A soft-output error control method for wireless video transmission

With the rapid development of wireless network and multimedia technology, the efficient transmission over unreliable channel is becoming more and more important. The error control technique for video coding and transmission has drawn considerable attention, tries to recover the data loss and bit errors due to congestion or physical channel fading. Currently, there are three kinds of error control schemes, namely, error resilient coding at the encoder, error concealment at the decoder and the retransmission in the transport layer. In this paper, an error control scheme is proposed which uses the soft information in channel decoding to recover the corrupted bit stream. When bit error is detected in a slice, soft information of channel decoding is employed to locate it, and the wrong bits are flipped and decoded again at the beginning of the slice. The combination of XOR at source and the syntax checking of H.264 decoder has increased the error detection rate from around 60% to 99% without increasing source redundancy. Simulation results show that, when the same error concealing algorithm is used, the PSNR of the proposed scheme using soft information of channel decoding at the decoder is 1-2dB higher than that using the traditional method.