A simple on-line turbo estimation of source statistics for joint source-channel VLC decoders : Application to MPEG-4 video

Inhalt:
The basic principle of joint source-channel decoding (JSCD) is to use a priori source knowledge in order to reduce the error rates at the decoder side taking advantage of the residual redundancy left in the compressed source. Often authors assume that the source statistics are perfectly known by the receiver. Here, we propose a simple estimation method of these statistics in the case of variable length encoded sources. This estimation module is part of a source controlled channel decoding (SCCD) system. Simulations carried out for a theoretical source and using a turbo code illustrate the estimator convergence as well as the possibility to reach the performance limits of this SCCD method. Furthermore it is shown that this approach can be also used for the decoding of MPEG-4 motion vectors.