Robust transmission of H.264/AVC sequences using list decoding and source constraints

Video compression standards commonly adopted in wireless multimedia transmission systems generally apply variable length codes (VLCs) to achieve the required data-rates. The resulting bitstreams are sensitive to transmission errors which cause visual artifacts that propagate in both spatial and temporal domains, thus reducing significantly the quality of the reconstructed video sequences. This paper proposes the application of a List Decoder to improve the quality of H.264/AVC encoded sequences. This method relies on sequence estimation and residual source redundancies to recover feasible images. The recovered images may still contain errors which may cause visually distorted macroblocks (MBs). Therefore, the Average Intersample Difference across Boundaries (AIDB) metric was used to detect these visually impaired MBs at pixel level which are then adequately concealed. Simulation results show that the proposed algorithm manages to achieve Peak Signal-to-Noise (PSNR) gains of up to 2.17 dB when compared to the conventional decoding method. The proposed solution is fully compatible with the H.264/AVC standard and no additional bandwidth is required.