| CPC H04N 19/61 (2014.11) [H04N 19/124 (2014.11); H04N 19/176 (2014.11); H04N 19/45 (2014.11)] | 4 Claims |
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1. An image decoding apparatus, comprising:
circuitry configured to:
perform inverse quantization of quantized data of image data based on a first equation including a quantization parameter but not including a two-dimensional scaling factor for a scaling list process;
acquire transform information indicating whether a secondary transform different from a primary transform has been applied to a processing target block of the image data, wherein
the primary transform includes a transform of prediction error data, which is a difference between the image data and predicted image data, to a frequency domain to acquire transform coefficient data, and
the secondary transform includes a transform to concentrate the transform coefficient data at a low frequency domain; and
perform the scaling list process to acquire a primary coefficient for an inverse transform process of the primary transform, wherein
the primary coefficient is represented by a second equation including a product of the two-dimensional scaling factor and a secondary coefficient corresponding to the secondary transform, and
in the scaling list process, the circuitry is further configured to:
output, when the transform information indicates that the secondary transform has been applied to the processing target block, a result of the second equation different from a result of the first equation; and
control, when the transform information indicates that the secondary transform has not been applied to the processing target block, the two-dimensional scaling factor such that the result of the second equation becomes equal to the result of the first equation.
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