Abstract
The problem of multimedia communications over best-effort networks is addressed here
with multiple description coding (MDC) in a distributed framework. In this paper, we
first compare four video MDC schemes based on different time splitting patterns and temporal
two- or three-band motion-compensated temporal filtering (MCTF). Then, the latter schemes are extended
with systematic lossy description coding where the original sequence is separated into two
subsequences, one being coded as in the latter schemes, and the other being coded with a
Wyner-Ziv (WZ) encoder. This amounts to having a systematic lossy Wyner-Ziv coding of every other
frame of each description. This error control approach can be used as an alternative to automatic
repeat request (ARQ) or forward error correction (FEC), that is, the additional bitstream can be
systematically sent to the decoder or can be requested, as in ARQ. When used as an FEC mechanism, the
amount of redundancy is mostly controlled by the quantization of the Wyner-Ziv data. In this context,
this approach leads to satisfactory rate-distortion performance at the side decoders, however it suffers
from high redundancy which penalizes the central description. To cope with this problem, the
approach is then extended to the use of MCTF for the Wyner-Ziv frames, in which case only the
low-frequency subbands are WZ-coded and sent in the descriptions.