Patent ID: 8265405
Filing Date: 2012-09-11
Classification: H04N

Abstract:
1. An image decoding apparatus comprising: a decoding part for decoding coded data obtained by dividing a coding target image into macroblocks of a predetermined size, dividing each said macroblock into blocks of a predetermined shape and size specified based on a macroblock type, performing a motion compensated prediction in each unit of said block to output a motion vector, generating a predicted image from a reference image on the basis of the motion vector, calculating a difference between the predicted image and the coding target image to output a predictive residual image, performing transform coding of the predictive residual image in each unit of a predetermined transform block to output transform coefficients, quantizing the transform coefficients on the basis of a quantization parameter to output quantized transform coefficients, and performing compression coding of coding-related information containing the motion vector, the quantized transform coefficients, the macroblock type, and the quantization parameter to yield coded data, wherein the decoding part comprises wherein the decoding part has a function of, for each of the predeterminded transform blocks in a said macroblock, decoding coded block pattern information containing a nonzero coefficient existence flag indicating whether there exists a nonzero, said quantized transform coefficient, and wherein, on the occasion of decoding the coded block pattern information in a coding target macroblock, the decoding procedure provider provides a decoding procedure corresponding to a coding procedure provided so as to decrease a code length as a spatial correlation of the coded block pattern information becomes higher between the coding target macroblock and a neighboring macroblock thereto.