# US 2019/0174130 A1 · Method of run-length coding for palette predictor

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- Number: US 2019/0174130 A1
- Document ID: US20190174130A1
- Status: Published application
- Kind: A1
- Application number: 16/267,467
- Filed: 2019-02-05
- Published: 2019-06-06
- Earliest claimed: 2014-06-20
- Assignees: Hfi Innovation Inc.
- Applicants: Hfi Innovation Inc.
- Inventors: Shih-Ta HSIANG
- Web page: https://patentgrep.com/patent/US20190174130A1

## CPC

- H04N 19/13: Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
- H04N 19/176: the region being a block, e.g. a macroblock
- 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 19/91: Entropy coding, e.g. variable length coding [VLC] or arithmetic coding
- H04N 19/93: Run-length coding
- H04N 19/124: Quantisation
- H04N 19/96: Tree coding, e.g. quad-tree coding
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

Methods and apparatus of palette coding based on a palette predictor in a video coding system are disclosed. A set of run lengths associated with re-use flags of a current palette with respect to a palette predictor is determined and the set of run lengths includes an Escape code to indicate an end of run length coding for the re-use flags of the current palette. A set of code values is determined for the set of run lengths by adaptively assigning an Escape code value to the Escape code depending on a current index of predictor run length coding. The set of run lengths is then encoded or decoded according to the set of code values. According to another method, a context model is determined for at least a portion of the binary string depending on current coding information, previous coding information or both.

## Claims

### Claim 1

A method of palette coding based on a palette predictor in a video coding system, the method comprising:
determining a set of run lengths associated with re-use flags of a current palette with respect to a palette predictor, wherein the re-use flags of the current palette indicate whether respective entries of the palette predictor are re-used by the current palette, and the set of run lengths includes an Escape code to indicate an end of run length coding for the re-use flags of the current palette;
determining a set of code values for the set of run lengths by adaptively assigning an Escape code value to the Escape code depending on a current index of predictor run length coding; and
encoding or decoding the set of run lengths according to the set of code values.

### Claim 2 (depends on 1)

The method of claim 1, wherein the Escape code value assigned to the Escape code further depends on a number of palette colors in a previous block coded in a palette mode.

### Claim 3 (depends on 1)

The method of claim 1, wherein a value of two is assigned to the Escape code if the current index of predictor run length coding is less than a total number of palette colors in a previous block coded in a palette mode, and a value of one is assigned to the Escape code otherwise.

### Claim 4

An apparatus for palette coding based on a palette predictor in a video coding system, the apparatus comprising one or more electronic circuits or processors arranged to:
determine a set of run lengths associated with re-use flags of a current palette with respect to a palette predictor, wherein the re-use flags of the current palette indicate whether respective entries of the palette predictor are re-used by the current palette, and the set of run lengths includes an Escape code to indicate an end of run length coding for the re-use flags of the current palette;
determine a set of code values for the set of run lengths by adaptively assigning an Escape code value to the Escape code depending on a current index of predictor run length coding; and
encode or decode the set of run lengths according to the set of code values.

### Claim 5 (depends on 4)

The apparatus of claim 4, wherein the Escape code value assigned to the Escape code further depends on a number of palette colors in a previous block coded in a palette mode.

### Claim 6 (depends on 4)

The apparatus of claim 4, wherein a value of two is assigned to the Escape code if the current index of predictor run length coding is less than a total number of palette colors in a previous block coded in a palette mode, and a value of one is assigned to the Escape code otherwise.