# US 11,909,974 B2 · Chroma quantization parameter adjustment in video encoding and decoding

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- Number: US 11,909,974 B2
- Document ID: US11909974B2
- Status: Granted
- Kind: B2
- Application number: 17/043,280
- Filed: 2019-03-27
- Published: 2021-02-18
- Granted: 2024-02-20
- Earliest claimed: 2018-03-30
- Assignees: InterDigital VC Holdings, Inc.
- Applicants: InterDigital VC Holdings, Inc.
- Inventors: Fabrice Leleannec; Franck Galpin; Tangi Poirier; Edouard Francois
- Web page: https://patentgrep.com/patent/US11909974B2

## CPC

- H04N 19/124: Quantisation
- H04N 19/146: Data rate or code amount at the encoder output
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/186: the unit being a colour or a chrominance component
- H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence)
- H04N 19/51: Motion estimation or motion compensation
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N 19/96: Tree coding, e.g. quad-tree coding
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A video coding system uses a value of a chroma quantization parameter table to quantize or de-quantize chroma values of a block of the video, the chroma quantization parameter table being directly coded in a set of parameters at the picture level or at the sequence level of the coded video stream. A corresponding encoding method, encoding device, decoding method, decoding device, and non-transitory readable medium are proposed.

## Claims

### Claim 1

A method comprising:
selecting, for a block of an image, a chroma quantization parameters table from amongst a plurality of pre-determined chroma quantization parameters tables based on an encoding performance level;
encoding said block based on the selected chroma quantization parameters table, wherein the encoding comprises quantizing chroma values of said block according to said at least one value of the selected chroma quantization parameters table; and
generating a bitstream comprising at least said encoded block and high-level syntax information comprising a flag representative of the encoding performance level.

### Claim 2 (depends on 1)

The method of claim 1, wherein the encoding performance level is automatically chosen according to information related to coding, said information being related to the coding tree configuration or the coding mode or the partitioning mode.

### Claim 3 (depends on 1)

The method of claim 1, wherein the plurality of pre-determined chroma quantization parameters tables are one-directional tables for which outputs are greater or equal to zero, and a plurality of values of each table are increasing as a function of the input index.

### Claim 4 (depends on 1)

A non-transitory computer readable medium comprising computer-executable instructions to enable a processor to perform the method of claim 1.

### Claim 5

A method comprising:
accessing metadata for a block of an image or video, said metadata comprising a high-level syntax flag representative of an encoding performance level;
selecting a chroma quantization parameters table from amongst a plurality of pre-determined chroma quantization parameters tables based on the high-level syntax flag representative of the encoding performance level; and
de-quantizing chroma values of the block using at least one value of the selected chroma quantization parameters table.

### Claim 6 (depends on 5)

The method of claim 5, further comprising producing a reconstructed image based on the de-quantized chroma values of a plurality of blocks of the image.

### Claim 7 (depends on 5)

The method of claim 5, wherein the plurality of pre-determined chroma quantization parameters tables are one-directional tables for which outputs are greater or equal to zero, and a plurality of values of each table are increasing as a function of the input index.

### Claim 8 (depends on 5)

A non-transitory computer readable medium comprising computer-executable instructions to enable a processor to perform the method of claim 5.

### Claim 9

A device comprising:
a non-transitory computer readable medium storing a plurality of pre-determined chroma quantization parameters tables; and
one or more processors configured to:
select, for a block of an image, a chroma quantization parameters table from amongst the plurality of pre-determined chroma quantization parameters tables based on an encoding performance level;
encode said block based on the selected chroma quantization parameters table, wherein the encoding comprises quantizing chroma values of said block according to said at least one value of the selected chroma quantization parameters table; and
generate a bitstream comprising at least said encoded block and high-level syntax information comprising a flag representative of the encoding performance level.

### Claim 10 (depends on 9)

The device of claim 9, wherein the encoding performance level is automatically chosen according to information related to coding, said information being related to the coding tree configuration or the coding mode or the partitioning mode.

### Claim 11 (depends on 9)

The device of claim 9, wherein the plurality of pre-determined chroma quantization parameters tables are one-directional tables for which outputs are greater or equal to zero, and a plurality of values of each table are increasing as a function of the input index.

### Claim 12

A device comprising:
a non-transitory computer readable medium storing a plurality of pre-determined chroma quantization parameters tables; and
one or more processors configured to:
access metadata for a block of an image or video, said metadata comprising a high-level syntax flag representative of an encoding performance level;
select a chroma quantization parameters table from amongst the plurality of pre-determined chroma quantization parameters tables based on the high-level syntax flag representative of the encoding performance level;
de-quantize chroma values of the block using at least one value of the selected chroma quantization parameters table; and
produce a reconstructed image based on the de-quantized chroma values of a plurality of blocks of the image.

### Claim 13 (depends on 12)

The device of claim 12, further comprising a display configured to display the reconstructed image.

### Claim 14 (depends on 12)

The device of claim 12, further comprising an antenna configured to receive a signal over the air comprising an image or a video.

### Claim 15 (depends on 12)

The device of claim 12, further comprising an output configured to provide the reconstructed image.

### Claim 16 (depends on 12)

The device of claim 12, wherein the plurality of pre-determined chroma quantization parameters tables are one-directional tables for which outputs are greater or equal to zero, and a plurality of values of each table are increasing as a function of the input index.

### Claim 17 (depends on 1)

The method of claim 1, wherein the high-level syntax information comprising the flag representative of the encoding performance level is inserted in a sequence parameter set or a picture parameter set or a slice header.

### Claim 18 (depends on 5)

The method of claim 5, wherein the high-level syntax information comprising the flag representative of the encoding performance level is inserted in a sequence parameter set or a picture parameter set or a slice header.

### Claim 19 (depends on 9)

The device of claim 9, wherein the high-level syntax information comprising the flag representative of the encoding performance level is inserted in a sequence parameter set or a picture parameter set or a slice header.

### Claim 20 (depends on 12)

The device of claim 12, wherein the high-level syntax information comprising the flag representative of the encoding performance level is inserted in a sequence parameter set or a picture parameter set or a slice header.