Efficient H.263 to H.264/AVC video transcoding using enhanced rate control

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 and is expected to replace the existing standards such as H.263 and MPEG-1/2/4. In this paper, we propose an enhanced rate control method for H.263 to H.264/AVC transcoding. Specifically, we develop a model to approximate the relationship between the total number of coding bits and quantization step sizes between the precoded and transcoded videos for selecting quantization parameters at the sequence and frame levels. In addition, a new frame-layer bit allocation scheme based on the frame complexity obtained from the precoded video is employed in order to achieve more accurate bit rate and constant visual quality. The experimental results show the accuracy of the model and the effectiveness of the proposed method.