US 12,244,803 B2
Chroma transform type determination
In Suk Chong, Mountain View, CA (US); Hui Su, Sunnyvale, CA (US); and Aki Kuusela, Palo Alto, CA (US)
Assigned to GOOGLE LLC, Mountain View, CA (US)
Appl. No. 18/273,666
Filed by Google LLC, Mountain View, CA (US)
PCT Filed Jan. 25, 2021, PCT No. PCT/US2021/014955
§ 371(c)(1), (2) Date Jul. 21, 2023,
PCT Pub. No. WO2022/159115, PCT Pub. Date Jul. 28, 2022.
Prior Publication US 2024/0089433 A1, Mar. 14, 2024
Int. Cl. H04N 19/12 (2014.01); H04N 19/103 (2014.01); H04N 19/119 (2014.01); H04N 19/124 (2014.01); H04N 19/13 (2014.01); H04N 19/172 (2014.01); H04N 19/176 (2014.01); H04N 19/186 (2014.01); H04N 19/61 (2014.01)
CPC H04N 19/12 (2014.11) [H04N 19/103 (2014.11); H04N 19/119 (2014.11); H04N 19/124 (2014.11); H04N 19/13 (2014.11); H04N 19/172 (2014.11); H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/61 (2014.11)] 19 Claims
OG exemplary drawing
 
10. An apparatus, comprising:
a processor configured to:
receive a bitstream including encoded coding blocks of a current image partitioned into multiple coding blocks, a coding block of the multiple coding blocks encoded by:
generating a luma prediction block for a luma coding block comprising luminance information of the coding block;
generating a luma residual block as a difference between the luma coding block and the luma prediction block;
generating a quantized luma block after transforming the luma residual block using a luma transform type;
entropy encoding the quantized luma block into a bitstream;
generating a chroma prediction block for a chroma coding block comprising chrominance information of the coding block;
generating a chroma residual block as a difference between the chroma coding block and the chroma prediction block;
determining an initial chroma transform type for the chroma residual block as the luma transform type;
generating a quantized chroma block using the chroma residual block transformed by a final chroma transform type, wherein when the initial chroma transform type is a transform type other than a default transform type, the final chroma transform type is the initial chroma transform type or the default transform type, and quantized coefficients of the quantized chroma block depend upon quantized coefficients of the quantized luma block; and
entropy encoding the quantized chroma block into the bitstream;
entropy decode the quantized luma block;
generate a dequantized luma block by dequantizing the quantized luma block;
generate the luma residual block by transforming the dequantized luma block using the luma transform type;
generate a luma prediction block for the luma coding block;
generate the luma coding block by adding the luma prediction block to the luma residual block;
entropy decode the quantized chroma block;
generate a dequantized chroma block by dequantizing the quantized chroma block;
determine a chroma transform type for the dequantized chroma block as the luma transform type;
generate the chroma residual block by transforming the dequantized chroma block using the chroma transform type;
generate a chroma prediction block for the chroma coding block;
generate the chroma coding block by adding the chroma prediction block to the chroma residual block; and
reconstruct the coding block by combining the luma coding block and the chroma coding block.