Picture decoding device, picture decoding method and picture decoding program
AssigneeJVC KENWOOD Corporation
InventorsHiroya NAKAMURA, Motoharu UEDA, Shigeru FUKUSHIMA, Toru KUMAKURA
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Abstract
In a picture coding device for coding picture signals including a brightness signal and a color-difference signal in a block unit using intra-prediction and coding information regarding an intra-prediction mode, when aspect ratios of pixels of the brightness signal and the color-difference signal are different from each other, a bitstream generator converts a mode number of a first intra-color-difference prediction mode used when the aspect ratios are equal to each other into a scaled mode number and derives a second intra-color-difference prediction mode used when the aspect ratios are different from each other.
Claims3
A picture decoding device for decoding information regarding an intra-prediction mode in a prediction block unit and decoding picture signals including a brightness signal and a color-difference signal in a conversion block unit using intra-prediction, comprising:
- an intra-brightness prediction mode decoder that decodes a syntax element regarding an intra-prediction mode of the brightness signal from a bitstream in which information regarding an intra-brightness prediction mode showing an intra-prediction method of a prediction block of the bright signal is coded and derives the intra-prediction mode of the brightness signal;
- an intra-color-difference prediction mode decoder that decodes a syntax element regarding an intra-color-difference prediction mode of the color difference signal from the bitstream in which information regarding an intra-color-difference prediction mode showing an intra-prediction method of a prediction block of the color-difference signal is coded and derives a first intra-color-difference prediction mode by referring to the intra-brightness prediction mode;
- a brightness signal intra-predictor that predicts a brightness signal of a conversion block of the brightness signal from a surrounding brightness signal of the conversion block of the brightness signal, according to the intra-brightness prediction mode specified for each prediction block of the brightness signal;
- and
- a color-difference signal intra-predictor that predicts a color-difference signal of a conversion block of the color-difference signal from a surrounding color-difference signal of the conversion block of the color-difference signal, according to the intra-color-difference prediction mode specified for each prediction block of the color-difference signal, wherein
- when aspect ratios of pixels of the brightness signal and the color-difference signal are different from each other, the intra-color-difference prediction mode decoder converts a mode number of the first intra-color-difference prediction mode used when the aspect ratios are equal to each other and derives a second intra-color-difference prediction mode used when the aspect ratios are different from each other.
A picture decoding method for decoding information regarding an intra-prediction mode in a prediction block unit and decoding picture signals including a brightness signal and a color-difference signal in a conversion block unit using intra-prediction, comprising:
- decoding a syntax element regarding an intra-prediction mode of the brightness signal from a bitstream in which information regarding an intra-brightness prediction mode showing an intra-prediction method of a prediction block of the bright signal is coded and deriving the intra-prediction mode of the brightness signal;
- decoding a syntax element regarding an intra-color-difference prediction mode of the color-difference signal from the bitstream in which information regarding an intra-color-difference prediction mode showing an intra-prediction method of a prediction block of the color-difference signal is coded and deriving a first intra-color-difference prediction mode by referring to the intra-brightness prediction mode;
- predicting a brightness signal of a conversion block of the brightness signal from a surrounding brightness signal of the conversion block of the brightness signal, according to the intra-brightness prediction mode specified for each prediction block of the brightness signal;
- and
- predicting a color-difference signal of a conversion block of the color-difference signal from a surrounding color-difference signal of the conversion block of the color-difference signal, according to the intra-color-difference prediction mode specified for each prediction block of the color-difference signal, wherein
- when aspect ratios of pixels of the brightness signal and the color-difference signal are different from each other, the decoding a syntax element regarding an intra-color-difference prediction mode converts a mode number of the first intra-color-difference prediction mode used when the aspect ratios are equal to each other and derives a second intra-color-difference prediction mode used when the aspect ratios are different from each other.
A non-transitory computer-readable recording medium having embodied thereon a picture decoding program for decoding information regarding an intra-prediction mode in a prediction block unit and decoding picture signals including a brightness signal and a color-difference signal in a conversion block unit using intra-prediction, the picture decoding program causing a computer to execute:
- decoding a syntax element regarding an intra-prediction mode of the brightness signal from a bitstream in which information regarding an intra-brightness prediction mode showing an intra-prediction method of a prediction block of the bright signal is coded and deriving the intra-prediction mode of the brightness signal;
- decoding a syntax element regarding an intra-color-difference prediction mode of the color-difference signal from the bitstream in which information regarding an intra-color-difference prediction mode showing an intra-prediction method of a prediction block of the color-difference signal is coded and deriving a first intra-color-difference prediction mode by referring to the intra-brightness prediction mode;
- predicting a brightness signal of a conversion block of the brightness signal from a surrounding brightness signal of the conversion block of the brightness signal, according to the intra-brightness prediction mode specified for each prediction block of the brightness signal;
- and
- predicting a color-difference signal of a conversion block of the color-difference signal from a surrounding color-difference signal of the conversion block of the color-difference signal, according to the intra-color-difference prediction mode specified for each prediction block of the color-difference signal, wherein
- when aspect ratios of pixels of the brightness signal and the color-difference signal are different from each other, the decoding a syntax element regarding an intra-color-difference prediction mode converts a mode number of the first intra-color-difference prediction mode used when the aspect ratios are equal to each other and derives a second intra-color-difference prediction mode used when the aspect ratios are different from each other.
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