Soft-input decoding of variable-length codes applied to the H.264 standard

This paper presents the application to H.264 standard of a soft-input VLC decoding algorithm based on MAP sequence estimation techniques and using residual source redundancy information to provide channel error protection and correction. This algorithm relies on the presence of soft values and of contextual information available at the input of the source decoder, and is fully compatible with the existing H.264 standard. Numerical results obtained with this considered soft-input decoding algorithm to the decoding of a H.264 encoded video sequence under the assumption of an unequal error protection scheme are presented. Performance obtained for the ´Foreman´ ITU reference sequence show that the proposed algorithm provides gains up to 12 to 15 dB in terms of PSNR when compared to classical hard input decoding methods.