Fast error resilient H.263 to H.264 video transcoding using RD optimized intra fresh

A key issue of error resilient transcoding using “intra fresh” algorithm is how to decide the intra coding rate and adjust corresponding bits for error resilience, so that jointly optimization between video source and error resilience bit can be achieved. To provide practical solution for this issue, we propose to use rate distortion (RD) optimization criterion to decide the application of intra coding mode at MB level. To reduce the implementation complexity of RD optimization intra fresh method, we also present a fast mode decision algorithm that takes advantage of error propagation distortion estimation as assistance to decide if an early termination of existing coding mode choices is necessary. The algorithm is implemented to realize fast error resilient H.263 to H.264 video transcoding. Compared with error resilient transcoding method using random intra update, the proposed algorithm can enhance speed up to 7.2 times while maintaining better picture quality.