# US 2020/0288160 A1 · Method and apparatus for reference sample memory reuse for intra picture block compensation

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- Number: US 2020/0288160 A1
- Document ID: US20200288160A1
- Status: Published application
- Kind: A1
- Application number: 16/880,578
- Filed: 2020-05-21
- Published: 2020-09-10
- Earliest claimed: 2019-01-13
- Assignees: Tencent America LLC
- Applicants: Tencent America LLC
- Inventors: Xiaozhong XU; Shan Liu; Xiang Li
- Web page: https://patentgrep.com/patent/US20200288160A1

## CPC

- H04N 19/423: characterised by memory arrangements (H04N19/433 takes precedence)
- H04N 19/45: {performing compensation of the inverse transform mismatch, e.g. Inverse Discrete Cosine Transform [IDCT] mismatch}
- H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/51: Motion estimation or motion compensation
- H04N 19/593: involving spatial prediction techniques
- H04N 19/82: involving filtering within a prediction loop
- H04N 19/96: Tree coding, e.g. quad-tree coding
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A method includes determining whether a reference block for a current block is located in a different coding tree unit (CTU) than a CTU of the current block. If the reference block is located in the different CTU, the method includes determining whether the CTU of the current block and a memory have a same size. If the CTU of the current block and reference sample memory have a same size, the method includes (i) determining a first area in the CTU of the current block collocated with a second area in the different CTU; (ii) determining, based on a decoding status of the first area, whether a memory location of the memory for the reference block is available; and (iii) if the memory location for the reference block is available, retrieving, from the memory location, one or more samples to decode the current block.

## Claims

### Claim 1

(canceled)

### Claim 2

A method of video decoding for a decoder, the method comprising:
receiving a coded video bitstream;
determining whether a reference block for a current block is located in a different coding tree unit (CTU) than a CTU of the current block, the reference block and current block being located in a picture which is part of the coded video bitstream;
in response to the determination that the reference block is located in the different CTU:
(i) determining a first area in the CTU of the current block that is collocated with a second area in the different CTU, the first area and the second area having a same position in the CTU of the current block and the different CTU of the reference block;
(ii) determining, based on a decoding status of the first area, whether a memory location of a reference sample memory for the reference block is available; and
(iii) in response to the determination that the memory location for the reference block is available, retrieving, from the memory location corresponding to the reference block, one or more samples to decode the current block.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the first area is the current block, and the second area is the reference block.

### Claim 4 (depends on 2)

The method according to claim 2, wherein each of the first area and second area have a size that is 2M×2N.

### Claim 5 (depends on 4)

The method according to claim 4, wherein M=6 and N=6.

### Claim 6 (depends on 2)

The method of claim 2, wherein the memory location corresponding to the reference block is determined to be available in response to a determination that the decoding status of the first area indicates that the first area does not include at least one block that is at least partially decoded.

### Claim 7 (depends on 2)

The method of claim 2, further comprising:
determining whether a size of the CTU of the current block is less than a size of the reference sample memory;
in response to the determination that the size of the CTU of the current block is less than the size of the reference sample memory, determining whether a distance between the different CTU of the reference block and the CTU of the current block is less than or equal to a threshold defined as:
((reference sample memory size/CTU size)−1)*(CTU width); and
in response to the determination that the distance is less than or equal to the threshold, retrieving, from the memory location corresponding to the reference block, one or more samples to decode the current block.

### Claim 8 (depends on 7)

The method of claim 7, further comprising:
in response to the determination that the distance is greater than the threshold,
(i) determining a first area in the CTU of the current block that is collocated with a second area in the different CTU, the first area having position coordinates in the CTU of the current block that is a same as position coordinates of the second area in the different CTU of the reference block;
(ii) determining, based on a decoding status of the first area, whether a memory location of the reference sample memory for the reference block is available; and
(iii) in response to the determination that the memory location for the reference block is available, retrieving, from the memory location corresponding to the reference block, one or more samples to decode the current block.

### Claim 9

A video decoding apparatus for video decoding, comprising:
processing circuitry configured to:
receive a coded video bitstream,
determine whether a reference block for a current block is located in a different coding tree unit (CTU) than a CTU of the current block, the reference block and current block being located in a picture which is part of the coded video bitstream,
in response to the determination that the reference block is located in the different CTU:
(i) determine a first area in the CTU of the current block that is collocated with a second area in the different CTU, the first area and the second area having a same position in the C U of the current block and the different CTU of the reference block,
(ii) determine, based on a decoding status of the first area, whether a memory location of a reference sample memory for the reference block is available, and
(iii) in response to the determination that the memory location for the reference block is available, retrieve, from the memory location corresponding to the reference block, one or more samples to decode the current block.

### Claim 10 (depends on 9)

The video decoding apparatus according to claim 9, wherein the first area is the current block, and the second area is the reference block.

### Claim 11 (depends on 9)

The video decoding apparatus according to claim 9, wherein each of the first area and second area have a size that is 2M×2N.

### Claim 12 (depends on 11)

The video decoding apparatus according to claim 11, wherein M=6 and N=6.

### Claim 13 (depends on 9)

The video decoding apparatus according to claim 9, wherein the memory location corresponding to the reference block is determined to be available in response to a determination that the decoding status of the first area indicates that the first area does not include at least one block that is at least partially decoded.

### Claim 14 (depends on 9)

The video decoding apparatus according to claim 9, the processing circuitry further configured to:
determine whether a size of the CTU of the current block is less than a size of the reference sample memory,
in response to the determination that the size of the CTU of the current block is less than the size of the reference sample memory, determine whether a distance between the different CTU of the reference block and the CTU of the current block is less than or equal to a threshold defined as:
((reference sample memory size/CTU size)−1)*(CTU width), and
in response to the determination that the distance is less than or equal to the threshold, retrieving, from the memory location corresponding to the reference block, one or more samples to decode the current block.

### Claim 15 (depends on 14)

The video decoding apparatus according to claim 14, further comprising:
in response to the determination that the distance is greater than the threshold,
(i) determine a first area in the CTU of the current block that is collocated with a second area in the different CTU, the first area having position coordinates in the CTU of the current block that is a same as position coordinates of the second area in the different CTU of the reference block,
(ii) determine, based on a decoding status of the first area, whether a memory location of the reference sample memory for the reference block is available, and
(iii) in response to the determination that the memory location for the reference block is available, retrieve, from the memory location corresponding to the reference block, one or more samples to decode the current block.

### Claim 16

A non-transitory computer readable medium having instructions stored therein, which when executed by a processor in a video decoder causes the processor to execute a method comprising:
receiving a coded video bitstream;
determining whether a reference block for a current block is located in a different coding tree unit (CTU) than a CTU of the current block, the reference block and current block being located in a picture which is part of the coded video bitstream;
in response to the determination that the reference block is located in the different CTU:
(i) determining a first area in the CTU of the current block that is collocated with a second area in the different CTU, the first area and the second area having a same position in the CTU of the current block and the different CTU of the reference block;
(ii) determining, based on a decoding status of the first area, whether a memory location of a reference sample memory for the reference block is available; and
(iii) in response to the determination that the memory location for the reference block is available, retrieving, from the memory location corresponding to the reference block, one or more samples to decode the current block.

### Claim 17 (depends on 16)

The non-transitory computer readable medium according to claim 16, wherein the first area is the current block, and the second area is the reference block.

### Claim 18 (depends on 16)

The non-transitory computer readable medium according to claim 16, wherein each of the first area and second area have a size that is 2M×2N.

### Claim 19 (depends on 18)

The non-transitory computer readable medium according to claim 18, wherein M=6 and N=6.

### Claim 20 (depends on 16)

The non-transitory computer readable medium according to claim 16, wherein the memory location corresponding to the reference block is determined to be available in response to a determination that the decoding status of the first area indicates that the first area does not include at least one block that is at least partially decoded.

### Claim 21 (depends on 16)

The non-transitory computer readable medium of claim 16, the method further comprising:
determining whether a size of the CTU of the current block is less than a size of the reference sample memory;
in response to the determination that the size of the CTU of the current block is less than the size of the reference sample memory, determining whether a distance between the different CTU of the reference block and the CTU of the current block is less than or equal to a threshold defined as:
((reference sample memory size/CTU size)−1)*(CTU width); and
in response to the determination that the distance is less than or equal to the threshold, retrieving, from the memory location corresponding to the reference block, one or more samples to decode the current block.