Error - Resilient Standard - Compliant Video Coding

In this chapter we review and compare two approaches to robust video transmission that can be implemented within the H.263 video compression standard. The focus of this chapter is on channel adaptive approaches that rely on a feedback channel between transmitter and receiver carrying acknowledgment information. Based on the feedback information, rapid error recovery is achieved by intra refresh of erroneous image regions. The consideration of spatial error propagation provides an additional advantage. Though the average gain is less than 0.3 dB, annoying artifacts can be avoided in particularly unfavorable cases. The feedback messages that need to be deened outside the scope of H.263 are supported in the ITU-T Recommendation H.324 that describes terminals for low bit-rate multimedia communication. In order to investigate the innuence of error concealment we provide simulation results for concealment with the zero motion vector and the true motion vector as a lower and an upper bound respectively. Experimental results with bursty bit error sequences simulating a wireless DECT channel at various Signal to Noise Ratios are presented