# US 2018/0324445 A1 · Method and device for encoding/decoding multi-layer video signal

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- Number: US 2018/0324445 A1
- Document ID: US20180324445A1
- Status: Published application
- Kind: A1
- Application number: 16/036,910
- Filed: 2018-07-16
- Published: 2018-11-08
- Earliest claimed: 2013-10-22
- Assignees: Kt Corporation
- Applicants: Kt Corporation
- Inventors: Bae Keun LEE; Joo Young KIM
- Web page: https://patentgrep.com/patent/US20180324445A1

## CPC

- H04N 19/33: in the spatial domain
- 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 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635)
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/172: the region being a picture, frame or field
- H04N 19/174: the region being a slice, e.g. a line of blocks or a group of blocks
- H04N 19/182: the unit being a pixel
- H04N 19/187: the unit being a scalable video layer
- H04N 19/50: using predictive coding (H04N19/61 takes precedence)
- H04N 19/59: involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N 19/82: involving filtering within a prediction loop
- H04N 19/436: using parallelised computational arrangements
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A method for decoding a multi-layer video signal, according to the present invention, determines whether a corresponding picture in a lower layer is used as an inter-layer reference picture for a current picture in an upper layer, on the basis of a temporal level identifier of the lower layer, performs inter-layer prediction for the current picture by using the corresponding picture if the corresponding picture in the lower layer is used as the inter-layer reference picture for the current picture in the upper layer, reconstructs the current picture by using a prediction sample acquired through the inter-layer prediction and a residual sample of the current picture, and selectively applies a loop filter to a tile boundary of the reconstructed current picture on the basis of a layer filter flag for the upper layer.

## Claims

### Claim at position 1

1-15. (canceled)

### Claim 16

A method for decoding a multi-layer video signal, the method comprising:
obtaining a maximum temporal level identifier relating to a lower layer, the maximum temporal level identifier indicating a maximum temporal level identifier to which an inter-layer prediction of an upper layer is allowed;
determining whether a corresponding picture of the lower layer is used as an inter-layer reference picture for a current picture of the upper layer by comparing the obtained maximum temporal level identifier with a temporal level identifier of the corresponding picture of the lower layer;
performing the inter-layer prediction of the current picture of the upper layer using the corresponding picture of the lower layer, if the corresponding picture of the lower layer is used in the inter-layer prediction of the current picture of the upper layer;
reconstructing the current picture using a prediction sample obtained by the inter-layer prediction and a residual sample relating to the current picture; and
applying a loop filter to tile boundaries of the reconstructed current picture,
wherein a tile alignment present flag is obtained from a bitstream when video usability information is presented in the bitstream,
wherein the tile alignment present flag equal to 1 indicates that a first restriction is applied, and the tile alignment present flag equal to 0 indicates that the first restriction may or may not be applied, wherein the first restriction is to restrict all pictures belonging to a video sequence to consist of a single tile,
wherein a layer filter flag is obtained from the bitstream when the tile alignment present flag equal to 0, the layer filter flag equal to 1 indicates that a second restriction is applied, and the layer filter flag equal to 0 indicates that the second restriction may or may not be applied, wherein the second restriction is to restrict the loop filter is not to be applied to tile boundaries of each picture belonging to the upper layer,
wherein a tile boundary alignment flag is obtained based on the tile alignment present flag from the bitstream, and the tile boundary alignment flag indicates whether a third restriction is applied, and
wherein the third restriction is to restrict that i) two samples of the corresponding picture of the lower layer belong to one tile when two samples of the current picture of the upper layer belong to one tile, and ii) the two samples of the corresponding picture of the lower layer belong to different tiles, when the two samples of the current picture of the upper layer belong to different tiles.

### Claim 17 (depends on 16)

The method according to claim 16, wherein a 8-tap filter is applied to the corresponding picture of the lower layer for performing inter-layer prediction of luminance components of the current picture, and
wherein coefficient sets of the 8-tap filter include {−1, 4, −10, 31, 47, −9, 3, −1}.

### Claim 18 (depends on 16)

The method according to claim 16, wherein the corresponding picture is used for inter-layer prediction of a current block of the current picture, both x and y components of a motion vector relating to the current block are derived equal to zero.

### Claim 19

A method for encoding a multi-layer video signal with an encoding apparatus, the method comprising:
performing an inter-layer prediction on a current picture of an upper layer using a corresponding picture of a lower layer;
encoding a maximum temporal level identifier relating to the lower layer, the maximum temporal level identifier indicating a maximum temporal level identifier to which the inter-layer prediction of an upper layer is allowed;
encoding, a tile alignment present flag indicating whether a first restriction is applied, wherein the first restriction is to restrict all pictures belonging to a video sequence to consist of a single tile,
encoding, based on tile alignment present flag, a layer filter flag indicating whether a second restriction is applied, wherein the second restriction is to restrict a loop filter is not to be applied to tile boundaries of each picture belonging to the upper layer; and
encoding, based on tile alignment present flag, a tile boundary alignment flag indicating whether a third restriction is applied, wherein the third restriction is to restrict that i) two samples of the corresponding picture of the lower layer belong to one tile, when two samples of the current picture of the upper layer belong to one tile, and ii) the two samples of the corresponding picture of the lower layer belong to different tiles, when the two samples of the current picture of the upper layer belong to different tiles; and
generating, a bitstream including the maximum temporal level identifier, the tile alignment present flag, the layer filter flag and the tile boundary alignment flag.

### Claim 20 (depends on 19)

The method according to claim 19, wherein a re-sampling filter is applied to the corresponding picture of the lower layer for performing inter-layer prediction of luminance components of the current picture.

### Claim 21 (depends on 19)

The method according to claim 19, wherein the corresponding picture is used for inter-layer prediction of a current block of the current picture, both x and y components of a motion vector relating to the current block are determined equal to zero.