Joint Exploitation of Residual Source Information and MAC Layer CRC Redundancy for Robust Video Decoding

Cedric Marin (1) , Khaled Bouchireb (1) , Michel Kieffer (1) , Pierre Duhamel (1)

1 L2S - Laboratoire des signaux et systèmes

This paper presents a MAP estimation method allowing the robust decoding of compressed video streams by exploiting the bitstream structure (i.e., information about the source, related to variable-length codes and source characteristics) together with the knowledge of the MAC layer CRC (here considered as additional redundancy on the MAC packet). This method is implemented via a sequential decoding algorithm in which the branch selection metric in the decoding trellis incorporates a CRC-dependent factor, and the paths which are not compatible with the source constraints are pruned. A first implementation of the proposed algorithm performs exact computations of the metrics, and is thus computationally expensive. Therefore, we also introduce a suboptimal (with tunable complexity) version of the proposed metric computation. This technique is then applied to the robust decoding of sequences encoded using the H.264/AVC standard based on CAVLC, and transmitted using aWiFi-like packet structure. Significant link budget improvement results are demonstrated for BPSK modulated signals sent over AWGN channels, even in the presence of channel coding.

Domains: Computer Science [cs]; Networking and Internet Architecture [cs.NI]; Engineering Sciences [physics]; Signal and Image processing; Computer Science [cs]; Signal and Image Processing

Cedric Marin, Khaled Bouchireb, Michel Kieffer, Pierre Duhamel. Joint Exploitation of Residual Source Information and MAC Layer CRC Redundancy for Robust Video Decoding. IEEE Transactions on Wireless Communications, 2010, 9 (7), pp.2165 - 2175. ⟨hal-00549114⟩