# US 2017/0257529 A1 · Methods and systems for generating color remapping information supplemental enhancement information messages for video

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2017/0257529 A1
- Document ID: US20170257529A1
- Status: Published application
- Kind: A1
- Application number: 15/436,313
- Filed: 2017-02-17
- Published: 2017-09-07
- Earliest claimed: 2016-03-01
- Assignees: QUALCOMM Incorporated
- Applicants: QUALCOMM Incorporated
- Inventors: Adarsh Krishnan Ramasubramonian; Joel Sole Rojals; Dmytro Rusanovskyy; Done Bugdayci Sansli; Marta Karczewicz
- Web page: https://patentgrep.com/patent/US20170257529A1

## CPC

- H04N 1/60: Colour correction or control {(H04N1/54 takes precedence)}
- G06T 7/90: Determination of colour characteristics
- H04N 19/186: the unit being a colour or a chrominance component
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- G06T 2207/10016: Video; Image sequence
- G06T 2207/10024: Color image
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

Systems, methods, and computer readable media are described for providing improved color remapping. In some examples, a video bitstream is obtained that includes a plurality of pictures having a first color characteristic. A color remapping information (CRI) supplemental enhancement information (SEI) message is identified from the video bitstream. A restriction is placed on the CRI SEI message such that a value of a syntax element of the CRI SEI message is restricted based on a condition. One or more samples of the plurality of pictures is remapped from the first color characteristic to a second color characteristic using a color remapping model of the CRI SEI message according to the restriction. In some cases, the condition is a chroma format of the plurality of pictures, in which case the value of the syntax element of the CRI SEI message is restricted based on the chroma format. In some cases, the condition is a color remap value identifying a purpose of the color remapping model of the CRI SEI message, in which case the value of the syntax element of the CRI SEI message is restricted based on the color remap value.

## Claims

### Claim 1

A method of processing video data, the method comprising:
obtaining a video bitstream, the video bitstream including a plurality of pictures having a first color characteristic;
identifying, from the video bitstream, a color remapping information (CRI) supplemental enhancement information (SEI) message, wherein one or more values of at least one syntax element of the CRI SEI message are restricted based on a condition; and
remapping one or more samples of the plurality of pictures from the first color characteristic to a second color characteristic using a color remapping model of the CRI SEI message.

### Claim 2 (depends on 1)

The method of claim 1, further comprising:
determining a chroma format of the plurality of pictures, wherein the condition is the chroma format of the plurality of pictures, and wherein the one or more values of the at least one syntax element of the CRI SEI message are restricted based on the chroma format of the plurality of pictures.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
determining a color remap value identifying a purpose of the color remapping model of the CRI SEI message, wherein the condition is the color remap value, and wherein the one or more values of the at least one syntax element of the CRI SEI message are restricted based on the color remap value.

### Claim 4 (depends on 1)

The method of claim 1, further comprising:
determining a chroma format of the plurality of pictures; and
determining a color remap value identifying a purpose of the color remapping model of the CRI SEI message;
wherein the condition is the chroma format of the plurality of pictures and the color remap value, and wherein the one or more values of the at least one syntax element of the CRI SEI message are restricted based on the chroma format of the plurality of pictures and based on the color remap value.

### Claim 5 (depends on 1)

The method of claim 1, wherein the color remapping model of the CRI SEI message includes a pre-lookup table, a color remap matrix, and a post-lookup table.

### Claim 6 (depends on 5)

The method of claim 5, wherein the at least one syntax element of the CRI SEI message includes a color remap matrix present flag indicating whether the color remap matrix is present, and further comprising:
determining, based on the condition, the color remap matrix present flag is restricted to be equal to a value indicating the color remap matrix is not present; and
applying the color remapping model to the one or more samples without applying the color remap matrix when the color remap matrix present flag is restricted to be equal to the value.

### Claim 7 (depends on 6)

The method of claim 6, wherein the condition is a chroma format of the plurality of pictures, and wherein the color remap matrix present flag is determined to be restricted to be equal to the value when the chroma format is determined to be a 4:2:2 chroma format, a 4:2:0 chroma format, or a 4:0:0 chroma format.

### Claim 8 (depends on 6)

The method of claim 6, further comprising:
inferring the color remap matrix as being equal to an identity matrix when the color remap matrix present flag is restricted to be equal to the value; and
wherein applying the color remapping model to the one or more samples includes applying the identity matrix.

### Claim 9 (depends on 5)

The method of claim 5, wherein the at least one syntax element of the CRI SEI message includes a post-lookup table number syntax element indicating input and output values of the post-lookup table, and further comprising:
determining, based on the condition, the post-lookup table number syntax element is restricted to be equal to a value indicating the input and output values are equal to 0; and
applying the color remapping model to the one or more samples without applying the post-lookup table when the post-lookup table number syntax element is restricted to be equal to the value.

### Claim 10 (depends on 9)

The method of claim 9, further comprising:
inferring the post-lookup table as being an identity mapping when the post-lookup table number syntax element is restricted to be equal to the value; and
wherein applying the color remapping model to the one or more samples includes performing the identity mapping.

### Claim 11 (depends on 5)

The method of claim 5, wherein the at least one syntax element of the CRI SEI message includes a pre-lookup table number syntax element indicating input and output values of the pre-lookup table, and further comprising:
determining, based on the condition, the pre-lookup table number syntax element is restricted to be equal to a value indicating the input and output values are equal to 0; and
applying the color remapping model to the one or more samples without applying the pre-lookup table when the pre-lookup table number syntax element is restricted to be equal to the value.

### Claim 12 (depends on 11)

The method of claim 11, further comprising:
inferring the pre-lookup table as being an identity mapping when the pre-lookup table number syntax element is restricted to be equal to the value; and
wherein applying the color remapping model to the one or more samples includes performing the identity mapping.

### Claim 13

An apparatus comprising:
a memory configured to store video data; and
a processor configured to:
obtain a video bitstream, the video bitstream including a plurality of pictures having a first color characteristic;
identify, from the video bitstream, a color remapping information (CRI) supplemental enhancement information (SEI) message, wherein one or more values of at least one syntax element of the CRI SEI message are restricted based on a condition; and
remap one or more samples of the plurality of pictures from the first color characteristic to a second color characteristic using a color remapping model of the CRI SEI message.

### Claim 14 (depends on 13)

The apparatus of claim 13, wherein the processor is configured to:
determine a chroma format of the plurality of pictures, wherein the condition is the chroma format of the plurality of pictures, and wherein the one or more values of the at least one syntax element of the CRI SEI message are restricted based on the chroma format of the plurality of pictures.

### Claim 15 (depends on 13)

The apparatus of claim 13, wherein the processor is configured to:
determine a color remap value identifying a purpose of the color remapping model of the CRI SEI message, wherein the condition is the color remap value, and wherein the one or more values of the at least one syntax element of the CRI SEI message are restricted based on the color remap value.

### Claim 16 (depends on 13)

The apparatus of claim 13, wherein the processor is configured to:
determine a chroma format of the plurality of pictures; and
determine a color remap value identifying a purpose of the color remapping model of the CRI SEI message;
wherein the condition is the chroma format of the plurality of pictures and the color remap value, and wherein the one or more values of the at least one syntax element of the CRI SEI message are restricted based on the chroma format of the plurality of pictures and based on the color remap value.

### Claim 17 (depends on 13)

The apparatus of claim 13, wherein the color remapping model of the CRI SEI message includes a pre-lookup table, a color remap matrix, and a post-lookup table.

### Claim 18 (depends on 17)

The apparatus of claim 17, wherein the at least one syntax element of the CRI SEI message includes a color remap matrix present flag indicating whether the color remap matrix is present, and wherein the processor is configured to:
determine, based on the condition, the color remap matrix present flag is restricted to be equal to a value indicating the color remap matrix is not present; and
apply the color remapping model to the one or more samples without applying the color remap matrix when the color remap matrix present flag is restricted to be equal to the value.

### Claim 19 (depends on 18)

The apparatus of claim 18, wherein the condition is a chroma format of the plurality of pictures, and wherein the color remap matrix present flag is determined to be restricted to be equal to the value when the chroma format is determined to be a 4:2:2 chroma format, a 4:2:0 chroma format, or a 4:0:0 chroma format.

### Claim 20 (depends on 18)

The apparatus of claim 18, wherein the processor is configured to:
infer the color remap matrix as being equal to an identity matrix when the color remap matrix present flag is restricted to be equal to the value; and
wherein applying the color remapping model to the one or more samples includes applying the identity matrix.

### Claim 21 (depends on 17)

The apparatus of claim 17, wherein the at least one syntax element of the CRI SEI message includes a post-lookup table number syntax element indicating input and output values of the post-lookup table, and wherein the processor is configured to:
determine, based on the condition, the post-lookup table number syntax element is restricted to be equal to a value indicating the input and output values are equal to 0; and
apply the color remapping model to the one or more samples without applying the post-lookup table when the post-lookup table number syntax element is restricted to be equal to the value.

### Claim 22 (depends on 21)

The apparatus of claim 21, wherein the processor is configured to:
infer the post-lookup table as being an identity mapping when the post-lookup table number syntax element is restricted to be equal to the value; and
wherein applying the color remapping model to the one or more samples includes performing the identity mapping.

### Claim 23 (depends on 17)

The apparatus of claim 17, wherein the at least one syntax element of the CRI SEI message includes a pre-lookup table number syntax element indicating input and output values of the pre-lookup table, and wherein the processor is configured to:
determine, based on the condition, the pre-lookup table number syntax element is restricted to be equal to a value indicating the input and output values are equal to 0; and
apply the color remapping model to the one or more samples without applying the pre-lookup table when the pre-lookup table number syntax element is restricted to be equal to the value.

### Claim 24 (depends on 23)

The apparatus of claim 23, wherein the processor is configured to:
infer the pre-lookup table as being an identity mapping when the pre-lookup table number syntax element is restricted to be equal to the value; and
wherein applying the color remapping model to the one or more samples includes performing the identity mapping.

### Claim 25 (depends on 13)

The apparatus of claim 13, further comprising:
a display for displaying the remapped one or more samples.

### Claim 26 (depends on 13)

The apparatus of claim 13, wherein the apparatus comprises a mobile device with a camera.

### Claim 27

A computer readable medium having stored thereon instructions that when executed by a processor perform a method, including:
obtaining a video bitstream, the video bitstream including a plurality of pictures having a first color characteristic;
identifying, from the video bitstream, a color remapping information (CRI) supplemental enhancement information (SEI) message, wherein one or more values of at least one syntax element of the CRI SEI message are restricted based on a condition; and
remapping one or more samples of the plurality of pictures from the first color characteristic to a second color characteristic using a color remapping model of the CRI SEI message.

### Claim 28

An apparatus comprising:
means for obtaining a video bitstream, the video bitstream including a plurality of pictures having a first color characteristic;
means for identifying, from the video bitstream, a color remapping information (CRI) supplemental enhancement information (SEI) message, wherein one or more values of at least one syntax element of the CRI SEI message are restricted based on a condition; and
means for remapping one or more samples of the plurality of pictures from the first color characteristic to a second color characteristic using a color remapping model of the CRI SEI message.

### Claim 29

A method of encoding video data, the method comprising:
obtaining video data at an encoder;
encoding, into a video bitstream, a plurality of pictures based on the video data, the plurality of pictures having a first color characteristic; and
encoding, into the video bitstream, a color remapping information (CRI) supplemental enhancement information (SEI) message, the CRI SEI message including a color remapping model for remapping one or more samples of the plurality of pictures from the first color characteristic to a second color characteristic, wherein one or more values of at least one syntax element of the CRI SEI message are restricted based on a condition.

### Claim 30 (depends on 29)

The method of claim 29, wherein the condition is a chroma format of the plurality of pictures, and wherein the one or more values of the at least one syntax element of the CRI SEI message are restricted based on the chroma format of the plurality of pictures.

### Claim 31 (depends on 29)

The method of claim 29, wherein the condition is a color remap value identifying a purpose of the color remapping model of the CRI SEI message, and wherein the one or more values of the at least one syntax element of the CRI SEI message are restricted based on the color remap value.

### Claim 32 (depends on 29)

The method of claim 29, wherein the condition is a chroma format of the plurality of pictures and a color remap value identifying a purpose of the color remapping model of the CRI SEI message, and wherein the one or more values of the at least one syntax element of the CRI SEI message are restricted based on the chroma format of the plurality of pictures and based on the color remap value.

### Claim 33 (depends on 29)

The method of claim 29, wherein the color remapping model of the CRI SEI message includes a pre-lookup table, a color remap matrix, and a post-lookup table.

### Claim 34 (depends on 33)

The method of claim 33, wherein the at least one syntax element of the CRI SEI message includes a color remap matrix present flag indicating whether the color remap matrix is present, and wherein the color remap matrix present flag is restricted to be equal to a value based on the condition, the value of the color remap matrix present flag indicating the color remap matrix is not present.

### Claim 35 (depends on 34)

The method of claim 34, wherein the condition is a chroma format of the plurality of pictures, and wherein the color remap matrix present flag is restricted to be equal to the value when the chroma format is determined to be a 4:2:2 chroma format, a 4:2:0 chroma format, or a 4:0:0 chroma format.

### Claim 36 (depends on 34)

The method of claim 34, wherein the color remap matrix is inferred as being equal to an identity matrix when the color remap matrix present flag is restricted to be equal to the value.

### Claim 37 (depends on 33)

The method of claim 33, wherein the at least one syntax element of the CRI SEI message includes a post-lookup table number syntax element indicating input and output values of the post-lookup table, and wherein the post-lookup table number syntax element is restricted to be equal to a value based on the condition, the value of the post-lookup table number syntax element indicating the input and output values are equal to 0.

### Claim 38 (depends on 37)

The method of claim 37, wherein the post-lookup table is inferred as being an identity mapping when the post-lookup table number syntax element is restricted to be equal to the value.

### Claim 39 (depends on 33)

The method of claim 33, wherein the at least one syntax element of the CRI SEI message includes a pre-lookup table number syntax element indicating input and output values of the pre-lookup table, and wherein the pre-lookup table number syntax element is restricted to be equal to a value based on the condition, the value of the pre-lookup table number syntax element indicating the input and output values are equal to 0.

### Claim 40 (depends on 39)

The method of claim 39, wherein the pre-lookup table is inferred as being an identity mapping when the pre-lookup table number syntax element is restricted to be equal to the value.

### Claim 41

An apparatus comprising:
a memory configured to store video data; and
a processor configured to:
obtain video data at an encoder;
encode, into a video bitstream, a plurality of pictures based on the video data, the plurality of pictures having a first color characteristic; and
encode, into the video bitstream, a color remapping information (CRI) supplemental enhancement information (SEI) message, the CRI SEI message including a color remapping model for remapping one or more samples of the plurality of pictures from the first color characteristic to a second color characteristic, wherein one or more values of at least one syntax element of the CRI SEI message are restricted based on a condition.

### Claim 42 (depends on 41)

The apparatus of claim 41, wherein the condition is a chroma format of the plurality of pictures, and wherein the one or more values of the at least one syntax element of the CRI SEI message are restricted based on the chroma format of the plurality of pictures.

### Claim 43 (depends on 41)

The apparatus of claim 41, wherein the condition is a color remap value identifying a purpose of the color remapping model of the CRI SEI message, and wherein the one or more values of the at least one syntax element of the CRI SEI message are restricted based on the color remap value.

### Claim 44 (depends on 41)

The apparatus of claim 41, wherein the condition is a chroma format of the plurality of pictures and a color remap value identifying a purpose of the color remapping model of the CRI SEI message, and wherein the one or more values of the at least one syntax element of the CRI SEI message are restricted based on the chroma format of the plurality of pictures and based on the color remap value.

### Claim 45 (depends on 41)

The apparatus of claim 41, wherein the color remapping model of the CRI SEI message includes a pre-lookup table, a color remap matrix, and a post-lookup table.

### Claim 46 (depends on 45)

The apparatus of claim 45, wherein the at least one syntax element of the CRI SEI message includes a color remap matrix present flag indicating whether the color remap matrix is present, and wherein the color remap matrix present flag is restricted to be equal to a value based on the condition, the value of the color remap matrix present flag indicating the color remap matrix is not present.

### Claim 47 (depends on 46)

The apparatus of claim 46, wherein the condition is a chroma format of the plurality of pictures, and wherein the color remap matrix present flag is restricted to be equal to the value when the chroma format is determined to be a 4:2:2 chroma format, a 4:2:0 chroma format, or a 4:0:0 chroma format.

### Claim 48 (depends on 46)

The apparatus of claim 46, wherein the color remap matrix is inferred as being equal to an identity matrix when the color remap matrix present flag is restricted to be equal to the value.

### Claim 49 (depends on 45)

The apparatus of claim 45, wherein the at least one syntax element of the CRI SEI message includes a post-lookup table number syntax element indicating input and output values of the post-lookup table, and wherein the post-lookup table number syntax element is restricted to be equal to a value based on the condition, the value of the post-lookup table number syntax element indicating the input and output values are equal to 0.

### Claim 50 (depends on 49)

The apparatus of claim 49, wherein the post-lookup table is inferred as being an identity mapping when the post-lookup table number syntax element is restricted to be equal to the value.

### Claim 51 (depends on 45)

The apparatus of claim 45, wherein the at least one syntax element of the CRI SEI message includes a pre-lookup table number syntax element indicating input and output values of the pre-lookup table, and wherein the pre-lookup table number syntax element is restricted to be equal to a value based on the condition, the value of the pre-lookup table number syntax element indicating the input and output values are equal to 0.

### Claim 52 (depends on 51)

The apparatus of claim 51, wherein the pre-lookup table is inferred as being an identity mapping when the pre-lookup table number syntax element is restricted to be equal to the value.

### Claim 53 (depends on 41)

The apparatus of claim 41, wherein the apparatus comprises a mobile device with a camera for capturing pictures.

### Claim 54

A computer readable medium having stored thereon instructions that when executed by a processor perform a method, including:
obtaining video data at an encoder;
encoding, into a video bitstream, a plurality of pictures based on the video data, the plurality of pictures having a first color characteristic; and
encoding, into the video bitstream, a color remapping information (CRI) supplemental enhancement information (SEI) message, the CRI SEI message including a color remapping model for remapping one or more samples of the plurality of pictures from the first color characteristic to a second color characteristic, wherein one or more values of at least one syntax element of the CRI SEI message are restricted based on a condition.

### Claim 55

An apparatus comprising:
means for obtaining video data at an encoder;
means for encoding, into a video bitstream, a plurality of pictures based on the video data, the plurality of pictures having a first color characteristic; and
means for encoding, into the video bitstream, a color remapping information (CRI) supplemental enhancement information (SEI) message, the CRI SEI message including a color remapping model for remapping one or more samples of the plurality of pictures from the first color characteristic to a second color characteristic, wherein one or more values of at least one syntax element of the CRI SEI message are restricted based on a condition.