Patent ID: 9538174
Date: 2017-01-03
CPC Classifications: H04N

Claim:
1. A method for decoding two-level scanned transform coefficients corresponding to an M×N block, wherein the M×N block is divided into sub-blocks and each with an L×L block size, transform coefficients of the M×N block are scanned across sub-blocks of the M×N block according to a first scanning pattern, each sub-block is scanned according to a second scanning pattern, and wherein M=L×M1, N=L×N1, and M, N, M1, N1, and L are positive integers, the method comprising: receiving the sub-blocks of the transform coefficients in the first scanning pattern, wherein the sub-blocks of the transform coefficients correspond to outputs from entropy decoding; storing the sub-blocks of the transform coefficients in an inverse scan buffer; retrieving the transform coefficients of the M×N block from the inverse scan buffer, wherein the M×N block comprises a plurality of rows of transform coefficients, or comprises a plurality of columns of transform coefficients; wherein the inverse scan buffer outputs the rows of transform coefficients in a row-by-row manner, or outputs the columns of transform coefficients in a column-by-column manner; and wherein at least a leading row of transform coefficients of the M×N block is output from the inverse scan buffer after said leading row of transform coefficient of the M×N block is fully received by the inverse scan buffer and before a last sub-block of the transform coefficients of the M×N block arrives at the inverse scan buffer, where among the rows of transform coefficients, the leading row of transform coefficients is first output from the inverse scan buffer; or at least a leading column of transform coefficients of the M×N block is output from the inverse scan buffer after said leading column of transform coefficient is fully received by the inverse scan buffer and before the last sub-block of the transform coefficients arrives at the inverse scan buffer, where among the columns of transform coefficients, the leading column of transform coefficients is first output from the inverse scan buffer; and providing said corresponding row or column of the transform coefficients for inverse quantization and inverse transform process.