Patent ID: 8630342
Filing Date: 2014-01-14
Classification: H04N

Abstract:
1. A coding method for coding image data on a block-by-block basis, comprising: receiving an image data unit of a predetermined size; generating a predicted error between a reference image and the received image data unit by referring to a motion compensation vector of the received image data unit; selecting, as orthogonal transformation sizes of all blocks included in a predetermined image data unit on which orthogonal transformation should be performed, a first size or a mixture of the first size and a second size, the first size being smaller than the second size, wherein, in the case where a motion compensation block size, which is used to perform motion compensation on the block on which orthogonal transformation should be performed, is smaller than the second size, only the first size is selected as the orthogonal transformation size in said selecting; orthogonally transforming the predicted error of a block, from all blocks included in the predetermined image data unit, having the selected orthogonal transformation size to obtain transformation coefficients; quantizing the transformation coefficients using a quantization matrix corresponding to the selected orthogonal transformation size; variable length coding the quantized transformation coefficients to obtain a coded stream; inserting, into the coded stream, size information indicating whether orthogonal transformation sizes of all blocks included in the predetermined image data unit are the first size or the mixture of the first size and the second size; inversely quantizing the transformation coefficients; performing inverse orthogonal transformation on the inversely quantized transformation coefficients; adding the reference image to the decoded signal from the inverse orthogonal transformation; and storing the decoded image in memory for future reference.