US 12,244,805 B2
Chroma quantization parameter (QP) derivation for video coding
Adarsh Krishnan Ramasubramonian, Irvine, CA (US); Geert Van der Auwera, Del Mar, CA (US); Wei-Jung Chien, San Diego, CA (US); Han Huang, San Diego, CA (US); Yu Han, San Diego, CA (US); Bappaditya Ray, La Jolla, CA (US); and Marta Karczewicz, San Diego, CA (US)
Assigned to QUALCOMM Incorporated, San Diego, CA (US)
Filed by QUALCOMM Incorporated, San Diego, CA (US)
Filed on Aug. 19, 2020, as Appl. No. 16/997,321.
Claims priority of provisional application 62/911,870, filed on Oct. 7, 2019.
Claims priority of provisional application 62/891,063, filed on Aug. 23, 2019.
Prior Publication US 2021/0058620 A1, Feb. 25, 2021
Int. Cl. H04N 19/124 (2014.01); H04N 19/176 (2014.01); H04N 19/186 (2014.01); H04N 19/44 (2014.01)
CPC H04N 19/124 (2014.11) [H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/44 (2014.11)] 24 Claims
OG exemplary drawing
 
15. A device for decoding video data, the device comprising:
memory configured to store video data; and
processing circuitry coupled to the memory and configured to:
determine chroma blocks in a chroma quantization group (QG) of the video data, wherein the chroma QG corresponds to a plurality of luma QGs, and each of the luma QGs includes one or more luma blocks;
determine a quantization parameter predictor that is the same for each of the chroma blocks of the chroma QG;
determine an offset value that is the same for two or more of the chroma blocks of the chroma QG, wherein the offset value is indicative of an adjustment in a degree of quantization;
determine a quantization parameter value for each of the two or more of the chroma blocks in the chroma QG based on the quantization parameter predictor and the offset value, wherein the quantization parameter value equals a degree of quantization applied to coefficients of one or more transform coefficient blocks of the chroma blocks, wherein to determine the quantization parameter value for each of the two or more of the chroma blocks, the processing circuitry is configured to:
determine the quantization parameter value for only one of the two or more chroma blocks in the chroma QG; and
assign the determined quantization parameter value for the other chroma blocks of the two or more chroma blocks in the chroma QG,
wherein quantization parameter values for at least two of the plurality of luma QGs are different, and
wherein quantization parameter values for all of the two or more chroma blocks in the chroma QG are the same;
inverse quantize the coefficients of the one or more transform coefficient blocks of the chroma blocks based on the determined quantization parameter value;
generate one or more residual blocks based on the inverse quantized coefficients; and
reconstruct the chroma blocks based on the one or more residual blocks.