KR101348566B1 - Methods of decision of candidate block on inter prediction and appratuses using the same - Google Patents

Abstract

A method of determining a candidate block in performing inter-picture prediction and an apparatus using such a method are disclosed. The image decoding method includes a step of including a lower left second block in a merge candidate list when a lower left second block is available, a step of including an upper right second block in a merge candidate list when the upper right second block is available If the upper left first block is available, including the lower left first block in the merge candidate list if the first lower left block is available, the upper right first block if the first upper right block is available, If the upper left second block is available, including an upper left second block in the merge candidate list and, if the temporal candidate prediction block is available, including a temporal candidate prediction block in the merge candidate block list have. Therefore, the coding efficiency can be increased and the complexity can be reduced.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of determining a candidate block in performing inter-picture prediction, and a device using such a method. [0002]

The present invention relates to a method of determining a candidate block in performing inter-picture prediction and an apparatus using such a method, and more particularly, to a sub-decoding method and apparatus.

Recently, the demand for high resolution and high quality images such as high definition (HD) image and ultra high definition (UHD) image is increasing in various applications. As the video data becomes higher resolution and higher quality, the amount of data increases relative to the existing video data. Therefore, when the video data is transmitted or stored using a medium such as a conventional wired / wireless broadband line, The storage cost will increase. High-efficiency image compression techniques can be utilized to solve such problems as image data becomes high-resolution and high-quality.

An inter picture prediction technique for predicting a pixel value included in a current picture from a previous or a subsequent picture of a current picture using an image compression technique, an intra picture prediction technique for predicting a pixel value included in a current picture using pixel information in the current picture, There are various techniques such as an entropy encoding technique in which a short code is assigned to a value having a high appearance frequency and a long code is assigned to a value having a low appearance frequency. Image data can be effectively compressed and transmitted or stored using such an image compression technique.

It is an object of the present invention to provide a method for calculating candidate motion prediction information when performing an inter picture prediction mode to increase the image coding efficiency.

It is still another object of the present invention to provide an apparatus for performing a method of calculating candidate motion prediction information when an inter picture prediction mode is performed to increase image coding efficiency.

According to an aspect of the present invention, there is provided a method of decoding an image, the method comprising: if the lower left second block is available, including the lower left second block in a merge candidate list; If the block is available, including the upper right second block in the merge candidate list, if the lower left first block is available, including the lower left first block in the merge candidate list, If the first block is available, including the upper right first block in the merge candidate list; if the upper left second block is available, including the upper left second block in the merge candidate list; And if the temporal candidate prediction block is available, including the temporal candidate prediction block in the merged candidate block list. The merge candidate block list may include a fixed number of merge candidate blocks, and when the merged candidate blocks of the fixed number or more are included in the merged candidate block list, only a fixed number of merge candidate blocks And may be included in the merge candidate block list. The merged candidate block list may include a fixed number of merged candidate blocks and when the merged candidate block of less than the fixed number is included in the merged candidate block list, May be added to the merge candidate block list. The additional merge candidate generation method may be at least one of a combination merge candidate generation method, a scaling merge candidate generation method, and a zero vector merge candidate generation method.

According to another aspect of the present invention, there is provided a method for decoding an image, the method comprising: calculating a motion vector calculated in a first available block determined based on a lower left first block order in a lower left second block, Calculating a motion vector calculated in a first block determined based on an upper right second block, an upper right first block, and an upper left second block as a candidate prediction motion vector; calculating a temporal prediction candidate block A step of calculating a motion vector calculated in the temporal prediction candidate block as a candidate prediction motion vector and a step of constructing an AMVP list using the calculated candidate prediction motion vector. The AMVP list may include a fixed number of candidate prediction motion vectors and, when the fixed number of candidate prediction motion vectors are included in the AMVP list, only a fixed number of candidate prediction motion vectors, It can be included in the AMVP list. The AMVP list may include a fixed number of candidate predictive motion vectors and, when the number of candidate predictive motion vectors less than the fixed number is included in the AMVP list, the zero vector may be included in the AMVP list as a candidate predictive motion vector .

According to another aspect of the present invention, there is provided a method of decoding an image, the method comprising: if the upper left block is available, including the upper left block in the merge candidate list; If the upper right second block is available, including the upper right second block in the merge candidate list, if the upper left second block is available, including the upper left first block in the merge candidate list, If the upper left second block is available, including the upper left second block in the merge candidate list if the available upper left second block is available, adding the lower left second block to the merge candidate list if available, If so, the temporal candidate prediction block may be included in the merge candidate list. The merge candidate block list may include a fixed number of merge candidate blocks, and when the merged candidate blocks of the fixed number or more are included in the merged candidate block list, only a fixed number of merge candidate blocks And may be included in the merge candidate block list. The merged candidate block list may include a fixed number of merged candidate blocks and when the merged candidate block of less than the fixed number is included in the merged candidate block list, May be added to the merge candidate block list. The additional merge candidate generation method may be at least one of a combination merge candidate generation method, a scaling merge candidate generation method, and a zero vector merge candidate generation method.

According to another aspect of the present invention, there is provided a method of decoding an image, the method comprising: receiving a motion vector calculated in a first available block determined based on a lower left first block order in a lower left second block, Calculating a predicted motion vector as a predicted motion vector, calculating a motion vector calculated in a first block determined based on an upper right second block, an upper left first block, and an upper left second block as a candidate prediction motion vector, Calculating a motion vector calculated in the temporal prediction candidate block as a candidate prediction motion vector and constructing an AMVP list using the calculated candidate prediction motion vector if the block is available. The AMVP list may include a fixed number of candidate prediction motion vectors and, when the fixed number of candidate prediction motion vectors are included in the AMVP list, only a fixed number of candidate prediction motion vectors, It can be included in the AMVP list. The AMVP list may include a fixed number of candidate predictive motion vectors and, when the number of candidate predictive motion vectors less than the fixed number is included in the AMVP list, the zero vector may be included in the AMVP list as a candidate predictive motion vector .

According to another aspect of the present invention, there is provided a method of decoding an image, the method comprising: when a left lower first block and a lower left second block are available, the merged candidate list is included in a merge candidate list, Block is not available, if the upper left second block is included in the merge candidate list in place of the unavailable block, and both of them are not available, the upper left second block may be used instead of the lower left first block The upper right first block and the upper right second block are included in the merge candidate list if the first upper right block and the upper right second block are available, If at least one of the blocks is not available, the upper left second block may be inserted into the merge candidate list in place of the unavailable block. And when both are not available, it may comprise the step of including the steps and the temporal prediction candidate block in place of the bottom left of the first block including the top of the left second blocks to merge candidate list to the merge candidate list. The merged candidate block list may include a fixed number of merged candidate blocks and when the merged candidate block of less than the fixed number is included in the merged candidate block list, To the merge candidate block list.

According to another aspect of the present invention, there is provided a method of decoding an image, the method comprising: if a left upper block and a lower left second block are available, the merged candidate list is included in the merged candidate list, If at least one of the lower second blocks is not available, the upper left second block is included in the merge candidate list instead of the unavailable block, and if both are not available, the upper left second block If the upper left first block and the upper right second block are available, at least one of the upper left first block and the upper right second block is available in the merge candidate list, If not, the upper left second block is included in the merge candidate list in place of the unavailable block It may be if it is not available, on behalf of the upper left corner of the first block comprises the step of including the steps and the temporal candidate prediction blocks to include the top left second blocks to merge candidate list to the merge candidate list. The merged candidate block list may include a fixed number of merged candidate blocks and when the merged candidate block of less than the fixed number is included in the merged candidate block list, May be added to the merge candidate block list.

As described above, according to the method of determining a candidate block in performing inter-view prediction according to an embodiment of the present invention and the apparatus using the method, when merging spatial candidate prediction blocks used in inter- When used, it can be used in the same way to reduce the complexity and increase the coding efficiency.

1 is a block diagram illustrating an image encoding apparatus according to an embodiment of the present invention.
2 is a block diagram of an image decoder according to another embodiment of the present invention.
3 is a conceptual diagram for defining a name of a spatial candidate prediction block according to another embodiment of the present invention.
4 is a conceptual diagram illustrating a method of constructing a candidate block list for inter-picture prediction in the merge mode and AMVP according to another embodiment of the present invention.
5 is a flowchart illustrating a method of implementing a merge candidate list according to another embodiment of the present invention.
6 is a flowchart illustrating a method of implementing an AMVP candidate list according to another embodiment of the present invention.
7 is a conceptual diagram illustrating a method of constructing a candidate block list for inter-picture prediction in the merge mode and AMVP according to another embodiment of the present invention.
FIG. 8 is a flowchart illustrating a method of constructing a merge candidate list according to another embodiment of the present invention.
9 is a conceptual diagram illustrating a method of constructing a candidate block list for inter-picture prediction in the merge mode and AMVP according to another embodiment of the present invention.
10 is a flowchart illustrating a method of implementing a merge candidate list according to another embodiment of the present invention.
11 is a conceptual diagram illustrating a method of constructing a candidate block list for inter-picture prediction in the merge mode and AMVP according to another embodiment of the present invention.
12 is a flowchart illustrating a method of constructing a merge candidate list for inter-view prediction in the merge mode according to another embodiment of the present invention.
13 is a flowchart illustrating an inter-picture prediction method using Merging and AMVP 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. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Hereinafter, preferred 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, the image encoding apparatus 100 includes a picture dividing unit 105, a predicting unit 110, a transforming unit 115, a quantizing unit 120, a reordering unit 125, an entropy encoding unit 130, An inverse quantization unit 135, an inverse transform unit 140, a filter unit 145, and a memory 150. [

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 the separate embodiments of the components are also included in the scope of the present invention unless otherwise departing from the spirit 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 picture division unit 105 can divide the inputted picture into at least one processing unit. At this time, the processing unit may be a prediction unit (PU), a transform unit (TU), or a coding unit (CU). The picture dividing unit 105 divides one picture into a plurality of coding units, a prediction unit, and a combination of conversion units, and generates a coding unit, a prediction unit, and a conversion unit combination So that the picture can be encoded.

For example, one picture may be divided into a plurality of coding units. In order to divide an encoding unit in a picture, a recursive tree structure such as a quad tree structure can be used. An encoding unit, which is divided into other encoding units with one image or a maximum-size encoding unit as a root, Can be divided by the number of child nodes. An encoding unit that is no longer divided according to certain restrictions becomes a leaf node. That is, when it is assumed that only one square division is possible for one coding unit, one coding unit can be divided into a maximum of four different coding units.

Hereinafter, in the embodiment of the present invention, the meaning of a coding unit can be used not only in the unit of coding but also in the meaning of a unit of decoding.

The prediction unit may be a prediction unit having a shape of at least one square or a rectangle having the same size in one coding unit or a shape of one prediction unit among the prediction units divided in one coding unit is different from the shape of another prediction unit It can be divided into shapes.

Intra prediction can be performed without dividing into a plurality of prediction units (NxN) when a prediction unit performing intra-frame prediction based on an encoding unit is not the minimum encoding unit at the time of generation.

The prediction unit 110 may include an inter-picture prediction unit for performing inter-picture prediction and an intra-picture prediction unit for performing intra-picture prediction. It is possible to determine whether to use intra-picture prediction or intra-picture prediction for a prediction unit, and to determine concrete information (for example, intra-picture 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 may be input to the conversion unit 115. In addition, the prediction mode information, motion vector information, and the like used for the prediction may be encoded by the entropy encoding unit 130 together with the residual value, and then transmitted to the decoder. When using a specific encoding mode, It is also possible to encrypt the original block as it is without generating a block and transmit it to the decoding unit

The inter picture prediction unit may predict a prediction unit based on information of at least one picture of a previous picture or a following picture of the current picture. The inter picture prediction unit may include a reference picture interpolation unit, a motion prediction unit, and a motion compensation unit.

In the reference picture interpolating unit, reference picture information is supplied from the memory 150, 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 pixel or less in units of quarter pixels. In the case of a chrominance signal, a DCT-based interpolation filter having different filter coefficients may be used to generate pixel information of an integer pixel or less in units of 1/8 pixels.

The motion predictor may perform motion prediction based on the reference picture interpolated by the reference picture interpolator. 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 to calculate 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 differently performing the motion prediction method. As the motion prediction method, various methods such as a skip method, a merge method, and an AMVP (Advanced Motion Vector Prediction) method can be used.

The intra prediction unit can generate a prediction unit based on the reference pixel information around the current block which is the pixel information in the current picture. In the case where the neighboring blocks of the current prediction unit are the blocks in which the inter-screen prediction is performed, and the reference pixels are the pixels performing the inter-screen prediction, the intra-picture prediction is performed on the reference pixels included in the block in which the inter- Block reference pixel information. That is, when the reference pixel is not available, the reference pixel information that is not available may be replaced by at least one reference pixel among the available reference pixels.

In the 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 performing prediction. The mode for predicting the luminance information may be different from the mode for predicting the chrominance information, and intra prediction mode information or predicted luminance signal information in which luminance information is predicted can be used to predict the chrominance information.

When intra prediction is performed, when the size of the prediction unit is the same as the size of the conversion unit, the intra prediction is performed based on pixels existing on the left side of the prediction unit, pixels existing on the upper left side, Prediction can be performed using the reference pixel based on the conversion unit when the size of the prediction unit and the size of the conversion unit are different when the intra prediction is performed. In addition, intra prediction using NxN division can be used only for the minimum coding unit.

In the intra prediction method, an AIS (Adaptive Intra Smoothing) filter can be applied to a reference pixel according to a prediction mode, and a prediction block can be generated. The type of the AIS filter applied to the reference pixel may be different. To perform the intra prediction method, the intra prediction mode of the current prediction unit can be predicted from the intra prediction mode of the prediction unit existing around the current prediction unit. When the prediction mode of the current prediction unit is predicted using the mode information predicted from the peripheral prediction unit and the intra prediction mode of the current prediction unit is the same as the intra prediction mode of the current prediction unit, Information indicating that the prediction mode of the neighbor prediction unit is the same can be transmitted. If the prediction mode of the current prediction unit differs from that of the neighbor prediction unit, the prediction mode information of the current block can be encoded by performing entropy encoding.

In addition, a residual block including a prediction unit that has been predicted based on the prediction unit generated by the prediction unit 110 and residual information that is a difference value between the original block of the prediction unit and the residual block may be generated. The generated residual block may be input to the conversion unit 115. The transforming unit 115 transforms the residual block including residual information of the prediction unit generated through the original block and the predictor 110 into a transform block such as DCT (Discrete Cosine Transform) or DST (Discrete Sine Transform) . Whether to apply the DCT or the DST to transform the residual block can be determined based on the intra prediction mode information of the prediction unit used to generate the residual block.

The quantization unit 120 may quantize the values converted into the frequency domain by the conversion unit 115. [ The quantization factor may vary depending on the block or the importance of the image. The values calculated by the quantization unit 120 may be provided to the inverse quantization unit 135 and the reorder unit 125.

The reordering unit 125 may reorder the coefficient values with respect to the quantized residual values.

The reordering unit 125 may change the two-dimensional block type coefficient to a one-dimensional vector form through a coefficient scanning method. For example, the reordering unit 125 may scan from a DC coefficient to a coefficient of a high frequency region by using a Zig-Zag Scan method and change it into a one-dimensional vector. Depending on the size of the transformation unit and the intra prediction mode, the vertical scan method that scans two-dimensional block shape coefficients in the column direction rather than the zig-zag scan method, and the horizontal scan method that scans the two-dimensional block shape coefficients in the row direction Can be used. That is, it is possible to determine whether any scan method among the jig-zag scan, the vertical scan, and the horizontal scan is used according to the size of the conversion unit and the intra prediction mode.

The entropy encoding unit 130 may perform entropy encoding based on the values calculated by the reordering unit 125. 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 130 receives residual coefficient information, block type information, prediction mode information, division unit information, prediction unit information, transmission unit information, and motion vector information of the encoding unit from the reordering unit 125 and the prediction unit 110 , Reference frame information, block interpolation information, filtering information, and the like.

The entropy encoding unit 130 can entropy-encode the coefficient value of the encoding unit input from the reordering unit 125. [

In the entropy coding unit 130, a table for performing entropy coding such as a variable length coding table may be stored, and entropy coding may be performed using a stored variable length coding table. In performing entropy coding, it is possible to change a codeword allocation for a code number of a corresponding code word by using a method using a counter or a direct swapping method for a part of codewords included in a table have. For example, in a table for mapping a code number and a code word, in the case of a few upper code numbers assigned with a code word of a smaller number of bits, a code number having the largest number of code numbers It is possible to change the mapping order of the table that adaptively maps code words and code numbers so that code words can be assigned. When the counted number of times in the counter reaches a predetermined threshold value, the counter counting can be performed by dividing the counted number recorded in the counter in half.

The code number in the table that does not perform counting is a bit number assigned to the corresponding code number through the method of converting the code number and the digit directly above when the information corresponding to the code number is generated by using the direct swapping method The entropy encoding can be performed with a smaller number.

The inverse quantization unit 135 and the inverse transformation unit 140 dequantize the quantized values in the quantization unit 120 and invert the converted values in the conversion unit 115. [ The residual value generated by the inverse quantization unit 135 and the inverse transform unit 140 is combined with the prediction unit predicted through the motion estimation unit, the motion compensation unit and the intra prediction unit included in the prediction unit 110, Reconstructed Block can be created.

The filter unit 145 may include at least one of a deblocking filter, an offset correction unit, and an adaptive loop filter (ALF).

The deblocking filter 145 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, the horizontal filtering and the vertical filtering may be performed in parallel when the vertical filtering and the horizontal filtering are performed.

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.

The ALF (Adaptive Loop Filter) can perform filtering based on a value obtained by comparing the filtered restored 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 size and the coefficient of the ALF to be applied may be changed according to each block. The ALF may have various forms, and the number of coefficients included in the filter may also vary. The filtering-related information (filter coefficient information, ALF On / Off information, filter type information) of the ALF can be transmitted in a predetermined parameter set in the bitstream.

The memory 150 may store the reconstructed block or picture calculated through the filter unit 145 and the reconstructed block or picture stored therein may be provided to the predictor 110 when inter-picture prediction is performed.

2 is a block diagram of an image decoder according to another embodiment of the present invention.

2, the image decoder 200 includes an entropy decoding unit 2110, a reordering unit 215, an inverse quantization unit 220, an inverse transform unit 225, a prediction unit 230, a filter unit 235, , And a memory 240 may be included.

When an image bitstream is input in the image encoder, the input bitstream may be decoded in a procedure opposite to that of the image encoder.

The entropy decoding unit 210 can perform entropy decoding in a procedure opposite to that in which entropy encoding is performed in the entropy encoding unit of the image encoder. For example, a VLC table used for performing entropy encoding in an image coder can be implemented as an entropy decoding table in the same variable-length coding table to perform entropy decoding. Information for generating a prediction block from the information decoded by the entropy decoding unit 210 may be provided to the predicting unit 230 and residual values obtained by performing entropy decoding in the entropy decoding unit may be input to the rearranging unit 215.

The entropy decoding unit 210 may change the codeword allocation table using a counter or a direct swapping method as in the case of the entropy coding unit and may perform entropy decoding based on the changed codeword allocation table have.

The entropy decoding unit 210 can decode information related to intra-picture prediction and inter-picture prediction performed by the encoder. As described above, when there is a predetermined constraint in performing intra-frame prediction and inter-frame prediction in the image encoder, entropy decoding based on such constraints is performed to provide information related to intra-frame prediction and inter-frame prediction for the current block Can receive.

The reordering unit 215 can perform reordering based on a method in which the entropy decoding unit 210 rearranges the entropy-decoded bitstreams in the encoding unit. The coefficients represented by the one-dimensional vector form can be rearranged by restoring the coefficients of the two-dimensional block form again. The reordering unit may perform reordering by receiving information related to the coefficient scanning performed by the encoding unit and performing a reverse scanning based on the scanning order performed by the encoding unit.

The inverse quantization unit 220 can perform inverse quantization based on the quantization parameters provided by the encoder and the coefficient values of the re-arranged blocks.

The inverse transform unit 225 may perform inverse DCT and inverse DST on the DCT and DST performed by the transform unit on the quantization result performed by the image encoder. The inverse transform can be performed based on the transmission unit determined by the image encoder. In the transform unit of the image encoder, DCT and DST can be selectively performed according to a plurality of information such as a prediction method, a size and a prediction direction of a current block, and an inverse transform unit 225 of the image decoder performs transform The inverse transform can be performed based on the transformed information.

When performing a conversion, conversion can be performed based on an encoding unit rather than a conversion unit.

The prediction unit 230 may generate a prediction block based on the prediction block generation related information provided by the entropy decoding unit 210 and the previously decoded block or picture information provided in the memory 240. [

As described above, when the intra prediction is performed in the same manner as in the image encoder, when the size of the prediction unit and the size of the conversion unit are the same, pixels located on the left side of the prediction unit, pixels located on the upper left side, The intra prediction is performed on the prediction unit on the basis of the existing pixel. However, when the intra prediction is performed, when the size of the prediction unit differs from the size of the conversion unit, Prediction can be performed. In addition, intra prediction using NxN division can be used only for the minimum coding unit.

The prediction unit 230 may include a prediction unit determination unit, an inter picture prediction unit, and an intra prediction unit. The prediction unit determination unit receives various information such as prediction unit information input from the entropy decoding unit, prediction mode information of the intra prediction method, motion prediction related information of the inter picture prediction method, and separates the prediction unit from the current coding unit. Screen prediction or intra-picture prediction can be discriminated. The inter-picture prediction unit may use information necessary for inter-picture prediction of the current prediction unit provided by the image encoder to predict the current prediction unit based on information included in at least one of the previous picture of the current picture or the following picture including the current prediction unit The inter-picture prediction can be performed.

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

The intra prediction unit can generate a prediction block based on the pixel information in the current picture. If the prediction unit is a prediction unit that performs intra prediction, the intra prediction can be performed based on the intra prediction mode information of the prediction unit provided by the image encoder. The intra-frame prediction unit may include an AIS filter, a reference pixel interpolator, and a DC filter. The AIS filter performs filtering on the reference pixels of the current block and can determine whether to apply the filter according to the prediction mode of the current prediction unit. The AIS filtering can be performed on the reference pixel of the current block using the prediction mode of the prediction unit provided in the image encoder and the AIS filter information. 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 reference pixel interpolator may interpolate the reference pixels to generate reference pixels in units of pixels less than an integer value when the prediction mode of the prediction unit is a prediction unit that performs intra-frame prediction on the basis of the pixel value obtained by interpolating the reference pixels . 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.

The restored block or picture may be provided to the filter unit 235. The filter unit 235 may include a deblocking filter, an offset correction unit, and an ALF.

When information on whether a deblocking filter is applied to a corresponding block or picture from the image encoder or a deblocking filter is applied, information on whether a strong filter or a weak filter is applied can be provided. In the deblocking filter of the video decoder, the deblocking filter related information provided by the video encoder is provided, and the video decoder can perform deblocking filtering for the corresponding block. The vertical deblocking filtering and the horizontal deblocking filtering are performed in the same manner as in the image encoder, and at least one of the vertical deblocking and the horizontal deblocking can be performed in the overlapping portion. Vertical deblocking filtering or horizontal deblocking filtering that has not been performed previously can be performed at the overlapping portions of the vertical deblocking filtering and the horizontal deblocking filtering. Parallel processing of deblocking filtering is possible through the deblocking filtering process.

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 can perform filtering based on the comparison between the reconstructed image and the original image after filtering. The ALF can be applied to the encoding unit based on the ALF application information and the ALF coefficient information provided from the encoder. Such ALF information may be provided in a specific parameter set.

The memory 240 may store the reconstructed picture or block to be used as a reference picture or a reference block, and may also provide the reconstructed picture to the output unit.

As described above, in the embodiment of the present invention, a coding unit (coding unit) is used as a coding unit for convenience of explanation, but it may be a unit for performing not only coding but also decoding. Hereinafter, an encoding / decoding method of an intra prediction mode using the two candidate intra prediction modes described with reference to FIGS. 3 to 8 according to an embodiment of the present invention is implemented according to the functions of the respective modules described above with reference to FIGS. 1 and 2. And such an encoder and a decoder are included in the scope of the present invention.

3 is a conceptual diagram for defining a name of a spatial candidate prediction block according to another embodiment of the present invention.

(X, y), the width of the current prediction unit is defined as nPSW, and the width is defined as a variable called nPSH. MinPuSize, which is a variable for representing a spatial candidate prediction unit, indicates the size of the smallest prediction unit usable in the prediction unit.

Hereinafter, in the embodiment of the present invention, a block including pixels located at (x-1, y) is referred to as a top block 300, and a block including pixels located at (x, y-1) The block including the pixels located at the left first block 310, (x-MinPuSize, y-1) is defined as the upper left second block 320.

In addition, the block including the pixel located at the position (x + nPSW-MinPuSize, y-1) is included in the upper right first block 330, the pixel existing at the position (x + nPW + 1, y-1) (X-1, y + nPSH-MinPuSize) is defined as the upper right second block 340 and the block including the pixel located at the position (x-1, y + , y + nPSH) is defined as a lower-left second block 360. The block in the lower left second block 360 is a block that includes pixels located at positions (y + n,

4 is a conceptual diagram illustrating a method of constructing a candidate block list for inter-picture prediction in the merge mode and AMVP according to another embodiment of the present invention.

Referring to FIG. 4, in the merge mode, when it is assumed that all blocks are available, the candidate block list is divided into a left lower second block 400, a second upper right second block 410, Block 420, a fourth upper right first block 430, a fifth upper left second block 440, and a sixth temporal candidate prediction block 450.

In implementing the merge candidate block list, merge candidates having the same motion information can be excluded from the merge candidate block list except merge candidates having the highest priority.

The merge candidate included in the merge candidate block list may have a fixed number. For example, a merge candidate block list may have five merge candidates fixedly. In addition, in the case of having five merge candidates, the number of spatial candidate prediction blocks may be limited to a certain number. For example, if it is possible that the merge candidate list includes four spatial candidate prediction blocks, the left lower second block 400, the upper right second block 410, the lower left first block 420, If there is a block that is not available in the right first block 430, the upper left second block 440, which is the fifth in the order of priority, may replace a block that is not available in the merge candidate list.

In the case of using AMVP, the availability of the block may be determined in the order of the lower left second block 400 and the lower left first block 420, and the available motion vector of the first block may be used as the candidate prediction motion vector. Next, the availability of the block is determined in the order of the upper right second block 410, the upper right first block 430, and the upper left second block 440, and the motion vector of the first available block is determined as a candidate prediction motion vector And finally the motion vector of the temporal candidate prediction block can be used as the candidate prediction motion vector. The calculated candidate prediction motion vector may be included in the candidate prediction motion vector list, and when there are three candidate prediction motion vectors, only two candidate prediction motion vectors may be used.

5 is a flowchart illustrating a method of implementing a merge candidate list according to another embodiment of the present invention.

If the lower left second block is available, the lower left second block is inserted into the merge candidate list (step S500).

If the upper right second block is available, the upper right second block is inserted into the merge candidate list (step S510).

If the lower left first block is available, the lower left first block is inserted into the merge candidate list (step S520).

If the first upper right block is available, the upper right first block is inserted into the merge candidate list (step S530).

If the upper left second block is available, the upper left second block is inserted into the merge candidate list (step S540).

If the temporal candidate prediction block () is available, the temporal candidate prediction block () is inserted into the merge candidate list (step S550).

If the remaining 6 merge candidates are all available after constructing the merged candidate block list by the above procedure, merge candidate lists can be generated by sequentially selecting only 5 merge candidates. Also, in implementing the merge candidate list, when a plurality of merge candidates have the same motion information (motion vector, reference picture index, etc.), only the merge candidate having the highest priority is left in the merge candidate block list, It can be deleted from the merge candidate block list.

If a list having a certain number of merge candidates can not be generated through the above-described merge candidate list generation process in FIG. 5, a merge candidate list can be generated by performing a process of generating additional merge candidates.

For example, the combinatorial merge candidate generation method can generate merge candidates having new motion information by combining the merge candidate motion information included in the existing merge candidate list. If motion information in one direction included in the merge candidate list is referred to as first motion information and motion information in another direction is referred to as second motion information, new motion information can be generated by combining first motion information and second motion information And the generated new motion information can be included in the merge candidate list as merge candidates. Hereinafter, in the embodiment of the present invention, this merge information generation method is referred to as a combination merge candidate generation method.

The scaling merge candidate generation method can generate a new motion vector by reversing the direction of existing motion vectors. For example, if a vector having a value of A as the first merge candidate exists in the merge candidate list, the second merge candidate having a negative value A vector can be included in the merge candidate list. At this time, on the basis of the picture interval information related to the reference picture indicated by the existing A vector in the reference picture list, the reference picture having the same picture interval in the opposite direction is referred to as a reference picture indicated by the negative value A vector You can decide. If the distance between the reference picture indicated by the A vector and the reference picture indicated by the negative value A vector is different from the current picture, the vector value can be changed by scaling. In the case of implementing a method in which the complexity is not high, when a negative value A vector is taken, a scaling merge candidate generation method is generated only when the distance between the current picture and the reference picture in the opposite direction is the same, The remaining merge candidates can be included in the merge candidate list.

In addition, a new merge candidate list can be generated by replacing the value of the motion vector in the existing merge candidate list with a zero vector. This merge information generation method is called a zero vector merge candidate generation method.

If the merge candidate list included in the merge candidate list is not completely filled in the process of constructing the merge candidate list with the spatial candidate prediction block and the temporal candidate prediction block described above in FIG. 5, the merge candidate list is generated through the additional merge candidate generation process You can create merged candidates that are included.

6 is a flowchart illustrating a method of implementing an AMVP candidate list according to another embodiment of the present invention.

The motion vector calculated in the first available block determined based on the lower left first block order in the lower left second block is calculated as a candidate predicted motion vector (step S600).

The motion vector calculated in the first block determined based on the top right second block, the top right first block, and the top left second block is calculated as a candidate prediction motion vector (step S610).

If the temporal prediction candidate block is available, the motion vector calculated in the temporal prediction candidate block is calculated as a candidate prediction motion vector (step S620).

The candidate predicted motion vector calculated in step S600 through step S620 may be included in the candidate predicted motion vector list. When the same sized vector exists among the calculated candidate prediction motion vectors, the remaining candidate prediction motion vectors may be removed from the candidate prediction motion vector list except only the candidate prediction motion vectors having high priority. If two fixed numbers of candidate prediction motion vectors are used in the candidate prediction motion vector list as described above, If three candidate prediction motion vectors are present in the candidate prediction motion vector list, only two candidate prediction motion vectors may be used in order of priority. If the number of candidate motion vectors is less than two, a method of adding zero vectors To implement a candidate predicted motion vector list.

7 is a conceptual diagram illustrating a method of constructing a candidate block list for inter-picture prediction in the merge mode and AMVP according to another embodiment of the present invention.

Referring to FIG. 7, in order to construct a merge candidate list, a left upper block 700, a second upper left block 710, a third upper right second block 720, 2 block 730, the fifth upper left second block 740, and the sixth temporal candidate prediction block 750, as shown in FIG.

When implementing the merged candidate block list, the priority order of the upper left second block 740 of the list and the temporal candidate prediction block 750 of the list, which is the sixth in the list, are changed first to select the upper left block 700, The second upper left block 730, the fourth lower left second block 730, the fifth temporal candidate prediction block 750, the sixth upper upper left block 710, 2 block 740 may be used to construct a merged candidate block list.

As described above, the merged candidate block list may have a fixed number. For example, it is possible to have five merge candidates in the merge candidate block list, and in the case of having five merge candidates, the number of spatial candidate prediction blocks can be limited to a certain number.

In addition, a merge candidate block having the same motion information may be excluded leaving only the merge candidate having the highest priority in the merge candidate block list. In addition, when a merged candidate block list having a predetermined number of merge candidates is used, merge candidate blocks can be included in the merge candidate block list through the above-described merge candidate generation process.

Also, when there is no predetermined number of merged candidate blocks in the merged candidate block list, the merged candidate merge candidate generation method, the scaling merge candidate generation method, and the zero vector merge candidate generation method are used as merge candidates It can be included in the block list.

In the case of AMVP, in the case of selecting one block at the top, the availability of the block is determined in the order of the upper right second block, the upper left first block, and the upper left second block, The predictive motion vector of the current predictive unit can be calculated by calculating the candidate predictive vector in the same manner as the disclosed method.

FIG. 8 is a flowchart illustrating a method of constructing a merge candidate list according to another embodiment of the present invention.

Referring to FIG. 8, if the upper left block is available, the upper left block is included in the merge candidate list (step S800).

If the upper left first block is available, the upper left first block is included in the merge candidate list (step S810).

If the upper right second block is available, the upper right second block is included in the merge candidate list (step S820).

If the lower left second block is available, the lower left second block is included in the merge candidate list (step S830).

If the upper left second block is available, the upper left second block is included in the merge candidate list (step S840).

If the temporal candidate prediction block is available, the temporal candidate prediction block is included in the merge candidate list (step S850).

As described above, if the merge candidate list is constructed through the above procedure and all six are available, the merge candidate list can be generated by sequentially selecting only five merge candidates. If a plurality of merge candidates have the same motion information (motion vector, reference picture index, etc.) in the merge candidate list, only the merge candidate with the highest priority is left in the merge candidate list, You can delete it from the list. If the number of merge candidates is insufficient in the merge candidate list, the merge candidate list may be additionally included in the merge candidate list through the additional merge candidate generation method described above.

9 is a conceptual diagram illustrating a method of constructing a candidate block list for inter-picture prediction in the merge mode and AMVP according to another embodiment of the present invention.

Referring to FIG. 9, first, the left lower first block 900 and the second lower left second block 910 are selected. If one of the lower-left first block 900 and the lower-left second block 910 is not available, the unused block may be replaced with the upper left second block 940. If the left lower first block 900 and the lower left second block 910 are not all available, the lower left first block 900 may be used as the upper left second block 940.

Next, first upper right first block 920 and second upper right second block 930 are selected. If one of the upper right side first block 920 and the upper right side second block 930 is not available, the upper left side second block 940 may be used by replacing the unusable block. If the upper right side first block 920 and the upper right side second block 930 are not all available, the upper left second block 940 may be used instead of the upper right first block 920. The temporal candidate prediction block 950 can always be included in the merge candidate list if available. 9, similarly, when a plurality of merge candidates have the same motion information (motion vector, reference picture index, etc.) in the merge candidate list implementation, only the merge candidate with the highest priority is left in the merge candidate list, Can be deleted from the merge list. If the number of merge candidates is insufficient in the merge candidate list, the merge candidate list may be additionally included in the merge candidate list through the additional merge candidate generation method described above.

The predictive motion vector of the current predictive unit can be calculated by calculating the candidate predictive vector in the same manner as the method disclosed in FIGS. 4 and 5 in the AMVP.

10 is a flowchart illustrating a method of implementing a merge candidate list according to another embodiment of the present invention.

10, when the left lower first block and the lower left second block are available, they are included in the merge candidate list. If at least one of the lower left first block and the lower left second block is not available, The upper left second block is included in the merge candidate list instead of the left upper left block and the upper left second block is included in the merge candidate list instead of the lower left first block (step S1000).

If the upper right side first block and the upper right side second block are available, they are included in the merge candidate list. If at least one of the upper right side first block and the upper right side second block is not available, If the left second block is included in the merge candidate list and both are not available, the upper left second block is included in the merge candidate list instead of the lower left first block (step S1010).

The temporal candidate prediction block is included in the merge candidate list (step S1020).

If a plurality of merge candidates have the same motion information (motion vector, reference picture index, etc.) in the merge candidate list, only the merge candidate having the highest priority is left in the merge candidate list, Can be deleted. If the number of merge candidates is insufficient in the merge candidate list, the merge candidate list may be additionally included in the merge candidate list through the additional merge candidate generation method described above.

11 is a conceptual diagram illustrating a method of constructing a candidate block list for inter-picture prediction in the merge mode and AMVP according to another embodiment of the present invention.

Referring to FIG. 11, first, the upper left block 1100 and the second lower left second block 1110 are selected. If the upper left block 1100 and the lower left second block 1110 are not available, the upper left block 1120 may be replaced with a block that is not available. If both the upper left block 1100 and the lower left second block 1110 are not available, the upper left second block 1120 may replace the upper left block 1100.

Next, first upper left first block 1130 and second upper right second block 1140 are selected. If the upper left first block 1130 and the upper right second block 1140 are not available, the unused block may be replaced with the upper left second block 1120. The upper left second block 1120 may replace the upper left first block 1130 when both the upper left first block 1130 and the upper right second block 1140 are not usable. The temporal candidate prediction block 1150, if available, may always be included in the merge candidate list.

If a plurality of merge candidates have the same motion information (motion vector, reference picture index, etc.) in the merge candidate list, only the merge candidate having the highest priority is left in the merge candidate list, Can be deleted. If the number of merge candidates is insufficient in the merge candidate list, the merge candidate list may be additionally included in the merge candidate list through the additional merge candidate generation method described above.

In the case of AMVP, in the case of selecting one block at the top, the availability of the block is determined in the order of the upper right second block, the upper left first block, and the upper left second block, The predictive motion vector of the current predictive unit can be calculated by calculating the candidate predictive vector in the same manner as the disclosed method.

12 is a flowchart illustrating a method of constructing a merge candidate list for inter-view prediction in the merge mode according to another embodiment of the present invention.

12, if a left upper block and a lower left second block are available in a merge candidate list to construct a merge candidate list, at least one of the left upper block and the lower left second block is not available The upper left second block is included in the merge candidate list in place of the unavailable block, and if both are not available, the upper left second block is included in the merge candidate list instead of the upper left block (step S1200).

If at least one of the upper left first block and the upper right second block is not available, the upper left first block and the upper right second block are included in the merge candidate list. If at least one of the upper left first block and the upper right second block is not available, If the left second block is included in the merge candidate list and both are not available, the upper left second block is included in the merge candidate list instead of the upper left first block (step S1210).

If the temporal candidate prediction block is available, it is included in the merge candidate list (step S1220).

13 is a flowchart illustrating an inter-picture prediction method using Merging and AMVP according to another embodiment of the present invention.

Referring to FIG. 13, it is determined whether the current prediction unit has been inter-picture predicted using a merge (step S1300).

Whether or not an inter-picture prediction method using a merge is used in the current prediction unit can be calculated based on the merge flag information.

If the current prediction unit is inter-screen predicted using a merge, a merge candidate list is generated (step S1310).

The method of generating the merge candidate list may be one of the methods of FIG. 13 in FIG. 4 described above.

A prediction block is generated in the current prediction unit based on the index information of the merge candidate list used in the current prediction unit (step S1320).

The encoder determines whether motion prediction information of a block among the merged candidate lists generated based on the merge candidate index information transmitted from the encoder is used and generates a prediction block of the current prediction unit based on the motion prediction information of the corresponding block.

If the current prediction unit is inter-screen predicted using AMVP, an AMVP candidate list is generated (step S1330).

The method of generating the AMVP candidate list may be one of the methods of FIG. 13 in FIG. 4 described above.

A prediction block is generated in the current prediction unit based on the index information of the AMVP candidate list used in the current prediction unit (step S1340).

The encoder determines whether motion prediction information of any block among the generated AMVP candidate list is used based on the index information of the AMVP candidate list transmitted from the encoder and generates a prediction block of the current prediction unit based on the motion prediction information of the corresponding block .

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

Claims (4)

Calculating a motion vector calculated in a first block determined to be available based on the order of the left lower second block in the lower left second block as a candidate prediction motion vector;
Calculating a motion vector calculated in a first block determined to be usable as a candidate predicted motion vector based on the order of the upper right second block, the upper right first block, and the upper left second block;
Calculating a motion vector calculated in the temporal prediction candidate block as a candidate prediction motion vector when the temporal prediction candidate block is available; And
And constructing a motion vector predictor list as the calculated candidate predicted motion vector. The method of claim 1, wherein the motion vector predictor list includes a fixed number of candidate prediction motion vectors. 2. The apparatus of claim 1, wherein the motion vector predictor list may include a fixed number of candidate predictive motion vectors, and when the fixed number or more candidate predictive motion vectors are included in the motion vector predictor list, Wherein the motion vector predictor list includes only a fixed number of candidate predictive motion vectors. 4. The method of claim 1 or 3, wherein the motion vector predictor list may include a fixed number of candidate prediction motion vectors, and the less than the fixed number of candidate prediction motion vectors is included in the motion vector predictor list Wherein the motion vector predictor list includes a zero vector as a candidate prediction motion vector.

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