RATE CONTROL OF SCALABLY CODED IMAGES

摘要

A method of rate-control for a sequence of scalably coded images having transform coefficients partitioned into coding units coded in a plurality of quality increments having respective significance values. The method defines subsets (step 29) each having one or more coding units, at least one image contributing at least one coding unit to two or more subsets. A list of requirements (LOR) is set (step 30) having at least one entry associated with each subset. The significance values are used to select quality increments to construct an admissible codestream that satisfies the LOR on the subsets (steps 34,36) . The quality increments may be selected to achieve high quality for different subsets subject to size requirements in the LOR. For certain requirements, the codestream will also exhibit approximately constant reconstructed image quality. The quality increments may also be selected to achieve small compressed sizes for different subsets subject to quality requirements in the LOR.