Error concealment aware rate shaping for wireless video transport

Abstract—Streaming of video, which is both source- and channel- coded, over wireless networks faces challenges of the time-varying packet loss rate and fluctuating bandwidth. Rate shaping (RS) has been proposed to reduce the bit rate of a precoded video bitstream to adapt to the real-time bandwidth variation. In our earlier work, rate shaping was extended to consider not only the bandwidth but also the packet loss rate variations. Rate-distortion optimized rate adaptation is performed on the precoded video that is a scalable coded bitstream protected by forward error correction codes. However, none prior work in rate shaping takes into account that the decoder may perform error concealment (EC) if any video data is lost during transmission. In this paper, we propose a novel rate shaping scheme that is aware of the EC method used at the decoder. We refer to this scheme as EC aware RS (ECARS). Given any precoded video, ECARS first evaluates the distortion measure considering a particular EC method used at the decoder. ECARS then performs rate-distortion optimization for rate adaptation. Furthermore, if the precoding process is also aware of the EC method used at the decoder, it can take advantage of the distortion measure based on the EC method, and ECARS can directly use the same distortion measure for the rate-distortion optimization. We present an example EC aware precoding process by means of macroblock prioritization. Experiment results of ECARS together with EC aware precoding are shown to have excellent performance. I