Joint source-channel turbo decoding of MPEG-4 motion vectors

The use of variable length codes (VLCs) is one of the key element in obtaining high compression rates in source coding. However the transmission of VLCs also introduces a high risk of error propagation. In this context joint source-channel decoding can be an efficient alternative to the classical approach of separated source-channel decoding. Our paper illustrates this situation with the application of a source-controlled channel decoding (SCCD) approach to the decoding of MPEG-4 motion vectors (MVs). Our simulation results show that our SCCD method leads to significant objective gains, more than 15 dB in peak signal-to-noise ratio (PSNR) for a transmission over an additive white Gaussian noise (AWGN) channel. This also leads to a higher visual quality as illustrated with transmission experiments over a mobile radio channel