US 11,659,182 B2
Chroma quantization in video coding
Alexandros Tourapis, Los Gatos, CA (US); and Guy Cote, Aptos, CA (US)
Assigned to Apple Inc., Cupertino, CA (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on Apr. 16, 2021, as Appl. No. 17/232,539.
Application 17/232,539 is a continuation of application No. 16/294,229, filed on Mar. 6, 2019, granted, now 10,986,341.
Application 16/294,229 is a continuation of application No. 15/342,128, filed on Nov. 3, 2016, granted, now 10,250,883, issued on Apr. 2, 2019.
Application 15/342,128 is a continuation of application No. 14/452,485, filed on Aug. 5, 2014, granted, now 9,510,002, issued on Nov. 29, 2016.
Claims priority of provisional application 61/875,664, filed on Sep. 9, 2013.
Prior Publication US 2021/0235088 A1, Jul. 29, 2021
Int. Cl. H04N 19/124 (2014.01); H04N 19/30 (2014.01); H04N 19/70 (2014.01); H04N 19/126 (2014.01); H04N 19/186 (2014.01); H04N 19/157 (2014.01); H04N 19/86 (2014.01); H04N 19/136 (2014.01); H04N 19/13 (2014.01); H04N 19/15 (2014.01); H04N 19/159 (2014.01); H04N 19/51 (2014.01); H04N 19/61 (2014.01); H04N 19/96 (2014.01); H04N 19/172 (2014.01); H04N 19/176 (2014.01)
CPC H04N 19/124 (2014.11) [H04N 19/126 (2014.11); H04N 19/13 (2014.11); H04N 19/136 (2014.11); H04N 19/15 (2014.11); H04N 19/157 (2014.11); H04N 19/159 (2014.11); H04N 19/186 (2014.11); H04N 19/30 (2014.11); H04N 19/51 (2014.11); H04N 19/61 (2014.11); H04N 19/70 (2014.11); H04N 19/86 (2014.11); H04N 19/172 (2014.11); H04N 19/176 (2014.11); H04N 19/96 (2014.11)] 14 Claims
OG exemplary drawing
 
1. A method of decoding video pictures, the method comprising:
receiving, in a bitstream, an encoded group of video pictures, including an encoded first video picture with a hierarchical coding structure having at least a first coding level, a second coding level and a third coding level, the encoded first video picture comprising two or more sets of chroma quantization parameter (QP) offset values at the first coding level and the second coding level, each set of chroma QP offset values providing information about chroma QPs of video units encompassed by one level of the hierarchical coding structure, the encoded first video picture further comprising one or more chroma quantization groups (QGs) at the third coding level;
for a particular chroma QG of the one or more chroma QGs at the third coding level, identifying an additional set of chroma QP offsets, the identifying comprising:
determining, based on information included in the first coding level or the second level, a range parameter for a specified range limiting the additional set of chroma QP offsets, and
identifying the additional set of chroma QP offsets using the range parameter; and
decoding the encoded first video picture by computing chroma QP values corresponding to the one or more chroma QGs of the encoded first video picture, the decoding comprising, for the particular chroma QG:
selecting the identified additional set of chroma QP offsets, and
computing the chroma QP values corresponding to the particular chroma QG using the selected set of the chroma QP offsets.