Macroblock Layer Rate Control in MPEG-2 to AVS-M Transcoder for Mobile Communication

The advanced audio video coding standard-mobile version (AVS-M) is established by AVS Working Group of China for mobile multimedia applications. To meet demands for communication between multimedia source and mobile system, transcoding from MPEG-2 to AVS-M is a key technology. In this paper, we propose a macroblock layer rate control algorithm for MPEG-2 to AVS-M transcoding with the consideration of the influence of new techniques adopted in AVS-M. Analyzing the relation between the mean absolute differences (MADs) of the transcoded and preceded frame, we establish a linear prediction model for MAD prediction when new techniques are used. Utilizing the macroblock layer bit allocation based on MAD, we establish a quadratic R-D model based on frame MAD. The experiment results show that the proposed algorithm based on two models can meet the target bitrate more accurately and achieve a better performance than the reference algorithm in AVS-M encoder.