KR102517444B1 - Apparatus and method for intra mode prediction of multi view or multi layer video - Google Patents

Abstract

The present invention relates to an intra prediction apparatus and method for image encoding and decoding, and for intra prediction of a current block in a multi-view or multi-layer image, using not only blocks adjacent to the current block but also co-located blocks of different views or layers. By performing intra prediction, there is an effect of increasing the overall image encoding efficiency by increasing the accuracy of intra prediction.

Description

Apparatus and method for predicting intra mode in multi-view or multi-layer image

The present invention relates to video encoding, and more particularly, to a technique for increasing the efficiency of intra mode prediction.

Since video data is generally large in capacity, encoding is required for storage or transmission. Intra prediction or inter prediction are examples of such encoding.

Inter-picture prediction is an encoding method of predicting a current picture by referring to pictures before and after the current picture temporally.

Intra-prediction is a method of increasing encoding efficiency by predicting pixels of a block to be currently encoded using spatial neighboring information already encoded in the current screen at the same time as a reference sample and encoding the difference between the original value and the predicted value.

Intra-prediction generally has lower coding performance than inter-prediction because intra-prediction has a smaller amount of information that can be referred to than inter-prediction.

The inventors of the present invention have made efforts to overcome the limitations of intra-screen prediction in the prior art. The present invention has been completed after much effort to complete an intra-screen (intra) mode prediction method and device using not only the current screen but also intra-mode information of other views or layers in a multi-view or multi-layer video.

The present invention provides an apparatus and method for determining an optimal intra mode for encoding of a current block by using intra mode information of another view or layer in which encoding has already been completed during intra prediction in a multi-view or multi-layer video. The purpose.

Meanwhile, other unspecified objects of the present invention will be additionally considered within the scope that can be easily inferred from the following detailed description and effects thereof.

delete

delete

delete

delete

delete

delete

delete

The present invention, in an intra prediction apparatus for encoding a multi-view or multi-layer image, includes adjacent blocks located at the same view or layer as a current block to be encoded and adjacent to the current block. and an MPM selection unit that selects a Most Probable Mode (MPM) by an intra mode among blocks located at a different viewpoint or layer than the current block and located at the same positional coordinates as the current block, and based on the MPM and an intra mode predictor for predicting an intra mode of the current block, wherein the MPM selection unit is located at a plurality of viewpoints or layers different from the current block, is located at the same location coordinates as the current block, and the intra mode is a directional mode and is encoded. Provided is an intra prediction apparatus for video encoding, characterized in that a block of a viewpoint or layer closest to the current block is selected as an MPM list among blocks for which is completed.
In addition, according to the present invention, in an intra prediction method for encoding multi-view or multi-layer images, adjacent blocks located at the same view point or in the same layer as a current block to be encoded and adjacent to the current block, and views different from the current block or selecting an MPM based on an intra mode among blocks located in a different layer and located at the same location coordinates as the current block, and predicting the intra mode of the current block based on the MPM; In the step of selecting the MPM, the MPM is located at a plurality of viewpoints or hierarchies different from the current block, is located at the same position coordinates as the current block, has an intra mode as a directional mode, and among blocks that have been encoded, a viewpoint closest to the current block or An intra prediction apparatus for video encoding is provided, which is a step of selecting a block of a layer as an MPM list.
In addition, according to the present invention, in an intra prediction apparatus for decoding a multi-view or multi-layer image, adjacent blocks located at the same view or the same layer as a current block to be decoded and adjacent to the current block, and different blocks from the current block An MPM selection unit that selects an MPM according to an intra mode among blocks located at a viewpoint or a different layer and located at the same location coordinates as the current block; and an intra prediction unit that intra-predicts the current block based on the selected MPM. ;, wherein the MPM selection unit is located at a plurality of viewpoints or layers different from the current block, is located at the same location coordinates as the current block, has an intra mode as a directional mode, and is closest to the current block among encoded blocks. Provided is an intra prediction apparatus for video decoding, characterized in that a block of a view or a layer is selected from an MPM list.
In addition, according to the present invention, in an intra prediction method for decoding a multi-view or multi-layer image, adjacent blocks located at the same view or the same layer as a current block to be decoded and adjacent to the current block, and different blocks from the current block An MPM selection step of selecting an MPM by an intra mode among blocks located in a viewpoint or another layer and located at the same location coordinates as the current block; and an intra prediction step of intra-predicting the current block based on the selected MPM. and selecting the MPM includes the current block among blocks located at a plurality of viewpoints or layers different from the current block, located at the same location coordinates as the current block, whose intra mode is a directional mode, and whose encoding has been completed. It provides an intra prediction method for video decoding, characterized in that the step of selecting a block of a view or layer closest to the MPM list.
The current block may be a Luma block or a Chroma block.

According to the present invention, when intra-prediction is performed in a multi-view or multi-layer video, the encoding efficiency of the video can be increased by determining an optimal intra mode for encoding the current block using intra mode information of another view or another layer where encoding has already been completed. There is an effect.

On the other hand, even if the effects are not explicitly mentioned here, it is added that the effects described in the following specification expected by the technical features of the present invention and their provisional effects are treated as described in the specification of the present invention.

1 is a schematic structural diagram of an intra mode predictor of a video encoder according to a preferred embodiment of the present invention.
2 shows intra coding modes of HEVC and VVC.
3 shows an example of intra mode prediction using neighboring blocks of a current block.
4 shows an example of intra mode prediction using the same block as a current block of another view or another layer.
5 is a schematic flowchart of an intra mode prediction method of video encoding according to another preferred embodiment of the present invention.
6 is a schematic structural diagram of an intra prediction device of a video decoder according to another preferred embodiment of the present invention.
7 is a schematic flowchart of an intra prediction method of image decoding according to another preferred embodiment of the present invention.
※ It is revealed that the accompanying drawings are exemplified as references for understanding the technical idea of the present invention, and thereby the scope of the present invention is not limited.

Hereinafter, with reference to the drawings, look at the configuration of the present invention guided by various embodiments of the present invention and the effects resulting from the configuration. In the description of the present invention, if it is determined that a related known function may unnecessarily obscure the subject matter of the present invention as an obvious matter to those skilled in the art, the detailed description thereof will be omitted.

Terms such as 'first' and 'second' may be used to describe various elements, but the elements should not be limited by the above terms. The above terms may only be used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a 'first element' may be named a 'second element', and similarly, a 'second element' may also be named a 'first element'. can Also, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms used in the embodiments of the present invention may be interpreted as meanings commonly known to those skilled in the art unless otherwise defined.

Hereinafter, with reference to the drawings, look at the configuration of the present invention guided by various embodiments of the present invention and the effects resulting from the configuration.

1 is a schematic structural diagram of an intra mode predictor of a video encoder according to a preferred embodiment of the present invention.

The intra mode predictor 100 of the video encoder 1 according to the present invention includes an MPM selector 110 and an intra mode predictor 120.

Intra prediction encoding is a technique for effectively predicting a current block to be encoded using neighboring blocks having similar tendencies in a picture.

2 illustrates intra coding modes of High Efficiency Video Coding (HEVC) and Versatile Video Coding (VVC) video compression standards among such intra prediction.

2(a) is an intra mode of the ISO/IEC MPEG-H High Efficiency Video Coding (HEVC) video compression standard. Excluding ChromaFromLuma (CfL) included in a special profile, 35 modes (0 to 34) including 33 directional modes are supported.

In (b) of FIG. 2, the ISO/IEC MPEG-I Versatile video coding (VVC) video compression standard supports up to 87 coding modes including 65 normal directional modes and 20 wide-angle directional modes. Compared to HEVC, the number of encoding modes has increased more than twice.

In a picture, it is generally highly likely that prediction modes are similar between a current block and adjacent blocks. Therefore, when encoding the intra block prediction mode, the optimal mode (MPM: most probable mode) is selected using intra encoding mode information of neighboring blocks, and then, when encoding the intra block prediction mode of the current block, MPM is used to determine the bit rate for the encoding mode value. can reduce

Again in FIG. 1, the MPM selector 110 selects an MPM using mode information of neighboring blocks.

3 and 4 show examples of neighboring blocks used by the MPM selector 110 to select an MPM.

In FIG. 3 , the MPM selector 110 uses the upper block U and the left block L, which are neighboring blocks of the current block C. HEVC supports 3 MPMs in intra coding and VVC supports 6 MPMs.

The MPM selection unit 110 may configure the MPM list as shown in Table 1 below using the upper block (U) and the left block (L), which are neighboring blocks of the current block (C).

condition detailed conditions 6 MPM modes 1) When the left mode and the top mode are directional and identical to each other {Planar, Left, Left-1, Left+1, Left-2, Left+2} 2) When the left mode and the top mode are different, and both modes are directional mode 2.1) Max - Min = 1 {Planar, Left, Above, Min-1, Max+1, Min-2} 2.2) Max - Min >= 61 {Planar, Left, Above, Min+1, Max-1, Min+2} 2.3) Max - Min = 2 {Planar, Left, Above, Min+1, Min-1, Max-1} 2.4) Otherwise (2 < Max - Min < 61) {Planar, Left, Above, Min-1, Min+1, Max-1} 3) When the left mode and the top mode are different, and only one of them is a directional mode {Planar, Max, Max-1, Max+1, Max-2, Max+2} 4) When neither the left mode nor the top mode is directional mode (Planar, DC) {Planar, DC, Angular50, Angular18, Angular46, Angular54}

Based on the modes of the upper block (Above) and the left block (Left), set the larger mode to Max and the smaller mode to Min to set 6 MPM modes.

4 shows an example of generating an MPM using a block of a different view or layer other than the current screen.

Multi-view video is one of the three-dimensional images that provide images captured simultaneously using multiple cameras from different viewpoints. Unlike general video, two or more frames can exist at a moment.

Also, multi-layer video is a technology for integrating and transmitting different video data into one video. Multi-view video is also an example of multi-layer video.

In such a multi-view or multi-layer video, there is a possibility that a block of another view or of a different layer is more similar to the current block than a block adjacent to the current block. Therefore, the MPM selector 110 of the present invention is intended to increase the efficiency of intra mode prediction by using blocks adjacent to the current block as well as blocks of other views or layers.

(a) of FIG. 4 shows a state in which several multi-view or multi-layer videos are included at the same time.

In (b) of FIG. 4, the blocks (X', X'') located at the same position as the current block (C) exist at different viewpoints or screens of different layers, as shown in (a) and (c) of FIG. 4. .

Accordingly, the MPM selector 110 may construct an additional MPM list using a block that has been coded among the blocks X' and X''.

That is, when the coded block X' or block X'' is in the directional mode, the MPM list can be generated as follows, prioritizing the priorities in Table 1.

{Planar, IntraMode(X'), IntraMode(X')-1, IntraMode(X')+1, IntraMode(X')-2, IntraMode(X')+2 }

{Planar, IntraMode(X''), IntraMode(X'')-1, IntraMode(X'')+1, IntraMode(X'')-2, IntraMode(X'')+2 },

IntraMode(X') and IntraMode(X'') represent intra prediction encoding modes of blocks X' or X'', respectively.

The above MPM list using blocks of a different viewpoint or layer may take precedence over a list generated using blocks to the left and upper blocks of the current block as shown in Table 1.

In addition, when there are several blocks that have been coded in different views or layers, an MPM list may be generated using blocks of a view or layer closest to the current block.

However, when a block of a different viewpoint or layer is not in a directional mode, a method of using adjacent blocks in an existing screen may be used.

The intra mode predictor 120 may predict the intra mode of the current block using intra mode information of the MPM list selected by the MPM selector 110 .

5 is a schematic flowchart of an intra mode prediction method of video encoding according to another preferred embodiment of the present invention.

For intra-mode prediction of multi-view or multi-layer video encoding, an MPM is first selected (S110).

As described above, the MPM selection method may use blocks adjacent to the current block as well as blocks of other views or layers. Specifically, the MPM list is generated by using blocks located at the same position as the current block among blocks of another time point when encoding is completed or blocks of another layer.

In this case, when the intra mode of a block of another view or of another layer that has been encoded is a directional mode, an MPM list may be generated by prioritizing blocks of another view or of another layer. However, at this time, when the encoding is completed at another time or when the intra mode of a block of another layer is not a directional mode, an MPM list can be generated using a block adjacent to the current block, that is, an upper block or a left block, as in the prior art. .

When the MPM list is generated, the intra mode of the current block is predicted using it (S120).

According to the apparatus and method for predicting an intra mode of video encoding as described above, the accuracy of intra mode prediction can be improved and the efficiency of video encoding can be improved by using not only the current screen but also blocks of other views or layers to predict the intra mode. there is.

6 and 7 relate to an apparatus and method for decoding an encoded image.

6 is a schematic structural diagram of an intra prediction device of a video decoder according to another preferred embodiment of the present invention.

The intra prediction apparatus 200 of the video decoder 2 for decoding a multi-view or multi-layer video bitstream into an image may include an MPM selection unit 210 and an intra prediction unit 220.

The MPM selector 210 selects an MPM using an intra mode of a decoded neighboring block or a block of another view or layer. A method of generating the MPM list is the same as described above.

The intra prediction unit 220 determines an intra mode from the generated MPM list, performs intra prediction based on the determination, and decodes the current block.

7 is a schematic flowchart of an intra prediction method of image decoding according to another preferred embodiment of the present invention.

In an image decoding step for decoding a multi-view or multi-layer video bitstream into an image, an intra prediction method may include an MPM selection step (S210) and an intra prediction step (S220).

In the MPM selection step (S210), an MPM is selected using an intra mode of a decoded neighboring block or a block of another view or another layer. A method of generating the MPM list is the same as described above.

In the intra prediction step (S220), an intra mode is determined from the generated MPM list, intra prediction is performed thereon, and the current block is decoded.

The apparatus and method for intra-mode prediction for encoding or decoding a multi-view or multi-layer image as described above increases the accuracy of intra-mode prediction by using blocks of different views or layers of the multi-view or multi-layer image for intra-mode prediction. Therefore, there is an advantage of increasing image encoding efficiency.

The protection scope of the present invention is not limited to the description and expression of the embodiments explicitly described above. In addition, it is added once again that the scope of protection of the present invention cannot be limited due to obvious changes or substitutions in the technical field to which the present invention belongs.

Claims (8)

In an intra prediction device for encoding a plurality of multi-view images generated by simultaneously shooting at different viewpoints using multiple cameras:
MPM (Most Probable Mode) MPM selection unit for selecting; and
An intra mode prediction unit predicting an intra mode of the current block based on the MPM;
The MPM selection unit
It is located at a plurality of viewpoints different from the current block, is located at the same location coordinates as the current block, has an intra mode, is a directional mode, and selects a block at a viewpoint closest to the current block among blocks that have been coded as an MPM list. doing
Intra prediction device for video encoding.
In the intra-prediction method for encoding a plurality of multi-view images generated by simultaneously shooting at different viewpoints using multiple cameras:
Selecting an MPM by an intra mode among adjacent blocks located at the same time point as the current block to be encoded and adjacent to the current block, and blocks located at a different time point from the current block and located at the same position coordinates as the current block step; and
Predicting an intra mode of the current block based on the MPM;
The step of selecting the MPM is
Selecting a block of a viewpoint closest to the current block among blocks located at a plurality of viewpoints different from the current block, located at the same position coordinates as the current block, having an intra mode and a directional mode, and having completed encoding, as an MPM list.
Intra prediction method for video encoding.
In the intra-prediction device for decoding a plurality of multi-view images generated by simultaneously photographing at different viewpoints using multiple cameras:
Selecting an MPM by an intra mode among adjacent blocks located at the same time point as the current block to be decoded and adjacent to the current block, and blocks located at a different time point from the current block and located at the same location coordinates as the current block MPM selection department; and
An intra prediction unit for intra predicting the current block based on the selected MPM;
The MPM selection unit
It is located at a plurality of viewpoints different from the current block, is located at the same location coordinates as the current block, has an intra mode, is a directional mode, and selects a block at a viewpoint closest to the current block among blocks that have been coded as an MPM list. doing
Intra prediction device for video decoding.
In the intra-prediction method for decoding a plurality of multi-view images generated by simultaneously shooting at different viewpoints using multiple cameras:
Selecting an MPM by an intra mode among adjacent blocks located at the same time point as the current block to be decoded and adjacent to the current block, and blocks located at a different time point from the current block and located at the same location coordinates as the current block MPM selection step; and
Intra-prediction step of intra-predicting the current block based on the selected MPM;
The step of selecting the MPM is
Selecting a block of a viewpoint closest to the current block among blocks located at a plurality of viewpoints different from the current block, located at the same position coordinates as the current block, having an intra mode and a directional mode, and having completed encoding, as an MPM list.
Intra prediction method for video decoding.
delete delete delete According to claim 1,
The intra prediction apparatus for video encoding, characterized in that the current block is a luma block or a chroma block.

Images