EFFICIENT FREQUENCY SCALABLE VIDEO ENCODING WITH COEFFICIENT SELECTION

摘要

An improved technique for efficient frequency scaling wherein the number of coefficients to be included in each sub-block (e.g. 4x4) is selectable (201), and a code indicating the number of coefficients within each layer is inserted in the bitstream at the beginning of each encoded video sequence. This technique allows the original runs of zero coefficients in the highest resolution layer to remain intact by forming a sub-block for each scale from a selected number (201) of coefficients along a continuous scan. These sub-blocks may be decoded in a standard fashion, with an inverse discrete cosine transform applied to square sub-blocks obtained by the appropriate zero padding of and/or discarding of excess coefficients from each of the scales. This invention further improves coding efficiency by allowing an implicit end of block signal to separate blocks, making it unnecessary to transmit an explicit end of block signal in most cases. <IMAGE>