Low complexity H.264 list decoder for enhanced quality real-time video over IP

This paper presents a novel list decoding approach exploiting the receiver side user datagram protocol (UDP) checksum. The proposed method identifies the possible locations of errors in the packet by analyzing the calculated UDP checksum value at the receiver side. This makes it possible to considerably reduce the number of candidate bitstreams in comparison to conventional list decoding approaches. When a packet composed of N bits contains a single bit in error, instead of considering N candidate bitstreams, as is the case in conventional list decoding approaches, the proposed approach considers N/32 candidate bitstreams, leading to a 97% reduction in the number of candidates. Our simulation results on H.264 compressed sequences reveal that, on average, the error is corrected perfectly 80% of the time, and thus, the original bitstream is fully recovered when the first valid candidate is considered as the best candidate. In addition, the proposed approach provides, on average, a 2.78 dB gain over the error concealment approach used by the H.264 reference software, as well as 1.31 dB and 1.51 dB gains over the state-of-the-art error concealment and HO-MLD approaches, respectively.