ERROR RESILIENCE IN VIDEO AND MULTIPLEXING LAYERS FOR VERY-LOW BIT-RATE VIDEO CODING SYSTEMS

The transmission of audio-visual services on low-bit-rate, wireless te lecommunications systems requires the use of coding techniques that ar e both efficient in their use of bits and robust against errors introd uced in transmission, In this paper, we present efficient techniques f or improving the error resilience of audio-visual services, These tech niques are based on coding simultaneously for synchronization and erro r protection or detection, We apply the techniques to improve the perf ormance of the multiplexing protocol (which combines the video and aud io streams so that they can be transmitted on a single circuit), and a lso to improve the robustness of the coded video, We show through simu lations that the techniques are efficient in their use of bits and eff ective against bursty errors common in wireless channels, For a simula tion of the DECT channel at a bit-error rate of 10(-3), the techniques give an order of magnitude improvement in the probability of lost pac kets in the multiplexer layer over more conventional techniques, In th e video layer, the techniques give an improvement of between 1-2 dB ov er ITU-T Recommendation H.263. The techniques proposed for the video l ayer also have the advantage of permitting simple transcoding with bit streams complying with H.263.