Feedback-based error control for mobile video transmission

We review feedback-based low bit-rate video coding techniques for robust tr ansmission in mobile multimedia networks. For error control on the source c oding level, each decoder has to make provisions for error detection, resyn chronization, and error concealment, and we review techniques suitable Sor that purpose. Further, techniques are discussed for intelligent processing of acknowledgment information by the coding control to adapt the source cod er to the channel. We review and compare error tracking, error confinement, and reference picture selection techniques Sol channel-adaptive source cod ing. For comparison of these techniques, a system for transmitting low bit- rate video over a wireless channel is presented and the performance is eval uated for a range of transmission conditions. We also show how feedback-bas ed source coding can be employed Oz conjunction with precompressed video st ored on a media server. The techniques discussed ale applicable to a wide v ariety of interframe video schemes, including various I video coding standa rds. Several of the techniques have been incorporated into the H.263 video compression standard recently, and this standard is used as an example thro ughout.