Error Resilience of Video Transmission By Rate-Distortion Optimization and Adaptive Packetization Yuxin Liu, Paul Salama and Edwad Delp ICME 2002

Outline  Introduction  Error resilience in H.263+  Rate-distortion optimization  Proposed Scheme Adaptive Packetization Two-layer rate-distortion optimization  Experimental Result  Conclusion

Introduction  Packet loss Quality degradation Error propagation  Error Resilience coding efficiency

Error Resilience in H.263+  20 negotiable coding option Annex A to Annex T Improve coding efficiency and capabilities  About Error Resilience Annex K: Slice Structure Annex R: Independent Segment Annex N: Reference Picture Selection

Annex K in H.263+  Slice Structure mode a video picture segment replace GOB layer, more flexiable Every MB belongs to one and only one slice in the same frame  Two submode Rectangular Slice submode Arbitrary Slice Ordering submode

Annex K in H.263+ (cont.)  Allow slice header to act as resynchronization points  No data dependencies can cross the slice boundary Motion vector prediction Overlapped block motion compensation (OBMC) Advanced INTRA coding mode  Not prevent ME across boundary

Annex K in H.263+ (cont.)  Motion prediction

Annex R in H.263+  Independent Segment Decoding mode  To decode without other segment  If Annex K is in use, each slice forms a independent segment  Spatial error propagation and temporal error progation

Rate-Distortion optimization  Legrange multipliers:  I mode Inter Inter4v Intra Skip

Rate-Distortion optimization (cont.)  Distortion Quantization Error Packet Loss  Error Resilience by FEC coding across packet

Rate-Distortion optimization (cont.) B(1, 1)B(2, 1)B(l, 1)B(L, 1) B(1, 2)B(2, 2)B(l, 2)B(L, 2) B(1, n)B(2, n)B(l, n)B(L, n) B(1, k 1 ) FEC B(2, k 2 ) B(l, k l ) B(L, k L ) Block 1 Block 2Block lBlock L Packet 1 Packet 2 Packet n Packet N N

Proposed Scheme  The independency of ISD is in decoder view  propose a new packetization scheme No dependency across boundary  propose two-layer rate-distortion optimization

Adaptive Packetization  Obey following 5 principles: No dependency across the GOBs  Motion prediction, OBMC, advanced INTRA block prediction GOB is packeted with it ’ s reference GOBs If a GOB can ’ t fit into packet with it ’ s reference GOBs, the GOB is encoded in INTRA mode and is packeted into a new packet.

Adaptive Packetization (cont.) The number of GOBs in one packet depends on the maximan size of packet Each GOB can be reference at most once for motion estimation  Every packet contains at least one GOB which is INTRA mode

Adaptive Packetization (cont.) Reference picture current picture packet

Two-layer R-D optimization  First-layer RD optimization Determine the optimal coding mode Searching range

Two-layer R-D optimization (cont.)  Second-layer R-D optimization Choice the final GOB of all possible GOBs

Experimental Result

Experimental Result (cont.)

Conclusion  Adaptive packetization and two- layer R-D optimization is proposed  Use annexes of H.263+ to do error resilience