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Reliable and Smooth Fine Granular Scalable Video Streaming Zhibo Chen Yun He 2002 IEEE Region 10 Conference on Computer, Communications, Control and Power Engineering
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Outline Introduction Server Architecture Quality Weighted Bit Allocation Quality Weighted Error Control Simulation Conclusion
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Introduction Key of Video Streaming –Smooth Playback –Retransmission-based error control scheme Tradeoff Problem –Prefetch a new packet –Retransmit a lost packet
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Introduction FGS Stream –Base Layer (CBR) –Enhance Layer BaseEnhance
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Introduction Quality Weighted Bit Allocation (QWBA) –Achieve smooth quality of playback. Quality Weighted Error Control (QWEC) –Loss protection. –Tradeoff between prefetching and retransmission.
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Server Architecture R b ≤ R min
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QWBA Minimize the variance of the quality of the decoded video sequence, subject to a bit rate constraint on the enhance layer N : denote the number of frames in the preteching interval T R Ei : denote the bits allocated for the enhance layer in the i th frame R T = R B + R E
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QWBA Priori Information –BPSNR i –R Ei is in proportion to ∆PSNR i
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QWBA
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P : Sum of those p i with the constraint p i ≥ 0 N’ : the number of frames with p i ≥ 0, so N ≥ N
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QWEC Enhance layer needs to be divided into several packets Definition of enhance layer packet’s priority –Layer difference –Quality difference
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QWEC E num : sequence number of an enhance layer packet of a given frame (ex. 1, 2, 3, …N ) The lower V prio is the higher the priority of that packet V prio of all base layer packets : 0
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Comparison Forward error correction (FEC) –Increase bandwidth consumption –Lower performance on burst channel –Addition computation load
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Simulation QWBA QWEC Packet loss rate : 10%
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Simulation
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Conclusion QWBA manipulates the enhance layer stream according the PSNR variation of base layer based a solid theoretical analysis to achieve a smooth playback quality. QWEC gives a packet’s priority definition considering both layer difference and quality difference.
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