# US 10,504,208 B2 · Method of removing deblocking artifacts

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- Number: US 10,504,208 B2
- Document ID: US10504208B2
- Status: Granted
- Kind: B2
- Application number: 14/349,557
- Filed: 2013-01-08
- Published: 2015-06-04
- Granted: 2019-12-10
- Earliest claimed: 2012-01-09
- Assignees: Infobridge Pte. Ltd.
- Applicants: Infobridge Pte. Ltd.
- Inventors: Min Jang
- Web page: https://patentgrep.com/patent/US10504208B2

## CPC

- H04N 19/124: Quantisation
- H04N 1/409: Edge or detail enhancement; Noise or error suppression
- H04N 19/107: between spatial and temporal predictive coding, e.g. picture refresh
- H04N 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635)
- H04N 19/137: Motion inside a coding unit, e.g. average field, frame or block difference
- H04N 19/14: Coding unit complexity, e.g. amount of activity or edge presence estimation (H04N19/146 takes precedence)
- 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 19/194: involving only two passes
- H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence)
- H04N 19/82: involving filtering within a prediction loop
- H04N 19/86: involving reduction of coding artifacts, e.g. of blockiness
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

Provided is a method determines a boundary strength for each 4-sample edge lying on 8×8 sample grid, determines whether deblocking filtering is performed on the 4-sample edge or not if the boundary strength is not equal to zero, selects a deblocking filter if the deblocking filtering is performed on the 4-sample edge, and filters the 4-sample edge using the selected filter. Accordingly, the computational complexity required to determine the boundary strength according to the present invention is reduced by 50% or more when compared with the HEVC under development. Also, the memory capacity and bandwidth required to determine the boundary strength are reduced by 50% or more without deterioration of image quality.

## Claims

### Claim 1

A method of removing blocking artifacts by a decoding apparatus, the method comprising:
determining, by the decoding apparatus, a boundary strength for only each of every 4-sample edge in a coding unit which lies on grid lines of an 8×8 sample grid and is an edge of a prediction unit or a transform unit;
determining, by the decoding apparatus, whether or not deblocking filtering is performed on the 4-sample edge if the boundary strength for the 4-sample edge is not equal to zero, wherein the boundary strength for the 4-sample edge is determined based on two blocks immediately adjacent to and located on either side of the 4-sample edge;
selecting, by the decoding apparatus, a deblocking filter to be applied among a strong filter and a weak filter if the deblocking filtering is performed on the 4-sample edge;
filtering, by the decoding apparatus, the 4-sample edge using the selected deblocking filter, and
wherein the boundary strength is set equal to 0, 1 or 2.

### Claim 2 (depends on 1)

The method of claim 1, wherein the boundary strength is set equal to zero if the 4-sample edge is not the edge of the transform unit and the 4-sample edge is not the edge of the prediction unit.

### Claim 3 (depends on 1)

The method of claim 1, wherein vertical 4-sample edges are filtered first and then horizontal 4-sample edges are filtered.

### Claim 4 (depends on 3)

The method of claim 3, wherein the boundary strength is set equal to 2 if a prediction unit containing the sample p0 or a prediction unit containing the sample q0 is intra-coded.

### Claim 5 (depends on 4)

The method of claim 4, wherein the boundary strength is set equal to 1 or 0 if a prediction unit containing the sample p0 and a prediction unit containing the sample q0 are inter-coded.

### Claim 6 (depends on 1)

The method of claim 1, wherein whether or not the deblocking filtering is to be performed on the 4-sample edge is determined using a boundary quantization parameter.

### Claim 7 (depends on 6)

The method of claim 6, wherein the boundary quantization parameter is an average of a quantization parameter of P block containing sample p0 and a quantization parameter of Q block containing sample q0.

### Claim 8 (depends on 7)

The method of claim 7, wherein the average is a value rounded off.

### Claim 9 (depends on 7)

The method of claim 7, wherein the deblocking filter is selected using a boundary quantization parameter.