A MPEG4 Simple Profile transcoder for low data rate wireless applications

摘要

A synchronization scheme that can specify the start position of each macroblock in a compressed video bitstream for low data rate wireless applications is proposed by extending the Error Resilient Entropy Coding (EREC) method. Our scheme is implemented in the form of a transcoder, placed before and after the channel, of a MPEG-4 Simple Profile bitstream. We compare our proposed technique using reconstructed video quality (measured in PSNR) and the length of the extra redundancy bits incurred by the transcoder with the error resilient tools of H.263~+. A simple syntax-based codeword repair method is also proposed so that the transcoder generates a MPEG-4 compliant bitstream which can then be decoded with a standard MPEG-4 decoder such as MoMuSys (FDIS V1.0).