Efficient video transcoding between H.263 and H.264/AVC standards

A new video coding standard H.264/AVC has been recently developed and standardized, which represents a number of advances in standard video coding technology in terms of both coding efficiency enhancement and flexibility, and is expected to replace the existing standards such as H.263 and MPEG-1/2/4. In this paper we investigate and present efficient format transcoding and downsized transcoding methods between H.263 and H.264/AVC standards. Specifically, we use a vector median filter to estimate the new motion vectors required for transcoded videos. In addition, we also propose a fast intra-prediction mode selection based on the coarse edge information obtained from integer-transform coefficients. Experimental results show that the proposed method can gain a significant reduction in the complexity without degrading much the video quality.