2007

Summary 2 - Invited Paper from IEEE

Summary 2
Video Compression—From Concepts to the H.264/AVC Standard

A. Digital video communication is everywhere:
i. Broadcast, subscription, pay per view services over satellite, cable and terrestrial channel à using H.222.0 / MPEG2 systems
ii. Wire line and wireless real-time conversational services à using H.32X or session initiation protocol (SIP)
iii. Internet /Local Area Network (LAN) video streaming à using Real-Time Protocol/Internet Protocol (RTP/IP)
iv. Storage format (digital versatile disk, DVD, digital camcorders and personal video recorders)

B. The basic communication problem can be defined as:
i. Conveying source data with the highest fidelity possible within an available bit rate, or
ii. Conveying the source data using the lowest bit rate possible while maintaining a specified reproduction fidelity

C. Coding efficiency or rate-distortion performance:
i. Defined as the ability of a source coding system to make the trade-off well
ii. Coding system à referred as codec (coder and decoder)

D. Characterization of video codecs:
i. Throughput of the channel
§ A characteristic influenced by the transmission signal bit rate and the amount of protocol and error-correction coding overhead incurred by the transmission system
ii. Distortion of the decided video
§ Distortion is primarily induced by the video codec and by channel errors introduced in the path to the video decoder

E. Consideration issues for practical video transmission:
i. Delay (start-up latency and end-to-end delay)
§ Delay characteristics are influenced by many parameters (processing delay, buffering, structural delays of video and channel codecs, and the speed at which data are conveyed through the transmission channel)
ii. Complexity (computation, memory capacity, and memory access requirements)
§ Complexity of the video codecs, protocol stacks, and network

F. Practical source coding design problem:
i. Given a maximm allowed complexity, achieve an optimal trade-off between bit rate and distortion for the range of network environments envisioned in the scope of the applications

G. Related with Moore’s law as higher bit-rate channels available.

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