KR20170125154A - Method and apparatus of video decoder using curve intra prediction - Google Patents

Abstract

The present invention relates to an intra-prediction technology in a video compression technique and, more specifically, to a method and an apparatus for improving performance of an intra-prediction technology by performing curved intra-prediction. A video decoding method comprises: a step of extracting information for generating a prediction signal from a bit stream; a step of performing reference sample padding by using the extracted information; a step of generating a prediction sample by performing a curved intra-prediction using the extracted information; and a step of filtering the generated prediction sample.

Description

TECHNICAL FIELD [0001] The present invention relates to a video decoding method and a video decoding method using curved intra prediction,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video encoding and decoding technique, and more particularly, to a video decoding method and apparatus using a curve intra prediction method.

The market demand for high definition video is increasing, and a technology that can efficiently compress high resolution images is needed. The Moving Picture Expert Group (MPEG) of ISO / IEC and the Video Coding Expert Group of ITU-T jointly form Joint Collaborative Team on Video Coding (JCT-VC) Efficiency Video Coding) The video compression standard has been developed in January 2013 and has been actively researched and developed for the next generation compression standard. In the next-generation compression standard, it is important to use a more advanced and efficient compression method using intra-picture prediction for high-resolution / high-definition video services.

It is an object of some embodiments of the present invention to provide a method and apparatus for using curved intra prediction techniques in video compression techniques.

It is to be understood, however, that the technical scope of the present invention is not limited to the above-described technical problems, and other technical problems may exist.

According to an aspect of the present invention, there is provided an apparatus and method for decoding an image according to an embodiment of the present invention includes extracting information for generating a prediction signal from a bitstream, performing reference sample padding using the extracted information, Generating a prediction sample by performing curve in-frame prediction using the extracted information, and filtering the generated prediction sample.

According to an aspect of the present invention, there is provided an apparatus and method for decoding an image, the method comprising the steps of: obtaining information for generating a prediction signal from a bitstream; And if so, extracting information about the in-curve prediction from the bitstream.

According to an aspect of the present invention, there is provided an apparatus and method for decoding an image according to an embodiment of the present invention. The apparatus includes a reference sample padding unit, And performing reference sample padding.

According to an aspect of the present invention, there is provided an apparatus and method for decoding an image, the method including generating a prediction sample using information on a curve intra-picture prediction obtained from a bitstream.

According to an aspect of the present invention, there is provided an apparatus and method for decoding an image according to an embodiment of the present invention. The apparatus includes a left prediction sample row and a top prediction sample row of the generated prediction block. And when using the prediction or the vertical direction prediction, filtering using the variation amount of the surrounding reference sample.

It is an object of the present invention to provide a method and apparatus for performing intra-picture prediction in a picture intraprediction process used in an existing video compression technique for improving coding / decoding efficiency.

According to the above-described solution of the present invention, it is possible to improve the compression performance of video by improving the efficiency of the intra-picture prediction in the encoder / decoder through the curve intra-picture prediction.

1 illustrates a decoding apparatus including an intra prediction unit according to an embodiment of the present invention.
FIG. 2 illustrates a peripheral reference area when intra prediction is performed according to an exemplary embodiment of the present invention.
FIG. 3 illustrates a method of referring to pixels of neighboring blocks when performing intra-frame prediction according to an embodiment of the present invention.
FIG. 4 illustrates a method of referring to pixels of neighboring blocks when performing intra-frame prediction according to an embodiment of the present invention.
FIG. 5 illustrates a method of generating a nonexistent reference sample of a neighboring block when performing intra-frame prediction according to an exemplary embodiment of the present invention.
FIG. 6 illustrates a method of performing prediction using reference samples in different directions in each region of a prediction block when performing intra-frame prediction according to an embodiment of the present invention.
FIG. 7 illustrates another method of performing prediction using reference samples in different directions in each region of a prediction block when performing intra-frame prediction according to an embodiment of the present invention.
FIG. 8 illustrates a method of performing filtering on the leftmost predicted sample sequence of a prediction block to remove discontinuity with neighboring blocks when performing intra-frame prediction according to an embodiment of the present invention.
FIG. 9 illustrates a method of performing filtering on the uppermost predicted sample sequence of a prediction block in order to remove discontinuity with neighboring blocks when performing intra-frame prediction according to an embodiment of the present invention.
10 is a flowchart illustrating a procedure for performing intra prediction in accordance with an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings attached hereto, so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout this specification, when a part is referred to as being 'connected' to another part, it includes not only a case where it is directly connected but also a case where the part is electrically connected with another part in between.

In addition, when an element is referred to as being "comprising" an element throughout the specification, it is understood that the element may include other elements, but not other elements, unless specifically stated otherwise.

The term (or step) or step of (~) used in the present specification does not imply a step for.

Also, the terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

In addition, the components shown in the embodiments of the present invention are shown independently to represent different characteristic functions, which does not mean that each component is composed of separate hardware or software constituent units. That is, each constituent unit is described by arranging each constituent unit for convenience of explanation, and at least two constituent units of each constituent unit may be combined to form one constituent unit or one constituent unit may be divided into a plurality of constituent units to perform a function. The integrated embodiments and the separate embodiments of each of these components are also included in the scope of the present invention without departing from the essence of the present invention.

First, the terms used in the present application will be briefly described as follows.

The video decoding apparatus may be a personal computer (PC), a notebook computer, a portable multimedia player (PMP), a wireless communication terminal, a smart phone, , A TV application server and a service server, and may be a user terminal such as various devices, a communication device such as a communication modem for performing communication with a wired or wireless communication network, A memory for storing various programs for in-screen prediction and data, and a microprocessor for executing and controlling programs and the like.

In addition, an image encoded with a bitstream by an encoder can be transmitted in real time or in non-real time via a wired or wireless communication network such as the Internet, a local area wireless communication network, a wireless LAN network, a WiBro network, a mobile communication network, Universal Serial Bus), and the like, and can be decoded and restored into an image and reproduced.

In general, a moving picture may be composed of a series of pictures, and each picture may be divided into a coding unit such as a block. It is to be understood that the term " picture " described below can be used as a substitute for another term having an equivalent meaning such as an image, a frame, etc., and can be understood by those skilled in the art to which the present embodiment belongs will be.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the present invention, the same elements will not be described in detail.

1 illustrates a decoding apparatus including an intra prediction unit according to an embodiment of the present invention.

The decoding apparatus including the intra prediction unit includes an entropy decoding unit 110, an inverse quantization unit 120, an inverse transform unit 130, an intra prediction unit 140, an inter prediction unit 150, 160, and a reconstructed image storage unit 170. [0035]

The entropy decoding unit 110 decodes the input bitstream 100 and outputs decoded information such as syntax elements and quantized coefficients. The information to be output may include information for global motion compensation.

The inverse quantization unit 120 and the inverse transformation unit 130 receive the quantization coefficient, perform inverse quantization and inverse transformation in order, and output a residual signal.

The intra prediction unit 140 performs spatial prediction using the pixel values of the neighboring decoded neighboring blocks adjacent to the current block to be decoded to generate a prediction signal. The surrounding pixel values in the direction of the curve can be used to generate the prediction signal.

The inter-picture prediction unit 150 performs motion compensation using a motion vector extracted from the bit stream and a reconstructed image stored in the reconstructed image storage unit 170 to generate a prediction signal.

The prediction signals output from the intra-frame prediction unit 140 and the inter-frame prediction unit 150 are summed with the residual signals, and the reconstructed image generated through the summing is transmitted to the in-loop filter unit 160.

The restored picture to which filtering is applied in the in-loop filter unit 160 is stored in the reconstructed image storage unit 170 and can be used as a reference picture in the inter-picture prediction unit 150. [

FIG. 2 illustrates a peripheral reference area when intra prediction is performed according to an exemplary embodiment of the present invention.

A top reference sample 220, a left reference sample 230, and a top left reference sample 240 may be used to generate a prediction sample of the current intra-prediction block 210 having an MxN size.

The length of the upper reference sample 220 column may be longer than the width M of the current intra-frame prediction block 210. In addition, the length of the left reference sample 230 column may be longer than the vertical length N of the current intra-frame prediction block 210.

FIG. 3 illustrates a method of referring to samples of neighboring blocks when intra prediction is performed according to an embodiment of the present invention.

A prediction signal can be generated using a reference sample in the direction of the curve 320 when the prediction sample of the current intra-prediction block 310 having the MxN size is generated, and the curve is expressed in N-order, .

The information of the curve may be transmitted in a bitstream, and the information may include a degree or a coefficient of a curve equation.

FIG. 4 illustrates a method of referring to multiple reference samples of neighboring blocks when intra prediction is performed according to an embodiment of the present invention.

When generating the prediction sample 420 of the current intra-frame prediction block 410 having the MxN size, one or more pixels of the neighboring block in the direction of the curve 430 may be referred to.

If more than one reference sample is used, the prediction sample 420 may be generated with a weighted average value of the reference samples 440 and 450.

FIG. 5 illustrates a method of generating a nonexistent reference sample of a neighboring block when performing intra-frame prediction according to an exemplary embodiment of the present invention.

If a reference sample is partially present around the current intra-prediction block 510 having an MxN size, the reference sample that is not available 540, 550 may be used to generate a non-existent reference sample.

In the case of generating non-existent reference samples 520 and 530, the length of the reference sample to be generated may vary according to the curve 560 used in the current prediction block.

FIG. 6 illustrates a method of performing prediction using reference samples in different directions in each region of a prediction block when performing intra-frame prediction according to an embodiment of the present invention.

When the current in-frame prediction block having the MxN size is divided into two zones A and B by a curve 610, the zones A and B can generate prediction samples using reference samples in different directions.

There may be more than one reference sample used to generate a prediction sample in Zone A or Zone B, and each of the one or more respective reference samples may be located in different directions.

FIG. 7 illustrates another method of performing prediction using reference samples in different directions in each region of a prediction block when performing intra-frame prediction according to an embodiment of the present invention.

When the current intra-frame prediction block having the MxN size is divided into zones A, B, C, and D by a curve 710 and a straight line 720 connecting the edges of the block, the zones A, B, C, A sample can be used to generate a prediction sample.

The reference samples used to generate the predicted samples in each of the zones A, B, C, and D may be one or more, and each of the one or more respective reference samples may be located in different directions.

FIG. 8 illustrates a method of performing filtering on the leftmost predicted sample sequence of a prediction block to remove discontinuity with neighboring blocks when performing intra-frame prediction according to an embodiment of the present invention.

If the current in-frame prediction block having the MxN size is located on the left side of the prediction block, the prediction sample in the leftmost column of the prediction block can be filtered have.

When filtering is performed on the samples in the leftmost column of the prediction block, the left reference sample variation can be used.

For example, if the predicted block is divided into two regions A and B by curve 810 as shown in FIG. 8, and region A uses vertical prediction, the left reference samples The filtering 830 may be used to perform the filtering.

FIG. 9 illustrates a method of performing filtering on the uppermost predicted sample sequence of a prediction block in order to remove discontinuity with neighboring blocks when performing intra-frame prediction according to an embodiment of the present invention.

If the current in-frame prediction block having the MxN size is located at the top of the prediction block, the prediction sample in the uppermost row of the prediction block can be filtered have.

When the filtering is performed on the samples in the uppermost row of the prediction block, the upper reference sample variation amount can be used.

For example, if the prediction block is divided into two regions A and B by curve 910 as shown in FIG. 9, and region A uses horizontal prediction, the prediction samples of the top row 920, Filtering may be performed using the amount of change 930.

10 is a flowchart illustrating a procedure for performing intra prediction in accordance with an embodiment of the present invention.

First, curved intra prediction information is extracted 1010 from the bit stream. The extracted information may include a degree or a coefficient of an equation of a curve for expressing a curve. Using the information about the extracted curve and the presence or absence of reference pixels of the neighboring blocks, it is determined whether reference sample padding is necessary 1020. If reference sample padding is required, A sample is generated (1030). If reference sample padding is not required, a prediction sample of the current intra prediction block is generated (1040) using the reference sample. When generating a prediction sample, the reference sample is determined using the information on the curve extracted earlier. If the generation of the prediction block is finished, a determination is made 1050 as to whether to perform filtering on the prediction sample. If the left region of the prediction block uses vertical prediction or the upper region of the prediction block uses horizontal prediction to filter the prediction sample, the prediction sample filtering is performed 1060 using the variation of the surrounding reference sample. Filtering for the prediction sample can be performed on the leftmost sample column and the topmost sample row of the prediction block.

Claims (10)

A video decoding method comprising:
Extracting information for generating a prediction signal from the bitstream;
Performing reference sample padding using the extracted information;
Performing a curve in-frame prediction using the extracted information to generate a prediction sample;
And filtering the generated prediction samples. The method according to claim 1,
The step of acquiring information for generating a prediction signal from the bitstream
Extracting intra prediction mode information from the bitstream;
And extracting information on a curve intra-picture prediction from the bit stream when the extracted intra-picture prediction mode information indicates a curve intra-picture prediction. The method according to claim 1,
The step of performing the reference sample padding using the extracted information
Determining whether or not to perform reference sample padding using the information about the in-curve prediction obtained from the bitstream and the presence or absence of the reference sample of the neighboring block, and performing reference sample padding. The method according to claim 1,
Wherein the step of generating a prediction sample by performing curve in-frame prediction using the extracted information comprises:
And generating a prediction sample using information on a curve intra-picture prediction obtained from the bit stream. The method according to claim 1,
The step of filtering the generated prediction samples
Filtering using the variation amount of the neighboring reference samples when the region including the sample sequence for the left prediction sample row and the upper prediction sample row of the generated prediction block uses the horizontal prediction or the vertical prediction, Wherein the video decoding method comprises the steps of: A video decoding apparatus comprising:
Extracting information for generating a prediction signal from the bitstream;
Performing reference sample padding using the extracted information;
Performing a curve in-frame prediction using the extracted information to generate a prediction sample;
And filtering the generated prediction samples. The method according to claim 1,
The step of acquiring information for generating a prediction signal from the bitstream
Extracting intra prediction mode information from the bitstream;
And extracting information on a curve intra-picture prediction from the bit stream when the extracted intra-picture prediction mode information indicates a curve intra-picture prediction. The method according to claim 1,
The step of performing the reference sample padding using the extracted information
Determining whether or not to perform reference sample padding using the information about the in-curve prediction obtained from the bit stream and the presence or absence of the reference sample of the neighboring block, and performing reference sample padding. The method according to claim 1,
Wherein the step of generating a prediction sample by performing curve in-frame prediction using the extracted information comprises:
And generating a prediction sample using information on a curve intra-picture prediction obtained from the bit stream. The method according to claim 1,
The step of filtering the generated prediction samples
Filtering using the variation amount of the neighboring reference samples when the region including the sample sequence for the left prediction sample row and the upper prediction sample row of the generated prediction block uses the horizontal prediction or the vertical prediction, The video decoding apparatus comprising:

Images