Patent ID: 11863749
Assignee: MICROSOFT TECHNOLOGY LICENSING, LLC
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. In a computer system, a method comprising:
receiving encoded data in a bitstream, wherein the encoded data includes:
one or more syntax elements that control variation of quantization parameters along a spatial dimension within a frame of pixel values, the pixel values of the frame being organized spatially into multiple areas within the frame, the multiple areas being further organized spatially into groups, the one or more syntax elements that control variation of the quantization parameters along the spatial dimension including at least one syntax element that indicates whether variation of the quantization parameters is possible between the multiple areas within the respective groups;
one or more syntax elements that control variation of the quantization parameters along a color channel dimension, the pixel values of the frame also being organized by first, second, and third color channels, the one or more syntax elements that control variation of the quantization parameters along the color channel dimension including a syntax element that indicates whether, for a given group of the groups, the encoded data includes syntax elements that indicate how to vary the quantization parameters for the second and third color channels, respectively, for the given group; and
for the given group, the syntax elements that indicate how to vary the quantization parameters for the second and third color channels, respectively, for the given group; and

decoding the encoded data to reconstruct the frame, wherein the decoding includes:
determining the quantization parameters using the one or more syntax elements that control variation of the quantization parameters along the spatial dimension, the one or more syntax elements that control variation of the quantization parameters along the color channel dimension, and the syntax elements that indicate how to vary the quantization parameters for the second and third color channels, respectively, for the given group;
for blocks of at least some of the multiple areas of the frame, inverse quantizing transform coefficients using the determined quantization parameters; and
for the blocks of at least some of the multiple areas of the frame, performing inverse frequency transform operations on the inverse-quantized transform coefficients.