Very Low Bitrate Video Codec for Videophone Applications

Very Low Bitrate coding at below 64 kbit/s will be a crucial technique in forthcoming visual services such as video phone and multimedia system. The trend of increasing interest in, and demand for, telecommunication, interactive TV and Multimedia services, has led to significant acceleration of video coding research worldwide. The reference model method for developing the H.261 video coding algorithm through worldwide collaboration has been proved effective and efficient. The subsequent development of the draft recommendation H.263 for video coding at low bitrates employed the same reference model methodology, though the naming for the coding model was TMN (Test Model for Near term videophone at very low bitrate). In this paper, the history of TMNs is briefly reviewed to provide some background on the current status of work. Results of coding simulations are presented for the latest test model TMN5. The paper concludes with a discussion on future directions regarding possible improvements to the coding algorithm.