Rate adaptation transcoding for video streaming over wireless channels

In this work, we investigate the problem of bit rate adaptation transcoding for transmitting video over burst-error wireless channels. In particular, we consider a scenario consisting of packet-based transmission with an automatic repeat request (ARQ) error control scheme. We first analyze the buffering implications of inserting a video transcoder at the wireless access point with the variable bit rate channel as the target. We derive the conditions that both the source encoder and transcoder buffers have to satisfy for preventing the decoder buffer from underflowing. Furthermore, we propose a bit rate adaptation algorithm for VBR transcoders used in the wireless access point. Our experimental results demonstrate that visual quality can be improved by the proposed algorithm without violating the end-to-end delay requirements.