KR101496830B1 - Methods of derivation of temporal motion vector predictor and appratuses using the same - Google Patents

Abstract

A temporal candidate motion vector derivation method and an apparatus using such a method are disclosed. The image decoding method includes the steps of: determining whether neighboring pixels of the same position prediction unit belong to the same LCU as the LCU including the same position prediction unit; and determining whether the neighboring pixels of the same position prediction unit include the same position prediction unit And selecting the last temporal candidate prediction unit of the current prediction unit based on the result of the determination as to whether or not it belongs to the same LCU. Therefore, a temporal candidate motion vector similar to the motion vector of the current prediction unit can be set as a candidate predicted motion vector, and an unnecessary line buffer can be reduced.

Description

TECHNICAL FIELD [0001] The present invention relates to a temporal candidate motion vector derivation method and a temporal candidate motion vector derivation method,

The present invention relates to a temporal candidate motion vector derivation method and an apparatus using such a method, and more particularly to a subtraction / 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 image data has high resolution and high quality, the amount of data increases relative to the existing image data. Therefore, when the image data is transmitted using a medium such as a wired / wireless broadband line or stored using an existing storage medium, The storage cost is increased. 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 by 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 temporal candidate motion vector derivation method for increasing image coding efficiency.

It is still another object of the present invention to provide an apparatus for performing a temporal candidate motion vector derivation method in order to increase image coding efficiency.

According to another aspect of the present invention, there is provided a method of decoding an image, the method comprising the steps of: determining whether neighboring pixels in the same prediction unit belong to the same LCU as the LCU including the co- And selecting a last temporal candidate prediction unit of the current prediction unit based on a result of the determination whether the neighboring pixels of the co-located prediction unit belong to the same LCU as the LCU including the co-located prediction unit have. The neighboring pixel may be a pixel at (xP + nPSW, yP) and a pixel at (xP, yP + nPSH) when the upper left pixel position of the co-located prediction unit is (xP, yP) Wherein the step of selecting the last temporal candidate prediction unit of the current prediction unit on the basis of the determination result as to whether or not the neighboring pixels of the same position prediction unit belong to the same LCU as the LCU including the co- + nPSW, yP) exists at a position of the same LCU as the co-located prediction unit and the pixel at the position (xP, yP + nPSH) exists at a position of the LCU different from the co-located prediction unit, The final temporal candidate prediction unit of the current prediction unit may be set as the upper right temporal prediction unit. Wherein the step of selecting the last temporal candidate prediction unit of the current prediction unit on the basis of the determination result as to whether or not the neighboring pixels of the same position prediction unit belong to the same LCU as the LCU including the co- + nPSW, yP) exists at a position of the LCU different from the co-located prediction unit, and the pixel at the position (xP, yP + nPSH) exists at the same position of the LCU as the co- The final temporal prediction unit of the current prediction unit may be set as the lower left temporal candidate prediction unit. Wherein the step of selecting the last temporal candidate prediction unit of the current prediction unit on the basis of the determination result as to whether or not the neighboring pixels of the same position prediction unit belong to the same LCU as the LCU including the co- + nPSW, yP) is located at a position of the LCU different from the co-located prediction unit, and the pixel at the position (xP, yP + nPSH) is located at a position of the LCU different from the co- And the final temporal candidate prediction unit of the current prediction unit may be set as the lower right temporal candidate prediction unit. Wherein the step of selecting the last temporal candidate prediction unit of the current prediction unit based on a result of the determination as to whether neighboring pixels of the co-located prediction unit belong to the same LCU as the LCU including the co-

The pixel at the position (xP + nPSW, yP) exists at the same position of the LCU as the co-located prediction unit and the pixel at the position (xP, yP + nPSH) exists at the same position of the LCU as the co- , The last temporal prediction unit of the current prediction unit may be set as the upper left temporal prediction unit.

According to another aspect of the present invention, there is provided an image decoding apparatus for determining whether neighboring pixels of the same position prediction unit belong to the same LCU as the LCU including the same position prediction unit, A prediction unit for selecting a last temporal candidate prediction unit of the current prediction unit on the basis of a result of determining whether neighboring pixels of the co-located prediction unit belong to the same LCU as the LCU including the co-located prediction unit, And a filter unit that performs filtering based on a prediction block of the prediction unit calculated in the prediction block and a reconstruction block calculated based on the residual block. The neighboring pixel may be a pixel at (xP + nPSW, yP) and a pixel at (xP, yP + nPSH) when the upper left pixel position of the co-located prediction unit is (xP, yP) Wherein the predicting unit determines that the pixel at the position (xP + nPSW, yP) exists at the same position of the LCU as the co-located prediction unit and the pixel at the position (xP, yP + nPSH) The final temporal candidate prediction unit of the current prediction unit may be a prediction unit set as an upper right temporal candidate prediction unit. Wherein the predicting unit determines that the pixel at the position (xP + nPSW, yP) is at the position of the LCU different from the co-located prediction unit and the pixel at the position (xP, yP + nPSH) The last temporal prediction unit of the current prediction unit may be a prediction unit set as a lower left temporal candidate prediction unit. Wherein the predicting unit determines that the pixel at the position (xP + nPSW, yP) is at the position of the LCU different from the co-located prediction unit and the pixel at the position (xP, yP + nPSH) The final temporal prediction unit of the current prediction unit may be a prediction unit set as a lower right temporal prediction unit. Wherein the predicting unit determines that the pixel at the position (xP + nPSW, yP) is at the same position of the LCU as the co-located prediction unit and the pixel at the position (xP, yP + nPSH) The last temporal prediction unit of the current prediction unit may be a prediction unit set as an upper left temporal candidate prediction unit.

As described above, according to the temporal candidate motion vector derivation method and the apparatus using the temporal candidate motion vector estimation method according to the embodiment of the present invention, in determining the temporal candidate motion prediction unit for calculating the temporal candidate motion vector, The choice of the prediction unit can be different depending on whether it exists in an LCU or not. Therefore, a temporal candidate motion vector, which is more similar to the motion vector of the current prediction unit, can be set as a candidate predicted motion vector, and unnecessary line buffer memory can be reduced.

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 illustrating a method of calculating a temporal candidate prediction motion vector according to another embodiment of the present invention.
4 is a conceptual diagram illustrating a case in which another upper left temporal prediction unit is used as a temporal prediction unit in another embodiment of the present invention.
FIG. 5 is a conceptual diagram illustrating a case where the upper right temporal candidate prediction unit according to another embodiment of the present invention is used as a temporal candidate prediction unit.
6 is a conceptual diagram illustrating a case where a lower left temporal prediction unit according to another embodiment of the present invention is selected as a final temporal prediction unit.
7 is a conceptual diagram illustrating a case where the lower right temporal candidate prediction unit according to another embodiment of the present invention is selected as a final temporal candidate prediction unit.
8 is a conceptual diagram illustrating a temporal candidate prediction unit selection method for calculating a candidate prediction motion vector according to another embodiment of the present invention.
9 is a flowchart illustrating a method of calculating a final temporal prediction unit of a current prediction unit 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, 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 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 can perform motion prediction based on the reference picture interpolated by the reference picture interpolation 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 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 rearranging unit 125 may scan a DC coefficient to a coefficient of a high frequency region using a Zig-Zag scan method, and change the DC coefficient to a one-dimensional vector form. A vertical scanning method of scanning two-dimensional block type coefficients in a column direction instead of a jig-jag scanning method according to the size of a conversion unit and an intra-picture prediction mode, and a horizontal scanning method of scanning a two- Can be used. That is, it is possible to determine whether any of the jig-jag 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, the intra-picture prediction mode sub-picture decoding method using the two candidate intra-prediction modes described with reference to FIGS. 3 to 8 according to the embodiment of the present invention will be described with reference to FIG. 1 and FIG. And these encoders and decoders fall within the scope of the present invention.

3 is a conceptual diagram illustrating a method of calculating a temporal candidate prediction motion vector according to another embodiment of the present invention.

Referring to FIG. 3, in order to calculate a temporal candidate prediction motion vector of a current prediction unit, a temporal prediction prediction unit existing in a frame different from a frame including the current prediction unit can be defined as follows.

If the position of the sample located at the upper left of the current prediction unit is (xP, yP), the same position can be set to the same position (xP, yP) in the other frame.

In the method of calculating the temporal candidate prediction vector according to the embodiment of the present invention, the temporal candidate prediction unit for calculating the temporal candidate prediction vector includes an upper left temporal candidate prediction unit 300, an upper right temporal candidate prediction unit 310, A left temporal candidate prediction unit 320, and a lower right temporal candidate prediction unit 330. [ The upper left temporal prediction unit 300 is a prediction unit including a pixel located at (xP + nPSW-1, yP + nPSH-1), and the upper right temporal prediction unit 310 is (xP + nPSW, -1), the lower left temporal prediction unit 320 includes a prediction unit including pixels located at (xP + nPSW-1, yP + nPSH), a lower right temporal prediction unit 330 ) Can be defined as a prediction unit including pixels located at (xP + nPSW, yP + nPSH).

In order to calculate the temporal candidate prediction motion vector, one of the four temporal candidate prediction blocks may be selected as a temporal candidate prediction unit to calculate a candidate prediction motion vector. The selected temporal candidate prediction unit is referred to as a final temporal candidate prediction unit.

Hereinafter, in the embodiment of the present invention, a prediction unit of another frame including a pixel located at the same position as the predicted unit (xP, yP) is used as a co-located prediction unit.

FIG. 4 is a conceptual diagram illustrating a case where the upper left temporal candidate prediction unit is used as a temporal candidate prediction unit according to still another embodiment of the present invention.

Referring to FIG. 4, when the upper left temporal candidate prediction unit exists in the same LCU as the LCU (Largest Coding Unit) including the same position prediction unit, the upper left temporal candidate prediction unit 400 is referred to as the last temporal candidate It can be selected as a prediction unit.

In the case of a temporal candidate prediction unit existing in the same LCU as the LCU of the co-located prediction unit, the probability of having a motion vector similar to the prediction unit included in the LCU of the co-located prediction unit is high, The temporal candidate prediction unit (the upper right temporal candidate prediction unit 410, the lower left temporal candidate prediction unit 420, and the lower right temporal candidate prediction unit 430) included in the temporal prediction unit The temporal motion vector calculation method according to the embodiment of the present invention includes the upper left temporal candidate prediction unit 400 which is a temporal candidate prediction unit belonging to the LCU of the same position prediction unit, Can be selected as the final temporal candidate prediction unit of the current prediction unit.

FIG. 5 is a conceptual diagram illustrating a case where the upper right temporal candidate prediction unit according to another embodiment of the present invention is used as a temporal candidate prediction unit.

Referring to FIG. 5, the lower left temporal prediction unit 520 and the lower right temporal prediction unit 530 are included in LCUs different from the LCU of the same position prediction unit. Therefore, the probability that the motion vectors of the lower left temporal candidate prediction unit 520 and the lower right temporal candidate prediction unit 530 are similar to the motion vector of the current prediction unit than the motion vector of the prediction unit included in the co-located LCU is low The lower left temporal candidate prediction unit 520 and the lower right temporal candidate prediction unit 530 may be excluded from the last temporal candidate prediction unit.

The temporal candidate prediction unit included in the LCU of the co-located prediction unit is the upper left temporal candidate prediction unit 500 and the upper right temporal candidate prediction unit 510. In this case, The right temporal candidate prediction unit 510 can be selected as the final temporal candidate prediction unit.

6 is a conceptual diagram illustrating a case where a lower left temporal prediction unit according to another embodiment of the present invention is selected as a final temporal prediction unit.

Referring to FIG. 6, since the upper right temporal prediction unit 610 and the lower right temporal prediction unit 630 are included in the LCU different from the LCU of the same position prediction unit, they are excluded from the final temporal prediction unit .

The temporal candidate prediction unit included in the LCU of the co-located prediction unit is an upper left temporal candidate prediction unit 600 and a lower left temporal candidate prediction unit 620. In this case, The left temporal candidate prediction unit 620 can be selected as the final temporal candidate prediction unit.

7 is a conceptual diagram illustrating a case where the lower right temporal candidate prediction unit according to another embodiment of the present invention is selected as a final temporal candidate prediction unit.

7, the upper left temporal prediction unit 700, the upper right temporal prediction unit 710, the lower left temporal prediction unit 720, and the lower right temporal prediction unit 730 are located in the same position prediction unit It is included in the same LCU as the LCU. In this case, the temporal candidate prediction unit 730 positioned at the lower right can be selected as the final temporal candidate prediction unit.

8 is a conceptual diagram illustrating a temporal candidate prediction unit selection method for calculating a candidate prediction motion vector according to another embodiment of the present invention.

As described above with reference to FIGS. 4 to 7, the final temporal candidate prediction unit is a unit for determining whether the temporal candidate prediction unit is included in the same LCU as the same position prediction unit and whether the temporal candidate prediction unit is included in the same LCU. And may be determined depending on whether or not the prediction unit is included in a prediction unit different from the prediction unit.

The temporal candidate prediction block for calculating the candidate prediction motion vector may have four (upper left temporal candidate prediction unit, upper right temporal candidate prediction unit, lower left temporal candidate prediction unit, and lower right temporal candidate prediction unit).

8 shows a first LCU 800, a second LCU 803, a third LCU 805, and a fourth LCU 807 that are in one frame.

The first LCU 800 may be divided into a first encoding unit 810, a second encoding unit 820, a third encoding unit 830, and a fourth encoding unit 840.

First, the first encoding unit 810 can be divided into a first-first prediction unit 813 and a first-second prediction unit 815, which are two prediction units. The temporal candidate prediction unit included in the same LCU as the first-first prediction unit 813 and the first-second prediction unit 815 includes an upper left temporal candidate prediction unit, an upper right temporal candidate prediction unit, a lower left temporal candidate prediction unit Unit, and bottom right temporal candidate prediction unit. In this case, as in the case of FIG. 7, the temporal candidate prediction units 814 and 816 existing on the lower right can be selected as the final temporal candidate prediction unit.

The second encoding unit 820 may include a second-1 prediction unit 823 and a second-2 prediction unit 827, which are two prediction units. In the case of the second-first prediction unit 823, the same method as in the case of the first-first prediction unit 813 and the first-second prediction unit 815 is performed, while the lower right temporal prediction unit 824 is referred to as a final- You can choose in units. For the 2 nd prediction unit 827, the upper right temporal prediction unit and the lower right temporal prediction unit are included in different LCUs. Accordingly, the second-2 prediction unit 827 can be selected as the last temporal candidate prediction unit of the current prediction unit in the lower left temporal prediction unit 829. [

The third coding unit 830 is a third prediction unit 845 which is one prediction unit. In the case of the third prediction unit 845, since the lower left temporal prediction unit and the lower right temporal prediction unit belong to different LCUs, The upper left temporal prediction unit is excluded from the final temporal candidate prediction unit since it is included in the same prediction unit as the current prediction unit. That is, the upper right temporal prediction unit 837 may be selected as the last temporal candidate prediction unit of the current prediction unit.

In the case of the fourth encoding unit 840, the 4-1 prediction unit 845, the 4-2 prediction unit 850, the 4-3 prediction unit 855, the 4-4 prediction unit 860, .

Since all the temporal candidate prediction units of the 4-1 prediction unit 845 are included in the same LCU, the lower right temporal candidate prediction unit 847 can be selected as the final temporal candidate prediction unit of the current prediction unit. The upper right temporal prediction unit of the 4-2 prediction unit 850 can select the lower left temporal candidate prediction unit 853 as the last temporal candidate prediction unit for the same reason as the 3-2 prediction unit 827. [ The fourth to third prediction unit 855 can select the upper right temporal candidate prediction unit 857 as the last temporal prediction unit of the current prediction unit for the same reason as the third prediction unit 835.

In the case of the fourth to fourth prediction unit 860, the upper right temporal candidate prediction unit, the lower left temporal prediction unit, and the lower right temporal prediction unit are the fourth-fourth prediction unit 860 The fourth-fourth prediction unit 860 can select the upper left candidate prediction unit 863 as the last temporal candidate prediction unit since the fourth-fourth prediction unit 860 exists in the LCU different from the included LCU.

9 is a flowchart illustrating a method of calculating a final temporal prediction unit of a current prediction unit according to another embodiment of the present invention.

It is assumed that the position of the upper left pixel of the co-located prediction unit is (xP, yP), the width of the co-located prediction unit is nPSW, and the height is nPSH.

If the pixel at (xP + nPSW, yP) is at the same LCU location as the co-location prediction unit and the pixel at (xP, yP + nPSH) is at the location of the LCU that is different from the co- Step S900), and the temporal prediction unit of the current prediction unit may be the upper right prediction unit (step 910).

If the pixel at (xP + nPSW, yP) is at the position of the LCU different from the co-location prediction unit and the pixel at the position (xP, yP + nPSH) exists at the same position of the LCU as the co-location prediction unit Step S920), and the temporal prediction unit of the current prediction unit may be the lower left prediction unit (step 930).

If a pixel at (xP + nPSW, yP) exists at a location of another LCU that is different from the co-location prediction unit and a pixel at (xP, yP + nPSH) Step S940), and the temporal prediction unit of the current prediction unit may be the lower right prediction unit (step 950).

If the pixel at (xP + nPSW, yP) is at the same LCU location as the co-location prediction unit and the pixel at (xP, yP + nPSH) is at the same LCU location as the co-location prediction unit Step S960), and the temporal prediction unit of the current prediction unit may be the upper left prediction unit (step 970).

The final temporal candidate prediction motion vector in the final temporal candidate prediction unit determined based on the above procedure can be used in the temporal candidate prediction unit calculation method when using the merging method and in the temporal candidate prediction unit calculation method when using the AMVP method.

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 (6)

An entropy decoding unit for entropy decoding a bitstream to derive a quantized transform coefficient;
An inverse quantization unit for inversely quantizing the quantized transform coefficients to derive an inversely quantized transform coefficient;
An inverse transformer which inversely transforms the inversely quantized transform coefficients to derive residual values of pixels;
A reference picture interpolating unit for generating subpixels using the integer pixels included in the reference picture;
An inter-picture prediction unit for performing inter-picture prediction to generate prediction values of the pixels; And
And an adder for adding the residual values of the pixels and the predicted values to restore the pixels,
The reference picture interpolator generates subpixels in units of quarter pixels in the case of luminance pixels, generates subpixels in units of one-eighth pixels in the case of color difference signals,
Wherein the inter picture prediction unit selects a temporal candidate prediction unit for calculating a temporal candidate prediction motion vector of a current prediction unit from the reference picture,
The selection of the temporal candidate prediction unit is performed in consideration of whether or not the current prediction unit is in contact with a block boundary of a maximum coding unit including the current prediction unit,
Wherein the block boundary includes at least one of a lower block boundary or a right block boundary of the maximum coding unit. delete The method according to claim 1,
Wherein when the current prediction unit is in contact with the lower block boundary of the maximum coding unit, the prediction unit adjacent to the lower right side of the prediction unit at the same position as the current prediction unit is not selected as the temporal prediction prediction unit A video decoding apparatus. The method according to claim 1,
If the prediction unit adjacent to the lower right side of the prediction unit at the same position as the current prediction unit is included in the maximum coding unit at the same position as the maximum coding unit including the current prediction unit, Wherein the prediction unit is selected as a prediction unit. The method according to claim 1,
And an offset correcting unit for correcting the reconstructed pixels on a pixel-by-pixel basis using an offset. delete

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