Granted Patent B2

US 12,309,372 · App. 18/439,264 · Granted May 20, 2025

Inventors: Sergey Yurievich Ikonin (Moscow, RU); Roman Igorevich Chernyak (Moscow, RU); Timofey Mikhailovich Solovyev (Moscow, RU); Alexander Alexandrovich Karabutov (Moscow, RU); Elena Alexandrovna Alshina (Munich, DE); Jianle Chen (San Diego, CA)

Assignee: HUAWEI TECHNOLOGIES CO., LTD.

H04N19/126H04N19/124H04N19/132H04N19/172H04N19/174H04N19/184H04N19/186H04N19/44

Abstract

Claims (56)

1. A method comprising:

receiving a bitstream comprising a sequence parameter set (SPS);

parsing the bitstream to obtain a luminance quantization parameter (QP) and information of a chroma QP mapping table which associates a QP index (QPi) to a chrominance QP (QPc), wherein the chroma QP mapping table is signaled in the SPS;

obtaining a QPi based at least in part on the obtained luminance QP;

obtaining the chroma QP mapping table based on the obtained information of the chroma QP mapping table;

obtaining a first QPc based on the obtained chroma QP mapping table and the obtained QPi; and

obtaining a second QPc based on the first QPc, wherein

qP Chroma =Clip3(−QpBdOffset,63,Qp Y );

qP Cb =ChromaQpTable[0][qP Chroma ];

qP Cr =ChromaOpTable[1][qP Chroma ]; or

qP CbCr =ChromaQpTable[2][qP Chroma ];

wherein the Qp Y represents the luminance QP Y ;

wherein the ChromaOpTable represents the chroma QP mapping table;

wherein the qP Chroma represents the obtained QPi;

wherein the qP Cb , qP Cr or qP CbCr represents the first QPc;

wherein the QpBdOffset represents a bit depth offset calculated based on a bit depth of samples of luma and chroma arrays using the following:

QpBdOffset=6*bit_depth_minus8,

wherein the bit_depth_minus8 is in a range of 0 to 8, inclusive.

2. A decoder comprising:

one or more electronic circuits or processors configured to:

receive a bitstream comprising a sequence parameter set (SPS);

parse the bitstream to obtain a luminance quantization parameter (QP) and information of a chroma QP mapping table which associates a QP index (QPi) to a chrominance QP (QPc), wherein the chroma QP mapping table is signaled in the SPS;

obtain a QPi based at least in part on the obtained luminance QP;

obtain the chroma QP mapping table based on the obtained information of the chroma QP mapping table;

obtain a first QPc based on the obtained chroma QP mapping table and the obtained QPi; and

obtain a second QPc based on the first QPc, wherein

qPChroma=Clip3(−QpBdOffset,63,Qp Y );

qPCb=ChromaQpTable[0][qPChroma];

qPCr=ChromaQpTable[1][qPChroma]; or

qPCbCr=ChromaQpTable[2][qPChroma];

wherein the QpY represents the luminance QP;

wherein the ChromaQpTable represents the chroma QP mapping table;

wherein the qPChroma represents the QPi;

wherein the qPCb, qPCr or qPCbCr represents the first QPc; and

wherein the QpBdOffset represents a bit depth offset calculated based on a bit depth of samples of luma and chroma arrays using the following:

QpBdOffset=6*bit_depth_minus8,

wherein the bit_depth_minus8 is in a range of 0 to 8, inclusive.

3. A non-transitory computer-readable medium having instructions stored therein, which when executed by a processor, cause a decoder to:

receive a bitstream comprising a sequence parameter set (SPS);

parse the bitstream to obtain a luminance quantization parameter (QP) and information of a chroma QP mapping table which associates a QP index (QPi) to a chrominance QP (QPc), wherein the chroma QP mapping table is signaled in the SPS;

obtain a QPi based at least in part on the luminance QP;

obtain a chroma QP mapping table based on the information of the chroma QP mapping table;

obtain a first QPc based on the chroma QP mapping table and the QPi; and

obtain a second QPc based on the first QPc;

wherein:

qP Chroma =Clip3(−QpBdOffset,63,Qp Y );

qP Cb =ChromaOpTable[0][qP Chroma ];

qP Cr =ChromaQpTable[1][qP Chroma ]; or

qP CbCr =ChromaQpTable[2][qP Chroma ];

wherein the Qp Y represents the luminance QP;

wherein the ChromaOpTable represents the chroma QP mapping table;

wherein the qP Chroma represents the QPi;

wherein the qP Cb , qP Cr or qP CbCr represents the first QPc; and

wherein the QpBdOffset represents a bit depth offset calculated based on a bit depth of samples of luma and chroma arrays using the following:

QpBdOffset=6*bit_depth_minus8,

wherein the bit_depth_minus8 is in a range of 0 to 8, inclusive.

Priority Claims (1)

Continuity (6)

References Cited (36)