KR20180041576A - Image encoding method/apparatus, image decoding method/apparatus and and recording medium for storing bitstream - Google Patents

Abstract

The present invention provides an image encoding method and an image decoding method. The image encoding method according to the present invention includes a first division step of dividing a current image into a plurality of blocks and a second division step of dividing a division target block including the boundary of the current image among the plurality of blocks into a plurality of lower blocks. The second division step is recursively performed by using the lower block including the boundary of the current image as the division target block until there is not the lower block including the boundary of the current image among the lower blocks. Accordingly, the present invention can improve the compression efficiency of the image.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image encoding method / apparatus, an image decoding method / apparatus, and a recording medium storing a bitstream.

The present invention relates to an image encoding / decoding method and apparatus. And more particularly, to a method and apparatus for processing image boundaries in image encoding / decoding. More particularly, the present invention relates to a method and apparatus for efficiently processing boundaries of an image in a padding and tree structure of an image.

In recent years, demand for multimedia data such as video has been rapidly increasing on the Internet. However, the rate at which the bandwidth of a channel develops is hard to follow the amount of multimedia data that is rapidly increasing. As part of this trend, Video Coding Expert Group (VCEG) of the International Organization for Standardization (ITU-T) and MPEG (Moving Picture Expert Group) of ISO / IEC are studying video compression standards through cooperative research.

The video compression consists largely of intra-picture prediction, inter-picture prediction, transform, quantization, entropy coding, and an in-loop filter. Among them, intra prediction is a technique of generating a prediction block for a current block using reconstructed pixels existing around the current block. In this case, since the encoding process is performed on a block-by-block basis, if the size of the image does not become a multiple of the block size, there is a problem that encoding is not performed on a block-by-block basis.

An object of the present invention is to provide a padding method and apparatus for adjusting the size of an image on a block-by-block basis in coding / decoding an image.

It is another object of the present invention to provide a method and an apparatus for efficiently dividing a block into a plurality of blocks.

It is another object of the present invention to provide a computer-readable recording medium storing a bitstream generated by a video encoding method / apparatus according to the present invention.

A method of encoding an image according to the present invention includes a first dividing step of dividing a current image into a plurality of blocks and a division target block including a boundary of the current image among the plurality of blocks into a plurality of sub- And a second subdivision step of dividing the subblock including the boundary of the current image into a plurality of subblocks, It can be recursively performed as a division target block.

In the image encoding method according to the present invention, the first segmentation step may be a step of dividing the current image into a plurality of maximum blocks having the same size.

In the image encoding method according to the present invention, the second segmentation step may be a step of performing a quadtree segmentation or a binary tree segmentation on the segmentation target block.

In the image coding method according to the present invention, when the partitioning target block is of a size that can be quad-tree partitioned, the second partitioning step performs the quadtree partitioning on the partitioning target block, If the quadtree partitioning is not possible, the second partitioning step may perform the binary tree partitioning on the partitioning target block.

In the image coding method according to the present invention, when the quadtree partitioning or the binary tree partitioning is performed on the partitioning target block in the second partitioning step, The first division information indicating whether or not the division target block is divided into binary trees may not be coded.

In the image coding method according to the present invention, when the binary tree segmentation is performed on the segmentation target block in the second segmentation step, the dividing direction of the binary tree segmentation is included in the segmentation object block, Can be determined based on the type of the block to be coded which is an area within the boundary of the image.

In the image encoding method according to the present invention, when the binary tree segmentation is performed on the segmentation target block in the second segmentation step, the segmentation direction information indicating the segmentation direction of the binary tree segmentation may not be encoded.

In the image encoding method according to the present invention, the second segmenting step may further include a step of comparing a size of a remaining area included in the segmentation target block and outside the boundary of the current image with a predetermined threshold value And perform one of the quadtree partitioning and the binary tree partitioning on the partitioning target block based on the comparison result.

In the image coding method according to the present invention, the size of the remaining area may be smaller than the width and the length of the remaining area, and the second dividing step may be performed such that the size of the remaining area is larger than the predetermined threshold value The quadtree partitioning may be performed on the partitioning target block and the binary tree partitioning may be performed on the partitioning target block when the size of the remaining area is smaller than the predetermined threshold value.

In the image coding method according to the present invention, the second dividing step is a step of performing a binary tree division on the partitioning target block, and the partitioning direction of the binary tree partitioning is included in the partitioning object block, And can be determined based on the shape of the remaining area which is an area outside the boundary of the current image.

In the image coding method according to the present invention, the dividing direction of the binary tree division may be a vertical direction when the shape of the remaining area is a vertically long block, a horizontal direction when the shape of the remaining area is a horizontally long block, Direction.

A method of decoding an image according to the present invention includes a first dividing step of dividing a current image into a plurality of blocks, and a dividing step of dividing a division target block including the boundary of the current image among the plurality of blocks into a plurality of sub- And a second subdivision step of dividing the subblock including the boundary of the current image into a plurality of subblocks, It can be recursively performed as a division target block.

In the image decoding method according to the present invention, the second segmentation step may be a step of performing a quadtree segmentation or a binary tree segmentation on the segmentation target block.

In the image decoding method according to the present invention, when the partitioning target block is of a size that can be quad-tree partitioned, the second partitioning step performs the quadtree partitioning on the partitioning target block, If the quadtree partitioning is not possible, the second partitioning step may perform the binary tree partitioning on the partitioning target block.

In the image decoding method according to the present invention, when the quadtree partitioning or the binary tree partitioning is performed on the partitioning target block in the second partitioning step, The second division information indicating whether the first division information or the division target block is binary tree-divided is not decoded from the bit stream but may be derived to a predetermined value.

In the image decoding method according to the present invention, when the binary tree segmentation is performed on the segmentation target block in the second segmentation step, the dividing direction of the binary tree segmentation is included in the segmentation object block, And can be determined based on the type of the block to be decoded which is an area within the boundary of the image.

In the image decoding method according to the present invention, when the binary tree division is performed on the partitioning target block in the second partitioning step, the partitioning direction information indicating the partitioning direction of the binary tree partitioning is not decoded from the bitstream , And can be derived to a predetermined value.

In the image decoding method according to the present invention, the second dividing step may further include a step of comparing a size of a remaining area included in the dividing target block and outside the boundary of the current image with a predetermined threshold value And perform one of the quadtree partitioning and the binary tree partitioning on the partitioning target block based on the comparison result.

In the image decoding method according to the present invention, the size of the remaining area is a smaller one of a horizontal length and a vertical length of the remaining area, and in the second dividing step, the size of the remaining area is larger than the predetermined threshold value The quadtree partitioning may be performed on the partitioning target block and the binary tree partitioning may be performed on the partitioning target block when the size of the remaining area is smaller than the predetermined threshold value.

In the image decoding method according to the present invention, the second dividing step is a step of performing a binary tree division on the partitioning target block, and the dividing direction of the binary tree partitioning is included in the partitioning object block, And can be determined based on the shape of the remaining area which is an area outside the boundary of the current image.

In the image decoding method according to the present invention, the dividing direction of the binary tree division may be a vertical direction when the shape of the remaining area is a vertically long block, a horizontal direction when the shape of the remaining area is a horizontally long block, Direction.

The computer readable recording medium according to the present invention can store a bit stream generated by the image encoding method according to the present invention.

According to the present invention, in coding / decoding an image, a padding method and apparatus for adjusting the size of an image on a block-by-block basis can be provided.

Further, according to the present invention, a block dividing method and an apparatus for efficient image boundary processing in image coding / decoding can be provided.

According to another aspect of the present invention, there is provided a computer-readable recording medium storing a bit stream generated by a video encoding method / apparatus according to the present invention.

The compression efficiency of the image can be improved by using the padding method and apparatus or the block dividing method and apparatus according to the present invention.

1 is a block diagram schematically illustrating an image encoding apparatus according to an embodiment of the present invention.
FIG. 2 shows the types of intra prediction modes defined in the image encoding / decoding apparatus.
FIG. 3 illustrates an in-screen prediction method based on a planar mode.
Fig. 4 shows reference pixels for intra-frame prediction.
FIG. 5 illustrates an intra prediction method based on a horizontal mode and a vertical mode.
FIG. 6 is a block diagram of a video decoding apparatus according to an embodiment of the present invention. Referring to FIG.
7 is a diagram for explaining a padding process according to an embodiment of the present invention.
8A and 8B are views for explaining a padding process according to the present invention.
Fig. 9 is a diagram for explaining the operation of the image divider 101 of Fig.
FIG. 10 is a diagram for explaining an operation in the decoder according to the present invention.
11 is a diagram illustrating a case where the size of the current image is not a multiple of the maximum block size.
12A to 12E are diagrams for explaining an image dividing method according to an embodiment of the present invention.
13A to 13E are diagrams for explaining an image dividing method according to another embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

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. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, the same reference numerals will be used for the same constituent elements in the drawings, and redundant explanations for the same constituent elements will be omitted.

1 is a block diagram illustrating an image encoding apparatus according to an embodiment of the present invention.

1, an image encoding apparatus 100 includes an image division unit 101, an intra-frame prediction unit 102, an inter-frame prediction unit 103, a subtraction unit 104, a conversion unit 105, An inverse transform unit 106, an entropy encoding unit 107, an inverse quantization unit 108, an inverse transformation unit 109, a multiplication unit 110, a filter unit 111, and a memory 112.

Each of the components shown in FIG. 1 is shown independently to represent different characteristic functions in the image encoding apparatus, and does not mean that each component is composed of separate hardware or one software configuration unit. That is, each constituent unit is included in each constituent unit for convenience of explanation, and at least two constituent units of the constituent units 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 separate embodiments of the components are also included within the scope of the present invention, unless they depart from the essence of the present invention.

In addition, some of the components are not essential components to perform essential functions in the present invention, but may be optional components only to improve performance. The present invention can be implemented only with components essential for realizing the essence of the present invention, except for the components used for the performance improvement, and can be implemented by only including the essential components except the optional components used for performance improvement Are also included in the scope of the present invention.

The image divider 100 may divide the input image into at least one block. At this time, the input image may have various shapes and sizes such as a picture, a slice, a tile, and a segment. A block may mean a coding unit (CU), a prediction unit (PU), or a conversion unit (TU). The partitioning may be performed based on at least one of a quadtree or a binary tree. The quad tree is a method of dividing the upper block into sub-blocks whose width and height are half of the upper block. A binary tree is a method of dividing an upper block into sub-blocks, either width or height, which is half of the upper block. Through the binary tree-based partitioning described above, a block can have a square as well as a non-square shape.

Hereinafter, in the embodiment of the present invention, a coding unit may be used as a unit for performing coding, or may be used as a unit for performing decoding.

The predicting units 102 and 103 may include an inter-picture predicting unit 103 for performing inter-prediction and an intra-picture predicting unit 102 for performing intra-prediction. It is possible to determine whether to use inter prediction or intra prediction for a prediction unit and to determine concrete information (e.g., intra prediction mode, motion vector, reference picture, etc.) according to each prediction method. At this time, the processing unit in which the prediction is performed may be different from the processing unit in which the prediction method and the concrete contents are determined. For example, the method of prediction, the prediction mode and the like are determined as a prediction unit, and the execution of the prediction may be performed in a conversion unit.

The residual value (residual block) between the generated prediction block and the original block can be input to the conversion unit 105. In addition, the prediction mode information, motion vector information, and the like used for prediction can be encoded by the entropy encoding unit 107 and transmitted to the decoder along with the residual value. When a specific encoding mode is used, it is also possible to encode the original block as it is without generating a prediction block through the predicting units 102 and 103, and to transmit it to the decoding unit.

The intra prediction unit 102 can generate a prediction block based on reference pixel information around the current block which is pixel information in the current picture. If the prediction mode of the neighboring block of the current block in which intra prediction is to be performed is inter prediction, a reference pixel included in a neighboring block to which inter prediction is applied may be replaced with a reference pixel in another neighboring block to which intra prediction is applied. That is, when the reference pixel is not available, the reference pixel information that is not available may be replaced with at least one reference pixel of the available reference pixels.

In intra prediction, the prediction mode may have a directional prediction mode in which reference pixel information is used according to a prediction direction, and a non-directional mode in which direction information is not used in prediction. The mode for predicting the luminance information may be different from the mode for predicting the chrominance information and the intra prediction mode information or predicted luminance signal information used for predicting the luminance information may be utilized to predict the chrominance information.

The intra prediction unit 102 may include an Adaptive Intra Smoothing (AIS) filter, a reference pixel interpolator, and a DC filter. The AIS filter is a filter that performs filtering on the reference pixels of the current block and can adaptively determine whether to apply the filter according to the prediction mode of the current prediction unit. When the prediction mode of the current block is a mode in which AIS filtering is not performed, the AIS filter may not be applied.

When the intra prediction mode of the intra prediction unit 102 is a prediction unit that performs intra prediction on the basis of the pixel value obtained by interpolating the reference pixel, the reference pixel interpolator 102 interpolates the reference pixel, Lt; / RTI > The reference pixel may not be interpolated in the prediction mode in which the prediction mode of the current prediction unit generates the prediction block without interpolating the reference pixel. The DC filter can generate a prediction block through filtering when the prediction mode of the current block is the DC mode.

A residual block including residue information that is a difference value between the prediction unit generated by the prediction units 102 and 103 and the original block of the prediction unit can be generated. The generated residual block may be input to the conversion unit 130 and converted.

2 is a diagram for explaining an example of the intra prediction mode. The intra prediction mode shown in FIG. 2 has a total of 35 modes. The 0-th mode represents a planar mode, the 1-th mode represents a DC mode, and the 2-th to 34-th modes represent an angular mode.

3 is a diagram for explaining intra-picture prediction in the planar mode.

3 is a diagram for explaining the planar mode. The reconstructed pixel at the same position in the Y-axis and the reconstructed pixel T at the upper right of the current block are generated by linear interpolation as shown in the figure to generate a predicted value of the first pixel P1 in the current block. Similarly, in order to generate the predicted value of the second pixel P2, the reconstructed pixel at the same position in the X axis and the reconstructed pixel L at the lower left of the current block are generated by linear interpolation as shown in the figure. A value obtained by averaging two prediction pixels P1 and P2 becomes a final prediction pixel. In the planar mode, prediction blocks are derived in the same manner as described above to generate a prediction block of the current block.

4 is a diagram for explaining the DC mode. Calculates the average of the restored pixels around the current block, and uses the average value as a predicted value of all the pixels in the current block.

5 is a diagram for explaining an example of generating a prediction block using mode 10 (horizontal mode) and mode 26 (vertical mode) in FIG. In the case of using the 10th mode, each reference pixel tangent to the left side of the current block is copied in the right direction to generate a prediction block of the current block. Similarly, in the 26th mode, each reference pixel tangent to the upper side of the current block is copied downward to generate a prediction block of the current block.

Referring again to FIG. 1, the inter-picture predicting unit 103 may predict a prediction unit based on information of at least one of a previous picture or a following picture of the current picture. In some cases, The prediction unit may be predicted on the basis of information of a certain area. The inter-picture predicting unit 103 may include a reference picture interpolating unit, a motion predicting unit, and a motion compensating unit.

In the reference picture interpolating unit, reference picture information is supplied from the memory 112 and pixel information of an integer pixel or less can be generated in the reference picture. In the case of a luminance pixel, a DCT-based interpolation filter having a different filter coefficient may be used to generate pixel information of an integer number of pixels or less in units of quarter pixels. In the case of a color difference signal, a DCT-based 4-tap interpolation filter having a different filter coefficient may be used to generate pixel information of an integer number of pixels or less in units of 1/8 pixel.

The motion prediction unit may perform motion prediction based on the reference picture interpolated by the reference picture interpolating unit. Various methods such as Full Search-based Block Matching Algorithm (FBMA), Three Step Search (TSS), and New Three-Step Search Algorithm (NTS) can be used as methods for calculating motion vectors. The motion vector may have a motion vector value of 1/2 or 1/4 pixel unit based on the interpolated pixel. The motion prediction unit can predict the current prediction unit by making the motion prediction method different. Various methods such as a skip method, a merge method, and an AMVP (Advanced Motion Vector Prediction) method can be used as the motion prediction method.

The subtracting unit 104 subtracts the current block to be encoded from the intra prediction unit 102 or the inter prediction unit 103 to generate a residual block of the current block.

The transforming unit 105 can transform the residual block including the residual data by using a conversion method such as DCT, DST, Karhunen Loeve Transform (KLT), or the like. At this time, the conversion method can be determined based on the intra prediction mode of the prediction unit used to generate the residual block. For example, depending on the intra prediction mode, DCT may be used in the horizontal direction, and DST may be used in the vertical direction.

The quantization unit 106 may quantize the values converted into the frequency domain by the conversion unit 105. The quantization factor may vary depending on the block or the importance of the image. The values calculated by the quantization unit 106 may be provided to the inverse quantization unit 108 and the entropy coding unit 107. [

The transforming unit 105 and / or the quantizing unit 106 may be selectively included in the image encoding apparatus 100. That is, the image encoding apparatus 100 can perform at least one of conversion or quantization on the residual data of the residual block, or may skip both the conversion and the quantization, thereby encoding the residual block. A block entering the input of the entropy encoding unit 107 is generally referred to as a transform block even though either the transform or the quantization is not performed in the image coding apparatus 100 or both the transform and the quantization are not performed.

The entropy coding unit 107 entropy-codes the input data. For entropy encoding, various encoding methods such as Exponential Golomb, Context-Adaptive Variable Length Coding (CAVLC), and Context-Adaptive Binary Arithmetic Coding (CABAC) may be used.

The entropy encoding unit 107 receives the residual value coefficient information of the encoding unit and the block type information, the prediction mode information, the division unit information, the prediction unit information, the transmission unit information, the motion vector information, the reference frame information , Block interpolation information, filtering information, and the like. In the entropy encoding unit 107, the coefficient of the transform block is encoded in units of partial blocks in the transform block by encoding a non-zero coefficient, a coefficient having an absolute value of 1 or larger than 2, . The coefficient that is not encoded with only the flag can be encoded through the absolute value of the difference between the coefficient encoded through the flag and the coefficient of the actual conversion block. The inverse quantization unit 108 and the inverse transformation unit 109 dequantize the quantized values in the quantization unit 106 and inversely transform the values converted in the conversion unit 105. The residual value generated in the inverse quantization unit 108 and the inverse transformation unit 109 is predicted through the motion estimation unit, the motion compensation unit and the intra prediction unit 102 included in the prediction units 102 and 103 A reconstructed block can be created by combining with prediction units. The multiplier 110 generates a reconstruction block by multiplying the prediction block generated by the prediction units 102 and 103 and the residual block generated through the inverse transform unit 109. [

The filter unit 111 may include at least one of a deblocking filter, an offset correction unit, and an Adaptive Loop Filter (ALF).

The deblocking filter can remove block distortion caused by the boundary between the blocks in the reconstructed picture. It may be determined whether to apply a deblocking filter to the current block based on pixels included in a few columns or rows included in the block to determine whether to perform deblocking. When a deblocking filter is applied to a block, a strong filter or a weak filter may be applied according to the deblocking filtering strength required. In applying the deblocking filter, horizontal filtering and vertical filtering may be performed concurrently in performing vertical filtering and horizontal filtering.

The offset correction unit may correct the offset of the deblocked image with respect to the original image in units of pixels. In order to perform offset correction for a specific picture, pixels included in an image are divided into a predetermined number of areas, and then an area to be offset is determined and an offset is applied to the area. Alternatively, Can be used.

Adaptive Loop Filtering (ALF) can be performed based on a comparison between the filtered reconstructed image and the original image. After dividing the pixels included in the image into a predetermined group, one filter to be applied to the group may be determined and different filtering may be performed for each group. The information related to whether to apply the ALF may be transmitted for each coding unit (CU), and the shape and the filter coefficient of the ALF filter to be applied may be changed according to each block. Also, an ALF filter of the same type (fixed form) may be applied irrespective of the characteristics of the application target block.

The memory 112 may store the reconstructed block or picture calculated through the filter unit 111 and the reconstructed block or picture stored therein may be provided to the predictor 102 or 103 when the inter prediction is performed.

6 is a block diagram illustrating an image decoding apparatus 600 according to an embodiment of the present invention.

6, an image decoding apparatus 600 includes an entropy decoding unit 601, an inverse quantization unit 602, an inverse transformation unit 603, a multiplication unit 604, a filter unit 605, a memory 606, Prediction units 607 and 608, as shown in FIG.

When the image bit stream generated by the image encoding apparatus 100 is input to the image decoding apparatus 600, the input bit stream may be decoded according to a process opposite to that performed by the image encoding apparatus 100 .

The entropy decoding unit 601 can perform entropy decoding in a procedure opposite to that in which the entropy encoding unit 107 of the image encoding apparatus 100 performs entropy encoding. For example, various methods such as Exponential Golomb, Context-Adaptive Variable Length Coding (CAVLC), and Context-Adaptive Binary Arithmetic Coding (CABAC) may be applied in accordance with the method performed by the image encoder. In the entropy decoding unit 601, the coefficient of the transform block is based on a non-zero coefficient, a coefficient whose absolute value is 1 or larger than 2, and various kinds of flags indicating the sign of a coefficient, etc., Lt; / RTI > A coefficient not represented by only the flag can be decoded through a sum of a coefficient represented by a flag and a signaled coefficient.

The entropy decoding unit 601 can decode information related to the intra prediction and the inter prediction performed in the encoder. The inverse quantization unit 602 performs inverse quantization on the quantized transform block to generate a transform block. And operates substantially the same as the inverse quantization unit 108 of FIG.

The inverse transform unit 603 performs inverse transform on the transform block to generate a residual block. At this time, the conversion method can be determined on the basis of the prediction method (inter or intra prediction), the size and / or type of the block, the intra prediction mode, and the like. And operates substantially the same as the inverse conversion unit 109 of Fig.

The multiplication unit 604 generates a reconstruction block by multiplying the prediction block generated by the intra prediction unit 607 or the inter prediction unit 608 and the residual block generated through the inverse transform unit 603. And operates substantially the same as the vaporization section 110 of FIG.

The filter unit 605 reduces various types of noise occurring in the restored blocks.

The filter unit 605 may include a deblocking filter, an offset correction unit, and an ALF.

When information on whether or not a deblocking filter has been applied to the corresponding block or picture from the image encoding apparatus 100 and a deblocking filter are applied, information on whether a strong filter or a weak filter is applied can be provided. In the deblocking filter of the video decoding apparatus 600, the deblocking filter related information provided from the video encoding apparatus 100 is provided, and the video decoding apparatus 600 can perform deblocking filtering on the corresponding block.

The offset correction unit may perform offset correction on the reconstructed image based on the type of offset correction applied to the image and the offset value information during encoding.

The ALF may be applied to an encoding unit based on ALF application information, ALF coefficient information, and the like provided from the image encoding apparatus 100. Such ALF information may be provided in a specific set of parameters. The filter unit 605 operates substantially the same as the filter unit 111 of Fig.

The memory 606 stores the reconstruction block generated by the multiplication unit 604. And operates substantially the same as the memory 112 of Fig.

The prediction units 607 and 608 may generate a prediction block based on the prediction block generation related information provided by the entropy decoding unit 601 and the previously decoded block or picture information provided in the memory 606. [

The prediction units 607 and 608 may include an intra prediction unit 607 and an inter prediction unit 608. [ Although not shown separately, the prediction units 607 and 608 may further include a prediction unit determination unit. The prediction unit determination unit receives various information such as prediction unit information input from the entropy decoding unit 601, prediction mode information of the intra prediction method, motion prediction related information of the inter prediction method, and identifies prediction units in the current coding unit. It is possible to determine whether the unit performs inter prediction or intra prediction. The inter picture prediction unit 608 uses the information necessary for inter prediction of the current prediction unit provided by the image coding apparatus 100 to generate information on at least one of the previous picture of the current picture including the current prediction unit or the following picture The inter prediction of the current prediction unit can be performed. Alternatively, the inter prediction may be performed on the basis of the information of the partial region previously reconstructed in the current picture including the current prediction unit.

In order to perform the inter-picture prediction, whether the motion prediction method of the prediction unit included in the coding unit based on the coding unit is a skip mode, a merge mode, or an AMVP mode Can be determined.

Intra prediction unit 607 generates a prediction block using the pixels located near the current block to be coded and the previously reconstructed pixels.

The intra prediction unit 607 may include an Adaptive Intra Smoothing (AIS) filter, a reference pixel interpolator, and a DC filter. The AIS filter is a filter that performs filtering on the reference pixels of the current block and can adaptively determine whether to apply the filter according to the prediction mode of the current prediction unit. AIS filtering can be performed on the reference pixels of the current block using the prediction mode of the prediction unit and the AIS filter information provided by the image coding apparatus 100. [ When the prediction mode of the current block is a mode in which AIS filtering is not performed, the AIS filter may not be applied.

The intra-picture prediction unit 607 interpolates the reference pixels to interpolate the reference pixels in the fractional unit position when the prediction mode of the prediction unit is a prediction unit that performs intra-prediction based on the pixel value obtained by interpolating the reference pixels Can be generated. The reference pixel at the generated fractional unit position can be used as the predictive pixel of the pixel in the current block. The reference pixel may not be interpolated in the prediction mode in which the prediction mode of the current prediction unit generates the prediction block without interpolating the reference pixel. The DC filter can generate a prediction block through filtering when the prediction mode of the current block is the DC mode.

Intra prediction section 607 operates substantially the same as intraframe prediction section 102 in FIG.

The inter-picture prediction unit 608 generates an inter-prediction block using the reference picture and the motion information stored in the memory 606. The inter-picture predicting unit 608 operates substantially the same as the inter-picture predicting unit 103 of Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates in particular to padding and edge processing of images, and various embodiments of the present invention will now be described in more detail with reference to the drawings.

According to an embodiment of the present invention, a preprocessing process may be performed before the image to be encoded is input to the image divider 101 of FIG. The encoding target image may have various horizontal and vertical sizes in pixel units. However, since the encoding and decoding of an image are performed in units of blocks rather than pixels, a padding process may be required to adjust the size of an object image to be coded on a block-by-block basis.

7 is a diagram for explaining a padding process according to an embodiment of the present invention.

In the example shown in Fig. 7, the to-be-encoded image includes a block area and a non-block area. The preprocessing process is performed on the image to be encoded, so that a padded area can be added. The encoding target image to which the padded region is added can be input to the image divider 101 of FIG.

In the example shown in FIG. 7, the unit of the minimum block may be 4x4. The horizontal or vertical length of the block may be 2 ^{< n} >. Thus, for example, when the lengths of the horizontal and vertical lengths of the video to be coded are 9, respectively, the right one column and the bottom one row of the video to be coded may be non-block areas not included in the block area. In this manner, when the current picture to be coded includes a non-block area, padding can be performed in consideration of the size of the minimum block. Thus, by performing the padding considering the size of the block, the padded encoding object image does not include the non-block region. The padded encoding target image is input to the image divider 101 of FIG. 1 and is divided into a plurality of blocks, whereby block-based encoding can be performed.

8A and 8B are views for explaining a padding process according to the present invention.

First, padding can be performed in the horizontal direction by using the pixel closest to the pixel to be padded. In the example shown in FIG. 8A, the three uppermost padding target pixels can be padded using the pixel A of the non-block area adjacent to the left.

Thereafter, padding can be performed in the vertical direction using the pixel closest to the pixel to be padded. In the example shown in FIG. 8B, the leftmost three padding target pixels can be padded using the pixel I of the non-block area adjacent to the top.

In the above example, the padding process from the horizontal direction to the vertical direction has been described, but the present invention is not limited to this, and padding from the vertical direction to the horizontal direction may be performed. The size of the minimum block may be a block unit to be described with reference to FIG. 9 or a sub-block unit.

Fig. 9 is a diagram for explaining the operation of the image divider 101 of Fig.

The input image may be divided into a plurality of maximum blocks. The size of the largest block may be preset or signaled via a bitstream. For example, if the size of the input image is 128x128 and the size of the largest block is 64x64, the input image can be divided into four maximum blocks.

Each maximum block is input to the image divider 101 of Fig. 1 and can be divided into a plurality of blocks. The input image may not be divided into a plurality of maximum blocks but may be input to the image divider 101 immediately. The minimum size of the partitioned block and / or the maximum size of the block that can be divided into sub-blocks may be preset or may be signaled in the header of the upper level of the block. The upper level may be at least one of a video, a sequence, a picture, a slice, a tile, and a large coding unit (LCU).

The current block may be divided into four sub-blocks or two sub-blocks.

The division of the current block into four sub-blocks can be referred to as a quad-tree partition. The current block can be divided into four sub-blocks having the same size by quad tree partitioning. The first division information is information indicating whether the current block is quad-tree divided. The first division information may be, for example, a flag of 1 bit.

The division of the current block into two sub-blocks can be referred to as a binary-tree segmentation. The current block may be divided into two sub-blocks having the same or different size by binary tree segmentation. The second division information is information indicating whether or not the current block is divided into binary trees. The second division information may be, for example, a flag of 1 bit. If the current block is binary tree segmented, the partition direction information can be further signaled. The division direction information may indicate whether the division of the current block is a division in a horizontal direction or a division in a vertical direction. The dividing direction information may be, for example, a flag of 1 bit. If the current block is divided into two subblocks having different sizes, the partition type information can be further signaled. The division type information can represent the division ratio of two sub-blocks.

The current block can be recursively partitioned using quadtree partitioning and binary tree partitioning. For example, when the current block is quad-tree-divided into four sub-blocks, each sub-block may be recursively quad-tree divided, binary tree-divided, or not partitioned. If the current block is binary tree divided into two subblocks, each subblock may be recursively quad-tree divided, binary tree divided, or not partitioned. Or, quad tree partitioning may not be performed for the sub-blocks generated by the binary tree partitioning.

The encoder may determine whether to partition the quad tree with respect to the input current block. The first division information can be coded based on the determination (S901). If the current block is quad-tree divided (Yes in S902), the current block can be quad-tree divided into four blocks (S903). Each of the four blocks generated by the quadtree division may be inputted again to the step S901 in a predetermined order (S904, S916). The predetermined order may be a Z-scan order. In step S904, the first block in the predetermined order among the four blocks is specified and input as the current block in step S901.

If the current block is not quad-tree-divided (No in S902), the encoder can determine whether to divide the binary tree for the current block. Based on the determination, the second division information can be encoded (S905). If the current block is divided into binary trees (Yes in S906), the encoder determines whether the current block is to be horizontally divided or vertically divided, and the division direction information can be encoded based on the determination (S907). If the current block is horizontally divided (Yes in S908), the horizontal division of the current block may be performed (S909). Otherwise (No in S908), vertical division of the current block may be performed (S910). If the binary tree division for the current block is an asymmetric division, the division ratio is determined and the division type information can be further encoded. In this case, steps S909 and S910 may be performed in consideration of the partition type information. Each of the two sub-blocks generated by the binary tree division may be input again to the step S905 in a predetermined order (S911, S914). The predetermined order may be left to right, or bottom to top. In step S911, the first sub-block in the predetermined order among the two sub-blocks is identified and input as the current block in step S905. If quad tree partitioning is again allowed for the sub-blocks generated by the binary tree partitioning, each of the two blocks generated by the binary tree partitioning may be input to step S901 in a predetermined order.

If the current block is not divided into binary trees (No in S906), encoding of the current block or the current sub-block may be performed (S912). The encoding in step S912 may include prediction, conversion, quantization, and the like.

If the sub-block encoded in step S912 is not the last sub-block generated by the binary tree division (No in step S913), the next sub-block generated by the binary tree segmentation is specified, (S914).

If the subblock encoded in step S912 is the last subblock generated by the binary tree division (Yes in S913), it is determined whether or not the block to which the encoded subblock belongs is the last one of the blocks generated by the quadtree division (S915). If it is the last block (Yes in S915), the encoding of the maximum block or the current image input in step S901 can be ended. If it is not the last block (No in S915), the next block generated by the quadtree segmentation is specified and may be input as the current block in step S901 (S916).

FIG. 10 is a diagram for explaining an operation in the decoder according to the present invention.

The decoder may decode the first division information of the input current block (S1001). If the current block is quad-tree divided (Yes in S1002), the current block can be quad-tree divided into four blocks (S1003). Each of the four blocks generated by the quadtree division may be input again to the step S1001 in a predetermined order (S1004, S1016). The predetermined order may be a Z-scan order. In step S1004, the first block in the predetermined order among the four blocks is specified and can be input as a current block in step S1001.

If the current block is not quad-tree-divided (No in S1002), the decoder can decode the second division information of the current block (S1005). When the current block is divided into binary trees (Yes in S1006), the decoder can decode the dividing direction information (S1007). If the current block is horizontally divided (Yes in S1008), the horizontal division of the current block may be performed (S1009). Otherwise (No in S1008), the vertical division of the current block may be performed (S1010). If the binary tree partition for the current block is an asymmetric partition, the partition type information can be further decoded. In this case, steps S1009 and S1010 may be performed in consideration of the partition type information. Each of the two sub-blocks generated by the binary tree division may be input again to step S1005 in a predetermined order (S1011, S1014). The predetermined order may be left to right, or bottom to top. In step S1011, the first sub-block in the predetermined order among the two sub-blocks is identified and input as a current block in step S1005. If quad tree partitioning is again allowed for the sub-blocks generated by the binary tree partitioning, each of the two blocks generated by the binary tree partitioning may be input to step S1001 in a predetermined order.

If the current block is not divided into binary trees (No in S1006), decoding of the current block or the current sub-block may be performed (S1012). Decoding in step S1012 may include prediction, dequantization, inverse transform, and the like.

If the sub-block decoded in step S1012 is not the last sub-block generated by the binary tree division (No in step S1013), the next sub-block generated by the binary tree division is specified, (S1014).

If the sub-block decoded in step S1012 is the last sub-block generated by the binary tree division (Yes in S1013), whether the block to which the decoded sub-block belongs is the last one among the blocks generated by the quadtree division (S1015). If it is the last block (Yes in S1015), the decoding of the maximum block or the current image input in the step S1001 can be ended. If the block is not the last block (No in S1015), the next block generated by the quadtree partitioning is specified and input as the current block in step S1001 (S1016).

11 is a diagram illustrating a case where the size of the current image is not a multiple of the maximum block size.

As shown in FIG. 11, when dividing the current image into a plurality of maximum blocks, a region corresponding to a portion of the maximum block size is left on the right or bottom of the current image. That is, in the case of the maximum block 2, the maximum block 5, the maximum block 6, the maximum block 7, or the maximum block 8, only the pixels of the current image exist in some areas.

Hereinafter, an image dividing method according to the present invention for efficiently dividing a current image as shown in FIG. 11 will be described.

12A to 12E are diagrams for explaining an image dividing method according to an embodiment of the present invention. Hereinafter, with reference to Figs. 12A to 12E, a description will be given of a dividing method of the maximum block 2 and / or a coding of division information in Fig. 12A to 12E, it is assumed that the size of the current image is 146x146, the size of the maximum block is 64x64, the minimum size of the block that can be quad-tree divided is 16x16, and the minimum size of the sub-block is 2x2 .

12A is an enlarged view of the maximum block 2, and a portion surrounded by a thick line is an area in the current image. The maximum block 2 may be the block to be divided described with reference to FIG. As shown in Fig. 12A, the rightmost position and the bottommost position of the maximum block 2 are not completely included in the area of the current image. In addition, the maximum block 2 size is 64x64, which is a size that can be divided into quad trees. In this case, the maximum block 2 can be quad-tree divided (S903). That is, step S901 for the maximum block 2 may be omitted. Thereafter, the block A0, which is the first block among the four blocks A0, A1, A2 and A3 generated by dividing the maximum block 2 by a quad tree, can be divided and encoded. Since the block A1 and the block A3 are not completely included in the area of the current image, the division and encoding may be omitted. The block A2 can be divided and coded according to the present invention like the block A0.

FIG. 12B is an enlarged view of the block A0 in FIG. 12A, and a portion surrounded by a thick line is an area in the current image. The block A0 may be the block to be divided described with reference to FIG. As shown in Fig. 12B, the rightmost position B1 and the bottommost position B3 of the block A0 are not completely included in the area of the current image. The size of the block A0 is 32x32, which is a size capable of dividing the quadtree. In this case, block A0 may be quad-tree partitioned (S903). That is, step S901 for block A0 may be omitted. Thereafter, the division and encoding of the block B0, which is the first block among the four blocks B0, B1, B2, and B3 generated by dividing the block A0 into quad-trees, can be performed. Block B0 may be segmented and encoded in the manner described with reference to FIG. That is, the block B0 can be coded without being divided or divided by quad tree partitioning and / or binary tree partitioning. The block B2 can be divided and coded according to the present invention like the block B0. Since the block B1 and the block B3 are not completely included in the area of the current image, the division and encoding may be omitted. The block B2 can be divided and coded in the same manner as the block B0. That is, step S901 can not be omitted for the block B0 and the block B2. However, for blocks B1 and B3, step S901 may be omitted as described later.

FIG. 12C is an enlarged view of the block B1 in FIG. 12B, and a portion surrounded by a thick line is an area in the current image. The block B1 may be the block to be divided described with reference to Fig. As shown in Fig. 12C, the rightmost position and the bottommost position of the block B1 are not completely included in the area of the current image. Also, the size of the block B1 is 16x16, which is a size in which quad tree partitioning is impossible. In this case, the block B 1 can not be quad-tree-divided and can be binary tree-divided. Further, since the current block to be coded is a vertically long rectangle, the dividing direction can be determined to be the vertical direction. Therefore, steps S901 to S907 may be omitted for the block B1, and the binary tree segmentation of step S909 or S910 may be performed according to the shape of the current block. Thereafter, the division and encoding for block C1, which is the first one of the two blocks C1 and C2 generated by binary tree segmentation of block B1, can be performed. Since the block C2 is not completely contained in the area of the current image, division and encoding may be omitted.

12D is an enlarged view of the block C1 of FIG. 12C, and a portion surrounded by a thick line is an area in the current image. The block C1 may be the block to be divided described with reference to FIG. As shown in Fig. 12D, the rightmost position and the lowermost position of the block C1 are not completely included in the area of the current image. In addition, since the binary tree division is applied to the upper block B1 of the block C1, the block C1 can also be binary tree divided. Further, since the current block to be coded is a vertically long rectangle, the dividing direction can be determined to be the vertical direction. Therefore, steps S905 to S907 may be omitted for the block C1, and the binary tree segmentation of step S909 or S910 may be performed according to the shape of the current block. Then, the division and encoding of the block D1, which is the first one of the two blocks D1 and D2 generated by binary tree segmentation of the block C1, can be performed. Since the block D2 is not completely contained in the area of the current image, division and encoding may be omitted.

FIG. 12E is an enlarged view of the block D1 of FIG. 12D, and a portion surrounded by a thick line is an area in the current image. The block D1 may be the block to be divided described with reference to FIG. 12E, the rightmost position and the lowermost position of the block D1 are not completely included in the area of the current image. In addition, since the binary tree division is applied to C1 which is the upper block of the block D1, the block D1 can also be divided into binary trees. Further, since the current block to be coded is a vertically long rectangle, the dividing direction can be determined to be the vertical direction. Therefore, steps S905 to S907 may be omitted for the block D1, and the binary tree segmentation of step S909 or S910 may be performed according to the shape of the block to be coded. Then, the division and coding for the block E1, which is the first one of the two blocks E1 and E2 generated by binary tree segmentation of the block D1, can be performed. The width of the block E1 is equal to 2 assuming the minimum size of the sub-block. Therefore, the vertical division can not be performed for the block E1. That is, the block E1 may be encoded without being divided, or may be divided after being horizontally divided. In this case, for block E1, only information regarding whether or not to divide can be signaled. Since block E2 is not completely contained in the area of the current image, segmentation and encoding may be omitted.

The division information abbreviation method of the maximum block 2 and the maximum block 5 shown in FIG. 11 may be the same. The method of omitting the division information of the maximum block 6 and the maximum block 7 may be the same as the method of omitting the division information of the maximum block 2 and the maximum block 5 and the difference in the direction of the width or the length. For the maximum block 8, it is possible to omit the partition information in the same manner as other maximum blocks by using a reference set horizontally or vertically.

Hereinafter, with reference to Figs. 12A to 12E, a method of dividing maximum block 2 and / or decoding of divided information in Fig. 11 will be described.

12A is an enlarged view of the maximum block 2, and a portion surrounded by a thick line is an area in the current image. The maximum block 2 may be the block to be divided described with reference to FIG. As shown in Fig. 12A, the rightmost position and the bottommost position of the maximum block 2 are not completely included in the area of the current image. In addition, the maximum block 2 size is 64x64, which is a size that can be divided into quad trees. In this case, the maximum block 2 can be quad-tree divided (S1003). That is, step S1001 for the maximum block 2 may be omitted. Then, the division and decryption of the block A0 which is the first block among the four blocks A0, A1, A2, and A3 generated by dividing the maximum block 2 by the quadtree can be performed. Since the block A1 and the block A3 are not completely contained in the area of the current image, the division and the decoding can be omitted. The block A2 can be divided and decoded according to the present invention like the block A0.

FIG. 12B is an enlarged view of the block A0 in FIG. 12A, and a portion surrounded by a thick line is an area in the current image. The block A0 may be the block to be divided described with reference to FIG. As shown in Fig. 12B, the rightmost position and the lowermost position of the block A0 are not completely included in the area of the current image. The size of the block A0 is 32x32, which is a size capable of dividing the quadtree. In this case, the block A0 may be quad-tree partitioned (S1003). That is, step S1001 for block A0 may be omitted. Thereafter, division and decryption of the block B0, which is the first block among the four blocks B0, B1, B2, and B3 generated by dividing the block A0 into quad-trees, can be performed. Block B0 may be partitioned and decoded in the manner described with reference to FIG. That is, block B0 may be decoded by quad tree partitioning and / or by binary tree partitioning or not partitioned. The block B2 can be divided and decoded according to the present invention like the block B0. Since the block B1 and the block B3 are not completely included in the area of the current image, division and decoding may be omitted. The block B2 can be divided and decoded in the same manner as the block B0. That is, step S1001 can not be omitted for the block B0 and the block B2. However, for blocks B1 and B3, step S1001 may be omitted as will be described later.

FIG. 12C is an enlarged view of the block B1 in FIG. 12B, and a portion surrounded by a thick line is an area in the current image. The block B1 may be the block to be divided described with reference to Fig. As shown in Fig. 12C, the rightmost position and the bottommost position of the block B1 are not completely included in the area of the current image. Also, the size of the block B1 is 16x16, which is a size in which quad tree partitioning is impossible. In this case, the block B 1 can not be quad-tree-divided and can be binary tree-divided. Further, since the block to be decoded is a vertically long rectangle, the dividing direction can be determined to be the vertical direction. Therefore, steps S1001 to S1007 may be omitted for the block B1, and the binary tree segmentation of step S1009 or S1010 may be performed according to the shape of the block to be decoded. Thereafter, the partitioning and decoding for the block C1, which is the first one of the two blocks C1 and C2 generated by binary tree segmentation of the block B1, can be performed. Since the block C2 is not completely contained in the area of the current image, division and decryption may be omitted.

12D is an enlarged view of the block C1 of FIG. 12C, and a portion surrounded by a thick line is an area in the current image. The block C1 may be the block to be divided described with reference to FIG. As shown in Fig. 12D, the rightmost position and the lowermost position of the block C1 are not completely included in the area of the current image. In addition, since the binary tree division is applied to the upper block B1 of the block C1, the block C1 can also be binary tree divided. Further, since the block to be decoded is a vertically long rectangle, the dividing direction can be determined to be the vertical direction. Therefore, steps S1005 to S1007 may be omitted for block C1, and the binary tree segmentation of step S1009 or S1010 may be performed according to the shape of the block to be decoded. Then, division and decryption of block D1, which is the first one of the two blocks D1 and D2 generated by binary tree segmentation of block C1, can be performed. Since the block D2 is not completely contained in the area of the current image, division and decoding may be omitted.

FIG. 12E is an enlarged view of the block D1 of FIG. 12D, and a portion surrounded by a thick line is an area in the current image. The block D1 may be the block to be divided described with reference to FIG. 12E, the rightmost position and the lowermost position of the block D1 are not completely included in the area of the current image. In addition, since the binary tree division is applied to C1 which is the upper block of the block D1, the block D1 can also be divided into binary trees. Further, since the block to be decoded is a vertically long rectangle, the dividing direction can be determined to be the vertical direction. Therefore, steps S1005 to S1007 may be omitted for block D1, and the binary tree segmentation of step S1009 or S1010 may be performed depending on the shape of the block to be decoded. Then, division and decryption for block E1, which is the first one of the two blocks E1 and E2 generated by binary tree segmentation of block D1, can be performed. The width of the block E1 is equal to 2 assuming the minimum size of the sub-block. Therefore, the vertical division can not be performed for the block E1. That is, the block E1 can be decoded without being divided, decoded after being horizontally divided, and decoded. In this case, for block E1, only information regarding whether or not to divide can be signaled. Since the block E2 is not completely contained in the area of the current image, division and decryption may be omitted.

In the embodiment described with reference to FIG. 12, the quadtree partitioning is performed on the partitioning target block, and if the predetermined condition is satisfied, the binary tree partitioning can be performed. In the above embodiment, whether or not the size of the block to be divided is a size that can be quad-tree divided corresponds to the predetermined condition. The predetermined condition may be set using a minimum size and / or a threshold of a quad-tree partitionable block and a block capable of binary tree partitioning.

When a threshold value is used, one of the quadtree division and the binary tree division is performed on the basis of the result of comparing the size of a region (hereinafter, referred to as " remaining region " Can be performed. In the following description, it is assumed that the threshold value is 32.

For example, in FIG. 12A, the size of the current block is 18x64, and the size of the remaining area is 46x64. Since the remaining area is a vertically long rectangle, the horizontal length of the remaining area can be compared with the threshold value. The remaining area has a horizontal length of 46, which is larger than the threshold value 32, so that quad tree partitioning can be performed on a 64x64 partitioning target block. In FIG. 12B, since the width of the remaining area is 14, which is smaller than the threshold value 32, binary tree segmentation can be performed on the 32x32 partitioning target block. That is, even if the size of the block to be divided is a size that can be quad-tree partitioned, the binary tree partitioning can be performed instead of quad-tree partitioning according to the above conditions. In this case, the direction of division of the binary tree division is based on the smallest of the horizontal and vertical blocks of the 18x32 encoding target block. Thus, the block A0 in Fig. 12B can be divided into two vertically long 16x32 blocks. Thereafter, the vertical binary tree segmentation can be repeatedly performed until the size of the block can not be split into binary trees.

The threshold value may be signaled through the header of the upper level of the above-mentioned block. The threshold value should be a value between a maximum size and a minimum size of a quad-tree partitionable block. Also, the threshold value may be set to be smaller than a maximum size of a block that can be divided into binary trees. If the threshold value is set to be larger than the maximum size of a block capable of binary tree segmentation, the threshold value may be changed to a maximum size of a block capable of binary tree segmentation.

13A to 13E are diagrams for explaining an image dividing method according to another embodiment of the present invention.

13A is an enlarged view of the maximum block 2, and a portion surrounded by a thick line is an area in the current image. The maximum block 2 may be the block to be divided described with reference to FIG. As shown in Fig. 13A, the rightmost position and the bottommost position of the maximum block 2 are not completely included in the area of the current image. In this case, the block dividing method can be selected based on the shape of the remaining area. Since the remaining area in FIG. 13A is a vertically long 46x64 block, it is possible to perform the vertical binary tree division on the maximum block 2. [ That is, steps S901 to S907 for the maximum block 2 may be omitted, and step S909 or S910 may be performed depending on the type of the remaining area.

FIG. 13B is an enlarged view of the block A0 in FIG. 13A, and a portion surrounded by a thick line is an area in the current image. The block A0 may be the block to be divided described with reference to FIG. As shown in Fig. 13B, the rightmost position and the lowermost position of the block A0 are not completely included in the area of the current image. In this case, the block dividing method can be selected based on the shape of the remaining area. Since the remaining area in Fig. 13B is a vertically long 14x64 block, vertical binary tree division can be performed on the block A0. Since the block B0 is a block in the current image area, it can be encoded using sub-block division. Steps S905 to S908 can not be omitted for the block B0.

FIG. 13C is an enlarged view of the block B1 in FIG. 13B, and a portion surrounded by a thick line is an area in the current image. The block B1 may be the block to be divided described with reference to Fig. As shown in Fig. 13C, the rightmost position and the bottommost position of the block B1 are not completely included in the area of the current image. In this case, the block dividing method can be selected based on the shape of the remaining area. Since the remaining area in Fig. 13C is a vertically long 14x64 block, it is possible to perform the vertical binary tree division on the block B1. That is, steps S901 to S907 for block B1 may be omitted, and step S909 or S910 may be performed depending on the type of the remaining area. Since the block C2 is not completely contained in the area of the current image, division and encoding may be omitted.

FIG. 13D is an enlarged view of block C1 in FIG. 13C, and a portion surrounded by a thick line is an area in the current image. The block C1 may be the block to be divided described with reference to FIG. As shown in FIG. 13D, the rightmost position and the bottommost position of the block C1 are not completely included in the area of the current image. In this case, the block dividing method can be selected based on the shape of the remaining area. Since the remaining area in FIG. 13C is a vertically long 6x64 block, it is possible to perform the vertical binary tree division on the block C1. That is, steps S901 to S907 for block C1 may be omitted, and step S909 or S910 may be performed depending on the type of the remaining area. Since the block D2 is not completely contained in the area of the current image, division and encoding may be omitted.

FIG. 13E is an enlarged view of the block D1 in FIG. 13D, and a portion surrounded by a thick line is an area in the current image. The block D1 may be the block to be divided described with reference to FIG. As shown in FIG. 13E, the rightmost position and the lowermost position of the block D1 are not completely included in the area of the current image. In this case, the block dividing method can be selected based on the shape of the remaining area. Since the remaining area in FIG. 13C is a vertically long 2x64 block, it is possible to perform the vertical binary tree division on the block D1. That is, steps S901 to S907 for block D1 may be omitted, and step S909 or S910 may be performed depending on the type of the remaining area. The width of the block E1 is equal to 2 assuming the minimum size of the sub-block. Therefore, the vertical division can not be performed for the block E1. That is, the block E1 may be encoded without being divided, or may be divided after being horizontally divided. In this case, for block E1, only information regarding whether or not to divide can be signaled. Since block E2 is not completely contained in the area of the current image, segmentation and encoding may be omitted.

Hereinafter, with reference to FIG. 13A to FIG. 13E, a description will be given of a dividing method of the maximum block 2 and / or a decoding of divided information shown in FIG.

13A is an enlarged view of the maximum block 2, and a portion surrounded by a thick line is an area in the current image. The maximum block 2 may be the block to be divided described with reference to FIG. As shown in Fig. 13A, the rightmost position and the bottommost position of the maximum block 2 are not completely included in the area of the current image. In this case, the block dividing method can be selected based on the shape of the remaining area. Since the remaining area in FIG. 13A is a vertically long 46x64 block, it is possible to perform the vertical binary tree division on the maximum block 2. [ That is, steps S1001 to S1007 for the maximum block 2 may be omitted, and step S1009 or S1010 may be performed depending on the type of the remaining area.

FIG. 13B is an enlarged view of the block A0 in FIG. 13A, and a portion surrounded by a thick line is an area in the current image. The block A0 may be the block to be divided described with reference to FIG. As shown in Fig. 13B, the rightmost position and the lowermost position of the block A0 are not completely included in the area of the current image. In this case, the block dividing method can be selected based on the shape of the remaining area. Since the remaining area in Fig. 13B is a vertically long 14x64 block, vertical binary tree division can be performed on the block A0. Since the block B0 is a block in the current image area, it can be decoded using sub-block division. Steps S1005 to S1008 can not be omitted for the block B0.

FIG. 13C is an enlarged view of the block B1 in FIG. 13B, and a portion surrounded by a thick line is an area in the current image. The block B1 may be the block to be divided described with reference to Fig. As shown in Fig. 13C, the rightmost position and the bottommost position of the block B1 are not completely included in the area of the current image. In this case, the block dividing method can be selected based on the shape of the remaining area. Since the remaining area in Fig. 13C is a vertically long 14x64 block, it is possible to perform the vertical binary tree division on the block B1. That is, steps S1001 to S1007 for block B1 may be omitted, and step S1009 or S1010 may be performed depending on the type of the remaining area. Since the block C2 is not completely contained in the area of the current image, division and decryption may be omitted.

FIG. 13D is an enlarged view of block C1 in FIG. 13C, and a portion surrounded by a thick line is an area in the current image. The block C1 may be the block to be divided described with reference to FIG. As shown in FIG. 13D, the rightmost position and the bottommost position of the block C1 are not completely included in the area of the current image. In this case, the block dividing method can be selected based on the shape of the remaining area. Since the remaining area in FIG. 13C is a vertically long 6x64 block, it is possible to perform the vertical binary tree division on the block C1. That is, steps S1001 to S1007 for block C1 may be omitted, and step S1009 or S1010 may be performed depending on the type of the remaining area. Since the block D2 is not completely contained in the area of the current image, division and decoding may be omitted.

FIG. 13E is an enlarged view of the block D1 in FIG. 13D, and a portion surrounded by a thick line is an area in the current image. The block D1 may be the block to be divided described with reference to FIG. As shown in FIG. 13E, the rightmost position and the lowermost position of the block D1 are not completely included in the area of the current image. In this case, the block dividing method can be selected based on the shape of the remaining area. Since the remaining area in FIG. 13C is a vertically long 2x64 block, it is possible to perform the vertical binary tree division on the block D1. That is, steps S1001 to S1007 for block D1 may be omitted, and step S1009 or S1010 may be performed depending on the type of the remaining area. The width of the block E1 is equal to 2 assuming the minimum size of the sub-block. Therefore, the vertical division can not be performed for the block E1. That is, the block E1 can be decoded without being divided, decoded after being horizontally divided, and decoded. In this case, for block E1, only information regarding whether or not to divide can be signaled. Since the block E2 is not completely contained in the area of the current image, division and decryption may be omitted.

In the embodiment described with reference to FIG. 13, only the binary tree division is performed for the block to be divided, and the direction of the binary tree division can be determined according to the shape of the remaining area.

In the embodiment described with reference to FIG. 9 and FIG. 10, it is possible to perform a dividing process on an image boundary on a sub-block unit or block basis. Information about whether or not to perform the division processing on the boundary of the image in which unit can be signaled. For example, the information may be signaled from the encoder to the decoder through the header of the upper level of the block described above.

Although the exemplary methods of this disclosure are represented by a series of acts for clarity of explanation, they are not intended to limit the order in which the steps are performed, and if necessary, each step may be performed simultaneously or in a different order. In order to implement the method according to the present disclosure, the illustrative steps may additionally include other steps, include the remaining steps except for some steps, or may include additional steps other than some steps.

The various embodiments of the disclosure are not intended to be all-inclusive and are intended to illustrate representative aspects of the disclosure, and the features described in the various embodiments may be applied independently or in a combination of two or more.

In addition, various embodiments of the present disclosure may be implemented by hardware, firmware, software, or a combination thereof. In the case of hardware implementation, one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays A general processor, a controller, a microcontroller, a microprocessor, and the like.

The scope of the present disclosure is to be accorded the broadest interpretation as understanding of the principles of the invention, as well as software or machine-executable instructions (e.g., operating system, applications, firmware, Instructions, and the like are stored and are non-transitory computer-readable medium executable on the device or computer.

Claims (22)

A first segmenting step of segmenting the current image into a plurality of blocks; And
A second dividing step of dividing a division target block including the boundary of the current image among the plurality of blocks into a plurality of sub-blocks,
The second dividing step recursively performs a sub-block including the boundary of the current image as the dividing target block until there is no sub-block including the boundary of the current image among the sub-blocks Lt; / RTI > The method according to claim 1,
Wherein the first dividing step comprises:
And dividing the current image into a plurality of maximum blocks of the same size. The method according to claim 1,
Wherein the second segmentation step comprises:
Performing a quadtree division or a binary tree division on the block to be divided. The method of claim 3,
If the partitioning target block is of a size that can be quad-tree partitioned, the second partitioning step performs the quadtree partitioning on the partitioning target block,
Wherein the second partitioning step performs the binary tree partitioning on the partitioning target block when the partitioning target block is of a size in which the quadtree partitioning is not possible. 5. The method of claim 4,
When the quadtree partitioning or the binary tree partitioning is performed on the partitioning target block in the second partitioning step, first division information indicating whether or not the partitioning target block is quad-tree partitioned, Wherein the second division information indicating whether or not the tree is divided is not coded. 5. The method of claim 4,
When the binary tree segmentation is performed on the partitioning target block in the second partitioning step,
Wherein the division direction of the binary tree division is determined based on a shape of a block to be coded which is included in the division target block and which is an area within the boundary of the current image. 5. The method of claim 4,
When the binary tree segmentation is performed on the partitioning target block in the second partitioning step,
Wherein the division direction information indicating the division direction of the binary tree division is not coded. The method of claim 3,
Wherein the second segmentation step comprises:
Further comprising the step of comparing a predetermined threshold value with a size of a remaining area included in the division target block and which is an area outside the boundary of the current image,
And performing one of the quadtree division and the binary tree division on the division target block based on the comparison result. 9. The method of claim 8,
The size of the remaining area is a smaller one of the horizontal length and the vertical length of the remaining area,
Wherein the second segmentation step comprises:
Performing the quadtree partitioning on the partitioning target block when the size of the remaining area is larger than the predetermined threshold value,
And if the size of the remaining area is smaller than the predetermined threshold value, performing the binary tree division on the block to be divided. The method according to claim 1,
The second partitioning step is a step of performing a binary tree division on the partitioning target block,
Wherein the division direction of the binary tree division is determined based on a shape of a remaining area included in the division target block and which is an area outside the boundary of the current image. 11. The method of claim 10,
The division direction of the binary tree division may be,
If the shape of the remaining area is a vertically long block,
And when the shape of the remaining area is a horizontally long block, the horizontal direction. A first segmenting step of segmenting the current image into a plurality of blocks; And
A second dividing step of dividing a division target block including the boundary of the current image among the plurality of blocks into a plurality of sub-blocks,
The second dividing step recursively performs a sub-block including the boundary of the current image as the dividing target block until there is no sub-block including the boundary of the current image among the sub-blocks / RTI > 13. The method of claim 12,
Wherein the second segmentation step comprises:
And performing a quadtree partitioning or a binary tree partitioning on the partitioning target block. 14. The method of claim 13,
If the partitioning target block is of a size that can be quad-tree partitioned, the second partitioning step performs the quadtree partitioning on the partitioning target block,
Wherein the second partitioning step performs the binary tree partitioning on the partitioning target block when the partitioning target block is of a size that is not capable of partitioning the quadtree. 15. The method of claim 14,
When the quadtree partitioning or the binary tree partitioning is performed on the partitioning target block in the second partitioning step, first division information indicating whether or not the partitioning target block is quad-tree partitioned, Wherein the second division information indicating whether or not a tree is divided is derived from a bit stream and is not decoded but a predetermined value. 15. The method of claim 14,
When the binary tree segmentation is performed on the partitioning target block in the second partitioning step,
Wherein the dividing direction of the binary tree division is determined based on a type of a block to be decoded which is included in the block to be divided and which is an area within the boundary of the current image. 15. The method of claim 14,
When the binary tree segmentation is performed on the partitioning target block in the second partitioning step,
Wherein the dividing direction information indicating the dividing direction of the binary tree division is not decoded from the bit stream but is guided to a predetermined value. 14. The method of claim 13,
Wherein the second segmentation step comprises:
Further comprising the step of comparing a predetermined threshold value with a size of a remaining area included in the division target block and which is an area outside the boundary of the current image,
And performing one of the quadtree partitioning and the binary tree partitioning on the block to be partitioned based on the comparison result. 19. The method of claim 18,
The size of the remaining area is a smaller one of the horizontal length and the vertical length of the remaining area,
Wherein the second segmentation step comprises:
Performing the quadtree partitioning on the partitioning target block when the size of the remaining area is larger than the predetermined threshold value,
And if the size of the remaining area is smaller than the predetermined threshold value, performing the binary tree division on the partitioning target block. 13. The method of claim 12,
The second partitioning step is a step of performing a binary tree division on the partitioning target block,
Wherein the division direction of the binary tree division is determined based on a shape of a remaining area included in the division target block and being a region outside the boundary of the current image. 21. The method of claim 20,
The division direction of the binary tree division may be,
If the shape of the remaining area is a vertically long block,
And when the shape of the remaining area is a horizontally long block, the horizontal direction. A computer-readable recording medium storing a bit stream generated by a video encoding method,
The image encoding method includes:
A first segmenting step of segmenting the current image into a plurality of blocks; And
A second dividing step of dividing a division target block including the boundary of the current image among the plurality of blocks into a plurality of sub-blocks,
The second dividing step recursively performs a sub-block including the boundary of the current image as the dividing target block until there is no sub-block including the boundary of the current image among the sub-blocks Lt; / RTI >

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