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Efficient Reverse-Play Algorithms for MPEG Video With VCR Support

Efficient Reverse-Play Algorithms for MPEG Video With VCR Support. Chang-Hong Fu, Yui-Lam Chan, and Wang-Chi Siu CSVT 2006. Ou tline. Introduction M B-Based Reversed-Play Video Streaming System Simulation Results Ideas of Backward Macroblocks. Introduction (1). clients. Environments.

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Efficient Reverse-Play Algorithms for MPEG Video With VCR Support

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  1. Efficient Reverse-Play Algorithms for MPEG Video With VCR Support Chang-Hong Fu, Yui-Lam Chan, and Wang-Chi Siu CSVT 2006

  2. Outline • Introduction • MB-Based Reversed-Play Video Streaming System • Simulation Results • Ideas of Backward Macroblocks

  3. Introduction (1) clients • Environments Limited storage: 1. Displayed buffer 2. Reference buffer server Stored videos

  4. Introduction (2) • Transmission of stored videos • Download mode • Downloading the entire video before playback • Unacceptable delay time • Streaming mode • Playing the video while downloading it • Hardly supporting VCR functionality due to the frame structure in MPEG standards … I P P P

  5. Introduction (3) n-1 0..n-1 0..n-2 … … I P P P P I L-1 0 1 2 n L Current frame

  6. Introduction (4) • Bandwidth requirement for forward play/reverse play • Total sent frames for playing a GOP reversely: (Average: ) 15 14 L = 15 1.5 Mb/s 30fps 13

  7. MB-Based Reversed-Play Video Streaming System (1) • MB-based reversed-play algorithm • MBs are categorized into several classes • Transmission of some MBs can be avoided • Some redundant MBs need not be decoded • Increasing the complexity of the server to reduce the client load and network load mv 3 1 mv 2 3 n-2 n-1 n Next to be displayed

  8. MB-Based Reversed-Play Video Streaming System (2) • BMB (Backward-MB) and FMB (Forward-MB) • BMB: mvn(k,j) = (0, 0)  MBn-1(k,j) is a BMB • Percentage of BMBs nth frame kth row and jth column MBn(k,j) = MBn-1(k,j) + en(k,j)  MBn-1(k,j) = MBn(k,j)- en(k,j) The server transmits VLC{Q[DCT(-en(k,j))]} to the decoder

  9. MB-Based Reversed-Play Video Streaming System (3) • Encoding of -en(k,j) at the server • DCT(-en(k,j)) = -DCT(en(k,j)) • Q[DCT(-en(k,j))] = -Q[DCT(en(k,j))] • VLC{Q[DCT(-en(k,j))]} = ? Sign FLC 10 2’s complement

  10. MB-Based Reversed-Play Video Streaming System (4) • Non-MC FMB • mvn-1(k,l) = 0  MBn-1(k,l) is a non-MC FMB MBn-1(k,l) = MC(mvn-2(k,l)) + en-2(k,l) + en-1(k,l)  Q[DCT(en-2(k,l) + en-1(k,l))] = Q[DCT(en-2(k,l))] + Q[DCT(en-1(k,l))] The server transmits VLC{Q[DCT(en-2(k,l) + en-1(k,l))]} to the decoder e1 e2 e4 e3

  11. MB-Based Reversed-Play Video Streaming System (5)

  12. Simulation results (1) • MPEG-2 coder • GOP size = 15 with only I-frames and P-frames • 30 fps with 200 frames • CIF or SIF (Salesman, Table tennis, and Football) and QCIF (Claire, Grandma, and Carphone) format

  13. Simulation Results (2) BMB Non-MC FMB (Sign Inversion) (DCT Addition)

  14. Simulation Results (3)

  15. BMB Simulation Results (4) n-5 n-4 n-3 n-2 n-1 n Salesman 1.5Mb/s Carphone 128kb/s

  16. Simulation Results (5)

  17. Ideas of BMBs • Error concealment of BMBs • Encoding residual of BMBs

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