CN116567208A - Video encoding/decoding device and method, and non-transitory recording medium - Google Patents

Abstract

The present disclosure relates to a video encoding/decoding device and method and a non-transitory recording medium. The present invention provides a method for encoding video, the method comprising: a step of determining the motion vector resolution of the current block; a step of determining the motion vector of the current block according to the motion vector resolution; by A step of predicting the current block using the motion vector and encoding the current block; and a step of encoding information on the resolution of the motion vector.

Description

Video encoding/decoding device and method, and non-transitory recording medium

This application is an invention patent application with the original application number 201780064071.X (international application number: PCT/KR2017/011484, application date: October 17, 2017, invention name: device and method for encoding or decoding images ) for a divisional application.

technical field

The present invention relates to high efficiency video coding or decoding.

Background technique

The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art.

Compared with audio data, still image data, etc., video data consumes a large amount of data, and therefore, many hardware resources including memory are required to store or transmit the video data itself without compression processing. Therefore, generally, when video data is stored or transmitted, an encoding device is used to compress and store or transmit the video data, and a decoding device receives, decompresses, and reproduces the compressed video data. Such video compression technologies include High Efficiency Video Coding (HEVC), which was established in early 2013, and H.264/AVC, which has a coding efficiency that is about 40% higher than that of H.264/AVC.

During inter-prediction encoding, which is a prediction method for encoding or decoding, information on a residual block obtained by predicting a current block and motion information used to predict the current block are signaled to a decoding apparatus. Here, the motion information includes information on a reference picture used to predict a current block and information on a motion vector, and in the case of the legacy HEVC standard, the motion vector is expressed in units of 1/4 pixels.

However, the size and resolution of images and the frame rate are gradually increasing, and therefore, the amount of data to be decoded is also increasing. Therefore, there is a need for compression techniques that are more efficient than conventional compression techniques.

Contents of the invention

technical problem

Therefore, the present invention has been made in consideration of the above problems, and an object of the present invention is to provide video encoding or decoding technology.

Technical solutions

According to one aspect of the present invention, there is provided a method for encoding video, the method comprising the following steps: determining the motion vector resolution of the current block; determining the current motion vector resolution according to the motion vector resolution of the current block a motion vector of a block; predicting and encoding the current block using the motion vector of the current block; and encoding information on a resolution of the motion vector of the current block.

According to another aspect of the present invention, a video decoding method for adaptively determining the motion vector resolution of a current block and decoding the current block includes the following steps: extracting the motion vector resolution of the current block from a bit stream information on the motion vector resolution, and determine the motion vector resolution of the current block based on the information on the motion vector resolution of the current block; and using the motion vector resolution according to the current block The motion vector of the current block determined by the rate is used to predict the current block and decode the current block.

According to another aspect of the present invention, a video decoding device for adaptively determining a motion vector resolution of a current block and decoding the current block includes: a motion vector resolution decoder, the motion vector resolution decoding The processor is configured to extract information about the motion vector resolution of the current block from a bitstream, and determine the motion of the current block based on the information about the motion vector resolution of the current block vector resolution; and a video decoder configured to predict the current block using the motion vector of the current block determined according to the motion vector resolution of the current block and to predict the current block to decode.

Description of drawings

Fig. 1 is a schematic block diagram showing a common video encoding device,

2 is a diagram showing an example of block separation using a quadtree plus binary tree (QTBT) structure,

FIG. 3 is a diagram showing an example of neighboring blocks of a current block,

4 is a diagram illustrating a video encoding device according to an embodiment of the present invention,

FIG. 5 is a diagram illustrating the interpolation and motion estimation process performed by the inter predictor 124 and the resolution of a reference picture,

Fig. 6 is a graph for comparing the motion degrees of two frames,

FIG. 7 is a diagram illustrating an example of a resolution determiner 410 according to an embodiment,

8 is a diagram illustrating an example of the resolution encoder 430 when motion vector resolution information of the current CU is encoded as a resolution difference value,

FIG. 9 is a diagram illustrating an example of a resolution encoder 430 representing a motion vector of a current CU as a resolution scale factor instead of a resolution difference,

Figure 10 is a schematic diagram of a common video decoding device,

FIG. 11 is a diagram illustrating a video decoding device 1100 according to an embodiment of the present invention,

12 is a flowchart illustrating a method of decoding video at a video decoding device 1100 according to a first embodiment of the present invention,

FIG. 13 is a diagram illustrating an example of adaptive determination of resolution,

Fig. 14 is a flow chart showing the case of adding some operations in Fig. 12,

15 is a flowchart illustrating a method of decoding video at a video decoding device 1100 according to a second embodiment of the present invention,

FIG. 16 is a diagram illustrating another example of adaptive determination of resolution,

Fig. 17 is a flowchart showing a case where some operations are added in Fig. 15,

18 is a flowchart illustrating a method of decoding video at a video decoding device 1100 according to a third embodiment of the present invention,

FIG. 19 is a flowchart showing a case where some operations are added to the flowchart of FIG. 18 .

Detailed ways

Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. Regarding the reference numerals of elements in the drawings, the same reference numerals designate the same elements, if possible, even though the elements are shown in different drawings. Also, in the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted for clarity and conciseness.

FIG. 1 is a schematic block diagram illustrating a common video encoding device.

The video encoding apparatus 100 may include a block separator 110, a predictor 120, a subtractor 130, a transformer 140, a quantizer 145, an encoder 150, an inverse quantizer 160, an inverse transformer 165, an adder 170, a filter unit 180, and memory 190. Each component of the video encoding apparatus 100 may be implemented in the form of a hardware chip, or may be implemented in the form of software such that one or more microprocessors execute the function of the software corresponding to each component.

The block separator 110 may separate each picture constituting a video into a plurality of coding tree units (CTUs), and then may recursively separate the CTUs using a tree structure. A leaf node in the tree structure may be a coding unit (CU), which is a basic unit of coding. The tree structure may be a quadtree (QT) structure in which a node is split into four lower nodes or a quadtree plus binary tree formed by mixing a QT structure with a binary tree (BT) structure in which a node is split into two lower nodes (QTBT) structure.

In the quadtree plus binary tree (QTBT) structure, first, the CTUs can be separated by the QT structure. Then, the leaf nodes of QT can be further separated by BT structure. Split information generated by splitting CTUs in the QTBT structure by the block splitter 110 may be encoded by the encoder 150 and may be transmitted to a decoding device.

In QT, a first flag (QT_split_flag) indicating whether to split the block of the corresponding node is encoded. When the first flag is 1, the block of the corresponding node is split into four blocks having the same size, and when the first flag is 0, the corresponding node is not further split by QT.

In BT, a second flag (BT_split_flag) indicating whether to split the block of the corresponding node is encoded. There can be multiple separation types in BT. For example, there may be two types of a type in which a block of a corresponding node is horizontally separated and a type in which a block is vertically separated into two blocks of the same size. Alternatively, there may be another type of splitting the block of the corresponding node into two blocks having an asymmetric shape. This asymmetrical shape may be formed by splitting the block of the corresponding node into two rectangular blocks with a size ratio of 1:3 or by splitting the block of the corresponding node in a diagonal direction. In case the BT has multiple split types, if the second flag indicating that the block is split is encoded, split type information indicating the split type of the corresponding block may be additionally encoded.

FIG. 2 is a diagram showing an example of block separation using the QTBT structure. (a) of FIG. 2 shows an example of separating blocks by a QTBT structure, and (b) of FIG. 2 shows blocks separated in a tree structure. In FIG. 2 , the solid line indicates the separation by the QT structure, and the broken line indicates the separation by the BT structure. In (b) of FIG. 2 , regarding the symbols of layers, layers without parentheses represent layers representing QT, and layers in parentheses represent layers of BT. Numbers in the BT structure indicated by dotted lines indicate separation type information.

In FIG. 2 , the CTU, which is the uppermost layer of QT, can be separated into four nodes of layer 1 . Therefore, the block splitter 110 may generate QT_split_flag=1 indicating that the CTU is split. The block corresponding to the first node of layer 1 is no longer separated by QT. Therefore, the chunk splitter 110 generates QT_split_flag=0.

Then, the block corresponding to the first node of layer 1 of QT can be BTed. In this embodiment, it is assumed that BT has two split types: a type that splits a block of a node horizontally into two blocks of the same size and a type that splits a block of a node vertically into two blocks of the same size. The first node of layer 1 of QT becomes the root node "(layer 0)" of BT. The block corresponding to the root node of the BT is further split into blocks of "(layer 1)", so the block splitter 110 generates BT_split_flag=1 indicating to split blocks by BT. Then, the block separator 210 generates split type information indicating whether the corresponding block is split horizontally or vertically. In FIG. 2 , the block corresponding to the root node of the BT is vertically split, so 1 indicating vertical split is generated as split type information. The first block among the blocks of "(layer 1)" split from the root node is further split according to the vertical split type, so BT_split_flag=1 and split type information 1 are generated. On the other hand, the second block (layer 1) split from the root node of BT is not split anymore, so BT_split_flag=0 is generated.

In order to efficiently signal information about blocks separated by the QTBT structure to a decoding device, the following information may be additionally encoded. Such information may be encoded as header information of the video, for example, may be encoded as a Sequence Parameter Set (SPS) or a Picture Parameter Set (PPS).

-CTU size: the block size of the top layer (ie, the root node) of QTBT;

-MinQTSize: the minimum block size of leaf nodes allowed in QT;

-MaxBTSize: the maximum block size of the root node allowed in BT;

-MaxBTDepth: maximum depth allowed in BT;

-MinBTSize: Minimum block size of leaf nodes allowed in BT.

A block in a QT whose size is the same as MinQTSize is not further separated, so the separation information (first flag) on the QT corresponding to the block is not encoded. Also, blocks with a size larger than MaxBTSize in QT have no BT. Therefore, the split information (second flag, split type information) on the BT corresponding to the block is not encoded. When the depth of the node of the BT reaches MaxBTDepth, the block of the node is not further split, and the split information (second flag, split type information) about the BT of the corresponding node is not encoded. In addition, blocks of the same size as MinBTSize in BT are not further split, and split information (second flag, split type information) on BT is not encoded. In this way, the maximum or minimum block size of the root node or leaf node of QT and BT can be defined at a high layer such as sequence parameter set (SPS) or picture parameter set (PPS), thus, it is possible to reduce the An encoded amount of information or information indicating the type of separation.

The same QTBT structure can be used to separate the luma and chrominance components of a CTU. However, the present invention is not limited thereto, and separate QTBT structures may be used to separate luma components and chrominance components, respectively. For example, in the case of intra (I) slices, different QTBT structures may be used to separate luma and chroma components.

Hereinafter, a block corresponding to a CU to be encoded or decoded is referred to as a 'current block'.

The predictor 120 predicts a current block to generate a prediction block. The predictor 120 may include an intra predictor 122 and an inter predictor 124 .

The intra predictor 122 predicts pixels in the current block using pixels (reference pixels) located around the current block in the current picture including the current block. There are various intra prediction modes according to prediction directions, and adjacent pixels and calculation expressions to be used are defined differently according to each prediction mode.

The inter predictor 124 searches for a block most similar to the current block within a reference picture encoded and decoded earlier than the current picture, and generates a prediction block of the current block using the searched block. In addition, the inter predictor 124 generates a motion vector corresponding to a displacement between a current block in a current picture and a prediction block in a reference picture. Motion information including information on a reference picture used to predict a current block and information on a motion vector is encoded by the encoder 150 and transmitted to the video decoding apparatus.

Various methods can be used to minimize the number of bits required to encode motion information.

In one example, when the reference picture and motion vector of the current block are the same as those of the neighboring blocks, the motion information about the current block can be sent to the decoder by encoding the information that can be used to identify the neighboring blocks. equipment. This approach is called "merge mode".

In the merge mode, the inter predictor 124 may select a predetermined number of merge candidate blocks (hereinafter referred to as 'merge candidates') from neighboring blocks of the current block.

As shown in FIG. 3, some or all of the left block L, upper block A, upper right block AR, lower left block BL, and upper left block AL adjacent to the current block in the current picture may be used as neighboring blocks. Also, a block located in a reference picture (which may be the same as or different from the reference picture used to predict the current block) instead of the current picture in which the current block is located may be used as a merging candidate. For example, a co-located block of the current block in a reference picture or a block adjacent to the co-located block may be further used as a merging candidate.

The inter predictor 124 constructs a merge list including a predetermined number of merge candidates using the neighboring blocks. Merge candidates to be used as motion information of the current block are among the merge candidates included in the merge list, and merge index information for identifying the selected candidate is generated. The generated merge index information is encoded by the encoder 150 and transmitted to the video decoding device.

As another method of encoding motion information, motion vector difference (MVD) can be encoded.

In this approach, the inter predictor 124 uses neighboring blocks of the current block to derive motion vector predictor (MVP) candidates for the motion vector of the current block. Some or all of the left block L, upper block A, upper right block AR, lower left block BL, and upper left block AL adjacent to the current block in the current picture shown in FIG. 3 may be used as adjacent blocks for deriving MVP candidates . In addition, blocks located in a reference picture (which may be the same as or different from the reference picture used to predict the current block) instead of the current picture in which the current block is located may be used as neighboring blocks for deriving MVP candidates. For example, a co-located block of the current block in a reference picture or a block adjacent to the co-located block may be used.

The inter predictor 124 uses motion vectors of neighboring blocks to derive MVP candidates, and uses the MVP candidates to determine the MVP of the motion vector of the current block. The inter predictor calculates a motion vector difference (MVD) by subtracting the MVP from the motion vector of the current block.

The MVP can be obtained by applying a predefined function (eg, calculation of median or mean) to the MVP candidate. In this case, the video decoding device also knows the predefined function. Since the neighboring blocks used to derive the MVP candidates are already encoded and decoded blocks, the video decoding apparatus already knows the motion vectors of the neighboring blocks. Accordingly, the video encoding apparatus 100 does not need to encode information for identifying MVP candidates. Therefore, in this case, information on the MVD and information on a reference picture used to predict a current block are encoded.

In another embodiment, the MVP may be determined by selecting any one of the MVP candidates. In this case, information for identifying the selected MVP candidate is additionally encoded together with information on the MVD and information on a reference picture used to predict the current block.

The subtracter 130 subtracts the prediction block generated by the intra predictor 122 or the inter predictor 124 from the current block to generate a residual block.

The transformer 140 transforms the residual signal in the residual block, which is a value in the spatial domain, into a transform coefficient in the frequency domain. The transformer 140 may transform the residual signal in the residual block using the size of the current block as a transformation unit, or may separate the residual block into a plurality of smaller subblocks and transform the residual signal in a transformation unit corresponding to the size of the subblock. There may be various methods of separating the residual block into smaller sub-blocks. For example, the residual block may be split into sub-blocks of the same predefined size, or the residual block may be split in the manner of a quadtree (QT) having the residual block as a root node.

The quantizer 145 quantizes the transform coefficient output from the transformer 140 and outputs the quantized transform coefficient to the encoder 150 .

The encoder 150 encodes the quantized transform coefficients using an encoding scheme such as CABAC to generate a bitstream. The encoder 150 may encode information related to block separation such as CTU size, MinQTSize, MaxBTSize, MaxBTDepth, MinBTSize, QT_split_flag, BT_split_flag, and split type, and the decoding device may separate blocks in the same manner as the encoding device.

The encoder 150 encodes information on a prediction type indicating whether a current block is encoded via intra prediction or inter prediction, and encodes the intra prediction information or the inter prediction information according to the prediction type.

When inter-predicting a current block, the encoder 150 encodes syntax elements of inter-prediction information. The syntax elements of the inter prediction mode may include the following information.

(1) Mode information indicating whether the motion information of the current block is coded in merge mode or coded in MVD coded mode

(2) Syntactic elements of motion information

When encoding motion information in a merge mode, the encoder 150 encodes, as a syntax element of the motion information, merge index information indicating which candidate is selected among merge candidates as a candidate for extracting motion information of a current block.

On the other hand, when motion information is encoded in a mode for encoding MVD, information on the MVD and information on a reference picture are encoded as syntax elements of the motion information. When the MVP is determined using a method of selecting any one candidate from a plurality of MVP candidates, the syntax element of the motion information may further include MVP identification information for identifying the selected candidate.

The inverse quantizer 160 inverse quantizes the quantized transform coefficients output from the quantizer 145 to generate transform coefficients. The inverse transformer 165 transforms the transform coefficient output from the inverse quantizer 160 from the frequency domain to the spatial domain, thus reconstructing the residual block.

The adder 170 adds the reconstructed residual block and the predicted block generated by the predictor 120 to reconstruct the current block. When performing intra prediction on a block having a subsequent sequence, pixels in the restored current block may be used as reference pixels.

The filter unit 180 performs deblock filtering on a boundary between reconstructed blocks in order to remove blocking artifacts due to encoding/decoding in units of blocks and stores the deblock filtered blocks in the memory 190 . When all blocks in a picture are restored, the restored picture can be used as a reference picture for inter prediction of blocks in a picture to be encoded subsequently.

For reference, a video encoding apparatus may encode a current block using a skip mode. In skip mode, only the motion information of the current block is encoded, and no other information about the current block, such as information about the residual block, is encoded. The above-mentioned merge index information may be used as motion information of the current block. When the current block has been encoded in the skip mode, the video decoding apparatus sets the motion information of the merge candidate indicated by the merge index information decoded from the bitstream as the motion information of the current block. In the skip mode, the prediction block predicted based on the motion information of the current block is reconstructed as the current block.

The skip mode may differ from the merge mode for encoding information on the residual block and motion information of the current block in that no information other than the motion information of the current block is encoded in the skip mode. However, methods for encoding motion information of a current block in skip mode and merge mode are the same, and therefore, all following descriptions of merge mode can be applied to skip mode in the same manner.

FIG. 4 is a diagram illustrating a video encoding apparatus 400 according to an embodiment of the present invention.

The video encoding apparatus 400 according to an embodiment of the present invention may include a resolution determiner 410 , a video encoder 420 and a resolution encoder 430 .

The resolution determiner 410 determines a motion vector resolution for motion estimation of the current CU. Motion vector resolution may be the minimum unit for expressing motion vectors. The motion vector resolution may indicate the resolution in the reference picture for compensating the motion of the current CU, that is, may indicate the pixels of the reference picture being interpolated. For example, when the motion vector resolution is 1/4 pixel, the reference picture can be interpolated to the position of 1/4 pixel, and the motion vector can be measured up to the unit of 1/4 pixel. Here, the minimum unit for determining the motion vector may be a fractional pixel such as 1/4 pixel or 1/2 pixel, or may be an integer pixel such as 1 pixel, 2 pixels, 3 pixels, or 4 pixels unit.

The video encoder 420 estimates motion in units of blocks (ie, in units of CUs) according to the determined motion vector resolution to determine the motion vector of the CU, and predicts and encodes the CU using the determined motion vector.

The resolution encoder 430 encodes information on a motion vector resolution for predicting a motion vector of a CU.

Here, the video encoder 420 may be implemented as the video encoding apparatus 100 described above with reference to FIG. 1 .

The function of the resolution determiner 410 may be included in the above-mentioned functions of the predictor 120 in the video encoding apparatus 100 and may be integrated in the predictor 120 .

The function of the resolution encoder 430 may be included in the above-mentioned functions of the encoder 150 of the video encoding apparatus 100 and may be integrated in the encoder 150 .

FIG. 5 is a diagram illustrating the interpolation and motion compensation process performed by the inter predictor 124 and the resolution of motion vectors.

FIG. 5 illustrates pixels of a reference picture stored in the memory 190 and sub-pixels formed by interpolating an integer number of pixels of the reference picture. As shown in FIG. 5, when an integer number of pixels A1 to F6 of a reference picture are filtered by an interpolation filter, for example, sub-pixels "a" to "s" may be generated, and when such interpolation is performed, The resolution of motion estimation and motion compensation can be increased by a factor of 2, 4 or more compared to integer pixel resolution.

Motion estimation is a process of searching for the most similar part of the current CU from an interpolated reference picture and outputting a block of the corresponding part and a motion vector indicating the corresponding block. The motion vectors generated in this process are encoded by the encoder 150 .

During motion estimation and motion compensation, when predicting a fretting image area, the motion vector can be expressed in units of fractional pixels (1/2 pixel, 1/4 pixel, 1/8 pixel, or 1/6 pixel), and when When predicting an image area with large motion, the motion vector may be expressed in units of one or more integer pixels (units of 1 pixel, 2 pixels, 3 pixels or 4 pixels).

FIG. 6 is a graph for comparing the degrees of motion of two frames.

In FIG. 6, when the reference frame and the current frame are compared in terms of the motion of the objects included therein, between these two frames, the objects corresponding to the circles in FIG. The motion of the corresponding object is estimated in units of pixels, and since the object corresponding to the triangle has a relatively large motion between the two frames, the motion can be estimated in units of integer pixels.

When the inter prediction mode of the CU that is an encoding target is the merge mode, motion information is not directly signaled, but an index value corresponding to a motion information candidate selected from a plurality of motion information candidates is signaled. Therefore, no information on the motion vector resolution of the selected motion information candidate is transmitted.

On the other hand, when the inter prediction mode of the CU is the mode to encode the MVD, the MVD information is signaled, therefore, the MVD can be represented more efficiently in units of fractional pixels or in units of integer pixels according to the resolution of the MVD information.

FIG. 7 is a diagram illustrating an example of a resolution determiner 410 according to an embodiment.

The resolution determiner 410 may include a resolution mode determiner 710 , an alternative resolution determiner 720 and an adaptive resolution determiner 730 . In some embodiments, the resolution determiner 410 may be implemented by omitting at least one component of the resolution mode determiner 710 , the alternative resolution determiner 720 and the adaptive resolution determiner 730 .

The resolution mode determiner 710 determines whether to activate the adaptive motion vector resolution mode. For example, whether to adaptively enable motion vector resolution may be selected with respect to higher layer image units included in a plurality of CUs. Here, the upper-layer image unit may be an image sequence, a picture, a slice, a CTU, and the like. When the motion vector resolution of the higher layer picture unit is not adaptively enabled (ie, when the corresponding mode is not the adaptive motion vector resolution mode), the default motion vector resolution is applied to all CUs in the higher layer picture unit. That is, a fixed default motion vector resolution such as 1/4 pixel may be applied to all CUs in the upper layer picture unit. Here, the default motion vector resolution may be a predetermined specific motion vector resolution shared by the video encoding device and the video decoding device, or may be a value determined by the video encoding device in the upper layer image area and signaled to the video decoding equipment. On the other hand, when the adaptive motion vector resolution mode is enabled to be applied, the substitute resolution determiner 720 and the adaptive resolution determiner 730 which will be described below adaptively determine the resolution of each CU to be inter-predicted. Motion vector resolution.

When the adaptive motion vector resolution mode is enabled to be applied, the substitute resolution determiner 720 determines a substitute resolution other than the default motion vector resolution. Alternate resolutions may be applied per unit of any of sequences, pictures, slices, CTUs, and CUs. Alternate resolutions may be determined for individual image units identical to the image unit to which the adaptive motion vector resolution mode is applied. For example, when the adaptive motion vector resolution mode is applied in units of SPS, the alternative resolution can also be determined in units of SPS, and when the adaptive motion vector resolution mode is applied in units of PPS or slices, it can also be determined in units of PPS or slice determines an alternate resolution for the cell. Alternatively, an alternative resolution may be determined for each image unit (eg, slice, CTU, or CU) that is smaller than the image unit to which the adaptive motion vector resolution mode is applied. For example, when the adaptive motion vector resolution mode is applied in units of SPS, the alternative resolution may be determined in units of any one of PPS, slice, and CTU, which are picture units of layers lower than the SPS, and when the resolution is determined in units of PPS When the adaptive motion vector resolution mode is applied by unit, an alternative resolution may be determined in units of either a slice or a CTU which is a picture unit of a layer lower than the PPS. Alternatively, the alternative resolution may be determined in units of CUs to be encoded.

The alternative resolution determiner 720 may select one of a plurality of motion vector resolution candidates as an alternative resolution.

The adaptive resolution determiner 730 may determine the motion vector resolution of the current CU. For example, the adaptive resolution determiner 730 may determine any one of a default motion vector resolution and an alternative resolution as the motion vector resolution of the current CU.

The resolution encoder 430 may generate and encode information on motion vector resolution based on the information determined by the resolution determiner 410 . Hereinafter, in the case where the motion vector resolution of the current CU is determined from among the default motion vector resolution and the alternative resolution, the resolution encoder 430 compares the motion vector resolution information with respect to the first and second embodiments. Methods for encoding are instantiated.

first embodiment

In the first embodiment, the image unit used to select whether to adaptively determine the motion vector resolution between the default motion vector resolution and the alternative resolution is the same as the image unit used to determine the alternative resolution, and the two Image units are larger than CUs.

When whether to adaptively enable the motion vector resolution is selected for each image sequence unit by the resolution mode determiner 710, the resolution encoder 430 may set Adaptive_MV_resolution_enabled_flag( That is, the first identification information) is inserted into the sequence parameter set (SPS).

When whether to adaptively enable motion vector resolution is selected for each picture unit by the resolution mode determiner 710, the resolution encoder 430 may insert Adaptive_MV_resolution_enabled_flag, which is a flag indicating whether to adaptively enable motion vector resolution, into in the Picture Parameter Set (PPS).

When whether to adaptively enable the motion vector resolution is selected for each slice (or CTU) unit by the resolution mode determiner 710, the resolution encoder 430 may set the flag as indicating whether to adaptively enable the motion vector resolution The Adaptive_MV_resolution_enabled_flag is inserted into the slice (or CTU) header.

When the resolution mode determiner 710 selects an adaptive motion vector resolution mode that adaptively enables motion vector resolution, Adaptive_MV_resolution_enabled_flag=ON (for example, ON=1) may be set. Otherwise, Adaptive_MV_resolution_enabled_flag=OFF may be set (for example, in the case of ON=1, OFF=0).

According to the first embodiment, a unit of determining a substitute resolution at the substitute resolution determiner 720 is the same as a unit of setting Adaptive_MV_resolution_enabled_flag. In case of Adaptive_MV_resolution_enabled_flag=ON, the alternative resolution determiner 720 determines an alternative resolution, and the resolution encoder 430 generates alternative_mv_resolution information indicating the determined alternative resolution. The resolution encoder 430 encodes alternative_mv_resolution information generated for the same respective units as the unit for setting Adaptive_MV_resolution_enabled_flag.

When one of a plurality of predefined motion vector resolution candidates is selected as an alternative resolution, the resolution encoder 430 may generate an alternative resolution for identifying the alternative resolution selected from the plurality of predefined motion vector resolution candidates. rate information and encode it as alternative_mv_resolution information.

When the adaptive resolution determiner 730 determines the default motion vector resolution to be used as the motion vector resolution of the current CU, the resolution encoder 430 may generate a motion vector resolution indicating that the default motion vector resolution is used as the current CU. rate mv_resolution_flag (that is, the second identification information).

When adaptive resolution determiner 730 determines an alternative resolution other than the default motion vector resolution to be used as the motion vector resolution of the current CU, resolution encoder 430 may generate a mv_resolution_flag of the motion vector resolution and encode it.

second embodiment

In a second embodiment, the image unit used to select whether to adaptively determine the motion vector resolution between the default motion vector resolution and the alternative resolution is a higher layer than the image unit used to determine the alternative resolution , and the picture unit used to determine the alternative resolution is a higher-level picture unit compared to the CU.

The first embodiment is an embodiment in which an image unit for selecting whether to adaptively determine a motion vector resolution between a default motion vector resolution and an alternative resolution is the same as an image unit for determining an alternative resolution, and Both of these picture units are larger than the CU.

When whether to adaptively enable the motion vector resolution is selected for each image sequence unit by the resolution mode determiner 710, the resolution encoder 430 may insert Adaptive_MV_resolution_enabled_flag which is a flag indicating whether to adaptively enable the motion vector resolution into the SPS.

When whether to adaptively enable motion vector resolution is selected for each picture unit by the resolution mode determiner 710, the resolution encoder 430 may insert Adaptive_MV_resolution_enabled_flag, which is a flag indicating whether to adaptively enable motion vector resolution, into In PPS.

Here, when the resolution mode determiner 710 selects an adaptive motion vector resolution mode that adaptively enables motion vector resolution, Adaptive_MV_resolution_enabled_flag=ON may be set. Otherwise, Adaptive_MV_resolution_enabled_flag=OFF may be set.

A unit determining a substitute resolution at the substitute resolution determiner 720 may be determined as a picture unit (for example, a slice or a CTU) smaller than a picture unit for which Adaptive_MV_resolution_enabled_flag is set and larger than a CU. In this case, the resolution encoder 430 may generate alternative_mv_resolution information indicating an alternative resolution of each slice or CTU and encode it.

When one of a plurality of predefined motion vector resolution candidates is selected as an alternative resolution, the resolution encoder 430 may generate an alternative resolution for identifying the alternative resolution selected from the plurality of predefined motion vector resolution candidates. rate information and encode it as alternative_mv_resolution information.

When the value of alternative_mv_resolution information indicates 0, motion vector resolutions of all CUs in a corresponding slice or CTU are not adaptively enabled.

When the motion vector resolution is adaptively enabled, the resolution encoder 430 may generate Alternative_enabled_flag information as a flag indicating whether to use an alternative resolution for each slice or CTU, and may encode the Alternative_enabled_flag information.

Here, when an alternative resolution is used, alternative_mv_resolution information indicating an alternative resolution may be generated and encoded for each slice or CTU.

When the adaptive resolution determiner 730 determines to use the default motion vector resolution as the motion vector resolution of the current CU, the resolution encoder 430 may generate mv_resolution_flag indicating that the default motion vector resolution is used as the motion vector resolution of the current CU and encode it.

When adaptive resolution determiner 730 determines to use an alternative resolution other than the default motion vector resolution as the motion vector resolution of the current CU, resolution encoder 430 may generate a motion vector resolution indicating that the alternative resolution is used as the current CU. rate mv_resolution_flag and may encode information about the mv_resolution_flag.

third embodiment

In the second embodiment, the image unit for adaptively determining the motion vector resolution between the default motion vector resolution and the alternative resolution is an image unit of a higher layer than the image unit for determining the alternative resolution , and the picture unit used to determine the alternative resolution is the CU unit.

When whether to adaptively enable motion vector resolution is selected by the resolution mode determiner 710 for each image sequence unit, each picture unit, each slice unit, or each CTU unit, the resolution encoder 430 may set the resolution as Adaptive_MV_resolution_enabled_flag indicating whether a flag for motion vector resolution is adaptively enabled is inserted into the SPS, PPS, slice header, or CTU header.

As in the first and second embodiments, Adaptive_MV_resolution_enabled_flag can be set to ON or OFF according to the selection result of whether to enable the motion vector resolution adaptively.

When the resolution mode determiner 710 selects the adaptive motion vector resolution mode that adaptively enables the motion vector resolution, if the default motion vector resolution is selected as the motion vector resolution of the current CU, the resolution encoder 430 may The mv_resolution_flag indicating that the default motion vector resolution is used as the motion vector resolution of the current CU is generated and encoded.

According to the third embodiment, a unit for determining a substitute resolution by the substitute resolution determiner 720 may be the same CU unit as a unit for determining a motion vector resolution.

When an alternative resolution other than the default motion vector resolution is used as the motion vector resolution of the current CU, the resolution encoder 430 may generate mv_resolution_flag indicating that the alternative resolution is used as the motion vector resolution of the current CU, and may generate The alternative resolution determiner 720 determines alternative_mv_resolution information of an alternative resolution, and may encode information on mv_resolution_flag and alternative_mv_resolution.

When one of a plurality of predefined motion vector resolution candidates is selected as an alternative resolution, the resolution encoder 430 may use the Rate information is encoded as alternative_mv_resolution information.

The adaptive resolution determiner 730 may select any one of a plurality of motion vector resolution candidates as the motion vector resolution of the current CU, instead of selecting any one of the default motion vector resolution and the alternative resolution as the motion vector resolution of the current CU. Vector resolution. In this case, in order to effectively encode the determined motion vector resolution information of the current CU, the resolution encoder 430 may encode the motion vector resolution information of the current CU into the motion vector resolution of the current CU and the alternative resolution rate, or the difference between the motion vector resolution of the current CU and the motion vector resolution of the previous CU, instead of encoding the motion vector resolution of the current CU itself.

FIG. 8 is a diagram illustrating an example of the resolution encoder 430 when motion vector resolution information of a current CU is encoded as a resolution difference value.

As shown in FIG. 8 , the resolution encoder 430 may include an encoding information generator 810 and a resolution difference calculator 820 . Detailed operations will be described below for the fourth embodiment.

Fourth Embodiment

When the resolution mode determiner 710 adaptively enables motion vector resolution in units of sequences, pictures, slices, or CTUs, the encoding information generator 810 can target each sequence, each picture, and each slice units or each CTU unit set Adaptive_MV_resolution_enabled_flag to ON.

The encoding information generator 810 may check for each CU in a higher picture unit whether a default motion vector resolution is used as the motion vector resolution of the corresponding CU. When the default motion vector resolution is used as the motion vector resolution of the current CU, the encoding information generator 810 may set the mv_resolution_flag corresponding to the current CU to OFF. When the default motion vector resolution is not used as the motion vector resolution of the current CU and any one selected from a plurality of motion vector resolution candidates is used as the motion vector resolution of the current CU, the encoding information generator 810 may set The mv_resolution_flag corresponding to the current CU is set to ON.

When the alternative resolution determiner 720 determines an alternative resolution value of each image unit that is the same as the unit for setting the Adaptive_MV_resolution_enabled_flag, the encoding information generator 810 may encode the determined alternative resolution as the same unit for setting the Adaptive_MV_resolution_enabled_flag The alternative_mv_resolution information of each image unit.

As described above, the unit for determining the alternative resolution is not limited to determining for each image unit that is the same as the unit for setting Adaptive_MV_resolution_enabled_flag, but may be determined for each CU unit or may be for a unit other than the unit for setting Adaptive_MV_resolution_enabled_flag Each image unit that is smaller and larger than the CU unit is determined, but its description has been given above, and thus its detailed description is omitted.

When any one selected from a plurality of motion vector resolution candidates is used as the motion vector resolution of the current CU, the resolution difference calculator 820 may calculate the difference between the motion vector resolution of the current CU and the motion vector resolution of the previous CU. The resolution difference (for example, the value obtained by subtracting the motion vector resolution of the previous CU from the motion vector resolution of the current CU) is included in the elements in the information.

However, when the current CU is the first CU in encoding order among the CUs in the higher layer image unit, the resolution difference calculator 820 may determine the motion vector resolution of the current CU as the resolution difference information, or may use The alternative resolution determined by the alternative resolution determiner 720 is determined as resolution difference information.

When any one selected from a plurality of motion vector resolution candidates is used as the motion vector resolution of the current CU, the resolution difference calculator 820 may calculate as a difference between the motion vector resolution of the current CU and alternative_mv_resolution A resolution difference value of (for example, a value obtained by subtracting alternative_mv_resolution from the motion vector resolution of the current CU) as an element included in the information on the motion vector resolution of the current CU.

The resolution difference information determined by the resolution difference calculator 820 may be stored as mv_resolution_delta.

When the motion vector resolution of the current CU is described as the mv_resolution_delta value, there is no need to generate a substitute resolution, and thus, the operation of the substitute resolution determiner 720 may be omitted.

The encoding information generator 810 may generate and encode information on the motion vector resolution of the current CU based on the results of the resolution mode determiner 710 and the adaptive resolution determiner 730 . The encoding information generator 810 may encode Adaptive_MV_resolution_enabled_flag as ON or OFF according to whether the resolution mode determiner 710 adaptively enables the motion vector resolution of the CU included in the higher layer image unit.

When Adaptive_MV_resolution_enabled_flag is ON, the adaptive resolution determiner 730 selects whether to use the default motion vector resolution as the motion vector resolution of the current CU, or to determine any one selected from a plurality of motion vector resolution candidates as the current CU motion vector resolution. The encoding information generator 810 encodes mv_resolution_flag according to the selection. When Adaptive_MV_resolution_enabled_flag is OFF, the encoding information generator 810 does not encode mv_resolution_flag.

When mv_resolution_flag is ON (that is, when any one selected from a plurality of motion vector resolution candidates is used as the motion vector resolution of the current CU), the encoding information generator 810 may set the The mv_resolution_delta of the resolution difference information calculated by the unit 820 is encoded. When mv_resolution_flag is OFF (ie, when the default motion vector resolution is used as the motion vector resolution of the current CU), the encoding information generator 810 may not encode mv_resolution_delta.

The resolution encoder 430 may represent the resolution difference value as a resolution scaling factor obtained through a division operation instead of a value obtained through a subtraction operation "-". Furthermore, the scale factor can be expressed on a logarithmic scale, and its detailed operation will be described for the fifth embodiment.

Fifth Embodiment

FIG. 9 is a diagram showing an example of the resolution encoder 430 representing the motion vector resolution of the current CU as a resolution scale factor instead of a resolution difference.

As shown in FIG. 9 , the resolution encoder 430 may include an encoding information generator 910 and a resolution scale information generator 920 . The resolution ratio information generator 920 of FIG. 9 may replace the resolution difference calculator 820 of FIG. 8 , and the encoding information generator 910 of FIG. 9 may replace the encoding information generator 810 of FIG. 8 .

The resolution difference calculator 820 and the resolution scale information generator 920 are different from each other in that the resolution difference calculator 820 calculates the resolution difference and generates mv_resolution_delta as information on the resolution difference, while the resolution scale The information generator 920 calculates a resolution scale factor and generates mv_resolution_scale as information on the resolution scale factor.

For example, the resolution ratio information generator 920 may calculate the ratio between the motion vector resolution of the current CU and the motion vector resolution of the previous CU (e.g., by dividing the motion vector resolution of the current CU by the motion vector resolution of the previous CU rate) as an element included in the information on the motion vector resolution of the current CU.

However, when the current CU is the first CU in encoding order among the CUs in the higher layer image unit, the resolution scale information generator 920 may determine the motion vector resolution of the current CU as the resolution scale factor information, or may use The alternative resolution determined by the alternative resolution determiner 720 is determined as resolution scale factor information.

The resolution scale information generator 920 may calculate a resolution scale factor (ie, a value obtained by dividing the motion vector resolution of the current CU by alternative_mv_resolution) which is a ratio between the motion vector resolution of the current CU and alternative_mv_resolution as the Element included in the information about the motion vector resolution of the current CU.

The resolution scale factor information determined by the resolution scale information generator 920 may be stored as mv_resolution_scale.

Except that the encoding information generator 810 of FIG. 8 encodes mv_resolution_delta, and instead of the encoding information generator 910 of map 9 encoding the information about the resolution scale factor (mv_resolution_scale), the rest of the encoding information generator 810 of FIG. 8 Operations may be the same as the remaining operations of the encoding information generator 910 of FIG. 9 . The encoding information generator 910 encodes information on a resolution scale factor (mv_resolution_scale). The operation of the encoding information generator 910 may be the same as that of the encoding information generator 810 of FIG. 8 except for encoding mv_resolution_scale instead of mv_resolution_delta.

In the above embodiments of the video encoding apparatus, a unit of a block for determining a motion vector resolution is described as a CU, but is not limited thereto, and may be a CTU/ in some embodiments. When a unit of a block for determining a motion vector resolution is a CTU, all CUs included in the CTU may have the same motion vector resolution value. In addition, all CUs encoded in the mvp mode among CUs included in the corresponding CTU may have the same motion vector resolution value as that of the corresponding CTU.

Hereinafter, a video decoding device will be described.

Fig. 10 is a schematic diagram of a common video decoding device.

The video decoding apparatus 1000 may include a decoder 1010 , an inverse quantizer 1020 , an inverse transformer 1030 , a predictor 1040 , an adder 1050 , a filter unit 1060 and a memory 1070 . As in the video encoding device of FIG. 1, each component of the video encoding device may be implemented in the form of a hardware chip or may be implemented in the form of software such that the microprocessor executes the function of the software corresponding to each component.

The decoder 1010 decodes a bitstream received from the video encoding device, thereby extracting information related to block separation to determine a current block to be decoded and extract prediction information required to reconstruct the current block, information on the residual block, and the like.

The decoder 1010 may extract information on the size of a CTU from a sequence parameter set (SPS) or a picture parameter set (PPS) to determine the size of the CTU, and may separate a picture into CTUs having the determined size. In addition, the decoder 1010 may set the CTU as the uppermost layer (ie, root node) of the tree structure, and may extract separation information of the CTU to separate the CTU using the tree structure. For example, when using the QTBT structure to split a CTU, the first flag (QT_split_flag) related to the split of QT can be extracted, and then each node can be split into four lower nodes. In addition, as for a node corresponding to a leaf node of QT, a second flag (BT_split_flag) and split type information related to splitting of BT may be extracted, and the corresponding leaf node may be split in the BT structure.

As an example of the block split structure of FIG. 2 , QT_split_flag corresponding to the uppermost node of the QTBT structure is extracted. The value of the extracted QT_split_flag is 1, so the uppermost node is split into four nodes of the lower layer (layer 1 of QT). In addition, the QT_split_flag of the first node of layer 1 is extracted. The value of the extracted QT_split_flag is 0, therefore, the first node of layer 1 is no longer split into the QT structure.

Since the first node of layer 1 of QT is a leaf node of QT, this operation is performed before the BT that adopts the first node of layer 1 of QT as the root node of BT. BT_split_flag corresponding to "(layer 0)" which is the root node of BT is extracted. Since BT_split_flag is 1, the root node of BT is split into two nodes of "(layer 1)". Since the root node of the BT is split, split type information indicating whether the block corresponding to the root node of the BT is split vertically or sorted horizontally is extracted. Since the split type information is 1, the block corresponding to the root node of the BT is split vertically. Then, the decoder 1010 extracts BT_split_flag of the first node of the split "(layer 1)" from the root node of the BT. Since BT_split_flag is 1, the split type information about the block of the first node of "(layer 1)" is extracted. Since the separation type information on the block of the first node of "(layer 1)" is 1, the block of the first node of "(layer 1)" is vertically separated. Then, BT_split_flag of the second node of "(layer 1)" split from the root node of BT is extracted. Since BT_split_flag is 0, the node is not further split by BT.

In this way, the decoder 1010 recursively extracts the QT_split_flag and splits the CTUs by QT structure. The decoder extracts the BT_split_flag of the leaf nodes of the QT. When BT_split_flag indicates split, split type information is extracted. In this way, the decoder 1510 can recognize that a CTU is separated into a structure as shown in FIG. 2A .

When information such as MinQTSize, MaxBTSize, MaxBTDepth, and MinBTSize are additionally defined in the SPS or PPS, the decoder 1010 may extract additional information and may use the additional information to extract separation information on QT and BT.

For example, blocks of the same size as MinQTSize in QT are not further separated. Therefore, the decoder 1010 does not extract the split information (QT_split_flag) related to the QT of the corresponding block from the bitstream (ie, the QT_split_flag of the corresponding block does not exist in the bitstream) and automatically sets the value to 0. Also, in QT, blocks with a size larger than MaxBTSize do not have BTs. Therefore, the decoder 1510 does not extract the BT split flag of the leaf node having a block larger than MaxBTSize in QT, and automatically sets the BT split flag to 0. In addition, when the depth of the corresponding node of BT reaches MaxBTDepth, the block of the node is not further separated. Therefore, the BT split flag of a node is not extracted from the bitstream, and the value of the BT split flag is automatically set to 0. Also, blocks of the same size as MinBTSize in BT are not further separated. Therefore, the decoder 1510 does not extract the BT split flag of a block of the same size as MinBTSize from the bitstream, and automatically sets the value of the flag to 0.

When the current block to be decoded is determined by separating the tree structure, the decoder 1010 extracts information on a prediction type indicating whether the current block is intra-predicted or inter-predicted.

When the prediction type information indicates inter prediction, the decoder 1010 may extract syntax elements of intra prediction information. First, mode information indicating a mode in which motion information about a current block is encoded among a plurality of encoding modes is extracted. Here, the various encoding modes may include a merge mode and a motion vector difference (MVD) encoding mode. When the mode information indicates the merge mode, the decoder 1010 extracts, as a syntax element of the motion information, merge index information indicating a candidate from among the merge candidates from which the motion vector of the current block is derived. On the other hand, when the mode information indicates the MVD encoding mode, the decoder 1010 extracts information on MVD and information on a reference picture referenced by the motion vector of the current block as syntax elements of the motion vector. When a video encoding apparatus uses any one of a plurality of motion vector predictor (MVP) candidates as an MVP of a current block, MVP identification information may be included in a bitstream. Therefore, in this case, MVP identification information as well as information on MVD and information on reference pictures are extracted as syntax elements of motion vectors.

The decoder 1010 extracts information on the quantized transform coefficient of the current block as information on the residual signal.

The inverse quantizer 1020 inverse quantizes the quantized transform coefficients, and the inverse transformer 1030 inverse transforms the inverse quantized transform coefficients from a frequency domain to a spatial domain to reconstruct a residual signal, thereby generating a residual block of a current block.

The predictor 1040 may include an intra predictor 1042 and an inter predictor 1044 . In case the prediction type of the current block is intra prediction, the intra predictor 1042 is activated, and in case the prediction type of the current block is inter prediction, the inter predictor 1044 is activated.

The intra predictor 1042 determines the intra prediction mode of the current block among various intra prediction modes from the syntax elements of the intra prediction mode extracted from the decoder 1010, and uses the neighboring reference of the current block according to the intra prediction mode. pixels to predict the current block.

The inter predictor 1044 determines motion information on the current block using syntax elements of the inter prediction information extracted from the decoder 1010, and predicts the current block using the determined motion information.

First, the inter predictor 1044 may check mode information of inter prediction extracted from the decoder 1010 . When the mode information indicates a merge mode, the inter predictor 1044 constructs a merge list including a predetermined number of merge candidates using neighboring blocks of the current block. The method of the inter predictor 1044 constructing the merging list is the same as that of the inter predictor 124 of the video encoding device. Also, using the merge index information received from the decoder 1010, one merge candidate is selected among the merge candidates in the merge list. The motion information of the selected merging candidate (ie, the motion vector and the reference picture of the merging candidate) is set as the motion vector and the reference picture of the current block.

On the other hand, when the mode information indicates the MVD encoding mode, the inter predictor 1044 derives MVP candidates using motion vectors of neighboring blocks of the current block, and determines the MVP of the motion vector of the current block using the MVP candidates. The method of deriving the MVP candidate by the inter predictor 1044 is the same as that of the inter predictor 124 of the video encoding apparatus. When the video encoding apparatus uses any one of a plurality of MVP candidates as the MVP of the current block, the syntax element of the motion information includes MVP identification information. Therefore, in this case, the inter predictor 1044 may select the candidate indicated by the MVP identification information from the MVP candidates as the MVP of the current block. However, when the video encoding device determines the MVP by applying a predefined function to a plurality of MVP candidates, the inter predictor 1044 may apply the same function as the video encoding device to determine the MVP. Once the MVP of the current block is determined, the inter predictor 1044 adds the MVP and the MVD extracted from the decoder 1010 to derive the motion vector of the current block. In addition, the inter predictor 1044 determines a reference picture referred to by the motion vector of the current block using information on the reference picture extracted from the decoder 1010 .

When determining the motion vector of the current block and the reference picture in the merge mode or the MVD encoding mode, the inter predictor 1044 generates a prediction block of the current block using a block at a position indicated by the motion vector in the reference picture.

The adder 1050 adds the residual block output from the inverse transformer to the prediction block output from the inter predictor or the intra predictor to reconstruct the current block. Pixels in the reconstructed current block may be used as reference pixels for intra prediction of a block to be decoded later.

The filter unit 1060 deblock-filters the boundaries between the reconstructed blocks in order to remove blocking artifacts caused by block-by-block encoding and stores the deblock-filtered blocks in the memory 1070 . When all blocks in a picture are reconstructed, the reconstructed picture can be used as a reference picture for inter-prediction of blocks in a subsequent picture to be encoded.

FIG. 11 is a diagram illustrating a video decoding device 1100 according to an embodiment of the present invention.

The video decoding apparatus 1100 according to an embodiment of the present invention may include a motion vector resolution decoder 1110 and a video decoder 1120 .

The motion vector resolution decoder 1110 parses information about the motion vector resolution of the current CU from the bitstream, and determines the motion vector resolution for estimating the motion of the current CU based on the parsed information of the motion vector resolution.

The video decoder 1120 predicts and decodes the current CU using the determined motion vector of the current CU according to the motion vector resolution of the current CU.

Here, the video decoder 1120 may be implemented as the video decoding device 1000 described above with reference to FIG. 10 .

The function of the motion vector resolution decoder 1110 may be included in the above-mentioned functions of the decoder 1010 in the video decoding apparatus 1000 and may be integrated in the decoder 1010 .

FIG. 12 is a flowchart illustrating a method of decoding video by the video decoding apparatus 1100 according to the first embodiment of the present invention.

As shown in FIG. 12, in the video decoding apparatus 1100 according to the first embodiment of the present invention, the motion vector resolution decoder 1110 parses Adaptive_MV_resolution_enabled_flag (ie, first identification information) from a bitstream (S1210). Adaptive_MV_resolution_enabled_flag means identification information indicating whether motion vector resolution is adaptively enabled, and may be determined in at least one image unit among image sequences, pictures, slices, and CTUs that are higher layer image units. The Adaptive_MV_resolution_enabled_flag may be parsed from a bitstream header of at least one upper layer image unit of an image sequence, picture, slice, and CTU.

After parsing the Adaptive_MV_resolution_enabled_flag, the motion vector resolution decoder post 1110 checks whether the Adaptive_MV_resolution_enabled_flag indicates that the motion vector resolution of the CU in the upper layer picture unit is adaptively enabled (i.e., Adaptive_MV_resolution_enabled_flag is ON) or indicates that the default motion vector resolution is used as the upper layer The motion vector resolution of the CU in the picture unit (ie, Adaptive_MV_resolution_enabled_flag is OFF) (S1220).

As a result of checking in operation S1220, when Adaptive_MV_resolution_enabled_flag is ON, the motion vector resolution decoder 1110 parses alternative_mv_resolution, which is information on alternative resolutions, from the bitstream (S1230). Here, alternative_mv_resolution may be resolved for the same image unit as the image unit used for Adaptive_MV_resolution_enabled_flag, or alternative_mv_resolution may be resolved from a bitstream for each image unit smaller than the image unit used for Adaptive_MV_resolution_enabled_flag. In addition, alternative_mv_resolution may be resolved for each CU in the image unit for Adaptive_MV_resolution_enabled_flag.

After operation S1230, the motion vector resolution decoder 1110 determines the motion vector resolution of the current CU as an encoding target according to whether the encoding mode of the current CU is a mode for encoding MVD (S1240). When information on Adaptive_MV_resolution_enabled_flag and alternative resolutions is transmitted in the bitstream for each higher layer picture unit, the motion vector resolution may also be adaptively determined for each CU in the higher layer picture unit.

When information on Adaptive_MV_resolution_enabled_flag is transmitted for each upper layer image unit of one of the image sequence and picture and alternative_mv_resolution is sent in the bitstream for each slice (or CTU) of an image unit smaller than the upper layer image unit, it is also possible for slices Each CU in a (or CTU) adaptively determines the motion vector resolution.

When it is checked that Adaptive_MV_resolution_enabled_flag is OFF in operation S1220, the motion vector resolution decoder 1110 performs operation S1240 of determining the motion vector resolution of the current CU according to whether the encoding mode of the current CU is a mode for encoding MVD.

Here, operation S1240 may include operations S1241 to S1246.

After operation S1230, the motion vector resolution decoder 1110 may parse the encoding mode of the current CU from the bitstream, and may check whether the encoding mode of the current CU is a mode for encoding MVD using MVP (ie, mvp mode) (S1241) .

When it is checked in operation S1241 that the encoding mode of the current CU is the mvp mode, the motion vector resolution decoder 1110 may check whether the Adaptive_MV_resolution_enabled_flag indicates that the motion vector resolution of the CU in the upper layer image unit is adaptively enabled (that is, Adaptive_MV_resolution_enabled_flag is ON ) also indicates that the default motion vector resolution is used as the motion vector resolution of the CU in the higher layer picture unit (ie, Adaptive_MV_resolution_enabled_flag is OFF) (S1242).

When it is checked that Adaptive_MV_resolution_enabled_flag is ON in operation S1242, the motion vector resolution decoder 1110 may parse from the bitstream to indicate which one of the default motion vector resolution and the alternative resolution is used as the motion vector resolution of the current CU mv_resolution_flag (that is, the second identification information) of the identification information (S1243), and then the subsequent operation of S1244 can be performed.

Here, although mv_resolution_flag is described as being sent in units of CUs, in some embodiments, mv_resolution_flag can be parsed in units of CTUs, and it is possible to check whether a CU is in mvp mode for each CU in the corresponding CTU, and when the corresponding CU is In the mvp mode, the subsequent operations of S1244 can be performed.

After parsing out mv_resolution_flag, the motion vector resolution decoder 1110 may check the value of mv_resolution_flag (S1244).

When it is checked in operation S1244 that mv_resolution_flag indicates that the alternative resolution is used as the motion vector resolution of the current CU (that is, when mv_resolution_flag is ON), the motion vector resolution decoder 1110 may determine the alternative resolution as the motion vector resolution of the current CU. Motion vector resolution (S1245).

When it is checked in operation S1244 that mv_resolution_flag indicates that the default motion vector resolution is used as the motion vector resolution of the current CU (ie, when mv_resolution_flag is OFF), the motion vector resolution decoder 1110 may determine that the default motion vector resolution is Motion vector resolution of the current CU (S1246).

When it is checked that Adaptive_MV_resolution_enabled_flag is OFF in operation S1242, the motion vector resolution decoder 1110 may determine a default motion vector resolution as the motion vector resolution of the current CU (S1246).

For example, when Adaptive_MV_resolution_enabled_flag indicating whether motion vector resolution is adaptively enabled and alternative_mv_resolution syntax indicating alternative resolution are located in the SPS, whether to apply the method according to the present invention may be determined for each image sequence unit.

For example, when the Adaptive_MV_resolution_enabled_flag in SPS is ON, the alternative_mv_resolution value of SPS (that is, alternative resolution) is 4 pixels, and the default motion vector resolution is 1/4 pixel, refer to the image sequence of SPS as the encoding target The motion vector resolution of all CUs can be determined to be 1/4 pixel or 4 pixels. That is, when mv_resolution_flag which is the header information of the current CU is OFF, the motion vector resolution of the current CU can be determined to be 1/4 pixel corresponding to the default motion vector resolution, and when the mv_resolution_flag of the current CU is ON , the motion vector resolution of the current CU may be determined to be 4 pixels corresponding to the alternative resolution.

When Adaptive_MV_resolution_enabled_flag and alternative_mv_resolution syntax are located in the PPS (or slice header), whether the method according to the present invention is applied can be determined in units of pictures (or in units of slices).

For example, when the Adaptive_MV_resolution_enabled_flag in PPS is ON, the alternative_mv_resolution value (ie, alternative resolution) of PPS is 4 pixels, and the default motion vector resolution is 1/4 pixel, a picture (or slice) referring to PPS (or slice header) The motion vector resolutions of all CUs in , which are encoding targets, may be determined to be 1/4 pixel or 4 pixels. That is, when mv_resolution_flag which is the header information of the current CU is OFF, the motion vector resolution of the current CU can be determined to be 1/4 pixel corresponding to the default motion vector resolution, and when the mv_resolution_flag of the current CU is ON , the motion vector resolution of the current CU may be determined to be 4 pixels corresponding to the alternative resolution.

When the Adaptive_MV_resolution_enabled_flag in SPS (or PPS) is ON, the alternative_mv_resolution value of the header of the slice (or CTU) of the image unit smaller than the image sequence (or picture) is 4 pixels and the default motion vector resolution is 1/4 pixels, The motion vector resolutions of all CUs that are encoding targets in the corresponding slice (or CTU) can be determined to be 1/4 pixel corresponding to the default motion vector resolution or 4 pixels corresponding to the alternative resolution, and thus can be determined at 1/4 4 pixels or a resolution of 4 pixels represents the motion vector of the current CU. That is, when mv_resolution_flag, which is the header information of the current CU, is 0 (that is, OFF), the motion vector of the current CU is expressed at a resolution of 1/4 pixel, and when the mv_resolution_flag of the current CU is ON, the motion vector of the current CU is expressed at a resolution of 4 pixels The resolution of represents the motion vector of the current CU.

When the Adaptive_MV_resolution_enabled_flag in SPS (or PPS) is ON, the alternative_mv_resolution value of the header of the slice (or CTU) of the image unit smaller than the image sequence (or picture) is 0 and the default motion vector resolution is 1/4 pixel, corresponding Motion vector resolutions of all CUs that are encoding targets in a slice (or CTU) may be determined to be 1/4 pixel corresponding to the default motion vector resolution. Here, mv_resolution_flag which is header information of a CU may not be necessary.

When Adaptive_MV_resolution_enabled_flag can be ON in SPS (or PPS), the value of Alternative_enabled_flag in the header of the slice (or CTU) of the image unit smaller than the image sequence (or picture) can be determined to determine the corresponding slice (or CTU). Motion vector resolution for all CUs of the encoding target. For example, when Alternative_enabled_flag is OFF and the default motion vector resolution is 1/4 pixel, the motion vector resolution of all CUs in the corresponding slice (or CTU) can be represented by 1/4 pixel corresponding to the default motion vector resolution, And mv_resolution_flag, which is header information of a CU that is an encoding target, may not be needed. On the other hand, when the Alternative_enabled_flag is ON, the alternative_mv_resolution value is 4 pixels and the default motion vector resolution is 1/4 pixel, the motion vector resolutions of all CUs in the corresponding slice (or CTU) can be determined to be the same as the default motion vector resolution 1/4 pixel for a resolution or 4 pixels for an alternate resolution. That is to say, when the mv_resolution_flag of the current CU is 0 (that is, OFF), the motion vector of the current CU can be represented with a resolution of 1/4 pixel, and when the mv_resolution_flag of the current CU is ON, the motion vector of the current CU can be represented with a resolution of 4 pixels The rate represents the motion vector of the current CU.

FIG. 13 is a diagram illustrating an example of adaptive determination of resolution.

When the Adaptive_MV_resolution_enabled_flag of the SPS header is ON, the alternative_mv_resolution of the header of the slice #0 is 2 pixels, and the default motion vector resolution (default MV resolution) is 1/4 pixel, the current CU including the circle in the corresponding slice #0 The motion vector resolution may be determined to be 1/4 pixel corresponding to the default motion vector resolution or 2 pixels corresponding to the alternate resolution. In this case, when the mv_resolution_flag which is the header information of the current CU is OFF, the motion vector of the current CU is expressed in 1/4 pixel units corresponding to the default motion vector resolution, and when the mv_resolution_flag of the current CU is ON, The motion vector of the current CU is represented in units of 2 pixels corresponding to alternative_mv_resolution.

When the alternative_mv_resolution of the header of slice #1 is 4 pixels, the motion vector resolution of the current CU including triangles in slice #1 can be determined to be 1/4 pixel corresponding to the default motion vector resolution or to correspond to the alternative resolution of 4 pixels. In this case, when the mv_resolution_flag which is the header information of the current CU is OFF, the motion vector of the current CU is expressed in 1/4 pixel units corresponding to the default motion vector resolution, and when the mv_resolution_flag of the current CU is ON, The motion vector of the current CU is expressed in units of 4 pixels corresponding to the alternative resolution.

After operation S1245 or S1246, the video decoder 1120 may derive a motion vector of the current block using the MVP (S1250).

Here, operation S1250 may include operations S1251 to S1255.

In operation S1251, the video decoder 1120 may derive MVP candidates, and may parse information (mvp_idx) for identifying the MVP of the current CU from the MVP candidates from the bitstream. Here, the adjacent blocks for MVP candidates may use some of the left block L, upper block A, upper right block AR, lower left block BL, and upper left block AL adjacent to the current CU in the current picture shown in FIG. all.

The video decoder 1120 may check whether the motion vector resolution of the block corresponding to mvp_idx is the same as that of the current CU (S1252).

When it is checked that the motion vector resolution of the block corresponding to mvp_idx is the same as that of the current CU, the video decoder 1120 may decode the MVD from the bitstream (S1254). When it is checked that the motion vector resolution of the block corresponding to mvp_idx is different from the motion vector resolution of the current CU, the video decoder 1120 may scale the MVP of the current block so that the resolution of the MVP is the same as the motion vector resolution of the current CU ( S1253), and the MVD can be decoded from the bit stream (S1254).

The video decoder 1120 adds the MVD and MVP parsed from the bitstream to generate a motion vector of the current CU (S1255).

For example, when the motion vector resolution of the current CU is 2 pixels, the motion vector resolution of the block corresponding to mvp_idx is 1/4 pixel, and the motion vector of the block corresponding to mvp_idx is set to 3, the block corresponding to mvp_idx The actual motion vector corresponds to 0.75. When scaling is performed according to the motion vector resolution of 2 pixels corresponding to the motion vector resolution of the current CU, the actual motion vector of the block corresponding to mvp_idx is converted to 0. This conversion formula can be expressed according to Formula 1 below.

[Formula 1]

MV'=Round(MV×neighbor_MV_Resol/curr_MV_Resol)

Here, MV represents a motion vector of a block corresponding to mvp_idx, neighboring_MV_resol represents a motion vector resolution of a block corresponding to mvp_idx, current_MV_resol represents a motion vector resolution of a current CU, MV' is a scaled motion vector, and Round represents a rounding operation.

Adaptive_MV_resolution_enabled_flag, mv_resolution_flag, alternative_mv_resolution, etc. may each be separate for each of the x-component and y-component of the motion vector, and the motion vector of the CU may also be calculated separately for each of the x-component and y-component according to Equation 2 below resolution.

[Formula 2]

MV _x '＝Round(MV _x ×neighbor_MV _x _Resol/curr_MVx_Resol)

MV _y '=Round(MV _y ×neighbor_MV _y _Resol/curr_MV _y _Resol)

As a result of the check in operation S1241, when it is checked that the coding mode of the current CU is not the mvp mode (for example, merge mode), the video decoder 1120 may derive the current CU's Motion vector (S1260).

Here, operation S1260 may include operations S1261 to S1264.

As a result of the check in operation S1241, when it is checked that the encoding mode of the current CU is not the mvp mode, the video decoder 1120 parses the information (candid_idx) for identifying the motion vector of the current CU from the merge candidates of the current CU from the bitstream ( S1261). Merge candidates of the current CU may use some or all of the left block L, upper block A, upper right block AR, lower left block BL, and upper left block AL adjacent to the current CU in the current picture shown in FIG. 3 . In addition, a block located in a reference picture (which is the same as or different from the reference picture used to predict the current CU) instead of the current picture in which the current block is located may be used as a motion vector candidate (ie, a merge candidate). For example, a co-located block of the current block in a reference picture or a block adjacent to the co-located block may be further used as a merging candidate.

The video decoder 1120 may check whether the motion vector resolution of the block corresponding to the candid_idx parsed from the bitstream is the same as the motion vector resolution predefined for the merge mode (S1262). Here, the motion vector resolution predefined for the merge mode may be the motion vector resolution defined in any unit of image sequence, picture, and slice.

When the motion vector resolution of the block corresponding to candid_idx is the same as the motion vector resolution predefined for the merge mode, the video decoder 1120 may set the motion vector of the block corresponding to candid_idx as the motion vector of the current CU (S1264). When the motion vector resolution of the block corresponding to candid_idx is different from the predefined motion vector resolution, the video decoder 1120 may scale the motion vector of the block corresponding to candid_idx so that the motion vector of the block corresponding to candid_idx is different from the predefined The motion vector resolutions are the same (S1263), and the scaled motion vector may be set as the motion vector of the current CU (S1264).

For reference, operations S1240, S1250, and S1260 may be sequentially and repeatedly performed for each CU.

FIG. 14 is a flowchart showing a case where some operations are added in FIG. 12 .

In FIG. 14, operation S1240 may include operations S1241, S1242_1, S1242_2, S1243, S1244, S1245, and S1246. In FIG. 14, operation S1250 may include operations S1251, S1252, S1253, and S1255.

Compared with FIG. 12 , FIG. 14 includes operations S1242_1 and S1242_2 in operation S1240 instead of operation S1242 of FIG. 12 , and does not include operation S1254 in operation S1250 of FIG. 12 .

For reference, among the functional blocks of FIG. 14 , functional blocks having the same reference numerals as those of the blocks of FIG. 12 perform the same operations as the blocks of FIG. 12 unless they have obviously different meanings in context. For example, operation S1243 of FIG. 14 is the same as operation S1243 of FIG. 12 .

In FIG. 14 , when it is checked in operation S1241 that the encoding mode of the current CU is a mode of encoding MVD using MVP (ie, mvp mode), the video decoder 1120 may parse information about MVD (mvd mode) from a bitstream. )(S1242_1).

After the MVD is resolved in operation S1242_1, the motion vector resolution decoder 1110 may check whether MVD is not 0 and whether Adaptive_MV_resolution_enabled_flag is ON (S1242_2). When MVD is not 0 and Adaptive_MV_resolution_enabled_flag is ON, the motion vector resolution decoder 1110 may proceed to operation S1243. When MVD is 0 or Adaptive_MV_resolution_enabled_flag is not ON, the motion vector resolution decoder 1110 may proceed to operation S1246.

In operation S1252 of FIG. 14 , when it is checked that the motion vector resolution of the block corresponding to mvp_idx is the same as the motion vector resolution of the current CU, the video decoder 1120 adds the MVD to the MVP to calculate the motion vector of the current CU (S1255). In operation S1252 of FIG. 14 , when it is checked that the motion vector resolution of the block corresponding to mvp_idx is not the same as the motion vector resolution of the current CU, the video decoder 1120 may perform operation S1253 of scaling the MVP so that the resolution of the MVP Same as the motion vector resolution of the current CU. After operation S1253, the video decoder 1120 may perform operation S1255 of adding the MVD to the MVP to calculate the motion vector of the current CU.

Operation S1251 may be performed before operation S1242_1 or may be performed between operations S1242_1 and S1242_2.

FIG. 15 is a flowchart illustrating a method of decoding video at a video decoding device 1100 according to a second embodiment of the present invention.

As a detailed example of the situation in FIG. 15 , when Adaptive_MV_resolution_enabled_flag is located in the SPS (PPS, slice, or CTU header) and mv_resolution_flag and alternative_mv_resolution information are located in the header of the CU that is the encoding target, it is possible to use the Adaptive_MV_resolution_enabled_flag value in units of image sequences (picture unit, slice unit, or CTU unit) determines whether to enable the adaptive motion vector resolution mode according to the present invention, and can adjust the motion vector resolution of a CU by selecting on a CU-by-CU basis according to the mv_resolution_flag value.

For example, when Adaptive_MV_resolution_enabled_flag in the SPS header (PPS header, slice header, or CTU header) is ON, the default motion vector resolution is 1/4 pixel, and mv_resolution_flag as the header information of the current CU is OFF, the alternative_mv_resolution information is not required to Determines the motion vector resolution of the current CU. In this case, the motion vector resolution of the current CU may be determined to be 1/4 pixel corresponding to the default motion vector resolution, and the motion vector of the current CU may be represented in a 1/4 pixel unit.

On the other hand, when the mv_resolution_flag is ON and the alternative_mv_resolution value of the CU header is 4 pixels, the motion vector resolution of the current CU can be determined as 4 pixels corresponding to the alternative resolution, and can be determined in 4 pixels corresponding to the alternative resolution The resolution of represents the motion vector of the current CU.

As shown in FIG. 15, in the video decoding apparatus 1100 according to the second embodiment of the present invention, the motion vector resolution decoder 1110 may parse Adaptive_MV_resolution_enabled_flag from the bitstream (S1510). Adaptive_MV_resolution_enabled_flag means identification information indicating whether motion vector resolution is adaptively enabled, and may be determined as at least one image unit (an image unit of a higher layer than a CU) among image sequences, pictures, slices, and CTUs. Adaptive_MV_resolution_enabled_flag may be parsed from a bitstream header of at least one image unit among image sequences, pictures, slices, and CTUs.

After parsing the Adaptive_MV_resolution_enabled_flag of each image unit of at least one of the image sequence, picture, slice, or CTU, the motion vector resolution decoder 1110 may, according to the coding mode of each block in the image unit in which the Adaptive_MV_resolution_enabled_flag is parsed, Whether it is a mode for encoding MVD (ie, mvp mode) is used to determine the motion vector resolution of each block (S1540).

Here, operation S1540 may include operations S1541 to S1547.

After operation S1510, the motion vector resolution decoder 1110 may parse the encoding mode of the current CU from the bitstream, and may check whether the encoding mode of the current CU is a mode for encoding MVD using MVP (ie, mvp mode) (S1541 ).

When the encoding mode of the current CU is mvp mode, check whether the Adaptive_MV_resolution_enabled_flag indicates that the motion vector resolution of the CU in the upper layer image unit is adaptively enabled (that is, Adaptive_MV_resolution_enabled_flag is ON) or indicates that the default motion vector resolution is used as the upper layer image The motion vector resolution in the CU in the unit (ie, Adaptive_MV_resolution_enabled_flag is OFF) (S1542).

When Adaptive_MV_resolution_enabled_flag is OFF, the motion vector resolution decoder 1110 may use a default motion vector resolution as the motion vector resolution of the current CU (S1547).

When Adaptive_MV_resolution_enabled_flag is ON, the motion vector resolution decoder 1110 may parse mv_resolution_flag( S1543).

After parsing out mv_resolution_flag, the motion vector resolution decoder 1110 may check the value of mv_resolution_flag (S1544).

When mv_resolution_flag indicates that an alternative resolution is used as the motion vector resolution of the current CU (that is, when mv_resolution_flag is ON), the motion vector resolution decoder 1110 may parse from the bitstream as information about the alternative resolution of the current CU alternative_mv_resolution (S1545), and the resolved alternative resolution may be set as the motion vector resolution of the current CU (S1546).

When mv_resolution_flag indicates that the default motion vector resolution is used as the motion vector resolution of the current CU (i.e., when mv_resolution_flag is OFF), the motion vector resolution decoder 1110 may set the default motion vector resolution as the motion vector resolution of the current CU Resolution (S1547).

Although mv_resolution_flag and/or alternative_mv_resolution information has been transmitted in units of CUs as described above, in some embodiments, mv_resolution_flag and/or alternative_mv_resolution may be encoded in units of CTUs. It is checked whether the encoding mode of each CU in the corresponding CTU is the mvp mode, and subsequent operations of operation S1540 may be performed on the CU whose encoding mode is the mvp mode.

FIG. 16 is a diagram illustrating another example of adaptive determination of resolution.

For example, when Adaptive_MV_resolution_enabled_flag in SPS (PPS, slice header or CTU header) is ON, the default motion vector resolution is 1/4 pixel, mv_resolution_flag in the header of a CU including a circle in the corresponding image sequence is ON and alternative_mv_resolution When it is 1 pixel, the motion vector resolution of the corresponding CU may be determined to be 1 pixel corresponding to the alternative resolution and the motion vector of the CU may be represented at a resolution of 1 pixel.

When mv_resolution_flag in the header of a CU including a triangle in the corresponding image sequence is ON and alternative_mv_resolution is 4 pixels, the motion vector resolution of the corresponding CU can be determined to be 4 pixels corresponding to the alternative resolution, and can be determined in the same way as the alternative resolution The resolution of 4 pixels corresponding to the rate represents the motion vector of the CU. In the case of a CU whose mv_resolution_flag value is set to OFF, the motion vector resolution of the CU can be determined to be 1/4 pixel corresponding to the default motion vector resolution, and can be determined by 1/4 pixel corresponding to the default motion vector resolution The resolution of pixels represents the motion vector of the CU.

After operation S1546 or S1547, the video decoder 1120 may derive the motion vector of the current block using the MVP (S1550).

In FIG. 15, operation S1550 may include operations S1551 to S1555.

Operations S1551 to S1555 are similar to operations S1251 to S1255, respectively, and thus, detailed descriptions of operations S1551 to S1555 are omitted.

When it is detected in operation S1541 that the encoding mode of the corresponding CU is not the mvp mode (for example, merge mode), the video decoder 1120 may derive the motion vector ( S1560).

Here, operation S1560 may include operations S1561 to S1564.

Operations S1561 to S1564 are similar to operations S1261 to S1264, respectively, and thus, detailed descriptions of operations S1561 to S1564 are omitted.

FIG. 17 is a flowchart showing a case where some operations are added in FIG. 15 .

In FIG. 17 , operation S1540 may include operations S1541, S1542_1, S1542_2, S1543, S1544, S1545, S1546, and S1547. In FIG. 17, operation S1550 may include operations S1551, S1552, S1553, and S1555.

For reference, among the functional blocks of FIG. 17 , functional blocks having the same reference numerals as those of the blocks of FIG. 15 perform the same operations as the blocks of FIG. 15 unless they have obviously different meanings in context. For example, operation S1543 of FIG. 17 is the same as operation S1543 of FIG. 15 .

When it is checked in operation S1541 of FIG. 17 that the encoding mode of the current CU is a mode in which MVD is encoded using MVP (that is, mvp mode), the video decoder 1120 may parse information about MVD (mvd) from the bitstream ( S1542_1).

After the MVD is resolved in operation S1542_1, the motion vector resolution decoder 1110 may check whether MVD is not 0 and Adaptive_MV_resolution_enabled_flag is ON (S1542_2). When MVD is not 0 and Adaptive_MV_resolution_enabled_flag is ON, the motion vector resolution decoder 1110 may proceed to operation S1543. When MVD is 0 or Adaptive_MV_resolution_enabled_flag is not ON, the motion vector resolution decoder 1110 may proceed to operation S1547.

Operation S1551 may be performed before operation S1542_1 or may be performed between operations S1542_1 and S1542_2.

Operations S1551, S1552, S1553, and S1555 of FIG. 17 are similar to operations S1251, S1252, S1253, and S1255 of FIG. 14, respectively, and thus, detailed descriptions of operations S1551, S1552, S1553, and S1555 of FIG. 17 are omitted.

FIG. 18 is a flowchart illustrating a method of decoding video at a video decoding device 1100 according to a third embodiment of the present invention.

As shown in FIG. 18, in the video decoding apparatus 1100 according to the third embodiment of the present invention, the motion vector resolution decoder 1110 may parse Adaptive_MV_resolution_enabled_flag from the bitstream (S1810). Adaptive_MV_resolution_enabled_flag means identification information indicating whether motion vector resolution is adaptively enabled, and may be determined in at least one image unit among image sequences, pictures, slices, or CTUs that are higher layer image units. The Adaptive_MV_resolution_enabled_flag may be parsed from a bitstream header of an image unit of at least one of an image sequence, picture, slice, and CTU.

The motion vector resolution decoder 1110 may check that the Adaptive_MV_resolution_enabled_flag indicates that the motion vector resolution is adaptive in the upper layer image unit of at least one of the image sequence, picture, slice, and CTU (ie, in all CUs in the upper layer image unit) Whether it is enabled (ie, in the case of ON) or indicates that the default motion vector resolution is used as the motion vector resolution of all CUs in the upper layer picture unit (in the case of OFF) (S1820).

When it is checked that Adaptive_MV_resolution_enabled_flag is OFF in operation S1820, the motion vector resolution decoder 1110 may use a default motion vector resolution as the motion vector resolution of the corresponding CU in the corresponding image unit (S1822).

When it is checked that Adaptive_MV_resolution_enabled_flag is ON in operation S1820, the motion vector resolution decoder 1110 may parse alternative_mv_resolution, which is information on an alternative resolution, from a bitstream (S1830). Here, alternative_mv_resolution may be parsed from the bitstream for each of the same picture units as the picture unit to which Adaptive_MV_resolution_enabled_flag is transmitted.

Alternatively, alternative_mv_resolution may be parsed from the bitstream for each image unit smaller than the image unit transmitting the Adaptive_MV_resolution_enabled_flag and larger than the CU which is the block unit for determining the motion vector resolution. For example, when the image unit transmitting the Adaptive_MV_resolution_enabled_flag is one of an image sequence and a picture, the unit for which alternative_mv_resolution is resolved may be a slice (or CTU).

Alternatively, alternative_mv_resolution may be resolved for each CU in a picture unit for Adaptive_MV_resolution_enabled_flag.

Also, alternative_mv_resolution cannot be resolved anywhere.

After operation S1830, the motion vector resolution decoder 1110 may determine the motion vector resolution of the current CU according to whether the encoding mode of the current CU is a mode of encoding MVD (S1840).

Here, operation S1840 may include operations S1841 to S1848.

After operation S1830, the motion vector resolution decoder 1110 may parse the encoding mode of the current CU from the bitstream, and may check whether the encoding mode of the current CU is a mode for encoding MVD using MVP (ie, mvp mode) (S1841 ).

When the encoding mode of the current CU is mvp mode, the motion vector resolution decoder 1110 may check whether the Adaptive_MV_resolution_enabled_flag indicates that the motion vector resolution of the CU in the higher layer picture unit is adaptively enabled (that is, when Adaptive_MV_resolution_enabled_flag is ON) or indicates The default motion vector resolution is used as the motion vector resolution of the CU in the higher layer picture unit (ie, when Adaptive_MV_resolution_enabled_flag is OFF) (S1842).

When Adaptive_MV_resolution_enabled_flag is ON, the motion vector resolution decoder 1110 can parse from the bitstream as identification information indicating which resolution among the default motion vector resolution and the alternative resolution is used as the motion vector resolution of the current CU mv_resolution_flag (S1843).

On the other hand, when Adaptive_MV_resolution_enabled_flag is OFF, the motion vector resolution decoder 1110 may determine a default motion vector resolution as the motion vector resolution of the current CU (S1848).

After parsing out the mv_resolution_flag of the current CU in operation S1843, the motion vector resolution decoder 1110 may check the value of mv_resolution_flag (S1844).

When it is checked in operation S1844 that mv_resolution_flag indicates that the motion vector resolution of the current CU is determined using a resolution difference value that is a difference between the motion vector resolution of the current CU and the motion vector resolution of the previous CU (that is, when mv_resolution_flag is ON), the motion vector resolution decoder 1110 may parse mv_resolution_delta, which is information on a difference between the motion vector resolution of the current CU and the motion vector resolution of the previous CU, from the bitstream (S1845). Here, when there is no alternative_mv_resolution value and the current CU is the first CU in decoding order among CUs in the higher layer image unit, mv_resolution_delta may represent information indicating the motion vector resolution of the current CU.

The motion vector resolution decoder 1110 may calculate the motion vector resolution of the current CU using mv_resolution_delta (S1846), and may set the calculation result as the motion vector resolution of the current CU (S1847).

When it is checked in operation S1844 that mv_resolution_flag indicates that the default motion vector resolution is used as the motion vector resolution of the current CU (that is, when mv_resolution_flag is OFF), the motion vector resolution decoder 1110 may determine the default motion vector resolution is the motion vector resolution of the current CU (S1848).

In operation S1846, when the current CU is the first CU in decoding order among the CUs in the higher layer image unit, the motion vector resolution decoder 1110 may determine mv_resolution_delta as the motion vector resolution of the current CU. When the current CU is a CU after the first CU in decoding order, the motion vector resolution decoder 1110 may add mv_resolution_delta to the motion vector resolution of the CU that has been encoded immediately before the current CU in encoding order to generate the current CU Motion vector resolution of the CU. In this case, the motion vector resolution decoder 1110 does not need the alternative_mv_resolution to generate the motion vector resolution of the current CU, and thus, the operation of parsing the alternative_mv_resolution from the bitstream may be omitted.

For example, when the Adaptive_MV_resolution_enabled_flag in the slice header is ON, the default motion vector resolution is 1/4 pixel, and the mv_resolution_flag which is the header information of the current CU is OFF, the mv_resolution_delta information may not be needed to determine the motion vector resolution of the current CU. In this case, the motion vector resolution of the current CU can be set to 1/4 pixel as the default motion vector resolution, and can be set at a resolution of 1/4 pixel corresponding to the default motion vector resolution of the motion vector Indicates the motion vector of the current CU.

On the other hand, when mv_resolution_flag is ON, the current CU is the first CU in decoding order, and the mv_resolution_delta of the current CU is 4 pixels, the motion vector resolution of the current CU can be determined to be 4 pixels corresponding to the mv_resolution_delta, and can Represents the motion vector of the current CU with a resolution of 4 pixels. When the current CU is not the first CU in decoding order, the motion vector resolution of the current CU can be set by combining the mv_resolution_delta of the current CU with the current The resolution of the motion vector of the previous CU of the CU is added to 4 pixels, and the motion vector of the current CU can be represented at the resolution of 4 pixels.

When the current CU is not the first CU in decoding order, in the case where the mv_resolution_flag of the current CU is ON and the mv_resolution_delta of the current CU is -2 pixels, the motion vector resolution of the current CU can be set by setting the - 2 pixels added to 4 pixels which is the motion vector resolution of the previous CU, and the motion vector of the current CU can be expressed in 2-pixel units.

In the embodiment described above with reference to FIG. 18 , the motion vector resolution decoder 1110 adds mv_resolution_delta to the motion vector resolution of the previous CU of the current CU to restore the motion vector resolution of the current CU, but the present invention is not limited thereto. The motion vector resolution decoder 1110 may add the mv_resolution_delta of the current CU to the alternative resolution to decode the motion vector resolution of the current CU.

As an example of the implementation of FIG. 18 , when Adaptive_MV_resolution_enabled_flag and alternative_mv_resolution are located in a slice (tile) header (SPS, PPS, or CTU), and mv_resolution_flag and mv_resolution_delta information is located in a slice (tile) (image sequence, picture, or CTU) unit When in the header of the CU, whether to apply the adaptive motion vector resolution mode and alternative resolution according to the present invention can be enabled according to the Adaptive_MV_resolution_enabled_flag, and the slice (tile) (image sequence, picture or Each CU in the CTU) unit adaptively determines the motion vector resolution, and mv_resolution_delta can be used to adjust the motion vector resolution of the current CU.

In this case, the mv_resolution_delta of the current CU can be represented as the difference between the alternative_mv_resolution (i.e., alternative resolution) in the slice (tile) header (or image sequence, picture, or CTU) and the motion vector resolution of the current CU difference. The motion vector resolution decoder 1110 may calculate the motion vector resolution of the current CU by adding alternative_mv_resolution and mv_resolution_delta.

For example, when the Adaptive_MV_resolution_enabled_flag of the slice header is ON, the alternative_mv_resolution value is 4 pixels as an alternative resolution, the default motion vector resolution is 1/4 pixel, and the mv_resolution_flag as the header information of the current CU is OFF, the mv_resolution_delta information may not be required To determine the motion vector resolution of the current CU. In this case, the motion vector resolution of the current CU may be determined to be 1/4 pixel corresponding to the default motion vector resolution, and the motion vector of the current CU may be represented at a resolution of 1/4 pixel.

When the mv_resolution_flag of the current CU is ON and the mv_resolution_delta of the current CU is 0, the motion vector resolution of the current CU can be set to 4 pixels corresponding to the value obtained by adding alternative_mv_resolution to mv_resolution_delta, and can be set in 4 pixels The resolution represents the motion vector of the current CU. When the mv_resolution_flag of the current CU is ON, if the mv_resolution_delta of the current CU is -2 pixels, the motion vector resolution of the current CU can be set to be the same as the 4 pixels of the alternative_mv_resolution as the slice header and corresponding to the mv_resolution_delta value of - 2 pixels obtained by adding 2 pixels, and can represent the motion vector of the current CU with a resolution of 2 pixels.

As another example of the embodiment of FIG. 18 , when Adaptive_MV_resolution_enabled_flag and alternative_mv_resolution as an alternative resolution are located in the slice (tile) header (or SPS, PPS, or CTU), the slice (tile) (image sequence , picture or CTU) to determine whether to apply the adaptive motion vector resolution mode and alternative resolution according to the present invention. When the mv_resolution_flag and mv_resolution_delta information is located in the header of the CU in the slice (tile) (image sequence, picture or CTU) unit, each of the slice (tile) (image sequence, picture or CTU) units can be The CU adaptively determines the motion vector resolution, and mv_resolution_delta can be used to adjust the motion vector resolution of the current CU.

Here, the mv_resolution_delta of the current CU can be expressed as the difference between the alternative_mv_resolution in a slice (tile) (SPS, PPS, or CTU) and the motion vector resolution of the current CU, or can be expressed as The difference between the motion vector resolution of the encoded CU and the motion vector resolution of the current CU.

For example, when the current CU is the first CU in decoding order, the mv_resolution_delta of the current CU can indicate the difference between the alternative_mv_resolution in the slice (tile) (SPS, PPS or CTU) header and the motion vector resolution of the current CU . When the current CU is not the first CU, mv_resolution_delta of the current CU may be represented as a difference between a motion vector resolution encoded immediately before the current CU and the motion vector resolution of the current CU.

For example, when the Adaptive_MV_resolution_enabled_flag of the slice header is ON, the alternative resolution is 4 pixels, the default motion vector resolution is 1/4 pixel, and the mv_resolution_flag as the header information of the current CU is OFF, the mv_resolution_delta of the current CU may not be required to determine The motion vector resolution of the current CU. In this case, the motion vector resolution of the current CU may be set to 1/4 pixel corresponding to the default motion vector resolution.

On the other hand, when mv_resolution_flag which is the header information of the current CU is ON, the current CU is the first CU, and the mv_resolution_delta of the CU is 4 pixels indicating the alternative_mv_resolution in the slice (tile) header and the motion vector resolution of the current CU The motion vector resolution of the current CU may be 6 pixels obtained by adding alternative_mv_resolution 4 pixels to the resolution difference +2 pixels. In this case, when the mv_resolution_flag of the next CU of the first CU is ON and the mv_resolution_delta of the corresponding next CU is -2 pixels, the motion vector resolution of the corresponding next CU can be set as the previous 4 pixels obtained by adding 6 pixels of the motion vector resolution of the CU to −2 pixels of the mv_resolution_delta of the corresponding next CU.

After operation S1847 or S1848 of FIG. 18 , the video decoder 1120 may derive the motion vector of the current CU using the MVP ( S1850 ).

Here, operation S1850 may include operations S1851 to S1855.

Operations S1851 to S1855 of FIG. 18 are similar to operations S1251 to S1255 of FIG. 12 , respectively, and thus, detailed descriptions of operations S1851 to S1855 are omitted.

When it is detected in operation S1841 that the encoding mode of the corresponding CU is not the mvp mode, the video decoder 1120 may derive a motion vector of the current CU from motion vectors of temporally or spatially neighboring blocks (ie, merge candidates) (S1860).

Here, operation S1860 may include operations S1861 to S1864.

Operations S1861 to S1864 of FIG. 18 are similar to operations S1261 to S1264 of FIG. 12 , respectively, and thus, detailed descriptions of operations S1861 to S1864 are omitted.

FIG. 18 is a flowchart for explaining the operation of the video decoding device 1100 according to the fourth embodiment of the present invention and the operation of the video decoding device 1100 according to the third embodiment of the present invention.

That is, according to the fourth embodiment, the video decoder 1120 may parse mv_resolution_scale instead of mv_resolution_delta from the bitstream, and may restore the motion vector resolution of the current CU using the parsed mv_resolution_scale.

In the third embodiment and the fourth embodiment, operations corresponding to operations S1845 to S1846 among the operations of FIG. 18 are different from each other, and the remaining operations are the same.

According to the fourth embodiment, operation S1845 may be implemented to parse mv_resolution_scale from a bitstream, and operation S1846 may be implemented to restore the motion vector resolution of the current CU using mv_resolution_scale.

When it is checked in operation S1844 that mv_resolution_flag indicates that the motion vector resolution of the current CU is determined using a resolution scale factor that is a value obtained by dividing the motion vector resolution of the current CU by the motion vector resolution of the previous CU (ie, , when mv_resolution_flag is ON), the motion vector resolution decoder 1110 may parse from the bitstream mv_resolution_scale ( S1845). Alternatively, mv_resolution_scale may be information indicating a value obtained by dividing the motion vector resolution of the current CU by the alternative resolution.

The motion vector resolution decoder 1110 may use mv_resolution_delta to calculate the motion vector resolution of the current CU (S1846).

In operation S1846, when the current CU is the first CU in decoding order among the CUs in the higher layer image unit, the motion vector resolution decoder 1110 may resolve the motion vector resolution corresponding to mv_resolution_scale into the motion vector of the current CU resolution. When the current CU is the CU after the first CU in decoding order, the motion vector resolution decoder 1110 can calculate the current CU by multiplying the motion vector resolution of the CU encoded immediately before the current CU by the scale factor of the current CU. Motion vector resolution of the CU. In this case, since an alternative resolution is not required to calculate the motion vector resolution of the current CU, the motion vector resolution decoder 1110 may omit the operation of parsing alternative_mv_resolution from the bitstream.

As another embodiment of using mv_resolution_scale to calculate the motion vector resolution of the current CU, the motion vector resolution decoder 1110 can decode the result obtained by multiplying the mv_resolution_scale in the current CU in the upper layer image unit by the alternative resolution into the current Motion vector resolution of the CU.

As another embodiment of using mv_resolution_scale to calculate the motion vector resolution of the current CU, when the current CU is the first CU in the decoding order among the CUs in the upper layer picture unit, the motion vector resolution decoder 1110 can combine mv_resolution_scale with Alternate resolution multiplication decodes the motion vector resolution of the current CU. On the other hand, when the current CU is the CU after the first CU in decoding order, the motion vector resolution decoder 1110 can multiply the motion vector resolution of the CU encoded just before the current CU by the mv_resolution_scale of the current CU To calculate the motion vector resolution of the current CU.

As an example of the operation of the video decoding device 1100 according to the fourth embodiment of the present invention, when Adaptive_MV_resolution_enabled_flag and alternative_mv_resolution are located in a slice (tile) header (SPS, PPS, or CTU) and mv_resolution_flag and mv_resolution_scale information is located in the current CU that is an encoding target When in the header of , the motion vector resolution decoder 1110 may determine whether to apply the adaptive motion vector resolution mode and alternative resolution according to the present invention in units of slices (tiles) (image sequences, pictures or CTUs). The motion vector resolution decoder 1110 may adaptively enable motion vector resolution in units of blocks in a slice (tile) (image sequence, picture, or CTU), and adjust the motion vector resolution of the current CU using the mv_resolution_scale value.

In this case, when the current CU is the first CU in a slice (tile) (image sequence, picture, or CTU) that is an upper-layer image unit, mv_resolution_scale can be expressed as value, and when the current CU is a CU after the first CU, mv_resolution_scale may be expressed as a multiplication value between the motion vector resolution of the CU encoded just before the current CU and the motion vector resolution of the current CU.

For example, when the Adaptive_MV_resolution_enabled_flag of the slice header is ON, the default motion vector resolution is 1/4 pixel, and the mv_resolution_flag as the header information of the current CU is OFF, the mv_resolution_scale information of the current CU may not be parsed, and the motion vector resolution of the current CU The rate can be set to 1/4 pixel corresponding to the default motion vector resolution.

When the mv_resolution_flag of the current CU is ON and the current CU is the first CU in decoding order, and the mv_resolution_scale of the current CU is 4, the motion vector resolution of the current CU may be 4 pixels corresponding to the mv_resolution_scale. When the current CU is the next CU of the first CU, the mv_resolution_flag of the current CU is ON, and the mv_resolution_scale of the current CU is 1/2, the motion vector resolution of the current CU can be set by setting the motion vector resolution of the previous CU 2 pixels obtained by multiplying 4 pixels of the current CU by 1/2 of the mv_resolution_scale of the current CU.

Alternatively, mv_resolution_scale of each CU may be expressed as a multiplication value between alternative_mv_resolution included in a slice (tile) header (SPS, PPS, or CTU) and a motion vector resolution of a current block.

For example, when the Adaptive_MV_resolution_enabled_flag of the slice header is ON, the alternative_mv_resolution value of the alternative resolution is 4 pixels, the default motion vector resolution is 1/4 pixel, and the mv_resolution_flag of the header information of the current CU is OFF, the current CU may not be parsed mv_resolution_scale information, and the motion vector resolution of the current CU can be set to 1/4 pixel corresponding to the default motion vector resolution.

On the other hand, when the mv_resolution_flag of the current CU is ON and the mv_resolution_scale of the current CU is 1, the motion vector resolution of the current CU can be set to be obtained by multiplying 4 pixels as alternative_mv_resolution by 1 as the mv_resolution_scale of the current CU of 4 pixels. When the mv_resolution_flag of the next CU is ON and the mv_resolution_scale is 1/2, the motion vector resolution of the corresponding next CU can be set by dividing 4 pixels as the alternative resolution with 1/2 of the mv_resolution_scale of the next CU 2 pixels are multiplied by 2.

In another embodiment, the mv_resolution_scale of each CU can use the multiplication value between the alternative_mv_resolution value in the slice (tile) header (SPS or PPS) and the motion vector resolution of the current CU, or can use the current The CU is represented by the multiplication value between the motion vector resolution of the CU encoded before and the motion vector resolution of the current CU. That is, when the current CU is the first CU in decoding order, the mv_resolution_scale of the current CU can indicate the multiplication between the motion vector resolution of the current CU and the alternative_mv_resolution in the slice (tile) header (SPS or PPS) value, and when the current CU is the CU after the first CU, the multiplication value between the motion vector resolution of the CU encoded just before the current CU and the motion vector resolution of the current CU can be used to represent the current CU mv_resolution_scale.

For example, when Adaptive_MV_resolution_enabled_flag of the slice header is ON, alternative_mv_resolution is 4 pixels, the default motion vector resolution is 1/4 pixel, and mv_resolution_flag as the header information of the current CU is OFF, the motion vector resolution of the current CU does not need mv_resolution_scale information, therefore, the motion vector resolution of the current CU can be set to 1/4 pixel corresponding to the default motion vector resolution, and the current CU's Motion vector.

On the other hand, when the mv_resolution_flag of the current CU is ON and the mv_resolution_scale of the current CU is 1, the motion vector resolution of the current CU can be set by comparing 4 pixels of alternative_mv_resolution as a slice header with 1 of mv_resolution_scale as the current CU Multiplied by 4 pixels. When the current CU is the next CU of the first CU, the mv_resolution_flag of the current CU is ON, and the mv_resolution_scale of the current CU is 1/2, the motion vector resolution of the current CU can be set by setting as just before the current CU 2 pixels obtained by multiplying 4 pixels of the motion vector resolution value of the coded CU by 1/2 of the mv_resolution_scale of the current CU.

FIG. 19 is a flowchart showing a case where some operations are added to the flowchart of FIG. 18 .

In FIG. 19 , operation S1840 may include operations S1841, S1842_1, S1842_2, S1843, S1844, S1845, S1846, S1847, and S1848. In addition, operation S1850 of FIG. 19 may include operations S1851, S1852, S1853, and S1855.

Compared with the case of FIG. 18 , FIG. 19 includes operations S1242_1 and S1242_2 in operation S1240 instead of operation S1242 of FIG. 18 , and operation S1854 of FIG. 18 may be excluded from operation S1850.

For reference, among the functional blocks of FIG. 19 , functional blocks having the same reference numerals as those of the blocks of FIG. 18 perform the same operations as the blocks of FIG. 18 unless they have obviously different meanings in context. For example, operation S1843 of FIG. 19 is the same as operation S1843 of FIG. 18 .

When it is checked in operation S1841 of FIG. 19 that the encoding mode of the current CU is a mode for encoding MVD using MVP (that is, mvp mode), the video decoder 1120 may decode information about MVD from the bitstream (S1842_1 ).

After decoding the MVD, the motion vector resolution decoder 1110 may check whether MVD is not 0 and Adaptive_MV_resolution_enabled_flag is ON (S1842_2). When MVD is not 0 and Adaptive_MV_resolution_enabled_flag is ON as a result of the check in operation S1842_2, the motion vector resolution decoder 1110 may proceed to operation S1843. When MVD is 0 or Adaptive_MV_resolution_enabled_flag is not ON, the motion vector resolution decoder 1110 may proceed to operation S1848.

Operation S1851 may be performed before operation S1842_1 or may be performed between operations S1842_1 and S1842_2.

Operations S1851, S1852, S1853, and S1855 of FIG. 19 are similar to operations S1251, S1252, S1253, and S1255 of FIG. 14, respectively, and thus, detailed descriptions of operations S1851, S1852, S1853, and S1855 of FIG. 19 are omitted.

According to the embodiment of the present invention, the case where the motion vector resolution decoder 1110 parses the Adaptive_MV_resolution_enabled_flag from the bitstream has been exemplified, but in some embodiments, the motion vector resolution decoder 1110 in the video decoding device 1100 may omit the The operation of parsing the Adaptive_MV_resolution_enabled_flag in the stream. In this case, the motion vector resolution decoder 1110 may perform the same operation as that performed when Adaptive_MV_resolution_enabled_flag is ON, or may perform the same operation as that performed when Adaptive_MV_resolution_enabled_flag is OFF. Accordingly, the video encoding apparatus 400 may omit the operation of encoding Adaptive_MV_resolution_enabled_flag.

The above embodiment of the video decoding device is not limited to the case of parsing mv_resolution_flag in units of CUs, and may parse mv_resolution_flag in units of CTUs to set one of a default motion vector resolution or an alternative resolution as the motion vector resolution. When the motion vector resolution is determined in units of CTUs, all CUs included in one CTU may have the same motion vector resolution. In this case, the upper layer image unit of the CTU unit may be one of an image sequence, a picture, or a slice.

While the invention has been particularly shown and described with reference to exemplary embodiments of the invention, it will be understood by those skilled in the art that other modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. Various changes in form and details have been made herein. The exemplary embodiments should be considered in a descriptive sense only and not for purposes of limitation. Therefore, the scope of the invention is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being included in the present invention.

Cross References to Related Applications

This application is based on and claims the registration under 35 U.S.C. of Korean Patent Applications No. 10-2016-0136066 and No. 10-2017-0025673 filed in the Korean Intellectual Property Office on October 19, 2016 and February 27, 2017, respectively. Priority under § 119(a), the disclosures of these two Korean patent applications are hereby incorporated by reference in their entirety. In addition, this non-provisional application claims priority in countries other than the United States on the same grounds based on said Korean patent application, the entire content of which is hereby incorporated by reference.

Claims (7)

1. A device for encoding video, the device comprising: a resolution determiner configured to determine a motion vector resolution of the current block; a video encoder, the video encoder configured to: determining the motion vector of the current block based on the motion vector resolution of the current block, and generating a motion vector difference value of the current block as a difference between the motion vector of the current block and a motion vector predictor derived from a neighboring block of the current block, and encode the information of the motion vector difference value; and a resolution encoder configured to: encoding an enable flag indicating whether to adaptively determine motion vector resolution into a bitstream, wherein the enable flag is encoded into a sequence parameter set or a picture parameter set of the bitstream, and encoding information about the motion vector resolution of the current block into the bitstream when the motion vector resolution is adaptively determined and the motion vector difference value of the current block is non-zero , wherein the resolution encoder encodes information about the motion vector resolution of the current block by the following steps, the steps comprising: encoding into the bitstream an mv resolution flag indicating whether the motion vector resolution of the current block is the default motion vector resolution as a quarter pixel unit, and When the motion vector resolution of the current block is not the default motion vector resolution, among multiple motion vector resolution candidates for indicating 1/2 pixel unit, 1 pixel unit and 4 pixel unit information of an alternate resolution of one encoded into the bitstream, Wherein, when the motion vector resolution is not adaptively determined, the motion vector resolution of the current block is determined as the default motion vector resolution, Wherein, when the motion vector difference value of the current block is zero, the motion vector resolution of the current block is determined as the default motion vector resolution. 2. The apparatus according to claim 1 , wherein the step of encoding information about the motion vector resolution comprises the step of comparing the motion vector resolution of the current block with the The difference between the motion vector resolutions of the coded blocks is coded as one element of the information on the motion vector resolution of the current block. 3. The apparatus according to claim 1 , wherein the step of encoding information on the motion vector resolution comprises the step of combining the motion vector resolution on the current block with Information on a ratio between motion vector resolutions of previously coded blocks is coded as one element of information on the motion vector resolution of the current block. 4. A video decoding device for adaptively determining a motion vector resolution of a current block and decoding the current block, the video decoding device comprising: a motion vector resolution decoder configured to: extracting an enable flag indicating whether to adaptively determine motion vector resolution from a bitstream, wherein the enable flag is extracted from a sequence parameter set or a picture parameter set of the bitstream, and extracting the motion for the current block from the bitstream when the enabled flag indicates that the motion vector resolution is adaptively determined and the motion vector difference value for the current block is non-zero information of a vector resolution, and determining the motion vector resolution of the current block based on the information about the motion vector resolution of the current block; and a video decoder configured to extract information about the motion vector difference value of the current block from the bitstream, and based on the motion vector resolution of the current block, the current determining the motion vector of the current block using the motion vector difference value of the block and the motion vector predictor derived from the neighboring blocks of the current block, Wherein, the motion vector resolution decoder extracts information about the motion vector resolution of the current block through the following steps, the steps comprising: extracting from the bitstream an mv resolution flag indicating whether the motion vector resolution of the current block is a default motion vector resolution of 1/4 pixel unit; and When the mv resolution flag indicates that the motion vector resolution of the current block is not the default motion vector resolution, extract information from the bitstream for indicating that the motion vector resolution includes 1/2 pixel unit, 1 pixel unit, and information of an alternative resolution among a plurality of motion vector resolution candidates in units of 4 pixels, Wherein, when the enabling flag indicates that the motion vector resolution is not adaptively determined, the motion vector resolution of the current block is set as the default motion vector resolution, Wherein, when the motion vector difference value of the current block is zero, the motion vector resolution of the current block is set as the default motion vector resolution. 5. The video decoding device according to claim 4, wherein the step of determining the motion vector resolution of the current block comprises the step of extracting the motion vector for the current block from the bitstream Information of a difference between a resolution and a motion vector resolution of a block encoded before the current block is used as an element of information on the motion vector resolution of the current block. 6. The video decoding device according to claim 4, wherein the step of determining the motion vector resolution of the current block comprises the step of extracting the motion vector for the current block from the bitstream As one element of the information on the motion vector resolution of the current block, information of a ratio between the resolution and the motion vector resolution of a block encoded before the current block. 7. A non-transitory recording medium storing a bitstream generated by a video encoding method, the video encoding method comprising the steps of: Encoding an enabling flag indicating whether to adaptively determine a motion vector resolution into a bitstream, wherein the enabling flag is encoded into a sequence parameter set or a picture parameter set of the bitstream; Determine the motion vector resolution of the current block; determining a motion vector of the current block according to the motion vector resolution of the current block; generating a motion vector difference value of the current block as a difference between the motion vector of the current block and a motion vector predictor derived from a neighboring block of the current block, and encoding the information of the motion vector difference into the bit stream; encoding information about the motion vector resolution of the current block into the bitstream when the motion vector resolution is adaptively determined and the motion vector difference value of the current block is non-zero in; and predicting the current block using the motion vector of the current block and encoding the current block, Wherein, the step of encoding information about the motion vector resolution of the current block includes the following steps: encoding into the bitstream an mv resolution flag indicating whether the motion vector resolution of the current block is the default motion vector resolution as a quarter pixel unit; and When the motion vector resolution of the current block is not the default motion vector resolution, among multiple motion vector resolution candidates for indicating 1/2 pixel unit, 1 pixel unit and 4 pixel unit information of an alternate resolution of one encoded into the bitstream, Wherein, when the motion vector resolution is not adaptively determined, the motion vector resolution of the current block is determined as the default motion vector resolution, Wherein, when the motion vector difference value of the current block is zero, the motion vector resolution of the current block is determined as the default motion vector resolution.