Adjusting quantization/scaling and inverse quantization/scaling when switching color spaces
AssigneeMicrosoft Technology Licensing, LLC
InventorsBin Li, Jizheng Xu, Gary J. Sullivan
Life of this patent
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Abstract
Innovations in adaptive encoding and decoding for units of a video sequence can improve coding efficiency when switching between color spaces during encoding and decoding. For example, some of the innovations relate to adjustment of quantization or scaling when an encoder switches color spaces between units within a video sequence during encoding. Other innovations relate to adjustment of inverse quantization or scaling when a decoder switches color spaces between units within a video sequence during decoding.
Claims20
One or more computer-readable memory or storage devices having stored thereon computer-executable instructions for causing a computing device, when programmed thereby, to perform operations comprising:
- receiving encoded data, as part of a bitstream, for a picture of a video sequence;
- and
- decoding the encoded data to reconstruct the picture, including:
- determining a color space for a given unit of the picture, including selecting, based on a signal in the encoded data, between a first color space and a second color space, the first color space being RGB and the second color space being YCoCg, wherein the color space for the given unit is determined to be the second color space;
- adjusting intermediate quantization parameter (“QP”) values for color components of the second color space according to per component color space adjustment factors, the per component color space adjustment factors adjusting the intermediate QP values for the color components of the second color space by rule for Y, Co, and Cg components, respectively, the per component color space adjustment factors depending on the second color space without signaling of syntax elements that indicate the per component color space adjustment factors;
- and
- decoding the given unit based at least in part on the adjusted intermediate QP values.
One or more computer-readable memory or storage devices storing encoded data, as part of a bitstream, for a picture of a video sequence, the encoded data being organized to facilitate decoding by a video decoder performing operations, the video decoder being implemented using memory and one or more processing units, the operations comprising:
- receiving the encoded data;
- and
- decoding the encoded data to reconstruct the picture, including:
- determining a color space for a given unit of the picture, including selecting, based on a signal in the encoded data, between a first color space and a second color space, the first color space being RGB and the second color space being YCoCg, wherein the color space for the given unit is determined to be the second color space;
- adjusting intermediate quantization parameter (“QP”) values for color components of the second color space according to per component color space adjustment factors, the per component color space adjustment factors adjusting the intermediate QP values for the color components of the second color space by rule for Y, Co, and Cg components, respectively, the per component color space adjustment factors depending on the second color space without signaling of syntax elements that indicate the per component color space adjustment factors;
- and
- decoding the given unit based at least in part on the adjusted intermediate QP values.
A computing device comprising:
- a video encoder configured to perform operations comprising encoding a picture of a video sequence to produce encoded data, the operations including:
- determining a color space for a given unit of the picture, including selecting between a first color space and a second color space, the first color space being RGB and the second color space being YCoCg, wherein the color space for the given unit is determined to be the second color space;
- adjusting intermediate quantization parameter (“QP”) values for color components of the second color space according to per component color space adjustment factors, the per component color space adjustment factors adjusting the intermediate QP values for the color components of the second color space by rule for Y, Co, and Cg components, respectively, the per component color space adjustment factors depending on the second color space without signaling of syntax elements that indicate the per component color space adjustment factors;
- and
- encoding the given unit based at least in part on the adjusted intermediate QP values;
- and
- one or more buffers configured to store the encoded data, as part of a bitstream, for output, the encoded data including a signal that indicates the color space for the given unit.
Dependencies are inferred from the claim text.