QP derivation and offset for adaptive color transform in video coding
AssigneeQUALCOMM Incorporated
InventorsKrishnakanth Rapaka, Li Zhang, Rajan Laxman Joshi, Marta Karczewicz
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Abstract
A device for decoding video data is configured to determine for one or more blocks of the video data that adaptive color transform is enabled; determine a quantization parameter for the one or more blocks; in response to a value of the quantization parameter being below a threshold, modify the quantization parameter to determine a modified quantization parameter; and dequantize transform coefficients based on the modified quantization parameter.
Claims28
A method of decoding video data, the method comprising:
- receiving an offset value in the video data;
- determining for one or more blocks of the video data that adaptive color transform is enabled;
- determining a red, green, and blue (RGB)-color space quantization parameter for the one or more blocks, wherein determining the RGB-color space quantization parameter comprises adding the offset value to a luma-chroma (YCbCr)-color space quantization parameter;
- in response to a value of the RGB-color space quantization parameter being below a threshold, modifying the RGB-color space quantization parameter to determine a modified RGB-color space quantization parameter;
- and
- dequantizing transform coefficients of a block from the one or more blocks based on the modified RGB-color space quantization parameter.
The method of 1, wherein determining for the one or more blocks of the video data that adaptive color transform is enabled comprises parsing a syntax element in the video data, wherein the syntax element indicates if adaptive color transform is enabled.
A device for decoding video data, the device comprising:
- a video data memory;
- one or more processors configured to:
- receive an offset value in the video data;
- determine for one or more blocks of the video data that adaptive color transform is enabled;
- determine a red, green, and blue (RGB)-color space quantization parameter for the one or more blocks, wherein determining the RGB-color space quantization parameter comprises adding the offset value to a luma-chroma (YCbCr)-color space quantization parameter;
- in response to a value of the RGB-color space quantization parameter being below a threshold, modify the RGB-color space quantization parameter to determine a modified RGB-color space quantization parameter;
- and
- dequantize transform coefficients of a block from the one or more blocks based on the modified RGB-color space quantization parameter.
An apparatus for decoding video data, the apparatus comprising:
- means for receiving an offset value in the video data;
- means for determining for one or more blocks of the video data that adaptive color transform is enabled;
- means for determining a red, green, and blue (RGB)-color space quantization parameter for the one or more blocks, wherein determining the RGB-color space quantization parameter comprises adding the offset value to a luma-chroma (YCbCr)-color space quantization parameter;
- means for modifying the RGB-color space quantization parameter to determine a modified RGB-color space quantization parameter in response to a value of the RGB-color space quantization parameter being below a threshold;
- and
- means for dequantizing transform coefficients of a block from the one or more blocks based on the modified RGB-color space quantization parameter.
A non-transitory computer-readable storage medium storing instructions that when executed by one or more processors cause the one or more processors to:
- receive in the video data an offset value;
- determine for one or more blocks of the video data that adaptive color transform is enabled;
- determine a red, green, and blue (RGB)-color space quantization parameter for the one or more blocks, wherein determining the RGB-color space quantization parameter comprises adding an offset to a luma-chroma (YCbCr)-color space quantization parameter;
- modify the RGB-color space quantization parameter to determine a modified RGB-color space quantization parameter in response to a value of the RGB-color space quantization parameter being below a threshold;
- and
- dequantize transform coefficients of a block from the one or more blocks based on the modified RGB-color space quantization parameter.
Dependencies are inferred from the claim text.