Moving picture decoding device, moving picture decoding method, and program obtaining chrominance values from corresponding luminance values
A decoding device includes a transformer sets a decoded luminance component of a prediction target block to the same number of samples as that of the chrominance component corresponding to the decoded luminance component of the prediction target block and generates a luminance reference signal. A specificator specifies luminance pixels having minimum and maximum pixel values of the decoded luminance component adjacent to the decoded luminance component of the prediction target block, respectively, outputs luminance pixel values obtained from specified luminance pixels, and outputs chrominance pixel values from pigment pixels corresponding to the luminance pixels. A derivator derives a linear prediction parameter from the two pixel values and a linear prediction model. A chrominance linear predictor obtains a chrominance prediction signal by applying the linear prediction model based on the linear prediction parameter to the luminance reference signal. The chrominance prediction and residual signals are summed to generate a reconstructed chrominance signal.
1. A moving picture decoder configured to decode encoded data, comprising a memory comprising programmed instructions stored in the memory and a processor configured to be capable of executing the programmed instructions stored in the memory to
decode the encoded data to obtain a chrominance residual signal;
set a decoded luminance component of a prediction target block to a same number of samples as that of a chrominance component corresponding to the decoded luminance component of the prediction target block, and generate a luminance reference signal;
specify pixels of luminance having a minimum and maximum pixel values of the decoded luminance component adjacent to the decoded luminance component of the prediction target block, respectively, output luminance pixel values obtained from the specified pixels of luminance, and output chrominance pixel values obtained from pixels of pigment corresponding to the pixels of luminance;
derive a linear prediction parameter from the luminance pixel value, the chrominance pixel value, and a linear prediction model;
obtain a chrominance prediction signal by applying the linear prediction model based on the linear prediction parameter to the luminance reference signal; and
add the chrominance prediction signal and the chrominance residual signal to generate a reconstructed chrominance signal, wherein
a maximum value of a difference between a maximum value and a minimum value of the chrominance pixel value is clipped to a predetermined range, the decoded luminance component adjacent to the decoded luminance component of the prediction target block is set to the same number of samples as that of the chrominance component corresponding to the decoded luminance component of the prediction target block, and the pixels having the minimum and maximum values of a luminance component are specified, respectively.
2. A moving picture decoding method for decoding encoded data, the moving picture decoding method comprising:
a step A of decoding the encoded data to obtain a chrominance residual signal;
a step B of setting a decoded luminance component of a prediction target block to a same number of samples as that of a chrominance component corresponding to the decoded luminance component of the prediction target block and generating a luminance reference signal;
a step C of specifying pixels of luminance having a minimum and maximum pixel values of the decoded luminance component adjacent to the decoded luminance component of the prediction target block, respectively, outputting luminance pixel values obtained from the specified pixels of luminance, and outputting chrominance pixel values obtained from pixels of pigment corresponding to the pixels of luminance;
a step D of deriving a linear prediction parameter from the luminance pixel value, the chrominance pixel value, and a linear prediction model;
a step E of obtaining a chrominance prediction signal by applying the linear prediction model based on the linear prediction parameter to the luminance reference signal;
a step F of adding the chrominance prediction signal and the chrominance residual signal to generate a reconstructed chrominance signal; and
a step G of clipping a maximum value of a difference between a maximum value and a minimum value of the chrominance pixel value to a predetermined range, wherein
in the step C, the decoded luminance component adjacent to the decoded luminance component of the prediction target block is set to the same number of samples as that of the chrominance component corresponding to the decoded luminance component of the prediction target block, and the pixels having the minimum and maximum values of a luminance component are specified respectively.
3. A non-transitory computer readable medium having stored thereon instructions for decoding encoded data, comprising machine executable code which when executed by at least one machine causes the machine to perform:
a step A of decoding the encoded data to obtain a chrominance residual signal;
a step B of setting a decoded luminance component of a prediction target block to a same number of samples as that of a chrominance component corresponding to the decoded luminance component of the prediction target block and generating a luminance reference signal;
a step C of specifying pixels of luminance having a minimum and maximum pixel values of the decoded luminance component adjacent to the decoded luminance component of the prediction target block, respectively, outputting luminance pixel values obtained from the specified pixels of luminance, and outputting chrominance pixel values obtained from pixels of pigment corresponding to the pixels of luminance;
a step D of deriving a linear prediction parameter from the luminance pixel value, the chrominance pixel value, and a linear prediction model;
a step E of obtaining a chrominance prediction signal by applying the linear prediction model based on the linear prediction parameter to the luminance reference signal;
a step F of adding the chrominance prediction signal and the chrominance residual signal to generate a reconstructed chrominance signal; and
a step G of clipping a maximum value of a difference between a maximum value and a minimum value of the chrominance pixel value to a predetermined range, wherein
in the step C, the decoded luminance component adjacent to the decoded luminance component of the prediction target block is set to the same number of samples as that of the chrominance component corresponding to the decoded luminance component of the prediction target block, and the pixels having the minimum and maximum values of a luminance component are specified respectively.