# US 2020/0396456 A1 · Methods and apparatus for determining quantization parameter predictors from a plurality of neighboring quantization parameters

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- Number: US 2020/0396456 A1
- Document ID: US20200396456A1
- Status: Published application
- Kind: A1
- Application number: 16/918,069
- Filed: 2020-07-01
- Published: 2020-12-17
- Earliest claimed: 2010-06-10
- Assignees: InterDigital VC Holdings, Inc.
- Applicants: Interdigital Vc Holdings, Inc.
- Inventors: Xiaoan LU; Joel SOLE; Peng YIN; Qian XU; Yunfei ZHENG
- Web page: https://patentgrep.com/patent/US20200396456A1

## CPC

- H04N 19/126: Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
- H04N 19/124: Quantisation
- H04N 19/157: Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
- 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 19/196: being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters (processing of motion vectors H04N19/513)
- H04N 19/197: {including determination of the initial value of an encoding parameter (H04N19/56 takes precedence)}
- H04N 19/198: {including smoothing of a sequence of encoding parameters, e.g. by averaging, by choice of the maximum, minimum or median value}
- H04N 19/51: Motion estimation or motion compensation
- H04N 19/513: Processing of motion vectors
- H04N 19/593: involving spatial prediction techniques
- H04N 19/61: in combination with predictive coding
- H04N 19/139: Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
- H04N 19/52: by predictive encoding
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

Methods and apparatus are provided for determining quantization parameter predictors from a plurality of neighboring quantization parameters. An apparatus includes an encoder for encoding image data for at least a portion of a picture using a quantization parameter predictor for a current quantization parameter to be applied to the image data. The quantization parameter predictor is determined using multiple quantization parameters from previously coded neighboring portions. A difference between the current quantization parameter and the quantization parameter predictor is encoded for signaling to a corresponding decoder.

## Claims

### Claim 1

In a video encoder, a method, comprising:
encoding image data for at least a portion of a picture using a quantization parameter predictor for a current quantization parameter to be applied to the image data, the quantization parameter predictor being determined using multiple quantization parameters from previously coded neighboring portions, and
encoding a difference between the current quantization parameter and the quantization parameter predictor for signaling to a corresponding decoder,
wherein said quantization parameter predictor is determined by finding a mean of the quantization parameters of the previously coded neighboring portion to the left and the previously coded neighboring portion above the portion currently being encoded when these neighboring portions are available, and
if at least one of said neighboring portions is not available, basing the quantization parameter predictor on a quantization parameter for a current slice.

### Claim 2 (depends on 1)

The method of claim 1, wherein the quantization parameter predictor is selected from one or more quantization parameters corresponding to a same portion of the picture as that used for a motion vector prediction, the one or more quantization parameters being among the multiple quantization parameters.

### Claim 3 (depends on 2)

The method of claim 2, wherein a motion vector competition is used to determine the motion vector predictor.

### Claim 4 (depends on 1)

The method of claim 1, wherein the image data is a transform unit, and the difference between the current quantization parameter and the quantization parameter predictor is only encoded when the transform unit includes non-zero coefficients.

### Claim 5

In a video decoder, a method, comprising:
decoding image data for at least a portion of a picture using a quantization parameter predictor for a current quantization parameter to be applied to the image data, the quantization parameter predictor being determined using multiple quantization parameters from previously coded neighboring portions; and
decoding a difference between the current quantization parameter and the quantization parameter predictor for use in decoding the image data, and
wherein said quantization parameter predictor is determined by finding a mean of the quantization parameters of the previously coded neighboring portion to the left and the previously coded neighboring portion above the portion currently being decoded when these neighboring portions are available, and
if at least one of said neighboring portions is not available, basing the quantization parameter predictor on a quantization parameter for a current slice.

### Claim 6 (depends on 5)

The method of claim 5, wherein the quantization parameter predictor is selected from one or more quantization parameters corresponding to a same portion of the picture as that used for a motion vector prediction, the one or more quantization parameters being among the multiple quantization parameters.

### Claim 7 (depends on 6)

The method of claim 6, wherein a motion vector competition is used to determine the motion vector predictor.

### Claim 8 (depends on 5)

The method of claim 5, wherein the image data is a transform unit, and the difference between the current quantization parameter and the quantization parameter predictor is only decoded when the transform unit includes non-zero coefficients.

### Claim 9 (depends on 1)

A non-transitory computer readable storage media having a computer program stored therein, when the computer program is executed by a processor, causing the processor to implement the method of claim 1.