Robust video transmission based on distributed multiple description coding

This paper proposes systematic lossy description coding for robust video transmission over error-prone channels. The problem of error propagation is addressed here by first structuring the data to be encoded into two descriptions. In a first approach, the two descriptions are constructed by splitting odd from even frames. Each description is separated into two sub-sequences, one being conventionally-encoded, the other one being coded with a Wyner-Ziv encoder. This amounts to having a systematic lossy Wyner-Ziv coding of every other frame of each description. This error control system can be used as an alternative to Automatic Repeat reQuest (ARQ) or Forward Error Correction (FEC), i.e. the additional bitstream can be systematically sent to the decoder or can be requested, similarly to an ARQ request. The amount of redundancy is mostly controlled by the quantization of the Wyner-Ziv data. This first approach leads to satisfactory lateral rate-distortion performance, however suffers from high redundancy which penalizes the central description. To cope with this problem, the approach is then extended to the use of motion-compensated temporal filtering (MCTF) for the Wyner-Ziv frames, in which case only the low-frequency subbands are WZ-coded and sent in the descriptions.