Error Resilience Codec for IP-Based Video Delivery
用于IP网络的差错复原编解码器

IP based video communication is becoming increasingly important in recent years. One inherent problem of IP based video communication is channel errors. Current video compression standards achieve efficient compression by using predictive coding and variable length entropy coding. Variable length coding techniques are highly vulnerable to channel errors. The channel errors cause the decoder to lost synchronization with the decoder. Predictive coding techniques make the errors quickly propagate across the entire video sequence. So the effect of these errors not only can cause great degradation of the quality of reconstructed images, even can lead to the failure of the whole video communication system. Error resilience techniques have been employed to reduce the effect of the channel errors. The syntax and the structure of compressed video stream have been modified to get error resilient video stream. So the decoder can much more easily detect errors and to recover the lost data from the errors. Error resilience techniques also use the spatial and the temporal correlations within the video sequence to reduce the degradation of the quality of reconstructed images.This article presents an integrated resolving scheme of error resilience technologies for IP based video delivery. This scheme employs severel error resilience technologies, such as the slice mode, resynchronization and error concealment, etc, it can greatly increase the error resilient capability of the video codec. We also implement error resilient H 263 and H 26L codec based on this scheme. This article also gives some simulation results of error resilience technologies based on Internet models. The result shows error resilience technologies can remarkably improve the subjective and objective quality of the reconstructed image.