Optimal coding of video sequence over ATM networks

We study video coding in the ATM environment under the constraints of finite encoder and decoder buffer sizes. ATM allows flexible transmission rates which can be tuned to better match picture property variation over time. We consider the leaky bucket policing mechanism and obtain the rate constraints on encoded video. We then address the optimization of video coding under the constraints. Two cases are investigated. In one the pictures are coded independently (e.g., motion JPEG), while in the other the coding quality of a later picture may depend on that of an earlier picture (e.g., MPEG). The aggregate distortion-rate relationship for the latter case exhibits a tree structure and its solution commands a higher degree of complexity than the former. We derive an efficient solution for distortion-rate relations which display certain monotonic and hierarchical characteristics. These characteristics are assumed to hold for most distortion-rate relations. Realistic nonconvex distortion-rate relations can be handled with a minor modification of the algorithm