KR101564942B1 - Method and apparatus for video encoding using deblocking filtering, and method and apparatus for video decoding using the same - Google Patents

Abstract

The picture is divided into coding units of a predetermined maximum size, and for each of the maximum coding units, coding depths for which the coding results are to be outputted for each region in which the maximum coding units are divided stepwise, coding related to the coding units, Disclosed is a video encoding method using deblocking filtering for determining a unit encoding mode and de-blocking filtering the video data inversely transformed into a spatial domain for each encoding unit in consideration of an encoding mode for each encoding unit.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for video encoding using deblocking filtering and a video decoding method using the deblocking filtering and a video decoding method using the deblocking filtering,

The present invention relates to encoding and decoding of video.

Background of the Invention [0002] As the development and dissemination of hardware capable of playing back and storing high-resolution or high-definition video content increases the need for video codecs to effectively encode or decode high-definition or high-definition video content. According to the existing video codec, video is encoded according to a limited encoding method based on a macroblock of a predetermined size.

The present invention relates to deblocking filtering considering the boundaries of various data units used during encoding and decoding, and video coding and video decoding according to the deblocking filtering.

A video coding method using deblocking filtering according to an embodiment of the present invention includes: dividing a picture into coding units of a predetermined maximum size; For each maximum encoding unit, as the depth is deepened, the maximum encoding unit is divided stepwise into a plurality of encoding units, which are predictive encoding based on prediction units of at least one size and type and encoding units of at least one size Determining an encoding depth for each encoding unit, a predicted encoding unit, and a coding unit-specific encoding mode for the encoding unit, the predicted encoding unit, and the conversion unit, by which the encoding result is outputted for each region where the maximum encoding unit is divided stepwise; And performing deblocking filtering on the video data inversely transformed into the spatial domain for each coding unit, considering the coding mode for each coding unit.

A video decoding apparatus using deblocking filtering according to an embodiment of the present invention includes parsing a received bit stream to extract video data encoded for each encoding unit and encoding unit, Performing entropy decoding and inverse quantization on the video data encoded for each coding unit to output a transform coefficient; Outputting video data in a spatial domain by performing inverse transform based on a transform unit of the encoding unit-specific encoding mode and predictive-decoding based on a prediction unit of the encoding unit-based encoding mode for the transform coefficient for each encoding unit; And performing deblocking filtering on the video data in the spatial domain in consideration of the encoding mode for each encoding unit.

The deblocking filtering step may further include a step of performing a deblocking filtering on the boundary of the prediction unit of each coding unit or the boundary of the conversion unit of each coding unit among the video data inversely transformed into the spatial area, Deblocking filtering can be performed. The deblocking filtering step may further include a boundary of the prediction unit or a boundary of the conversion unit, the boundary of the encoding unit, the boundary of the prediction unit, and the boundary of the conversion unit in the encoding unit- , It is possible to perform the deblocking filtering.

The deblocking filtering may be performed in consideration of at least one of a size of the encoding unit, a size of the prediction unit, and a size of the conversion unit among the coding units. can do. The deblocking filtering step may perform the deblocking filtering in consideration of the partition type of the encoding unit among the encoding modes of each encoding unit. The partition type according to an embodiment may include symmetric partitions and asymmetric partitions.

The performing of the deblock filtering according to an exemplary embodiment of the present invention may include at least one of a prediction mode of the prediction unit, existence of a coded residual component, a motion vector, a number of reference pictures, Considering one, the deblocking filtering can be performed.

The deblocking filtering step may include determining a boundary strength by considering the encoding mode for each encoding unit, determining whether deblocking filtering is applied, deblocking including information on a size of a filter tap, Determining a filtering implementation scheme, and performing deblocking filtering based on the determined deblocking filtering conditions.

A video coding apparatus using deblocking filtering according to an embodiment of the present invention includes a maximum coding unit division unit for dividing a picture into coding units of a predetermined maximum size; For each maximum encoding unit, as the depth is deepened, the maximum encoding unit is divided stepwise into a plurality of encoding units, which are predictive encoding based on prediction units of at least one size and type and encoding units of at least one size And a coding depth and a coding mode decision unit for determining a coding depth and a coding mode for determining a coding unit-specific coding mode for the coding unit, the prediction coding unit and the conversion unit for outputting the coding result for each region in which the maximum coding unit is divided stepwise part; And a deblocking filtering unit for performing deblocking filtering on the video data inversely transformed into the spatial domain for each coding unit, considering the coding mode for each coding unit.

A video decoding apparatus using deblocking filtering according to an embodiment of the present invention includes a data extracting unit for parsing a received bit stream to extract video data encoded for each encoding unit and encoding unit, An entropy decoding and inverse quantization unit for performing entropy decoding and inverse quantization on the video data encoded for each coding unit to output a transform coefficient; An inverse transform based on a transform unit of the coding unit-specific coding mode and prediction decoding based on a prediction unit of the coding unit-based coding mode, and outputs the video data in the spatial region, part; And a deblocking filtering unit for performing deblocking filtering on the video data in the spatial domain in consideration of the encoding mode for each encoding unit.

The present invention includes a computer-readable recording medium on which a program for implementing a video encoding method using deblocking filtering according to an embodiment of the present invention is recorded. The present invention includes a computer readable recording medium on which a program for implementing a video decoding method using deblocking filtering according to an embodiment of the present invention is recorded.

1 shows a block diagram of a video encoding apparatus according to an embodiment of the present invention.
2 shows a block diagram of a video decoding apparatus according to an embodiment of the present invention.
FIG. 3 illustrates a concept of an encoding unit according to an embodiment of the present invention.
4 is a block diagram of an image encoding unit based on an encoding unit according to an embodiment of the present invention.
5 is a block diagram of an image decoding unit based on an encoding unit according to an embodiment of the present invention.
FIG. 6 illustrates a depth-based coding unit and a prediction unit according to an embodiment of the present invention.
FIG. 7 shows a relationship between an encoding unit and a conversion unit according to an embodiment of the present invention.
FIG. 8 illustrates depth-specific encoding information, in accordance with an embodiment of the present invention.
FIG. 9 shows a depth encoding unit according to an embodiment of the present invention.
FIGS. 10A, 10B, and 10C illustrate the relationship between an encoding unit, a prediction unit, and a frequency conversion unit according to an embodiment of the present invention.
FIG. 11 shows encoding information for each encoding unit according to an embodiment of the present invention.
12 shows a flowchart of a video coding method according to an embodiment of the present invention.
13 shows a flowchart of a video decoding method according to an embodiment of the present invention.
14 shows a block diagram of a video encoding apparatus using deblocking, according to one embodiment.
15 shows a block diagram of a video decoding apparatus using deblocking, according to one embodiment.
FIG. 16 shows an example of a relationship between an encoding unit and several conversion units of prediction units according to an embodiment.
FIG. 17 shows another example of the relationship between an encoding unit and several prediction unit conversion units according to an embodiment.
FIG. 18 shows another example of the relationship of the encoding unit and the conversion unit of several prediction units according to the embodiment.
19 illustrates a deblocking filtering method determination method according to an embodiment.
FIG. 20 illustrates samples that are subject to deblocking filtering according to one embodiment.
FIG. 21 shows a flowchart of a video encoding method using deblocking filtering according to an embodiment.
22 shows a flowchart of a video decoding method using deblocking filtering according to an embodiment.

Hereinafter, a video encoding apparatus and a video decoding apparatus, a video encoding method, and a video decoding method according to an embodiment of the present invention will be described with reference to FIG. 1 to FIG. Referring to FIGS. 1 to 13, encoding and decoding of video based on spatially hierarchical data units according to an embodiment of the present invention will be described below, and with reference to FIGS. 14 to 22, The coding of the video using the deblocking filtering considering the coding unit, the prediction unit and the conversion unit and the decoding of the video will be described below.

Hereinafter, a video encoding apparatus, a video encoding apparatus, a video encoding method, and a video decoding method according to an embodiment of the present invention will be described with reference to FIGS. 1 to 13.

1 shows a block diagram of a video encoding apparatus according to an embodiment of the present invention.

The video coding apparatus 100 according to an embodiment includes a maximum coding unit division unit 110, a coding depth determination unit 120, and an output unit 130.

The maximum coding unit dividing unit 110 can divide a current picture based on a maximum coding unit which is a coding unit of a maximum size for a current picture of an image. If the current picture is larger than the maximum encoding unit, the image data of the current picture may be divided into at least one maximum encoding unit. The image data may be output to the coding depth determination unit 120 for each of at least one maximum coding unit.

An encoding unit according to an embodiment may be characterized by a maximum size and a depth. Depth indicates a stage in which coding units are hierarchically divided. As the depth increases, the depth coding units can be divided from the maximum coding unit to the minimum coding unit. The depth of the maximum encoding unit is the highest depth and the minimum encoding unit can be defined as the least significant encoding unit. As the depth of the maximum encoding unit increases, the size of the depth-dependent encoding unit decreases, so that the encoding unit of the higher depth may include a plurality of lower-depth encoding units.

As described above, according to the maximum size of an encoding unit, the image data of the current picture is divided into a maximum encoding unit, and each maximum encoding unit may include encoding units divided by depth. Since the maximum encoding unit according to an embodiment is divided by depth, image data of a spatial domain included in the maximum encoding unit can be hierarchically classified according to depth.

The maximum depth for limiting the total number of times the height and width of the maximum encoding unit can be hierarchically divided and the maximum size of the encoding unit may be preset.

The coding depth determiner 120 encodes at least one divided area in which the area of the maximum coding unit is divided for each depth, and determines the depth at which the final coding result is output for each of at least one of the divided areas. That is, the coding depth determination unit 120 selects the depth at which the smallest coding error occurs, and determines the coding depth as the coding depth by coding the image data in units of depth coding for each maximum coding unit of the current picture. The determined coding depth and the image data of each coding unit are output to the output unit 130.

The image data in the maximum encoding unit is encoded based on the depth encoding unit according to at least one depth below the maximum depth, and the encoding results based on the respective depth encoding units are compared. As a result of the comparison of the encoding error of the depth-dependent encoding unit, the depth with the smallest encoding error can be selected. At least one coding depth may be determined for each maximum coding unit.

As the depth of the maximum encoding unit increases, the encoding unit is hierarchically divided and divided, and the number of encoding units increases. In addition, even if encoding units of the same depth included in one maximum encoding unit, the encoding error of each data is measured and it is determined whether or not the encoding unit is divided into lower depths. Therefore, even if the data included in one maximum coding unit has a different coding error according to the position, the coding depth can be determined depending on the position. Accordingly, one or more coding depths may be set for one maximum coding unit, and data of the maximum coding unit may be divided according to one or more coding depth encoding units.

The predictive encoding and frequency conversion of the maximum encoding unit can be performed. Likewise, predictive coding and frequency conversion are performed on the basis of the depth coding unit for each maximum coding unit and for each depth below the maximum depth.

Since the number of coding units per depth is increased every time the maximum coding unit is divided by the depth, the coding including the predictive coding and the frequency conversion should be performed for every depth coding unit as the depth increases. For convenience of explanation, predictive coding and frequency conversion will be described based on a coding unit of a current depth among at least one maximum coding unit.

The video encoding apparatus 100 according to an exemplary embodiment may select various sizes or types of data units for encoding image data. To encode the image data, a step such as predictive encoding, frequency conversion, and entropy encoding is performed. The same data unit may be used for all steps, and the data unit may be changed step by step.

For example, the video coding apparatus 100 can select not only a coding unit for coding image data but also a data unit different from the coding unit in order to perform predictive coding of the image data of the coding unit.

For predictive coding of the maximum coding unit, predictive coding may be performed based on the partial data unit of the coding unit for each depth of the maximum coding unit. The partial data unit of the encoding unit may include a data unit in which at least one of the height and the width of the encoding unit and the depth encoding unit is divided.

For example, when the size of the encoding unit is 2Nx2N (where N is a positive integer), the size of the partial data unit may be 2Nx2N, 2NxN, Nx2N, NxN, and the like. Prediction coding may be performed based on data units of various types, in addition to data units of a type in which at least one of the height and the width of an encoding unit is divided by half. Hereinafter, a data unit on which prediction encoding is based may be referred to as a 'prediction unit'.

The prediction mode of the encoding unit may be at least one of an intra mode, an inter mode, and a skip mode. For example, the intra mode and the inter mode can be performed for prediction units of 2Nx2N, 2NxN, Nx2N, and NxN sizes. In addition, the skip mode can be performed only for a prediction unit of 2Nx2N size. Encoding is performed independently for each prediction unit within an encoding unit, and a prediction mode having the smallest encoding error can be selected.

In addition, the video encoding apparatus 100 according to an exemplary embodiment may perform frequency conversion of image data of an encoding unit based on not only an encoding unit for encoding image data but also a data unit different from the encoding unit.

For frequency conversion of a coding unit, frequency conversion may be performed based on a data unit having a size smaller than or equal to the coding unit. For example, a data unit for frequency conversion may include a data unit for intra mode and a data unit for inter mode. Hereinafter, the data unit on which the frequency conversion is based may be referred to as a 'conversion unit'.

The coding information according to the coding depth needs not only the coding depth but also prediction related information and frequency conversion related information. Therefore, the coding depth determiner 120 not only determines the coding depth at which the minimum coding error is generated, but also the partition type in which the coding unit of the coding depth is divided into prediction units, the prediction unit-specific prediction mode, Can be determined.

The coding depth determination unit 120 may measure the coding error of the depth-dependent coding unit using a Lagrangian Multiplier-based rate-distortion optimization technique.

The output unit 130 outputs, in the form of a bit stream, video data of the maximum encoding unit encoded based on at least one encoding depth determined by the encoding depth determination unit 120 and information on the depth encoding mode.

The encoded video data may be a result of encoding residual data of the video.

The information on the depth-dependent coding mode may include coding depth information, partition type information of a prediction unit of a coding unit of coding depth, prediction mode information per prediction unit, size information of a conversion unit, and the like.

The coding depth information can be defined using depth division information indicating whether or not coding is performed at the lower depth coding unit without coding at the current depth. If the current depth of the current encoding unit is the encoding depth, the current encoding unit is encoded in the current depth encoding unit, so that the division information of the current depth can be defined so as not to be further divided into lower depths. On the other hand, if the current depth of the current encoding unit is not the encoding depth, the encoding using the lower depth encoding unit should be tried. Therefore, the division information of the current depth may be defined to be divided into the lower depth encoding units.

If the current depth is not the encoding depth, encoding is performed on the encoding unit divided into lower-depth encoding units. Since there are one or more lower-level coding units in the current-depth coding unit, the coding is repeatedly performed for each lower-level coding unit so that recursive coding can be performed for each coding unit of the same depth.

At least one coding depth is determined in one maximum coding unit and at least one coding mode information is determined for each coding depth so that information on at least one coding mode can be determined for one maximum coding unit. Since the data of the maximum encoding unit is hierarchically divided according to the depth and the depth of encoding may be different for each position, information on the encoding depth and the encoding mode may be set for the data.

Accordingly, the output unit 130 according to the embodiment can set the corresponding encoding information for each minimum encoding unit included in the maximum encoding unit. That is, the coding unit of the coding depth includes at least one minimum coding unit that holds the same coding information. By using this, if the neighboring minimum encoding units have the same depth encoding information, it can be the minimum encoding unit included in the same maximum encoding unit.

For example, the encoding information output through the output unit 130 may be classified into encoding information per depth unit and encoding information per prediction unit. The under-coding-by-depth coding unit information may include prediction mode information and partition size information. The encoding information to be transmitted for each prediction unit includes information about the estimation direction of the inter mode, information about the reference picture index of the inter mode, information on the motion vector, information on the chroma component of the intra mode, information on the interpolation mode of the intra mode And the like. Information on the maximum size of a coding unit defined for each picture, slice or GOP, and information on the maximum depth can be inserted into the header of the bitstream.

According to the simplest embodiment of the video coding apparatus 100, the coding unit for depth is a coding unit which is half the height and width of the coding unit of one layer higher depth. That is, if the size of the current depth encoding unit is 2Nx2N, the size of the lower depth encoding unit is NxN. In addition, the current encoding unit of 2Nx2N size can include a maximum of 4 sub-depth encoding units of NxN size.

Therefore, the video decoding apparatus 100 according to an embodiment determines an encoding unit of an optimal shape and size for each maximum encoding unit based on the size and the maximum depth of the maximum encoding unit determined in consideration of the characteristics of the current picture . In addition, since each encoding unit can be encoded by various prediction modes, frequency conversion methods, and the like, an optimal encoding mode can be determined in consideration of image characteristics of encoding units of various image sizes.

Therefore, if an image having a very high image resolution or a very large data amount is encoded in units of existing macroblocks, the number of macroblocks per picture becomes excessively large. This increases the amount of compression information generated for each macroblock, so that the burden of transmission of compressed information increases and the data compression efficiency tends to decrease. Therefore, the video encoding apparatus according to an embodiment can increase the maximum size of the encoding unit in consideration of the image size, and adjust the encoding unit in consideration of the image characteristic, so that the image compression efficiency can be increased.

2 shows a block diagram of a video decoding apparatus according to an embodiment of the present invention.

The video decoding apparatus 200 includes a receiving unit 210, an image data and encoding information extracting unit 220, and an image data decoding unit 230. The definition of various terms such as coding unit, depth, prediction unit, conversion unit, and information on various coding modes for various processing of the video decoding apparatus 200 according to an embodiment is the same as that of FIG. 1 and the video coding apparatus 100 Are the same as described above.

The receiving unit 205 receives and parses the bitstream of the encoded video. The image data and encoding information extracting unit 220 extracts image data for each maximum encoding unit from the parsed bit stream and outputs the extracted image data to the image data decoding unit 230. The image data and encoding information extracting unit 220 can extract information on the maximum size of the encoding unit of the current picture from the header of the current picture.

Also, the image data and encoding information extracting unit 220 extracts information on the encoding depth and the encoding mode for each maximum encoding unit from the parsed bitstream. The information on the extracted coding depth and coding mode is output to the image data decoding unit 230. That is, the video data of the bit stream can be divided into the maximum encoding units, and the video data decoding unit 230 can decode the video data per maximum encoding unit.

Information on the coding depth and the coding mode per coding unit can be set for one or more coding depth information, and the information on the coding mode for each coding depth includes information on partition type information, prediction mode information, Size information of the conversion unit, and the like. In addition, as the encoding depth information, depth-based segmentation information may be extracted.

The encoding depth and encoding mode information extracted by the image data and encoding information extracting unit 220 may be encoded in the encoding unit such as the video encoding apparatus 100 according to one embodiment, And information on the coding depth and coding mode determined to repeatedly perform coding for each unit to generate the minimum coding error. Therefore, the video decoding apparatus 200 can decode the data according to the coding scheme that generates the minimum coding error to recover the video.

The image data and encoding information extracting unit 220 can extract information on the encoding depth and the encoding mode for each minimum encoding unit. If information on the coding depth and the coding mode of the corresponding maximum coding unit is recorded for each minimum coding unit, the minimum coding units having the same coding depth and information on the coding mode are estimated as data units included in the same maximum coding unit . That is, if the minimum coding units of the same information are collected and decoded, it is possible to decode based on the coding units of the coding depth with the smallest coding error.

The image data decoding unit 230 decodes the image data of each maximum encoding unit based on the information on the encoding depth and the encoding mode for each maximum encoding unit to reconstruct the current picture. The image data decoding unit 230 can decode the image data for each coding unit of at least one coding depth based on the coding depth information for each coding unit. The decoding process may include a prediction process including intra prediction and motion compensation, and an inverse frequency conversion process.

The image data decoding unit 230 decodes each of the prediction units and prediction modes for each coding unit on the basis of the partition type information and the prediction mode information of the prediction unit of the coding unit for each coding depth for each coding unit, Or motion compensation.

In addition, the image data decoding unit 230 may perform frequency inverse transform for each encoding unit on the basis of the size information of the conversion unit of each encoding depth-based encoding unit for frequency inverse conversion for each maximum encoding unit .

The image data decoding unit 230 can determine the coding depth of the current maximum encoding unit using the division information by depth. If the partition information indicates that the current depth is to be decoded, the current depth is the depth of the encoding. Therefore, the image data decoding unit 230 can decode the current depth encoding unit for the image data of the current maximum encoding unit using the partition type, the prediction mode, and the conversion unit size information of the prediction unit.

That is, it is possible to observe the encoding information set for the minimum encoding unit and to decode the minimum encoding units that hold the encoding information including the same division information, into one data unit.

The video decoding apparatus 200 according to an exemplary embodiment recursively performs encoding for each maximum encoding unit in the encoding process to obtain information on an encoding unit that has generated the minimum encoding error and can use the encoded information for decoding the current picture have. That is, it is possible to decode video data in the optimal encoding unit for each maximum encoding unit.

Accordingly, even if an image with a high resolution or an excessively large amount of data is used, the information on the optimal encoding mode transmitted from the encoding end is used, and the image data is efficiently encoded according to the encoding unit size and encoding mode, Can be decoded and restored.

FIG. 3 shows the concept of a hierarchical coding unit.

An example of an encoding unit may include 32x32, 16x16, 8x8, and 4x4 from an encoding unit with a width x height of 64x64. In addition to the square-shaped encoding units, there may be encoding units whose width x height is 64x32, 32x64, 32x16, 16x32, 16x8, 8x16, 8x4, 4x8.

With respect to the video data 310, the resolution is set to 1920 x 1080, the maximum size of the encoding unit is set to 64, and the maximum depth is set to 2. With respect to the video data 320, the resolution is set to 1920 x 1080, the maximum size of the encoding unit is set to 64, and the maximum depth is set to 4. With respect to the video data 330, the resolution is set to 352 x 288, the maximum size of the encoding unit is set to 16, and the maximum depth is set to 2.

It is preferable that the maximum size of the coding size is relatively large in order to improve the coding efficiency as well as to accurately characterize the image characteristics when the resolution or the data amount is large. Therefore, the maximum size of the video data 310 and 320 having the higher resolution than the video data 330 can be selected to be 64. FIG.

The maximum depth indicates the total number of layers in the hierarchical encoding unit. Therefore, since the maximum depth of the video data 310 is 2, the encoding unit 315 of the video data 310 is encoded from a maximum encoding unit having a major axis size of 64, Units. On the other hand, since the maximum depth of the video data 330 is 2, the encoding unit 335 of the video data 330 has a depth of two layers from the encoding units having the major axis size of 16, Units.

Since the maximum depth of the video data 320 is 4, the encoding unit 325 of the video data 320 has a depth of four layers from 32 to 16, 8, and 4 Encoding units. The deeper the depth, the better the ability to express detail.

4 is a block diagram of an image encoding unit based on an encoding unit according to an embodiment of the present invention.

The image encoding unit 400 according to an exemplary embodiment includes operations to encode image data in the encoding depth determination unit 120 of the video encoding apparatus 100. That is, the intraprediction unit 410 performs intraprediction on the intra-mode encoding unit of the current frame 405, and the motion estimation unit 420 and the motion compensation unit 425 perform intraprediction on the current frame 405 of the inter- And a reference frame 495. The inter-frame estimation and the motion compensation are performed using the reference frame and the reference frame.

The data output from the intraprediction unit 410, the motion estimation unit 420 and the motion compensation unit 425 is output as a quantized transform coefficient through the frequency transform unit 430 and the quantization unit 440. The quantized transform coefficients are reconstructed into spatial domain data through the inverse quantization unit 460 and the frequency inverse transform unit 470 and the data of the reconstructed spatial domain is passed through the deblocking unit 480 and the loop filtering unit 490 Processed and output to the reference frame 495. [ The quantized transform coefficient may be output to the bitstream 455 via the entropy encoding unit 450.

The motion estimation unit 420, the motion compensation unit 425, and the frequency transformation unit 420, which are components of the image encoding unit 400, are applied to the video encoding apparatus 100 according to an embodiment of the present invention. The quantization unit 440, the entropy encoding unit 450, the inverse quantization unit 460, the frequency inverse transform unit 470, the deblocking unit 480, and the loop filtering unit 490, The work should be performed based on the depth encoding unit considering the maximum depth.

In particular, the intra prediction unit 410, the motion estimation unit 420, and the motion compensation unit 425 determine the prediction unit and the prediction mode in the coding unit in consideration of the maximum size and depth of the coding unit, and the frequency conversion unit 430 ) Should consider the size of the conversion unit considering the maximum size and depth of the encoding unit.

5 is a block diagram of an image decoding unit based on an encoding unit according to an embodiment of the present invention.

The bit stream 505 passes through the parsing unit 510 and the encoded video data to be decoded and the encoding-related information necessary for decoding are parsed. The encoded video data is output as inverse quantized data through the entropy decoding unit 520 and the inverse quantization unit 530, and the image data in the spatial domain is restored through the frequency inverse transform unit 540.

The intra-prediction unit 550 performs intraprediction on the intra-mode encoding unit for the video data in the spatial domain, and the motion compensating unit 560 performs intra-prediction on the intra-mode encoding unit using the reference frame 585 And performs motion compensation for the motion compensation.

The data in the spatial domain that has passed through the intra prediction unit 550 and the motion compensation unit 560 may be post-processed through the deblocking unit 570 and the loop filtering unit 580 and output to the reconstruction frame 595. Further, the post-processed data via deblocking unit 570 and loop filtering unit 580 may be output as reference frame 585.

In order to decode the image data in the image data decoding unit 230 of the video decoding apparatus 200, operations after the parsing unit 510 of the image decoding unit 500 according to the embodiment may be performed.

The entropy decoding unit 520, the inverse quantization unit 530, and the frequency inverse transforming unit 520, which are the components of the video decoding unit 500, in order to be applied to the video decoding apparatus 200 according to one embodiment. The intraprediction unit 550, the motion compensation unit 560, the deblocking unit 570 and the loop filtering unit 580 all have to perform an operation based on the encoding unit of the encoding depth for each maximum encoding unit .

In particular, the intra prediction unit 550 and the motion compensation unit 560 determine a coding unit and a prediction mode in consideration of the maximum size and depth of a coding unit, and the frequency inverse transform unit 540 sets the maximum size and depth of the coding unit The size of the conversion unit should be considered.

FIG. 6 illustrates a depth-based coding unit and a prediction unit according to an embodiment of the present invention.

The video encoding apparatus 100 and the video decoding apparatus 200 according to an exemplary embodiment use a hierarchical encoding unit to consider an image characteristic. The maximum height, width, and maximum depth of the encoding unit may be adaptively determined according to the characteristics of the image, or may be variously set according to the demand of the user. The size of each coding unit may be determined according to the maximum size of a predetermined coding unit.

The hierarchical structure 600 of the encoding unit according to an embodiment shows a case where the maximum height and width of the encoding unit is 64 and the maximum depth is 4. Since the depth is deeper along the vertical axis of the hierarchical structure 600 of the encoding unit according to the embodiment, the height and width of the encoding unit for each depth are divided. In addition, along the horizontal axis of the hierarchical structure 600 of the coding unit, a prediction unit which is a partial data unit on which prediction coding of each depth coding unit is based is shown.

That is, the coding unit 610 is the largest coding unit among the hierarchical structures 600 of the coding units and has a depth of 0, and the size of the coding units, that is, the height and the width, is 64x64. A depth-1 encoding unit 620 having a size of 32x32, a depth-2 encoding unit 620 having a size 16x16, a depth-3 encoding unit 640 having a size 8x8, a depth 4x4 having a size 4x4, There is an encoding unit 650. An encoding unit 650 of depth 4 of size 4x4 is the minimum encoding unit.

The partial data units are arranged as a prediction unit of the encoding unit along the horizontal axis for each depth. That is, the prediction unit of the encoding unit 610 having a size of 64x64 with a depth of 0 is a partial data unit 610 having a size of 64x64, partial data units 612 having a size of 64x32 included in the encoding unit 610 of size 64x64, Partial data units 614 of size 32x64, and partial data units 616 of size 32x32. Conversely, the encoding unit may be a minimum-sized square data unit including the conversion units 610, 612, 614, and 616.

Likewise, the prediction unit of the encoding unit 620 of the size 32x32 of the depth 1 is the partial data unit 620 of the size 32x32, the partial data units 622 of the size 32x16, and the partial data unit 620 of the size 32x32 included in the encoding unit 620 of the size 32x32, Partial data units 624 of size 16x32, partial data units 626 of size 16x16.

Likewise, the prediction unit of a 16x16 size 16x16 encoding unit is a 16x16 partial data unit 630, a 16x8 partial data unit 632, and a 16x16 partial data unit 630 included in the 16x16 encoding unit 630, Partial data units 634 of size 8x16, and partial data units 636 of size 8x8.

Likewise, the prediction unit of the encoding unit 640 of the size 8x8 of the depth 3 includes the partial data unit 640 of the size 8x8, the partial data units 642 of the size 8x4, and the partial data units 640 of the size 8x8 included in the encoding unit 640 of the size 8x8, Partial data units 644 of size 4x8, and partial data units 646 of size 4x4.

Finally, a coding unit 650 of size 4x4 is the minimum coding unit and the coding unit of the lowest depth, and the prediction unit is a data unit 650 of size 4x4.

The coding depth determiner 120 of the video coding apparatus 100 according to an exemplary embodiment of the present invention determines the coding depth of the maximum coding unit 610 by multiplying the coding unit of each depth included in the maximum coding unit 610 Encoding is performed.

The number of coding units per depth to include data of the same range and size increases as the depth of the coding unit increases. For example, for data containing one coding unit at depth 1, four coding units at depth 2 are required. Therefore, in order to compare the encoding results of the same data by depth, they should be encoded using a single depth 1 encoding unit and four depth 2 encoding units, respectively.

For each depth-of-field coding, encoding is performed for each prediction unit of the depth-dependent coding unit along the horizontal axis of the hierarchical structure 600 of the coding unit, and a representative coding error, which is the smallest coding error at the corresponding depth, is selected . In addition, depths are deepened along the vertical axis of the hierarchical structure 600 of encoding units, and the minimum encoding errors can be retrieved by comparing the representative encoding errors per depth by performing encoding for each depth. The depth at which the minimum coding error occurs among the maximum coding units 610 can be selected as the coding depth and the partition type of the maximum coding unit 610. [

FIG. 7 shows a relationship between an encoding unit and a conversion unit according to an embodiment of the present invention.

The video coding apparatus 100 or the video decoding apparatus 200 according to an embodiment encodes or decodes an image in units of coding units smaller than or equal to the maximum coding unit for each maximum coding unit. The size of the conversion unit for frequency conversion during encoding can be selected based on data units that are not larger than the respective encoding units.

For example, in the video encoding apparatus 100 or the video encoding apparatus 200 according to an embodiment, when the current encoding unit 710 is 64x64 size, the 32x32 conversion unit 720 The frequency conversion can be performed.

In addition, the data of the encoding unit 710 of 64x64 size is encoded by performing the frequency conversion with the conversion units of 32x32, 16x16, 8x8, and 4x4 size of 64x64 or smaller, respectively, and then the conversion unit having the smallest error with the original Can be selected.

FIG. 8 illustrates depth-specific encoding information, in accordance with an embodiment of the present invention.

The encoding information encoding unit of the video encoding apparatus 100 according to an embodiment is information on an encoding mode, and includes information on a partition type 800, information on a prediction mode 810, Information 820 on the conversion unit size can be encoded and transmitted.

The partition type information 800 indicates information on a type in which the current encoding unit is divided as a prediction unit for predictive encoding of the current encoding unit. For example, the current encoding unit CU_0 of depth 0 and size 2Nx2N includes a prediction unit 802 of size 2Nx2N, a prediction unit 804 of size 2NxN, a prediction unit 806 of size Nx2N, a prediction unit 808 of size NxN ) And can be used as a prediction unit. In this case, information 800 regarding the partition type of the current encoding unit includes a prediction unit 802 of size 2Nx2N, a prediction unit 804 of size 2NxN, a prediction unit 806 of size Nx2N, and a prediction unit 808 of size NxN. Lt; / RTI >

The information 810 on the prediction mode indicates the prediction mode of each prediction unit. The prediction unit indicated by the information 800 relating to the partition type is predicted to be one of the intra mode 812, the inter mode 814 and the skip mode 816 through the prediction mode information 810, for example. Can be set.

In addition, the information 820 on the conversion unit size indicates whether to perform frequency conversion on the basis of which conversion unit the current encoding unit is performed. For example, the conversion unit may be one of a first intra-conversion unit size 822, a second intra-conversion unit size 824, a first inter-conversion unit size 826, have.

The encoding information extracting unit of the video decoding apparatus 200 according to the embodiment extracts the information 800 about the partition type, the information 810 about the prediction mode, the information 820 about the conversion unit size ) Can be extracted and used for decoding.

FIG. 9 shows a depth encoding unit according to an embodiment of the present invention.

Partition information may be used to indicate changes in depth. The division information indicates whether the current-depth encoding unit is divided into lower-depth encoding units.

The prediction unit 910 for the prediction encoding of the coding units of depth 0 and 2N_0x2N_0 has a partition type 912 of 2N_0x2N_0 size, a partition type 914 of 2N_0xN_0 size, a partition type 916 of N_0x2N_0 size, a partition of size N_0xN_0 Type < / RTI >

For each partition type, predictive encoding should be repeatedly performed for each prediction unit of 2N_0x2N_0 size, two 2N_0xN_0 size prediction units, two N_0x2N_0 size prediction units, and four N_0xN_0 size prediction units. For a prediction unit of size 2N_0x2N_0, size N_0x2N_0, size 2N_0xN_0, and size N_0xN_0, predictive coding may be performed in intra mode and inter mode. The skip mode can be performed only for predictive encoding in a prediction unit of size 2N_0x2N_0.

If the coding error by the partition type 918 of the size N_0xN_0 is the smallest, the depth 0 is changed to 1 (920), and the coding units 922, 924, 926 and 928 of the partition type of the depth 2 and the size N_0xN_0 are changed The minimum coding error can be repeatedly searched for.

Since encoding is repeatedly performed on the encoding units 922, 924, 926, and 928 of the same depth, encoding of only one of the encoding units of depth 1, for example, will be described. The prediction unit 930 for predicting the coding unit of the depth 1 and the size 2N_1x2N_1 (= N_0xN_0) includes a partition type 932 of size 2N_1x2N_1, a partition type 934 of size 2N_1xN_1, a partition type 936 of size N_1x2N_1, , And a partition type 938 of size N_1xN_1. For each partition type, predictive coding should be repeatedly performed for each prediction unit of a size 2N_1x2N_1, a prediction unit of two sizes 2N_1xN_1, a prediction unit of two sizes N_1x2N_1, and a prediction unit of four sizes N_1xN_1.

If the coding error by the partition type 938 of the size N_1xN_1 is the smallest, the coding units 942, 944, 946 and 948 of the depth 2 and the size N_2xN_2 are changed while changing the depth 1 to the depth 2 (940) The minimum coding error can be repeatedly searched for.

If the maximum depth is d, the depth-based segmentation information can be set until the depth d-1. That is, the prediction unit 950 for predictive coding of the coding unit of the depth d-1 and the size 2N_ (d-1) x2N_ (d-1) A partition type 954 of size 2N_ (d-1) xN_ (d-1), a partition type 956 of size N_ (d-1) x2N_ 1) xN_ (d-1) < / RTI >

(D-1) x2N_ (d-1), two predicted units of two sizes 2N_ (d-1) (d-1) x2N_ (d-1), four sizes N_ (d-1) xN_ (d-1). Since the maximum depth is d, the coding unit 952 of depth d-1 no longer undergoes the division process.

The video coding apparatus 100 according to an exemplary embodiment compares depth-based coding errors to determine the depth of coding for the coding unit 912, and selects the depth at which the smallest coding error occurs.

For example, a coding error for a coding unit of depth 0 is predicted for each partition type 912, 914, 916, and 918, and a prediction unit in which the smallest coding error occurs is determined. Similarly, a prediction unit having the smallest coding error can be searched for every depth 0, 1, ..., d-1. At the depth d, the coding error can be determined through predictive coding based on the prediction unit 960, which is a coding unit of size 2N_dx2N_d.

In this way, the minimum coding error of each of the depths 0, 1, ..., d-1, and d is compared and the depth with the smallest error is selected to be determined as the coding depth. The coding depth and the prediction unit of the corresponding depth can be encoded and transmitted as information on the coding mode. In addition, since the coding unit must be divided from the depth 0 to the coding depth, only the division information of the coding depth is set to '0', and the division information by depth is set to '1' except for the coding depth.

The encoding information extracting unit 220 of the video decoding apparatus 200 according to an exemplary embodiment may extract information on the encoding depth and prediction unit of the encoding unit 912 and decode the encoding unit 912. [ The video decoding apparatus 200 according to an exemplary embodiment of the present invention uses division information by depth to grasp the depth with the division information of '0' as a coding depth and can use it for decoding using information on the coding mode for the corresponding depth have.

FIGS. 10A, 10B, and 10C illustrate the relationship between an encoding unit, a prediction unit, and a frequency conversion unit according to an embodiment of the present invention.

The coding unit 1010 is coding units for coding depth determined by the video coding apparatus 100 according to the embodiment with respect to the maximum coding unit. The prediction unit 1060 is a prediction unit of each coding depth unit among the coding units 1010 and the conversion unit 1070 is a conversion unit of each coding depth unit.

When the depth of the maximum encoding unit is 0, the depth of the encoding units 1012 and 1054 is 1 and the depth of the encoding units 1014, 1016, 1018, 1028, 1050, The coding units 1020, 1022, 1024, 1026, 1030, 1032 and 1048 have a depth of 3 and the coding units 1040, 1042, 1044 and 1046 have a depth of 4.

A portion (1014, 1016, 1022, 1032, 1048, 1050, 1052, 1054) of the prediction units 1060 is a type in which the coding unit is divided. That is, the prediction units 1014, 1022, 1050 and 1054 are partition types of 2NxN, the prediction units 1016, 1048 and 1052 are partition types of Nx2N, and the prediction units 1032 are partition types of NxN. That is, the prediction unit of the depth-dependent coding units 1010 is smaller than or equal to each coding unit.

The image data of a part 1052 of the conversion units 1070 is subjected to frequency conversion or frequency inverse conversion in units of data smaller in size than the encoding unit. The conversion units 1014, 1016, 1022, 1032, 1048, 1050, 1052, and 1054 are data units of different sizes or types when compared with the prediction units of the prediction units 1060. That is, the video encoding apparatus 100 according to the embodiment and the video decoding apparatus 200 according to an embodiment can perform the intra prediction / motion estimation / motion compensation operation for the same encoding unit and the frequency conversion / , Each based on a separate data unit.

FIG. 11 shows encoding information for each encoding unit according to an embodiment of the present invention.

The output unit 130 of the video encoding apparatus 100 according to an exemplary embodiment outputs encoding information for each encoding unit and the encoding information extracting unit 220 of the video decoding apparatus 200 according to an exemplary embodiment extracts encoding information for each encoding unit It is possible to extract the encoding information.

The encoding information may include division information for the encoding unit, partition type information, prediction mode information, and conversion unit size information. The encoding information shown in FIG. 11 is an example that can be set in the video encoding apparatus 100 according to the embodiment and the video encoding apparatus 200 according to an embodiment.

The division information may indicate the coding depth of the corresponding encoding unit. That is, since depths that are no longer divided according to the division information are coding depths, partition type information, prediction mode, and conversion unit size information can be defined with respect to the coding depth. When it is necessary to further divide by one division according to the division information, encoding should be performed independently for each of four divided sub-depth coding units.

As the partition type information, the partition type of the conversion unit of the coding unit of the coding depth can be represented by 2Nx2N, 2NxN, Nx2N and NxN. The prediction mode may be represented by one of an intra mode, an inter mode, and a skip mode. The intra mode and the inter mode can be defined in the partition types 2Nx2N, 2NxN, Nx2N and NxN, and the skip mode can be defined only in the partition type 2Nx2N. The conversion unit size can be set to two kinds of sizes in the intra mode and two kinds of sizes in the inter mode.

The encoding unit-specific encoding information of the belonging encoding depth may be stored for each minimum encoding unit in the encoding unit. Therefore, if encoding information held in each of the adjacent minimum encoding units is checked, it can be confirmed whether or not the encoding information is included in the encoding unit of the same encoding depth. In addition, since the encoding unit of the encoding depth can be identified by using the encoding information held in the minimum encoding unit, the distribution of encoding depths in the maximum encoding unit can be inferred.

In this case, when the current encoding unit is predicted with reference to the neighboring data unit, the encoding information of the minimum encoding unit in the depth encoding unit adjacent to the current encoding unit is directly used, so that the data of the minimum encoding unit can be referred to.

In yet another embodiment, the encoding information of the depth encoding unit may be stored only for the minimum encoding unit represented in the depth encoding unit. In this case, when the current encoding unit is predicted by referring to the surrounding encoding unit, the data adjacent to the current encoding unit in the depth encoding unit may be retrieved using the encoding information of the adjacent depth encoding unit.

12 shows a flowchart of a video encoding method according to an embodiment of the present invention.

In step 1210, the current picture is divided into at least one maximum encoding unit. In addition, the maximum depth indicating the possible total number of divisions may be set in advance.

In step 1220, the area of the maximum coding unit is coded at least in one divided area for each depth, and the depth at which the final coding result is output for each of at least one of the divided areas is determined. The maximum encoding unit is divided into stages, and each time the depth is deepened, it is necessary to repeatedly perform encoding for each lower-depth encoding unit.

For each depth-based coding unit, the conversion unit for each partition type having the smallest coding error should be determined. In order to determine the coding depth that causes the minimum coding error of the coding unit, the coding error should be measured and compared for each coding unit of each depth.

In step 1230, video data as a final encoding result for each of at least one divided area and information on the coding depth and coding mode are output for each maximum coding unit. The information on the encoding mode may include information on the encoding depth or division information, partition type information of the encoding depth, prediction mode information, and conversion unit size information. Information on the encoded encoding mode can be transmitted to the decoding end together with the encoded video data.

13 shows a flowchart of a video decoding method according to an embodiment of the present invention.

In step 1310, the bitstream for the encoded video is received and parsed.

In step 1320, the image data of the current picture allocated to the largest coding unit of the maximum size from the parsed bitstream, and information on the coding depth and coding mode of each coding unit are extracted. The coding depth for each maximum coding unit is the depth selected with the smallest coding error for each maximum coding unit in the process of coding the current picture. The encoding of the maximum encoding unit is the image data encoded based on at least one data unit obtained by dividing the maximum encoding unit hierarchically by depth. Accordingly, the decoding efficiency of the image can be improved by decoding each image data after grasping the coding depth for each coding unit.

In step 1330, the image data of each maximum encoding unit is decoded based on the information on the encoding depth and the encoding mode for each maximum encoding unit. The decoded image data can be reproduced by a reproducing apparatus, stored in a storage medium, or transmitted via a network.

Hereinafter, encoding and decoding of video using deblocking filtering in consideration of encoding units, prediction units, and conversion units will be described with reference to FIGS. 14 to 22, according to an embodiment of the present invention.

14 shows a block diagram of a video encoding apparatus using deblocking filtering, according to one embodiment.

The video encoding apparatus 1400 using deblocking filtering according to an exemplary embodiment includes a maximum encoding unit division unit 1410, a coding depth and encoding mode determination unit 1420, and a deblocking filtering implementation unit 1430.

The video encoding apparatus 1400 using deblocking filtering according to an embodiment corresponds to an embodiment of the video encoding apparatus 100 according to an embodiment. The maximum coding unit dividing unit 1410 corresponds to the maximum coding unit dividing unit 110 and the coding depth and coding mode determining unit 1420 and deblocking filtering performing unit 1430 calculate the coding depth (120).

The maximum coding unit division unit 1410 according to an embodiment divides a picture of an input video into a maximum coding unit and outputs video data of the maximum coding unit to the coding depth and coding mode deciding unit 1420. [

The encoding depth and encoding mode determination unit 1420 according to an embodiment performs prediction encoding and various size conversions based on prediction units of various partition types for each encoding unit for each depth, Unit-based conversion is repeatedly performed to determine a coding unit for each depth and a coding mode for generating a minimum coding error independently for each divided region of the largest coding unit.

The encoding modes for the encoding units are divided into a partition type of the encoding unit indicating the size and type of the prediction unit at the time of performing the encoding in which the minimum encoding error occurs, a prediction mode such as the inter mode / intra mode / skip mode, Information.

The partition type of an encoding unit according to an exemplary embodiment includes an asymmetric partition that divides a height or a width of an encoding unit into 1: 3 or 3: 1, as well as a symmetric partition having a size of NxN, Nx2N, 2NxN, 2Nx2N It is possible. The size of the other conversion unit in one embodiment may be 2x2, 4x4, 8x8, 16x16, 32x32, 64x64, 128x128, and the like.

The deblocking filtering unit 1430 according to an exemplary embodiment receives the video data inversely transformed into the spatial domain and performs deblocking filtering on the video data in the spatial domain in consideration of the coding mode for each coding unit. The encoding depth and encoding mode decision unit 1420 decides the prediction encoding based on the prediction unit on a coding unit basis and the quantized transform coefficient on the basis of the conversion unit and the quantization on the basis of the inverse quantization and inverse transformation, And input to the de-blocking filtering performing unit 1430. [

The deblocking filtering performing unit 1430 according to an embodiment performs de-blocking filtering considering a coding mode-specific coding mode for a border of a prediction unit or a unit of conversion unit for each coding unit among the video data inversely transformed into a spatial region Perform filtering.

The deblocking filtering performing unit 1430 according to an exemplary embodiment may be repeatedly and repeatedly performed on the encoding units in the maximum encoding unit for each maximum encoding unit. For example, when the division information of the coding unit is 1, since the current depth is not the depth of the encoding, it proceeds to the higher depth without performing the deblocking filtering. If the division information of the coding unit is 0, deblocking filtering is performed on the left boundary, the upper boundary and the inner boundaries of the current depth coding unit since the current depth is the coding depth.

The deblocking filtering performing unit 1430 according to an exemplary embodiment performs de-blocking filtering in consideration of whether a boundary of a prediction unit or a boundary of a conversion unit corresponds to a boundary of an encoding unit, a boundary of a prediction unit, Filtering can be implemented. For example, the boundary strength can be set according to whether or not the boundary is at least a boundary of data units of an encoding unit, a prediction unit, and a conversion unit.

The deblocking filtering performing unit 1430 may perform a deblocking filtering method in consideration of at least one of the size of a coding unit, the size of a prediction unit, and the size of a conversion unit among encoding modes of each encoding unit have. In addition, the deblocking filtering performing unit 1430 according to an embodiment can perform deblocking filtering in consideration of the partition type of a coding unit.

In addition, the deblocking filtering performing unit 1430 according to an exemplary embodiment may include a prediction mode of a prediction unit, the presence or absence of a coded residual component, the number of reference pictures, and the index of a reference picture Considering at least one, deblocking filtering may be performed.

The deblocking filtering performing unit 1430 according to an embodiment may determine the boundary strength in consideration of the encoding mode for each encoding unit. In addition, the deblocking filtering performing unit 1430 according to an exemplary embodiment may determine whether deblocking filtering is applied or not by considering the encoding mode for each encoding unit, and may also determine an implementation method of deblocking filtering. The deblocking filtering performing unit 1430 according to an embodiment can perform deblocking filtering based on the boundary strength determined in consideration of a coding mode-specific coding mode, whether deblocking filtering is applied or not, and an implementation method.

The deblocking filtering implementation may include setting the length of the deblocking filter, the size of the filter tap, and the location of the sample to be deblock filtered. At this time, the deblocking filtering target sample may include the original value of the pixel which becomes the filter coefficient of the deblocking filtering and the pixel whose value is changed by deblocking filtering.

For example, a deblocking filter may be used to determine the output value of deblocking filtering based on a predetermined line format using filter coefficients as a variable, using an original value of pixels perpendicular to the boundary as a coefficient.

The deblocking filtered by the coding unit by the deblocking filtering unit 1430 according to an embodiment may be used as a reference picture for motion estimation and motion compensation of a next picture through loop filtering.

A video coding apparatus 1400 using deblocking filtering according to an exemplary embodiment performs quantization and entropy coding on transform coefficients for each coding unit, and outputs the coded video data for each coding unit, the coding depth for each coding unit, Lt; RTI ID = 0.0 > bitstream < / RTI >

15 shows a block diagram of a video decoding apparatus using deblocking filtering, according to one embodiment.

The video decoding apparatus 1500 using deblocking filtering according to an embodiment includes a data extracting unit 1510, an entropy decoding and inverse quantizing unit 1520, an inverse transforming and predicting decoding unit 1530, and a deblocking filtering performing unit 1540).

The video decoding apparatus 1500 using deblocking filtering according to an embodiment corresponds to an embodiment of the video decoding apparatus 200 according to an embodiment. The data extracting unit 1510 corresponds to the image data and the encoding information extracting unit 220 and includes an entropy decoding and inverse quantization unit 1520, an inverse transform and prediction decoding unit 1530, and a deblocking filtering Unit 1540 may correspond to the image data decoding unit 230. [

The data extracting unit 1510 parses the received bit stream to extract the encoded data for each encoding unit and the encoded data for each encoding unit. Information about the size of the maximum encoding unit can be extracted from the parsed bitstream.

The encoding mode of each encoding unit contains information on the encoding depth, prediction unit, prediction mode, conversion unit, and the like necessary for decoding the encoded video data. Accordingly, the encoded video data can be extracted from the bitstream parsed according to the encoding unit-by-encoding-unit-by-encoding-unit basis.

The entropy decoding and inverse quantization unit 1520 according to an embodiment performs entropy decoding and inverse quantization on the encoded video data input from the data extracting unit 1510 to output the transform coefficients. The quantized transform coefficients are output through entropy decoding of the encoded video data, and the transform coefficients for each encoding unit can be output from the quantized transform coefficients through inverse quantization.

The inverse transform and predictive decoding unit 1530 according to an embodiment performs inverse transform and predictive decoding on the transform coefficients for each coding unit input from the decoding and inverse quantization unit 1520 and outputs the video data in the spatial domain .

According to the inverse transformation according to the embodiment, the transform coefficient of the encoding unit can be inversely transformed based on the information on the transform unit that can be obtained from the encoding unit-specific encoding mode extracted by the data extracting unit 1510, The residual data for each coding unit can be output.

In accordance with the predictive decoding according to an embodiment, intraprediction and motion compensation can be performed on the residual data of the coding unit based on information on the prediction unit that can be grasped from the coding mode- Accordingly, the video data in the spatial domain of each coding unit can be output.

The deblocking filtering unit 1540 performs deblocking filtering on the video data in the spatial domain input from the inverse transform and prediction decoding unit 1530 in consideration of the encoding mode for each encoding unit.

The deblocking filtering performing unit 1540 performs deblocking filtering on the video data in the spatial region by the maximum encoding unit based on the encoding mode for each encoding unit input from the data extracting unit 1510 . The deblocking filtering may be performed on the boundary of the prediction unit or the boundary of the conversion unit for each coding unit.

The deblocking filtering performing unit 1530 according to an exemplary embodiment may be repeatedly and repeatedly performed on the encoding units in the maximum encoding unit for each maximum encoding unit. For example, when the division information of the coding unit is 1, since the current depth is not the depth of the encoding, it proceeds to the higher depth without performing the deblocking filtering. If the division information of the coding unit is 0, deblocking filtering is performed on the left boundary, the upper boundary and the inner boundaries of the current depth coding unit since the current depth is the coding depth.

The boundary of the prediction unit or the boundary of the conversion unit may be the boundary of the encoding unit, the boundary of the prediction unit, and the boundary of the conversion unit in the encoding unit-specific encoding mode, similarly to the de- Deblocking filtering can be performed depending on which of them corresponds.

In addition, the encoding mode to be considered in performing the deblocking filtering may be a size of a coding unit, a size of a prediction unit, a size of a conversion unit, a partition type of a coding unit, and the like in the coding mode. The deblocking filtering may be performed in consideration of at least one of the prediction mode, the presence or absence of the encoded residual component, the motion vector, the number of reference pictures, and the index, as in the video codec according to the existing standard.

A deblocking filtering implementation method including information on deblocking filter, deblocking filtering application, and size of a filter tap according to a boundary strength determined in consideration of the various coding modes described above, Deblocking filtering can be performed considering a coding mode according to a prediction unit and a conversion unit.

The deblocking filtered data may be output as a reconstructed image of the spatial domain according to an embodiment. In addition, the deblocking filtered data may be used as a reference picture for motion compensation of a next picture through loop filtering according to an embodiment.

The video coding apparatus 1400 using deblocking filtering according to an embodiment and the video decoding apparatus 1500 using deblocking filtering according to an embodiment may be configured to perform a decoding process for each coding unit Since the encoding unit is encoded, the size, type, and the like may be different even if adjacent encoding units are used.

Also, in the video coding apparatus 1400 using deblocking filtering and the video decoding apparatus 1500 using deblocking filtering according to an embodiment, the coding unit is not fixed as a macro block of size 16x16, 2x2, 4x4, 8x8, 16x16, 32x32, 64x64, 128x128, and 256x256 can be set.

Further, in the video coding apparatus 1400 using deblocking filtering and the video decoding apparatus 1500 using deblocking filtering according to an embodiment, the size of a conversion unit is fixed to a size 4x4 block or a size 8x8 block And a conversion unit in which the maximum size and the minimum size are not limited such as 2x2, 4x4, 8x8, 16x16, 32x32, 64x64, 128x128, and 256x256 can be set.

In addition, in the video coding apparatus 1400 using deblocking filtering and the video decoding apparatus 1500 using deblocking filtering according to an embodiment, prediction units for prediction coding and conversion / , The size of the conversion unit may be larger than the size of the prediction unit. The relationship of the encoding unit, the conversion unit, and the prediction unit has been described above with reference to Figs. 10A, 10B and 10C.

Therefore, the predetermined boundary may be a boundary of an encoding unit, a boundary of a prediction unit, or a boundary of a conversion unit. For example, the predetermined boundary may be the boundary of the encoding unit and the boundary of the prediction unit, or may be the boundary of the conversion unit, the boundary of the prediction unit, or the boundary of the conversion unit and the boundary of the prediction unit. The boundary of the data unit may be the boundary of both the encoding unit, the prediction unit and the conversion unit. In addition, the boundary of the predetermined data unit may be the boundary of the maximum encoding unit.

According to one embodiment, to determine whether deblocking filtering is to be performed on the boundary, the boundary characteristic should be analyzed. For example, to analyze boundary characteristics, the value of 'disable_deblocking_filter_idc' in the slice header may be used. 'disable_deblocking_filter_idc' is a parameter that determines whether deblocking filtering is applied to the slice boundary. If 'disable_deblocking_filter_idc' is 1, deblocking filtering is not performed on the slice boundary.

For example, if the value of 'disable_deblocking_filter_idc' is 1 and the predetermined boundary is a picture boundary, deblocking filtering can not be performed on the boundaries of coding units. Therefore, if the value of 'disable_deblocking_filter_idc' is not 1 or if the boundary is not the picture boundary, the deblocking filtering performing units 1430 and 1540 can perform deblocking filtering on the boundary of the encoding unit. Also, if the value of 'disable_deblocking_filter_idc' is not greater than or equal to 1, deblocking filtering may be performed on the boundary of the prediction unit or the boundary of the conversion unit.

According to the video encoding and the video decoding according to the embodiment, since the encoding unit, the prediction unit, and the conversion unit are all set individually, it is preferable that the deblocking method is individually determined according to each boundary characteristic. Accordingly, the video coding apparatus 1400 using deblocking filtering according to an embodiment and the video decoding apparatus 1500 using deblocking filtering according to an embodiment are capable of performing deblocking filtering in consideration of characteristics of boundaries of predetermined data units. You can set it up differently.

For example, if the predetermined boundary is the boundary of the maximum encoding unit, the deblocking filtering method for the boundary of the maximum encoding unit may be set.

In addition, when the predetermined boundary is the boundary of an encoding unit other than the maximum encoding unit, a deblocking filtering method for the boundary of the encoding unit can be set.

If the predetermined boundary is not the boundary between the maximum encoding unit and the encoding unit and is the boundary of the conversion unit, a deblocking filtering method for the boundary of the conversion unit may be set.

The deblocking filtering method for the boundary of the prediction unit may be set when the predetermined boundary is not the boundary of the maximum coding unit, coding unit and conversion unit, and is a boundary of the prediction unit.

The deblocking filtering method may include setting whether deblocking filtering is performed, the length of the deblocking filter, the number and location of the deblocking filtering target samples, and the like.

According to an exemplary embodiment, the length of the boundary may vary depending on structures such as a coding unit, a prediction unit, a size of a conversion unit, a type, and the like

Hereinafter, the relationship between an encoding unit, a prediction unit, and a conversion unit according to one embodiment is shown with reference to Figs. It is assumed in advance that the encoding units 1600, 1700, and 1800 in FIGS. 16 to 18 are not the maximum encoding units.

FIG. 16 shows an example of a relationship between an encoding unit and several conversion units of prediction units according to an embodiment.

The encoding unit 1600 of size 2Nx2N is predictively encoded based on a prediction unit conforming to the NxN partition type, and is converted based on the size NxN conversion unit. Thus, the boundaries 1612, 1614, 1616, 1620, 1626, 1630, 1632, and 1634 are boundaries of both the encoding unit, the prediction unit, and the conversion unit, .

The deblocking filtering performing units 1430 and 1540 according to an embodiment are capable of performing the deblocking filtering on the boundaries 1612, 1614, 1616, 1620, 1626, 1630, 1632, and 1634, The deblocking filtering method for the boundary can be applied.

In addition, the deblocking filtering performing units 1430 and 1540 according to an exemplary embodiment may perform the deblocking filtering on the boundaries of the conversion units for the boundaries 1618, 1622, 1624, and 1628, which are the boundaries of the conversion unit and not the boundary between the maximum encoding unit and the encoding unit The deblocking filtering method can be applied.

FIG. 17 shows another example of the relationship between an encoding unit and several prediction unit conversion units according to an embodiment.

A coding unit 1700 of size 2Nx2N is predictively coded based on a prediction unit conforming to the NxN partition type and is converted based on a size 2Nx2N conversion unit. Thus, the boundaries 1712, 1714, 1716, 1720, 1726, 1730, 1732, and 1734 are boundaries of the encoding unit, the prediction unit, to be.

The deblocking filtering performing units 1430 and 1540 according to an embodiment are capable of performing the deblocking filtering on the boundaries 1712, 1714, 1716, 1720, 1726, 1730, 1732, and 1734, The deblocking filtering method for the boundary can be applied.

In addition, the deblocking filtering performing units 1430 and 1540 according to an exemplary embodiment may perform the deblocking filtering according to the predictive unit for the boundaries 1718, 1722, 1724, and 1728, which are the boundaries of the maximum encoding unit, the encoding unit, A deblocking filtering method for the boundary of the input signal can be applied.

FIG. 18 shows another example of the relationship of the encoding unit and the conversion unit of several prediction units according to the embodiment.

The coding unit 1800 of size 4Nx4N is a case where the width of the coding unit 1800 is predictively coded based on a prediction unit following an asymmetric partition type that divides 3: 1 and converted based on a size 2Nx2N conversion unit. Thus, the boundaries 1812, 1814, 1816, 1820, 1822, and 1824 are boundaries of both the encoding unit, the prediction unit, and the conversion unit, 1832) is the boundary of the conversion unit only.

The deblocking filtering performing units 1430 and 1540 according to an embodiment are capable of performing the deblocking filtering on the boundaries of the coding units with respect to the boundaries 1812, 1814, 1816, 1820, 1822 and 1824, A blocking filtering method can be applied.

In addition, the deblocking filtering performing units 1430 and 1540 according to an exemplary embodiment may perform a deblocking filtering on the boundary of the conversion unit with respect to the boundaries 1826, 1828, 1830, and 1832, which are not the maximum encoding unit and the encoding unit, A blocking filtering method can be applied.

In addition, the deblocking filtering performing units 1430 and 1540 according to an exemplary embodiment may perform deblocking filtering on the boundaries of the prediction unit with respect to the boundary 1818, which is the boundary of the prediction unit and not the boundary between the maximum encoding unit, the encoding unit, A filtering method can be applied.

19 illustrates a deblocking filtering method determination method according to an embodiment.

For each boundary satisfying a combination of various conditions, each deblocking filtering method can be set. For example, various conditions may include a type of a data unit to which a boundary belongs, a prediction mode, a non-zero conversion coefficient in a block, a motion vector, a reference picture, a data unit size, various decoding techniques applied to the data unit, . Further, as the deblocking filtering method, whether or not deblocking filtering is performed, the length of the deblocking filter, and the position and the number of the deblocking filtering target samples can be set.

For example, the deblocking filtering performing units 1430 and 1540 according to an exemplary embodiment may perform the deblocking filtering according to the block type 1910 of two adjacent data units and the block size 1920 of two data units constituting the boundary of the encoding mode It is possible to determine an application unit 1930 that indicates the number of data units to which the deblocking filter is applied to a predetermined boundary.

Whether or not the boundaries of two adjacent data units among the predetermined boundary block type 1910 conditions are the maximum coding unit (LCU) boundary, the coding unit (CU) boundary, the prediction unit (PU) boundary and the conversion unit (TU) If the data size of the block size 1920 of two adjacent data units is equal to or larger than a predetermined threshold value and the data unit to which the deblocking filtering is applied is two blocks or one block, The conditions of the de-blocking filtering application target such as the absence of data units to which blocking filtering is applied can be determined.

A deblocking filtering method that satisfies each condition can also be set. For example, with respect to the deblocking filtering application units 1930 for the block boundary satisfying the combination of the block type 1910 condition and the block size 1920 condition, the deblocking filtering methods applied to each case are all Can be set individually. Referring to FIG. 19, the conditions of 36 filtering application targets are determined according to a combination of a block type 1910 condition, a block size 1920 condition, and an application unit 1930 condition, and deblocking filtering The performance units 1430 and 1540 can perform the deblocking filtering by individually determining the deblocking filtering method of the method 1 to the method 36 based on the condition of the boundary to which the deblocking filtering is applied. Since the deblocking filtering method of the method 1 to the method 36 means that each method is set for each of the 36 boundary conditions, the same method may be set for the other boundary conditions in duplicate. The same deblocking filtering method may be set. For example, the same deblocking filtering method may be set for block boundaries having the same block type, or the same deblocking filtering method may be set for block boundaries having the same block size.

In FIG. 19, only the conditions of the block type, the block size, and the number of data units to be applied are described for the data units constituting the boundary. However, the deblocking filtering performing units 1430 and 1540 according to the embodiment may perform the deblocking filtering method A prediction mode such as an intra / inter mode, a residual portion encoded in a block, a motion vector, the number and index of reference pictures, a coding technique type, and the like.

FIG. 20 illustrates samples that are subject to deblocking filtering according to one embodiment.

Deulyimyeo samples of the samples (2000) to be subjected to the deblocking filtering, _{p 3, p 2, p 1} , p 0 is the pixel to the left of the boundary, the sample _{q 0, q 1, q 2} , q 3 are located on the right border of Pixels. Although only horizontally arranged samples are shown in FIG. 20 where a deblocking filter is applied to the vertical boundary, a deblocking filter is applied to the samples similarly arranged in the vertical direction with respect to the horizontal boundary.

According to one embodiment, using the original values of the samples 2000 subject to deblocking filtering, the boundary strength, whether deblocking filtering is performed, and the length of the deblocking filter can be determined.

For example, using the original values of the samples 2000 subject to deblocking filtering, the edge strength can be determined. The determined boundary strength may be combined with the difference value condition between sample original values to determine whether to perform deblocking filtering on the boundary. In addition, depending on the combination of the boundary strength condition and the difference value condition between the sample original values, the length of the deblocking filter for the samples 2000 and the location and number of samples for which the filtering is performed to change the value can be determined.

According to one embodiment, if a boundary strength of the deblocking filter for the luma component is 4, except for the sample in the sample p _3, q ₃ of using a coefficient of the de-blocking filter, and D for the samples p _2, q ₂ Blocking results may be excluded.

In addition, the deblocking filtering performing units 1430 and 1540 according to an exemplary embodiment may determine whether the deblocking filtering performance of the deblocking filter 2000 is performed based on whether the current boundary is a boundary of an encoding unit, a prediction unit, The length of deblocking filter 2000, and the number and location of samples to be filtered.

FIG. 21 shows a flowchart of a video encoding method using deblocking filtering according to an embodiment.

In step 2110, the picture is divided into coding units of a predetermined maximum size.

In step 2120, for each maximum encoding unit, at least one encoding depth and encoding mode for each encoding unit for the encoding unit, predictive encoding, and conversion unit are determined.

In step 2130, deblocking filtering is performed on the video data inversely transformed into the spatial domain for each coding unit, taking into consideration the coding mode for each coding unit. It is determined whether or not the deblocking filter is applied to the boundary according to the type of the data unit including the encoding unit, the prediction unit and the conversion unit, the size of the data unit, the partition mode, The manner of implementation of deblocking filtering, including information about the strength of the edge, the size of the filter taps, and the like.

22 shows a flowchart of a video decoding method using deblocking filtering according to an embodiment.

In step 2210, the received bitstream is parsed and video data encoded for each encoding unit and encoding unit is extracted.

In step 2220, entropy decoding and inverse quantization are performed on the video data encoded for each coding unit, and the transform coefficients are output.

In step 2230, inverse conversion based on the conversion unit and prediction decoding based on the prediction unit in the encoding unit-specific encoding mode are performed on the conversion coefficient for each encoding unit to output the video data in the spatial region.

In step 2240, deblocking filtering is performed on the video data in the spatial domain in consideration of the encoding mode for each encoding unit. It is determined whether or not the deblocking filter is applied to the boundary according to the type of the data unit including the encoding unit, the prediction unit and the conversion unit, the size of the data unit, the partition mode, The manner of implementation of the deblocking filtering may be determined, including information about the edge strength, the size of the filter taps, and the like.

The above-described embodiments of the present invention can be embodied in a general-purpose digital computer that can be embodied as a program that can be executed by a computer and operates the program using a computer-readable recording medium. The computer-readable recording medium includes a storage medium such as a magnetic storage medium (e.g., ROM, floppy disk, hard disk, etc.) and an optical reading medium (e.g., CD-ROM, DVD, etc.).

The present invention has been described with reference to the preferred embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Claims (7)

In the image decoding method,
Determining at least one prediction unit in an encoding unit using partition type information indicating one of a symmetric partition type and an asymmetric partition type;
Determining at least one conversion unit in the coding unit using division information of a conversion unit indicating whether the current conversion unit of depth is divided into conversion units of lower depth;
Performing inverse conversion using the conversion unit and performing prediction using the prediction unit to restore the encoding unit;
A prediction mode, a motion vector, and a reference index, when the boundary included in the reconstructed coding unit is at least one of a boundary of the prediction unit and a boundary of the conversion unit, Determining a boundary strength;
Determining a deblocking filtering scheme that includes at least one of a number of filter taps and a location of pixels to be deblock filtered based on at least one of the boundary strength and sample values of pixels adjacent to the boundary; And
Performing deblocking filtering on the adjacent pixels according to the deblocking filtering scheme to generate a filtered encoding unit including the deblocking filtered pixels,
The maximum coding unit is hierarchically divided into coding units of depths including at least one of a current depth and a lower depth according to the division information,
When the division information indicates that the divided information is divided at the current depth, the current-depth coding unit is divided into four square lower-depth coding units independently of the surrounding coding units,
Wherein the at least one prediction unit and the at least one conversion unit are obtained from the current depth encoding unit when the segmentation information indicates that the segmentation information is not segmented. The method according to claim 1,
Wherein the prediction mode includes an inter prediction mode and an intra prediction mode. The method according to claim 1,
Wherein the deblocking filtering method is determined when the boundary strength does not correspond to the non-filtering. The method according to claim 1,
Wherein the boundary is one of a vertical boundary and a horizontal boundary. 5. The method of claim 4,
Wherein when the boundary is a vertical boundary, the adjacent pixels are located in a thermal erosion around the vertical boundary,
Wherein the adjacent pixels include left side pixels p3, p2, p1, p0 and right side pixels q0, q1, q2, q3. The method according to claim 1,
Wherein the filtered coding unit is used as a reference picture for motion compensation of other pictures. In the image decoding apparatus,
A processor for determining at least one prediction unit in an encoding unit using partition type information indicating one of a symmetric partition type and an asymmetric partition type;
Determining at least one conversion unit in the encoding unit using the division information of the conversion unit indicating whether the current conversion unit of depth is divided into the conversion units of the lower depth,
A reconstruction unit for performing inverse transform using the transform unit and performing prediction using the prediction unit to reconstruct the encoding unit; And
A prediction mode, a motion vector, and a reference index, when the boundary included in the reconstructed coding unit is at least one of a boundary of the prediction unit and a boundary of the conversion unit, Determining a deblocking filtering scheme that includes at least one of a number of filter taps and a location of pixels to be deblock filtered based on at least one of the boundary strength and the sample value of pixels adjacent to the boundary, And a deblocking filtering unit performing deblocking filtering on the adjacent pixels according to the deblocking filtering scheme to generate a filtered encoding unit including the deblocking filtered pixels,
The maximum encoding unit is hierarchically divided into encoding units of depths including at least one of a current depth and a low depth according to the segmentation information,
When the division information indicates that the divided information is divided at the current depth, the current-depth coding unit is divided into four square lower-depth coding units independently of the surrounding coding units,
Wherein the at least one prediction unit and the at least one conversion unit are obtained from the current depth encoding unit when the segmentation information indicates that the segmentation information is not segmented.

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