Patent ID: 8126062
Filing Date: 2012-02-28
Classification: H04N

Abstract:
1. A method comprising: (I) dividing an image into blocks of image data, forming a plurality of multi-block partitions by grouping adjacent blocks; and (II) for each multi-block partition: (a) for each ordered sequence of quantized transform coefficients of respective blocks of image data in the multi-block partition, determining a respective set of possible breakpoints, each possible breakpoint indicating an ending event recognized by a selected low-frequency coding method that includes recognizing any event that includes a cluster of one or more quantized coefficients having amplitude other than the most likely-to-occur amplitude, and for each possible breakpoint, determining the number of bits to encode the ordered sequence of quantized transform coefficients of the block using a hybrid coding method that includes using the selected low-frequency coding method until the ending event and a selected high-frequency coding method to encode a part of the sequence starting from immediately after the ending event; (b) determining a set of potential breakpoints to use for all blocks in the multi-block partition, wherein each potential breakpoint is one of the possible breakpoints of the sets of breakpoints determined in (a) for the respective sequences of the blocks in the multi-block partition, and for each potential breakpoint, determining the total number of bits to encode all the ordered sequences of quantized transform coefficients of the blocks in the multi-block partition using the hybrid coding method with the ending event indicated by the potential breakpoint; (c) comparing the total numbers of bits to encode all the ordered sequences of quantized transform coefficients of the blocks in the multi-block partition using the hybrid coding method with the ending events indicated by the potential breakpoints of the set determined in (b), and selecting as the single breakpoint the one potential breakpoint of the set determined in (b) that gives the minimum total number of bits; and (d) encoding all the sequences of the blocks in the multi-block partition using the hybrid coding method with the ending event indicated by the selected single breakpoint, including for each sequence encoding a first portion of the sequence up to the ending event using the selected low-frequency coding method and a second portion of the sequence from the first coefficient after the ending event to the end of the sequence using the selected high-frequency coding method.