# US 2021/0344965 A1 · Image processing device and image processing method

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- Number: US 2021/0344965 A1
- Document ID: US20210344965A1
- Status: Published application
- Kind: A1
- Application number: 17/324,110
- Filed: 2021-05-19
- Published: 2021-11-04
- Earliest claimed: 2011-06-28
- Assignees: Sony Group Corporation
- Applicants: Sony Group Corporation
- Inventors: Masaru IKEDA
- Web page: https://patentgrep.com/patent/US20210344965A1

## CPC

- H04N 19/80: Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation (H04N19/635, H04N19/86 take precedence)
- H04N 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635)
- H04N 19/124: Quantisation
- H04N 19/136: Incoming video signal characteristics or properties
- H04N 19/182: the unit being a pixel
- H04N 19/42: characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation (H04N19/635 takes precedence)
- H04N 19/82: involving filtering within a prediction loop
- H04N 19/86: involving reduction of coding artifacts, e.g. of blockiness
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

The present technology relates to an image processing device and an image processing method which allow a deblocking filtering process to apply filtering appropriately. A pixel (p0i) of which the value is 255 (solid line) before a deblocking process changes greatly to 159 (dot line) after a conventional deblocking process. Therefore, a clipping process having a clipping value of 10 is performed in strong filtering, whereby the pixel (p0i) of which the value is 255 (solid line) before the deblocking process becomes 245 (bold line). THUS, a change in the pixel value occurring in the conventional technique can be suppressed as much as possible. This disclosure can be applied to an image processing device, for example.

## Claims

### Claim 1

An image processing device comprising:
a decoding unit (612, 613) configured to decode an encoded stream to generate a decoded image;
a filtering unit (84) configured to apply a deblocking filter including a first deblocking filter or a second deblocking filter having a stronger filter strength than the first deblocking filter to pixels neighboring a block boundary within the decoded image generated by the decoding unit (612, 613); and characterised by
a controller (86) configured to control, when the second deblocking filter is applied as the deblocking filter, the second deblocking filter so as to apply a clipping process to a difference value that changes with the filtering process performed by the second deblocking filter using a second clipping value pv, which is 1 to 8 times that of a first clipping value tc, which is used in case that a clipping process is applied to a difference value that changes with the filtering process performed by the first deblocking filter.

### Claim 2 (depends on 1)

The image processing device according to claim 1, wherein
the controller (86) is configured to control the second deblocking filter so as to apply the clipping process according to the following expressions:
p
⁢
⁢
0
′
=
p
⁢
⁢
0
+
Clip
(
-
pv
)
-
(
pv
)
⁡
(
(
p
⁢
2
+
2
*
⁢
p
⁢
⁢
1
-
6
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
⁢
0
+
q
⁢
⁢
1
+
4
)
>>
3
)
;
=
Clip
(
p
⁢
⁢
0
-
pv
)
-
(
p
⁢
⁢
0
+
pv
)
⁡
(
(
p
⁢
2
+
2
*
⁢
p
⁢
1
+
2
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
0
+
q
⁢
⁢
1
+
4
)
>>
3
)
=
Clip
⁢
⁢
3
⁢
(
p
⁢
⁢
0
-
pv
,
p
⁢
⁢
0
+
pv
,
(
p
⁢
⁢
2
+
2
*
⁢
p
⁢
1
+
2
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
0
+
q
⁢
⁢
1
+
4
)
>>
3
)
;
p
⁢
⁢
1
′
=
p
⁢
⁢
1
+
Clip
(
-
pv
)
-
(
pv
)
⁡
(
(
p
⁢
⁢
2
-
3
*
⁢
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
2
)
>>
2
)
;
=
Clip
(
p
⁢
⁢
1
-
pv
)
-
(
p
⁢
⁢
1
+
pv
)
⁡
(
(
p
⁢
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
2
)
>>
2
)
;
=
Clip
⁢
⁢
3
⁢
(
p
⁢
⁢
1
-
pv
,
p
⁢
⁢
1
+
pv
,
(
p
⁢
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
2
)
>>
2
)
;
p
⁢
⁢
2
′
=
p
⁢
⁢
2
+
Clip
(
-
pv
)
-
(
pv
)
⁡
(
(
2
*
⁢
p
⁢
⁢
3
-
5
*
⁢
p
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
4
)
>>
3
)
;
=
Clip
(
p
⁢
⁢
2
-
pv
)
-
(
p
⁢
⁢
2
+
pv
)
⁡
(
(
2
*
⁢
p
⁢
3
+
3
*
⁢
p
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
4
)
>>
3
)
;
=
Clip
⁢
⁢
3
⁢
(
p
⁢
⁢
2
-
pv
,
p
⁢
2
+
pv
,
(
2
*
⁢
p
⁢
⁢
3
+
3
*
⁢
p
⁢
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
4
)
>>
3
)
;
q
⁢
⁢
0
′
=
q
⁢
⁢
0
+
Clip
(
-
pv
)
-
(
pv
)
⁡
(
(
p
⁢
⁢
1
+
2
*
⁢
p
⁢
⁢
0
-
6
*
⁢
q
⁢
0
+
2
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
4
)
>>
3
)
;
=
Clip
(
q
⁢
⁢
0
-
pv
)
-
(
q
⁢
⁢
0
+
pv
)
⁡
(
(
p
⁢
⁢
1
+
2
*
⁢
p
⁢
⁢
0
+
2
*
⁢
q
⁢
⁢
0
+
2
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
4
)
>>
3
)
;
=
Clip
⁢
⁢
3
⁢
(
q
⁢
⁢
0
-
pv
,
⁢
q
⁢
⁢
0
+
pv
,
(
p
⁢
⁢
1
+
2
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
0
+
2
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
4
)
>>
3
)
;
q
⁢
⁢
1
′
=
q
⁢
⁢
1
+
Clip
(
-
pv
)
-
(
pv
)
⁡
(
(
p
⁢
⁢
0
+
q
⁢
⁢
0
-
3
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
2
)
>>
2
)
;
=
Clip
(
q
⁢
⁢
1
-
pv
)
-
(
q
⁢
⁢
1
+
pv
)
⁡
(
(
p
⁢
⁢
0
+
q
⁢
⁢
0
+
q
⁢
⁢
1
+
q
⁢
⁢
2
+
2
)
>>
2
)
;
=
Clip
⁢
⁢
3
⁢
(
q
⁢
⁢
1
-
pv
,
q
⁢
⁢
1
+
pv
,
(
p
⁢
⁢
0
+
q
⁢
⁢
0
+
q
⁢
⁢
1
+
q
⁢
⁢
2
+
2
)
>>
2
)
;
q
⁢
⁢
2
′
=
q
⁢
⁢
2
+
Clip
(
-
pv
)
-
(
pv
)
⁡
(
(
p
⁢
0
+
q
⁢
0
+
q
⁢
⁢
1
-
5
*
⁢
q
⁢
2
+
2
*
⁢
q
⁢
3
+
4
)
>>
3
)
;
=
Clip
(
q
⁢
⁢
2
-
pv
)
-
(
q
⁢
⁢
2
+
pv
)
⁡
(
(
p
⁢
⁢
0
+
q
⁢
⁢
0
+
q
⁢
⁢
1
+
3
*
⁢
q
⁢
2
+
2
*
⁢
q
⁢
3
+
4
)
>>
3
)
;
=
Clip
⁢
⁢
3
⁢
(
q
⁢
⁢
2
-
pv
,
q
⁢
2
+
p
⁢
v
,
(
p
⁢
0
+
q
⁢
0
+
q
⁢
⁢
1
+
3
*
⁢
q
⁢
2
+
2
*
⁢
q
⁢
3
+
4
)
>>
3
)
;
wherein the pv is the second clipping value,
P0′, P1′, p2′, q0′, q1′, q2′ are the pixel values after applying the second deblocking filter, and
p0, p1, p2, q0, q1, q2 are the pixel values before applying the second deblocking filter.

### Claim 3 (depends on 1)

The image processing device according to claim 1, wherein
the controller (86) is configured to control the second deblocking filter so as to apply the clipping process according to the following expressions:
p
⁢
⁢
0
′
=
p
⁢
⁢
0
+
Clip
(
-
2
*
⁢
tc
)
-
(
2
*
⁢
tc
)
⁡
(
(
p
⁢
2
+
2
*
⁢
p
⁢
⁢
1
-
6
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
⁢
0
+
q
⁢
⁢
1
+
4
)
>>
3
)
;
=
Clip
(
p
⁢
⁢
0
-
2
*
⁢
tc
)
-
(
p
⁢
⁢
0
+
2
*
⁢
tc
)
⁡
(
(
p
⁢
2
+
2
*
⁢
p
⁢
1
+
2
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
0
+
q
⁢
⁢
1
+
4
)
>>
3
)
=
Clip
⁢
⁢
3
⁢
(
p
⁢
⁢
0
-
2
*
⁢
tc
,
p
⁢
⁢
0
+
2
*
⁢
tc
,
(
p
⁢
⁢
2
+
2
*
⁢
p
⁢
1
+
2
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
0
+
q
⁢
⁢
1
+
4
)
>>
3
)
;
p
⁢
⁢
1
′
=
p
⁢
⁢
1
+
Clip
(
-
2
*
⁢
tc
)
-
(
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
2
-
3
*
⁢
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
2
)
>>
2
)
;
=
Clip
(
p
⁢
⁢
1
-
2
*
⁢
tc
)
-
(
p
⁢
⁢
1
+
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
2
)
>>
2
)
;
=
Clip
⁢
⁢
3
⁢
(
p
⁢
⁢
1
-
2
*
⁢
tc
,
p
⁢
⁢
1
+
2
*
⁢
tc
,
(
p
⁢
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
2
)
>>
2
)
p
⁢
⁢
2
′
=
p
⁢
⁢
2
+
Clip
(
-
2
*
⁢
tc
)
-
(
2
*
⁢
tc
)
⁡
(
(
2
*
⁢
p
⁢
⁢
3
-
5
*
⁢
p
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
4
)
>>
3
)
;
=
Clip
(
p
⁢
⁢
2
-
2
*
⁢
tc
)
-
(
p
⁢
⁢
2
+
2
*
⁢
tc
)
⁡
(
(
2
*
⁢
p
⁢
3
+
3
*
⁢
p
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
4
)
>>
3
)
;
=
Clip
⁢
⁢
3
⁢
(
p
⁢
⁢
2
-
2
*
⁢
tc
,
p
⁢
⁢
2
+
2
*
⁢
tc
,
(
2
*
⁢
p
⁢
⁢
3
+
3
*
⁢
p
⁢
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
4
)
>>
3
)
;
q
⁢
⁢
0
′
=
q
⁢
⁢
0
+
Clip
(
-
2
*
⁢
tc
)
-
(
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
1
+
2
*
⁢
p
⁢
⁢
0
-
6
*
⁢
q
⁢
0
+
2
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
4
)
>>
3
)
;
=
Clip
(
q
⁢
⁢
0
-
2
*
⁢
tc
)
-
(
q
⁢
⁢
0
+
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
1
+
2
*
⁢
p
⁢
⁢
0
+
2
*
⁢
q
⁢
⁢
0
+
2
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
4
)
>>
3
)
;
=
Clip
⁢
⁢
3
⁢
(
q
⁢
⁢
0
-
2
*
⁢
tc
,
⁢
q
⁢
⁢
0
+
2
*
⁢
tc
,
(
p
⁢
⁢
1
+
2
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
0
+
2
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
4
)
>>
3
)
;
q
⁢
⁢
1
′
=
q
⁢
⁢
1
+
Clip
(
-
2
*
⁢
tc
)
-
(
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
0
+
q
⁢
⁢
0
-
3
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
2
)
>>
2
)
;
=
Clip
(
q
⁢
⁢
1
-
2
*
⁢
tc
)
-
(
q
⁢
⁢
1
+
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
0
+
q
⁢
⁢
0
+
q
⁢
⁢
1
+
q
⁢
⁢
2
+
2
)
>>
2
)
;
=
Clip
⁢
⁢
3
⁢
(
q
⁢
⁢
1
-
2
*
⁢
tc
,
q
⁢
⁢
1
+
2
*
⁢
tc
,
(
p
⁢
⁢
0
+
q
⁢
⁢
0
+
q
⁢
⁢
1
+
q
⁢
⁢
2
+
2
)
>>
2
)
;
(
(
(
(
(
q
⁢
⁢
2
′
=
q
⁢
⁢
2
+
Clip
(
-
2
*
⁢
tc
)
-
(
2
*
⁢
tc
)
(
⁢
(
p0
+
q
⁢
0
+
q
⁢
⁢
1
-
5
*
⁢
q
⁢
2
+
2
*
⁢
q
⁢
3
+
4
)
>>
3
)
;
=
⁢
Clip
(
q
⁢
⁢
2
-
2
*
⁢
tc
)
-
(
q
⁢
⁢
2
+
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
0
+
q
⁢
⁢
0
+
q
⁢
⁢
1
+
3
*
⁢
q
⁢
2
+
2
*
⁢
q
⁢
3
+
4
)
>>
3
)
;
=
Clip
⁢
⁢
3
⁢
(
q
⁢
⁢
2
-
2
*
⁢
tc
,
q
⁢
⁢
2
+
2
*
⁢
tc
,
(
p
⁢
0
+
q
⁢
0
+
q
⁢
⁢
1
+
3
*
⁢
q
⁢
2
+
2
*
⁢
q
⁢
3
+
4
)
>>
3
)
;
wherein tc is the first clipping value and the parameter used in case that the strength of the deblocking filter is selected,
the second clipping value pv equals 2*tc
p0′, p1′, p2′, q0′, q1′, q2′ are the pixel values after applying the second deblocking filter, and
p0, p1, p2, q0, q1, q2 are the pixel values before applying the second deblocking filter.

### Claim 4 (depends on 3)

The image processing device according to claim 3, wherein
the filtering unit (84) is configured to apply the second deblocking filter to the luminance components of the pixels neighboring the block boundary within the decoded image.

### Claim 5 (depends on 4)

The image processing device according to claim 4, wherein
the first deblocking filter is a weak filter applied to four pixels neighboring the block boundary; and
the second deblocking filter is a strong filter applied to six pixels neighboring the block boundary.

### Claim 6 (depends on 4)

The image processing device according to claim 4, wherein
the block boundary is a boundary of a transform unit as a unit of orthogonal transformation or a boundary of a prediction unit as a unit of prediction process.

### Claim 7 (depends on 6)

The image processing device according to claim 6, wherein
the decoding unit (612, 613) comprises:
an arithmetic decoder configured to decode the encoded stream to generate quantized data;
an inverse quantizer configured to perform inverse quantization on the quantized data generated by the arithmetic decoder to generate transform coefficient data; and
an inverse orthogonal transformer configured to perform inverse orthogonal transformation on the transform coefficient data generated by the inverse quantizer.

### Claim 8 (depends on 7)

The image processing device according to claim 7, wherein
the decoding unit (612, 613) is configured to decode the encoded stream on a coding unit basis, wherein the coding unit is formed by recursively splitting a largest coding unit into smaller coding units as block partitioning.

### Claim 9 (depends on 8)

The image processing device according to claim 8, wherein
the coding unit is recursively split according to quad-tree block structure.

### Claim 10 (depends on 9)

The image processing device according to claim 9, wherein
the largest coding unit is the coding unit in a root layer according to quad-tree block structure.

### Claim 11 (depends on 10)

The image processing device according to claim 10, wherein
the largest coding unit is a block of fixed block size at sequence level, and the coding unit is a block of variable block size.

### Claim 12

An image processing method comprising:
decoding an encoded stream to generate a decoded image;
applying a deblocking filter including a first deblocking filter or a second deblocking filter having a stronger filter strength than the first deblocking filter to pixels neighboring a block boundary within the decoded image; and characterised by
controlling, when the second deblocking filter is applied as the deblocking filter, the second deblocking filter so as to apply a clipping process to a difference value that changes with the filtering process performed by the second deblocking filter using a second clipping value pv, which is 1 to 8 times that of a first clipping value tc,
which is used in case that a clipping process is applied to a difference value that changes with the filtering process performed by the first deblocking filter.

### Claim 13 (depends on 12)

The image processing method according to claim 12, wherein
the second deblocking filter applies the clipping process to the difference value according to the following expressions:
p
⁢
⁢
0
′
=
p
⁢
⁢
0
+
Clip
(
-
pv
)
-
(
pv
)
⁡
(
(
p
⁢
2
+
2
*
⁢
p
⁢
⁢
1
-
6
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
⁢
0
+
q
⁢
⁢
1
+
4
)
>>
3
)
;
=
Clip
(
p
⁢
⁢
0
-
pv
)
-
(
p
⁢
⁢
0
+
pv
)
⁡
(
(
p
⁢
2
+
2
*
⁢
p
⁢
1
+
2
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
0
+
q
⁢
⁢
1
+
4
)
>>
3
)
=
Clip
⁢
⁢
3
⁢
(
p
⁢
⁢
0
-
pv
,
p
⁢
⁢
0
+
pv
,
(
p
⁢
⁢
2
+
2
*
⁢
p
⁢
1
+
2
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
0
+
q
⁢
⁢
1
+
4
)
>>
3
)
;
p
⁢
⁢
1
′
=
p
⁢
⁢
1
+
Clip
(
-
pv
)
-
(
pv
)
⁡
(
(
p
⁢
⁢
2
-
3
*
⁢
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
2
)
>>
2
)
;
=
Clip
(
p
⁢
⁢
1
-
pv
)
-
(
p
⁢
⁢
1
+
pv
)
⁡
(
(
p
⁢
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
2
)
>>
2
)
;
=
Clip
⁢
⁢
3
⁢
(
p
⁢
⁢
1
-
pv
,
p
⁢
⁢
1
+
pv
,
(
p
⁢
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
2
)
>>
2
)
;
p
⁢
⁢
2
′
=
p
⁢
⁢
2
+
Clip
(
-
pv
)
-
(
pv
)
⁡
(
(
2
*
⁢
p
⁢
⁢
3
-
5
*
⁢
p
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
4
)
>>
3
)
;
=
Clip
(
p
⁢
⁢
2
-
pv
)
-
(
p
⁢
⁢
2
+
pv
)
⁡
(
(
2
*
⁢
p
⁢
3
+
3
*
⁢
p
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
4
)
>>
3
)
;
=
Clip
⁢
⁢
3
⁢
(
p
⁢
⁢
2
-
pv
,
p
⁢
2
+
pv
,
(
2
*
⁢
p
⁢
⁢
3
+
3
*
⁢
p
⁢
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
4
)
>>
3
)
;
q
⁢
⁢
0
′
=
q
⁢
⁢
0
+
Clip
(
-
pv
)
-
(
pv
)
⁡
(
(
p
⁢
⁢
1
+
2
*
⁢
p
⁢
⁢
0
-
6
*
⁢
q
⁢
0
+
2
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
4
)
>>
3
)
;
=
Clip
(
q
⁢
⁢
0
-
pv
)
-
(
q
⁢
⁢
0
+
pv
)
⁡
(
(
p
⁢
⁢
1
+
2
*
⁢
p
⁢
⁢
0
+
2
*
⁢
q
⁢
⁢
0
+
2
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
4
)
>>
3
)
;
=
Clip
⁢
⁢
3
⁢
(
q
⁢
⁢
0
-
pv
,
⁢
q
⁢
⁢
0
+
pv
,
(
p
⁢
⁢
1
+
2
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
0
+
2
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
4
)
>>
3
)
;
q
⁢
⁢
1
′
=
q
⁢
⁢
1
+
Clip
(
-
pv
)
-
(
pv
)
⁡
(
(
p
⁢
⁢
0
+
q
⁢
⁢
0
-
3
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
2
)
>>
2
)
;
=
Clip
(
q
⁢
⁢
1
-
pv
)
-
(
q
⁢
⁢
1
+
pv
)
⁡
(
(
p
⁢
⁢
0
+
q
⁢
⁢
0
+
q
⁢
⁢
1
+
q
⁢
⁢
2
+
2
)
>>
2
)
;
=
Clip
⁢
⁢
3
⁢
(
q
⁢
⁢
1
-
pv
,
q
⁢
⁢
1
+
pv
,
(
p
⁢
⁢
0
+
q
⁢
⁢
0
+
q
⁢
⁢
1
+
q
⁢
⁢
2
+
2
)
>>
2
)
;
q
⁢
⁢
2
′
=
q
⁢
⁢
2
+
Clip
(
-
pv
)
-
(
pv
)
⁡
(
(
p
⁢
0
+
q
⁢
0
+
q
⁢
⁢
1
-
5
*
⁢
q
⁢
2
+
2
*
⁢
q
⁢
3
+
4
)
>>
3
)
;
=
Clip
(
q
⁢
⁢
2
-
pv
)
-
(
q
⁢
⁢
2
+
pv
)
⁡
(
(
p
⁢
⁢
0
+
q
⁢
⁢
0
+
q
⁢
⁢
1
+
3
*
⁢
q
⁢
2
+
2
*
⁢
q
⁢
3
+
4
)
>>
3
)
;
=
Clip
⁢
⁢
3
⁢
(
q
⁢
⁢
2
-
pv
,
q
⁢
2
+
p
⁢
v
,
(
p
⁢
0
+
q
⁢
0
+
q
⁢
⁢
1
+
3
*
⁢
q
⁢
2
+
2
*
⁢
q
⁢
3
+
4
)
>>
3
)
;
wherein the pv is the second clipping value,
p0′, p1′, p2′, q0′, q1′, q2′ are the pixel values after applying the second deblocking filter, and
p0, p1, p2, q0, q1, q2 are the pixel values before applying the second deblocking filter.

### Claim 14 (depends on 12)

The image processing method according to claim 12, wherein
the second deblocking filter applies the clipping process to the difference value according to the following expressions:
p
⁢
⁢
0
′
=
p
⁢
⁢
0
+
Clip
(
-
2
*
⁢
tc
)
-
(
2
*
⁢
tc
)
⁡
(
(
p
⁢
2
+
2
*
⁢
p
⁢
⁢
1
-
6
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
⁢
0
+
q
⁢
⁢
1
+
4
)
>>
3
)
;
=
Clip
(
p
⁢
⁢
0
-
2
*
⁢
tc
)
-
(
p
⁢
⁢
0
+
2
*
⁢
tc
)
⁡
(
(
p
⁢
2
+
2
*
⁢
p
⁢
1
+
2
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
0
+
q
⁢
⁢
1
+
4
)
>>
3
)
=
Clip
⁢
⁢
3
⁢
(
p
⁢
⁢
0
-
2
*
⁢
tc
,
p
⁢
⁢
0
+
2
*
⁢
tc
,
(
p
⁢
⁢
2
+
2
*
⁢
p
⁢
1
+
2
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
0
+
q
⁢
⁢
1
+
4
)
>>
3
)
;
p
⁢
⁢
1
′
=
p
⁢
⁢
1
+
Clip
(
-
2
*
⁢
tc
)
-
(
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
2
-
3
*
⁢
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
2
)
>>
2
)
;
=
Clip
(
p
⁢
⁢
1
-
2
*
⁢
tc
)
-
(
p
⁢
⁢
1
+
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
2
)
>>
2
)
;
=
Clip
⁢
⁢
3
⁢
(
p
⁢
⁢
1
-
2
*
⁢
tc
,
p
⁢
⁢
1
+
2
*
⁢
tc
,
(
p
⁢
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
2
)
>>
2
)
p
⁢
⁢
2
′
=
p
⁢
⁢
2
+
Clip
(
-
2
*
⁢
tc
)
-
(
2
*
⁢
tc
)
⁡
(
(
2
*
⁢
p
⁢
⁢
3
-
5
*
⁢
p
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
4
)
>>
3
)
;
=
Clip
(
p
⁢
⁢
2
-
2
*
⁢
tc
)
-
(
p
⁢
⁢
2
+
2
*
⁢
tc
)
⁡
(
(
2
*
⁢
p
⁢
3
+
3
*
⁢
p
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
4
)
>>
3
)
;
=
Clip
⁢
⁢
3
⁢
(
p
⁢
⁢
2
-
2
*
⁢
tc
,
p
⁢
⁢
2
+
2
*
⁢
tc
,
(
2
*
⁢
p
⁢
⁢
3
+
3
*
⁢
p
⁢
⁢
2
+
p
⁢
⁢
1
+
p
⁢
⁢
0
+
q
⁢
⁢
0
+
4
)
>>
3
)
;
q
⁢
⁢
0
′
=
q
⁢
⁢
0
+
Clip
(
-
2
*
⁢
tc
)
-
(
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
1
+
2
*
⁢
p
⁢
⁢
0
-
6
*
⁢
q
⁢
0
+
2
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
4
)
>>
3
)
;
=
Clip
(
q
⁢
⁢
0
-
2
*
⁢
tc
)
-
(
q
⁢
⁢
0
+
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
1
+
2
*
⁢
p
⁢
⁢
0
+
2
*
⁢
q
⁢
⁢
0
+
2
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
4
)
>>
3
)
;
=
Clip
⁢
⁢
3
⁢
(
q
⁢
⁢
0
-
2
*
⁢
tc
,
⁢
q
⁢
⁢
0
+
2
*
⁢
tc
,
(
p
⁢
⁢
1
+
2
*
⁢
p
⁢
0
+
2
*
⁢
q
⁢
0
+
2
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
4
)
>>
3
)
;
q
⁢
⁢
1
′
=
q
⁢
⁢
1
+
Clip
(
-
2
*
⁢
tc
)
-
(
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
0
+
q
⁢
⁢
0
-
3
*
⁢
q
⁢
⁢
1
+
q
⁢
⁢
2
+
2
)
>>
2
)
;
=
Clip
(
q
⁢
⁢
1
-
2
*
⁢
tc
)
-
(
q
⁢
⁢
1
+
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
0
+
q
⁢
⁢
0
+
q
⁢
⁢
1
+
q
⁢
⁢
2
+
2
)
>>
2
)
;
=
Clip
⁢
⁢
3
⁢
(
q
⁢
⁢
1
-
2
*
⁢
tc
,
q
⁢
⁢
1
+
2
*
⁢
tc
,
(
p
⁢
⁢
0
+
q
⁢
⁢
0
+
q
⁢
⁢
1
+
q
⁢
⁢
2
+
2
)
>>
2
)
;
(
q
⁢
⁢
2
′
=
q
⁢
⁢
2
+
Clip
(
-
2
*
⁢
tc
)
-
(
2
*
⁢
tc
)
⁡
(
(
p
⁢
0
+
q
⁢
0
+
q
⁢
⁢
1
-
5
*
⁢
q
⁢
2
+
2
*
⁢
q
⁢
3
+
4
)
>>
3
)
;
=
⁢
Clip
(
q
⁢
⁢
2
-
2
*
⁢
tc
)
-
(
q
⁢
⁢
2
+
2
*
⁢
tc
)
⁡
(
(
p
⁢
⁢
0
+
q
⁢
⁢
0
+
q
⁢
⁢
1
+
3
*
⁢
q
⁢
2
+
2
*
⁢
q
⁢
3
+
4
)
>>
3
)
;
=
Clip
⁢
⁢
3
⁢
(
q
⁢
⁢
2
-
2
*
⁢
tc
,
q
⁢
⁢
2
+
2
*
⁢
tc
,
(
p
⁢
0
+
q
⁢
0
+
q
⁢
⁢
1
+
3
*
⁢
q
⁢
2
+
2
*
⁢
q
⁢
3
+
4
)
>>
3
)
;
wherein tc is the first clipping value and the parameter used in case that the strength of the deblocking filter is selected, the second clipping value pv equals 2*tc p0′, p1′, p2′, q0′, q1′, q2′ are the pixel values after applying the second deblocking filter, and
p0, p1, p2, q0, q1, q2 are the pixel values before applying the second deblocking filter.

### Claim 15 (depends on 14)

The image processing method according to claim 14, further comprising
a step of applying the second deblocking filter to the luminance components of the pixels neighboring the block boundary within the decoded image.

### Claim 16 (depends on 15)

The image processing method according to claim 15, wherein
the first deblocking filter is a weak filter applied to four pixels neighboring the block boundary; and
the second deblocking filter is a strong filter applied to six pixels neighboring the block boundary.

### Claim 17 (depends on 15)

The image processing method according to claim 15, wherein
the block boundary is a boundary of a transform unit as a unit of orthogonal transformation or a boundary of a prediction unit as a unit of prediction process.

### Claim 18 (depends on 17)

The image processing method according to claim 17, the decoding is including:
decoding the encoded stream to generate quantized data;
performing inverse quantization on the quantized data to generate transform coefficient data; and
performing inverse orthogonal transformation on the transform coefficient data.

### Claim 19 (depends on 18)

The image processing method according to claim 18, wherein
the decoding the encoded stream is performed on a coding unit basis, wherein the coding unit is formed by recursively splitting a largest coding unit into smaller coding units as block partitioning.

### Claim 20 (depends on 19)

The image processing method according to claim 19, wherein
the coding unit is recursively split according to quad-tree block structure.

### Claim 21 (depends on 20)

The image processing method according to claim 20, wherein
the largest coding unit is the coding unit in a root layer according to quad-tree block structure.

### Claim 22 (depends on 21)

The image processing method according to claim 21, wherein
the largest coding unit is a block of fixed block size at sequence level, and the coding unit is a block of variable block size.