# US 11,445,192 B2 · Chroma quantization parameter extension

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- Number: US 11,445,192 B2
- Document ID: US11445192B2
- Status: Granted
- Kind: B2
- Application number: 16/995,735
- Filed: 2020-08-17
- Published: 2020-12-03
- Granted: 2022-09-13
- Earliest claimed: 2012-01-20
- Assignees: Sony Group Corporation
- Applicants: Velos Media, LLC
- Inventors: Jun Xu; Kazushi Sato; Ehsan Maani
- Web page: https://patentgrep.com/patent/US11445192B2

## CPC

- H04N 19/124: Quantisation
- H04N 19/126: Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
- H04N 19/13: Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
- H04N 19/147: according to rate distortion criteria (rate-distortion as a criterion for motion estimation H04N19/567)
- H04N 19/149: by estimating the code amount by means of a model, e.g. mathematical model or statistical model
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/174: the region being a slice, e.g. a line of blocks or a group of blocks
- 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 19/61: in combination with predictive coding
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N 19/80: Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation (H04N19/635, H04N19/86 take precedence)
- H04N 19/172: the region being a picture, frame or field
- H04N 19/436: using parallelised computational arrangements
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

The quantization parameters (QP) for Chroma are extended up to and more preferably to the same range as Luma QP (e.g., 0 to 51). Previous, values of Chroma QP only extended up to 39. Techniques are provided for determining extended Chroma QP values (e.g., for Cr and Cb) based on the Luma QP and picture level chroma offsets. In one preferred embodiment, slice level offsets are added making the method particularly well-suited for slice level parallel processing. The extension of Chroma QP enhances functionality, flexibility and friendliness of the High Efficiency Video Coding (HEVC) standard for various applications.

## Claims

### Claim 1

A decoding apparatus, comprising:
a processor; and
a memory storing computer instructions which, when executed by the processor, cause the decoding apparatus to:
obtain a picture level chroma QP offset and a slice level chroma QP offset from an encoded video;
derive a chroma QP based on a parameter determined by adding the picture level chroma QP offset and the slice level chroma QP offset to a luma QP, the chroma QP having a range equal to a luma QP range of 0 to 51;
perform inverse quantization based on the derived chroma QP.

### Claim 2 (depends on 1)

The decoding apparatus of claim 1, wherein the instructions further cause the decoding apparatus to:
clip the chroma QP, wherein:
when the chroma QP is less than 0, set the derived chroma QP to 0, and
when the chroma QP is greater than 51, set the derived chroma QP to 51.

### Claim 3 (depends on 1)

The decoding apparatus of claim 1,
wherein the slice level chroma QP offset is included in a slice header syntax in the encoded video, and
wherein the instructions further cause the decoding apparatus to obtain the slice level chroma QP offset from the slice header syntax.

### Claim 4 (depends on 1)

The decoding apparatus of claim 1,
wherein the picture level chroma QP offset is included as a picture parameter set syntax in the encoded video, and
wherein the instructions are further configured to cause the decoding apparatus to obtain the picture level chroma QP offset from the picture parameter set syntax.

### Claim 5 (depends on 1)

The decoding apparatus of claim 1, wherein the instructions are further configured to cause the decoding apparatus to:
generate transform data based on the inverse quantization; and
execute inverse orthogonal-transformation on the transform data.

### Claim 6

A decoding method, comprising:
obtaining, by a decoding apparatus, a picture level chroma QP offset and a slice level chroma QP offset from an encoded video;
deriving, by the decoding apparatus, a chroma QP based on a parameter determined by adding the picture level chroma QP offset and the slice level chroma QP offset to a luma QP, the chroma QP having a range equal to a luma QP range of 0 to 51; and
performing, by the decoding apparatus, inverse quantization (60) based on the chroma QP.

### Claim 7 (depends on 6)

The decoding method of claim 6, comprising:
clipping the chroma QP, wherein:
when the chroma QP is less than 0, set the derived chroma QP to 0, and
when the chroma QP is greater than 51, set the derived chroma QP to 51.

### Claim 8 (depends on 6)

The decoding method of claim 6, further comprising,
obtaining, by the decoding apparatus, the slice level chroma QP offset from a slice header syntax,
wherein the slice level chroma QP offset is included in the slice header syntax of the encoded video.

### Claim 9 (depends on 6)

The decoding method of claim 6, further comprising:
obtaining, by the decoding apparatus, the picture level chroma QP offset from a picture parameter set syntax,
wherein the picture level chroma QP offset is included in the picture parameter set syntax of the encoded video.

### Claim 10 (depends on 6)

The decoding method of claim 6, further comprising:
generating, by the decoding apparatus, transform data based on the inverse quantization; and
executing, by the decoding apparatus, inverse orthogonal-transformation on the transform data.