Bandwidth efficient transmission of MPEG-II video over noisy mobile links

摘要

We consider the performance of MPEG-II compressed video when transmitted over noisy channels. We present the results of bit sensitivity and resynchronisation sensitivity measurements, and propose techniques for substantially improving the resilience of MPEG-II to transmission errors without the addition of any extra redundancy into the bitstream. We find that it is errors in variable length encoded data which cause the greatest artifacts as errors in these data can cause loss of bitstream synchronisation. We develop the concept of a ‘black-box transcoder’ where we losslessly transcode MPEG-II into a different structure for transmission. We achieve bitstream-resynchronisation using a technique known as error-resilient entropy coding (EREC). Finally we improve the error-resilience of differentially coded information by replacing the standard 1D-DPCM with a more resilient hierarchical pyramid predictor. We consider the transmission of MPEG-II over three separate channels: a channel subject to random bit errors, a channel subject to burst errors, and a channel subject to ATM cell losses.