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  1. 1. H.264/SVC Error Resilience Strategies for 3G Video Service Liu Yunpeng Zhejiang University
  2. 2. Outline <ul><li>H.264/SVC and Error Resilience </li></ul><ul><li>Previous Work of H.264/SVC Error Resilience on Video Service </li></ul><ul><li>H.264/SVC main error resilience tools for mobile video service </li></ul><ul><li>H.264/SVC error resilience strategies for 3G mobile services </li></ul>
  3. 3. Outline (Cont.) <ul><li>Experiments and Analysis </li></ul><ul><li>Conclusion </li></ul>
  4. 4. H.264/SVC and Error Resilience <ul><li>Scalable Video Coding: An extension of the ITU-T Recommendation H.264|ISO/IEC International Standard ISO/IEC 14496-10 </li></ul><ul><li>For reliable delivery of video to diverse clients over heterogeneous networks using available system resources (See showing picture blow) </li></ul>
  5. 6. H.264/SVC and Error Resilience (Cont.) <ul><li>H.264/AVC: Taking error resilience into account in the standard in order to adapt the error-prone environment </li></ul><ul><li>H.264/AVC is the core codec algorithm for SVC </li></ul>Return Outline
  6. 7. Previous Work of H.264/SVC Error Resilience on Video Service <ul><li>From April, 2005 till January, 2009: many H.264/SVC error resilience tools are sequentially proposed </li></ul><ul><li>Mainly coming from JVT documents </li></ul>
  7. 8. Previous Work of H.264/SVC Error Resilience on Video Service (Cont.) <ul><li>CABAC Variants Options </li></ul><ul><li>Redundant Slice Coding Method </li></ul><ul><li>Error Concealment Algorithms </li></ul><ul><li>NAL Unit Information </li></ul><ul><li>Loss-aware Rate-distortion Optimized Macroblock Mode Decision Algorithm </li></ul><ul><li>Use of SP-Picture in SVC </li></ul>
  8. 9. Previous Work of H.264/SVC Error Resilience on Video Service (Cont.) <ul><li>SEI Message </li></ul><ul><li>SVC Slice Structure </li></ul><ul><li>FEC Technology </li></ul>Return Outline
  9. 10. H.264/SVC main error resilience tools for mobile video service <ul><li>Error Concealment </li></ul><ul><ul><li>Frame copy (FC) </li></ul></ul><ul><ul><li>Temporal direct motion vector generation (TD) </li></ul></ul><ul><ul><li>Motion and residual upsampling (BlSkip) </li></ul></ul><ul><ul><li>Reconstruction base layer upsampling (RU) </li></ul></ul>
  10. 11. SVC Slice Implementation <ul><li>Slice structure is an important tool for error resilience </li></ul><ul><li>Two types of slice support: fixed slice size in number of macroblocks and fixed slice size in number of bytes </li></ul><ul><li>Implemented to the JSVM software in future </li></ul>
  11. 12. Polyphase Downsampling (PD) Based Redundant Picture Coding <ul><li>The redundant picture can be coded as a simple repetition of a primary picture </li></ul><ul><li>PD based video coding suggests to apply polyphase downsampling to each 8x8 inter residual block before DCT (Showing Picture Below) </li></ul>
  12. 14. FEC Technology <ul><li>3GPP standard chooses Digital Foutain’s FEC as the part of MBMS </li></ul>Return Outline
  13. 15. H.264/SVC error resilience strategies for 3G mobile services <ul><li>Error Resilience Strategies for Multimedia Broadcast/Multicast Services (MBMS) </li></ul><ul><li>Error Resilience Strategies for Conversational Service </li></ul>
  14. 16. Error Resilience Strategies for Multimedia Broadcast/Multicast Services (MBMS) <ul><li>MBMS characteristics </li></ul><ul><ul><li>Transmit in a one-way mode: i.e. client only passively receives data, server may not retransmit for every client user </li></ul></ul><ul><ul><li>The pre-protection of sending end is particularly important </li></ul></ul>
  15. 17. MBMS Strategies <ul><li>The mechanism of feedback is prohibited </li></ul><ul><li>FEC is indispensible for coder and encoder </li></ul><ul><li>In order to enhance the error resilience capability of encoder, we need PD based redundant picture coding and SEI message </li></ul><ul><li>Error concealment and slice structure are optional </li></ul>
  16. 18. Error Resilience Strategies for Conversational Service <ul><li>Characteristics </li></ul><ul><ul><li>Both ends encoding and decoding </li></ul></ul><ul><ul><li>Relatively less computing ability and memory capability of mobile terminals </li></ul></ul>
  17. 19. Conversational Service Strategies <ul><li>Error concealment is the most important tool for conversational service </li></ul><ul><li>Retransmission are not allowed </li></ul><ul><li>Slice structure is very useful </li></ul><ul><li>FEC, redundant picture and SEI message will not be supported </li></ul>Return Outline
  18. 20. Experiments and Analysis <ul><li>The common off-line test conditions are described below in table </li></ul>
  19. 21. Proposed error resilience strategies for mobile video services are listed in Table
  20. 22. Relative parameters on test <ul><li>Video sequences format is YUV 4:2:0 </li></ul><ul><li>H.264/SVC scalable baseline profile </li></ul><ul><li>Encoded and decoded with JSVM9.8 </li></ul><ul><li>Base layer QCIF, enhancement layer CIF, two-layer spatial scalability </li></ul><ul><li>No SNR or temporal scalability </li></ul><ul><li>GOP size = 16 with one I frame for each 32 frames </li></ul>
  21. 23. Relative parameters on test (Cont.) <ul><li>Adaptive inter layer prediction </li></ul><ul><li>2 reference pictures </li></ul><ul><li>Same QP for two layers </li></ul><ul><li>Bit rate control of 128 kbps </li></ul><ul><li>Frame rate = 30 fjps </li></ul><ul><li>Total frame = 500 </li></ul>
  22. 24. Relative parameters on test (Cont.) <ul><li>For the decoder, BlSkip+TD error concealment method is adopted. Base layer uses TD method, and enhancement layer uses BlSkip method. </li></ul>
  23. 25. Experiment results for MBMS
  24. 26. Experiment results for conversational video services
  25. 27. Analysis <ul><li>Apparently appropriate error resilience strategy can help achieve better video quality. </li></ul><ul><li>Without appropriate error resilience, when RTP packets are lost, the PSNR value falls rapidly and has a permanent adverse effect on the following frames. </li></ul><ul><li>Our strategy can prevent falling of PSNR value and efficiently remove error drift to obtain satisfactory PSNR value. </li></ul><ul><li>Other error resilience tools may also be used for this case, but the computation loads for mobile terminals have to be considered as well. </li></ul>Return Outline
  26. 28. Conclusion <ul><li>3GPP video services may greatly benefit from the adoption of SVC </li></ul><ul><li>The latest 3GPP/3GPP2 standards have begun to support for SVC </li></ul><ul><li>Our future work will concentrate on optimizing the computational complexity of the proposed error resilience tools and adaptive strategies </li></ul>Return Outline
  27. 29. <ul><li>Thanks for your attention! </li></ul><ul><li>Q/A </li></ul>
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