Error resilient video coding for wireless channels

Abstract

This work describes how the introduction of redundancy by means of coding constraints known at the decoder side improves the error resilience of a video communication scheme. The decoder can exploit the a priori knowledge of the constraints to verify the integrity of the decoded bitstream. If the transmission errors cause the violation of the coding constraints, the decoder detects an error and recovers the synchronization with the bitstream. The improved detection capability results in better localization of the decoded frame areas affected by transmission errors, so allowing more accurate error concealment. The adoption of coding constraints does not require any feedback channel between the decoder and the coder since the decoder can be notified of the constraints during the initial negotiation phase. The syntax of the coder output is not affected and the coded bitstream remains standard compliant. Therefore, this technique is quite general and it is well suited to many transport schemes, either packet switched or circuit switched. Furthermore, it can be easily integrated with different error resilience tools. The improvement achievable in the decoded image quality using the coding constraints is here shown in the case of H.264 coded video.