# US 12,003,783 B2 · Adaptive loop filtering (ALF) for video coding

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

- Number: US 12,003,783 B2
- Document ID: US12003783B2
- Status: Granted
- Kind: B2
- Application number: 17/592,981
- Filed: 2022-02-04
- Published: 2022-05-19
- Granted: 2024-06-04
- Earliest claimed: 2011-12-20
- Assignees: Texas Instruments Incorporated
- Applicants: Texas Instruments Incorporated
- Inventors: Madhukar Budagavi; Minhua Zhou
- Web page: https://patentgrep.com/patent/US12003783B2

## CPC

- H04N 19/82: involving filtering within a prediction loop
- H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence)
- H04N 19/86: involving reduction of coding artifacts, e.g. of blockiness
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A method for adaptive loop filtering of a reconstructed picture in a video encoder is provided that includes determining whether or not sample adaptive offset (SAO) filtering is applied to the reconstructed picture, and using adaptive loop filtering with no offset for the reconstructed picture when the SAO filtering is determined to be applied to the reconstructed picture.

## Claims

### Claim 1

A method comprising:
receiving, at a decoder, a bit stream that includes signal parameters and an adaptive loop filter (ALF) signal that selectively indicates no offset when sample adaptive offset (SAO) filtering was applied and failing to indicate no offset when SAO filtering was not applied, wherein the signal parameters are associated with a set of pixels in a region;
in response to the ALF signal indicating no offset:
decoding, by the decoder, the signal parameters to generate a set of coefficients;
applying, by the decoder, ALF filtering on the set of pixels based on the set of coefficients to generate filtered data; and
outputting, by the decoder, the filtered data.

### Claim 2 (depends on 1)

The method of claim 1, wherein:
the ALF filtering is determined by computing a filtered pixel value q(x,y) for each pixel p(x,y) of the pixels as per q (x,y)=Σi=0Ncipi(x,y), where N+1 is a number of the set of coefficients and ci are the coefficients.

### Claim 3 (depends on 1)

The method of claim 1, wherein;
the region includes a plurality of rows; and
the signal parameters are signaled for the set of pixels associated with a first row of the region.

### Claim 4 (depends on 1)

The method of claim 1, wherein:
the region is a first region of a plurality of regions; and
the signal parameters are signaled for the set of pixels associated with the first region.

### Claim 5 (depends on 1)

The method of claim 1, further comprising:
in response to the ALF signal failing to indicate no offset:
decoding, by the decoder, the signal parameters to generate the set of coefficients and a set of offsets;
applying, by the decoder, the ALF filtering on the set of pixels based on the set of coefficients and the set of offsets to generate the filtered data; and
outputting, by the decoder, the filtered data.

### Claim 6 (depends on 1)

The method of claim 1, wherein:
a flag indicates no offset.

### Claim 7

A decoder, comprising:
entropy decoding component configured to receive a bit stream that includes signal parameters and an adaptive loop filter (ALF) signal that selectively indicates no offset when sample adaptive offset (SAO) filtering has been applied and fails to indicate no offset when SAO filtering was not applied, wherein the signal parameters are associated with a set of pixels in a region; and
in response to the ALF signal indicating no offset:
the entropy decoding component is further configured to decode the signal parameters to generate a set of coefficients; and
an ALF component is configured to apply ALF filtering on the set of pixels based on the set of coefficients to generate filtered data.

### Claim 8 (depends on 7)

The decoder of claim 7, wherein:
the ALF filtering is determined by computing a filtered pixel value q(x,y) for each pixel p(x,y) of the pixels as per q (x, y)=Σi=0Ncipi(x,y), where N+1 is a number of the set of coefficients and ci are the coefficients.

### Claim 9 (depends on 7)

The decoder of claim 7, wherein:
the region includes a plurality of rows; and
the signal parameters are signaled for the set of pixels associated with a first row of the region.

### Claim 10 (depends on 7)

The decoder of claim 7, wherein:
the region is a first region of a plurality of regions; and
the signal parameters are signaled for the set of pixels associated with the first region.

### Claim 11 (depends on 7)

The decoder of claim 7, further comprising:
in response to the ALF signal failing to indicate no offset:
the entropy decoding component is further configured to decode the signal parameters to generate the set of coefficients and a set of offsets; and
wherein the ALF component is configured to apply the ALF filtering on the set of pixels based on the set of coefficients and the set of offsets to generate the filtered data.

### Claim 12 (depends on 7)

The decoder of claim 7, wherein:
a flag indicates no offset.

### Claim 13 (depends on 7)

The decoder of claim 7, further including:
a reference buffer to receive the filtered data from the ALF component.

### Claim 14 (depends on 7)

The decoder of claim 7, further including:
a deblocking filter including a deblocking filter input configured to receive the set of coefficients, and a deblocking filter output.

### Claim 15 (depends on 14)

The decoder of claim 14, further including:
a sample adaptive offset (SAO) filter including a SAO input coupled to the deblocking filter output, and a SAO output coupled to the ALF component.