Abstract: An image decoding apparatus is provided that decodes a coded image, the coded image being generated by coding an image segmented into a plurality of blocks on a block basis. The image decoding apparatus includes a quantization parameter obtaining unit that obtains a quantization parameter for each block of the plurality of blocks, a decoding unit that decodes the coded image to obtain a reconstructed image, and a pixel difference value obtaining unit that obtains a pixel difference value. The image decoding apparatus also includes a comparing unit that compares the pixel difference value with a threshold value, and a removing unit that removes a coding distortion in an area disposed on both sides of a block boundary between the first block and the second block, by applying a filter for coding distortion removal.

Abstract: A semiconductor for decoding coded image and audio data, which includes an audio processor that decodes coded audio data, and an image decoder that decodes image data. The image decoder removes coding distortion in pixels of two adjacent transform blocks which are motion-compensated, having a coded motion compensation error equal to zero, and are located inside a same macroblock. The image decoder includes a motion compensation block boundary detector that determines whether the motion compensation error of the two adjacent transform blocks located inside the macroblock is zero, and determines whether a boundary of two adjacent transform block is also a boundary of two adjacent motion-compensation blocks. The image decoder also includes a filter that removes coding distortion in pixels of the two adjacent transform blocks, and a selector that selects whether or not the filter removes the coding distortion based on the determination of the motion compensation block boundary detector.

Abstract: A semiconductor for decoding coded image and audio data, which includes an audio processor that decodes coded audio data, and an image decoder that decodes image data. The image decoder removes coding distortion in pixels of two adjacent transform blocks which are motion-compensated, having a coded motion compensation error equal to zero, and are located inside a same macroblock. The image decoder includes a motion compensation block boundary detector that determines whether the motion compensation error of the two adjacent transform blocks located inside the macroblock is zero, and determines whether a boundary of two adjacent transform block is also a boundary of two adjacent motion-compensation blocks. The image decoder also includes a filter that removes coding distortion in pixels of the two adjacent transform blocks, and a selector that selects whether or not the filter removes the coding distortion based on the determination of the motion compensation block boundary detector.

Abstract: Mosaic-shaped block noise occurs when a compressed video signal is reproduced. This block noise is removed, but removing block noise from every block using a deblocking filter imposes a significant load on the deblocking filter. This load is therefore reduced by determining whether coding distortion removal (deblocking) is necessary, and applying a deblocking filter only when needed.

Abstract: A method for coding a picture segmented into a plurality of blocks. The method decodes the coded blocks to produce a reproduced image. A filter selection parameter determines a threshold value for each quantization parameter, so as to change between a mode to effect coding distortion removal by a filter and a mode not to effect the coding distortion removal. The determined filter selection parameter is coded. A difference between pixel values of pixels in the adjacent blocks on both sides of a boundary between adjacent blocks forming the reproduced image is compared with the determined threshold value determined by the filter selection parameter, and the coding distortion is removed using the filter when the difference is smaller than the threshold value, and not removed when the difference is larger than the threshold value.

Abstract: A coding distortion removal method for removing coding distortion in an image which was has been divided in to a plurality of macroblocks. The method operates under the following conditions such that: (i) a size of a pixel in a motion compensation block is smaller than a size of a pixel in said macroblock; (ii) a size of a pixel in a motion compensation block is larger than a size of a pixel in a coding unit; and (iii) a pixel difference between two adjacent motion compensation blocks located inside the macroblock is zero. The method disables the coding distortion removal at a boundary between blocks located inside each of the two adjacent motion compensation blocks, and enables the coding distortion removal at a boundary between the two adjacent motion compensation blocks.

Abstract: A semiconductor for decoding coded image and audio data, which includes an audio processor that decodes coded audio data, and an image decoder that decodes image data. The image decoder removes coding distortion in pixels of two adjacent transform blocks which are motion-compensated, having a coded motion compensation error equal to zero, and are located inside a same macroblock. The image decoder includes a motion compensation block boundary detector that determines whether the motion compensation error of the two adjacent transform blocks located inside the macroblock is zero, and determines whether a boundary of two adjacent transform block is also a boundary of two adjacent motion-compensation blocks. The image decoder also includes a filter that removes coding distortion in pixels of the two adjacent transform blocks, and a selector that selects whether or not the filter removes the coding distortion based on the determination of the motion compensation block boundary detector.

Abstract: An LSI device for decoding a coded image segmented and coded in a plurality of blocks. The LSI device includes a section which receives a filter selection parameter that determines a threshold value for each quantization parameter, for changing between conducting and non-conducting a coding distortion removal by the use of a filter. A decoder, decodes a coded block to obtain a reproduced image. A remover, removes a coding distortion from a region including both sides of a block boundary between adjacent decoded blocks that form the reproduced image, in accordance with a comparison of a difference value of the pixels in adjacent decoded blocks with the threshold value determined based on the filter selection parameter, such that the coding distortion removal is not conducted when the difference value is greater than the threshold value. The coding distortion removal is conducted by the use of the filter when the difference value is smaller than the threshold value.

Abstract: Mosaic-shaped block noise occurs when a compressed video signal is reproduced. This block noise is removed, but removing block noise from every block using a deblocking filter imposes a significant load on the deblocking filter. This load is therefore reduced by determining whether coding distortion removal (deblocking) is necessary, and applying a deblocking filter only when needed.

Abstract: Mosaic-shaped block noise occurs when a compressed video signal is reproduced. This block noise is removed, but removing block noise from every block using a deblocking filter imposes a significant load on the deblocking filter. This load is therefore reduced by determining whether coding distortion removal (deblocking) is necessary, and applying a deblocking filter only when needed.

Abstract: In an interlaced picture having a mixture of field structure macroblocks and frame structure macroblocks, a coding distortion removal method removes coding distortion in blocks composing the macroblock. The method removes a coding distortion in a block block which is included in a macroblock of a frame structure, and which is not adjacent to a boundary of a macroblock of field structure. A coding distortion in a block which is included in a macroblock of the field structure, and which is not adjacent to a boundary of a macroblock of the frame structure is then removed, and a coding distortion in a block which is adjacent to both a macroblock of the frame structure and a macroblock of the field structure is removed.

Abstract: Mosaic-shaped block noise occurs when a compressed video signal is reproduced. This block noise is removed, but removing block noise from every block using a deblocking filter imposes a significant load on the deblocking filter. This load is therefore reduced by determining whether coding distortion removal (deblocking) is necessary, and applying a deblocking filter only when needed.

Abstract: Mosaic-shaped block noise occurs when a compressed video signal is reproduced. This block noise is removed, but removing block noise from every block using a deblocking filter imposes a significant load on the deblocking filter. This load is therefore reduced by determining whether coding distortion removal (deblocking) is necessary, and applying a deblocking filter only when needed.

Abstract: A coding distortion removal method for removing coding distortion in an image which was has been divided in to a plurality of macroblocks. The method operates under the following conditions such that: (i) a size of a pixel in a motion compensation block is smaller than a size of a pixel in said macroblock; (ii) a size of a pixel in a motion compensation block is larger than a size of a pixel in a coding unit; and (iii) a pixel difference between two adjacent motion compensation blocks located inside the macroblock is zero. The method disables the coding distortion removal at a boundary between blocks located inside each of the two adjacent motion compensation blocks, and enables the coding distortion removal at a boundary between the two adjacent motion compensation blocks.

Abstract: An LSI device for decoding a coded image segmented and coded in a plurality of blocks. The LSI device includes a section which receives a filter selection parameter that determines a threshold value for each quantization parameter, for changing between conducting and non-conducting a coding distortion removal by the use of a filter. A decoder, decodes a coded block to obtain a reproduced image. A remover, removes a coding distortion from a region including both sides of a block boundary between adjacent decoded blocks that form the reproduced image, in accordance with a comparison of a difference value of the pixels in adjacent decoded blocks with the threshold value determined based on the filter selection parameter, such that the coding distortion removal is not conducted when the difference value is greater than the threshold value. The coding distortion removal is conducted by the use of the filter when the difference value is smaller than the threshold value.

Abstract: A method for coding a picture segmented into a plurality of blocks. The method decodes the coded blocks to produce a reproduced image. A filter selection parameter determines a threshold value for each quantization parameter, so as to change between a mode to effect coding distortion removal by a filter and a mode not to effect the coding distortion removal. The determined filter selection parameter is coded. A difference between pixel values of pixels in the adjacent blocks on both sides of a boundary between adjacent blocks forming the reproduced image is compared with the determined threshold value determined by the filter selection parameter, and the coding distortion is removed using the filter when the difference is smaller than the threshold value, and not removed when the difference is larger than the threshold value.

Abstract: In an interlaced picture having a mixture of field structure macroblocks and frame structure macroblocks, a coding distortion removal method removes coding distortion in blocks composing the macroblock. The method removes a coding distortion in a block block which is included in a macroblock of a frame structure, and which is not adjacent to a boundary of a macroblock of field structure. A coding distortion in a block which is included in a macroblock of the field structure, and which is not adjacent to a boundary of a macroblock of the frame structure is then removed, and a coding distortion in a block which is adjacent to both a macroblock of the frame structure and a macroblock of the field structure is removed.

Abstract: Mosaic-shaped block noise occurs when a compressed video signal is reproduced. This block noise is removed, but removing block noise from every block using a deblocking filter imposes a significant load on the deblocking filter. This load is therefore reduced by determining whether coding distortion removal (deblocking) is necessary, and applying a deblocking filter only when needed.

Abstract: Mosaic-shaped block noise occurs when a compressed video signal is reproduced. This block noise is removed but removing block noise from every block using a deblocking filter imposes a significant load on the deblocking filter. This load is therefore reduced by determining whether coding distortion removal (deblocking) is necessary, and applying a deblocking filter only when needed.

Abstract: Mosaic-shaped block noise occurs when a compressed video signal is reproduced. This block noise is removed, but removing block noise from every block using a deblocking filter imposes a significant load on the deblocking filter. This load is therefore reduced by determining whether coding distortion removal (deblocking) is necessary, and applying a deblocking filter only when needed.