KR20150084738A - Method and apparatus for video encoding considering scanning order of coding units with hierarchical structure, and method and apparatus for video decoding considering scanning order of coding units with hierarchical structure - Google Patents

Abstract

A beat stream for encoded video is received and performs parsing, the information on the maximum sized encoding unit assigned current picture′s encoded media data, maximum encoded unit dept and encoded mode are extracted, raster scan order of maximum encoded unit and zigzag scan order of dept encoded unit are considered to provided a method for video decoding through decoding media data based on the dept encoded unit and maximum encoded unit.

Description

[0001] The present invention relates to a video coding method and an apparatus, a video decoding method, and an apparatus and a video decoding method considering a scanning order of a hierarchical coding unit. with hierarchical structure}

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 conventional video codec, video is encoded according to a limited encoding method based on a macroblock of a predetermined size. The conventional video codec scans a macroblock according to a raster method to decode video data.

The present invention relates to data scan order and neighbor relationship between data associated with negative decoding of video.

According to an embodiment of the present invention, there is provided a video decoding method including: receiving and parsing a bitstream of encoded video; Extracting coded image data of a current picture allocated to a maximum coding unit which is a coding unit of a maximum size and coding depth and coding mode information per coding unit; And decoding the image data encoded by the maximum encoding unit based on information on the encoding depth and encoding mode of the maximum encoding unit in consideration of the raster scan order of the maximum encoding unit and the zigzag scan order of the depth encoding unit Wherein the maximum encoding unit is spatially divided according to at least one depth to include at least one depth-dependent encoding unit, and as the depth is deepened from the lowest depth, the maximum encoding unit from the highest encoding depth to the lowermost depth The maximum encoding unit is hierarchically divided up to the minimum encoding unit.

The decoding step may include analyzing a hierarchical structure of at least one depth encoding unit for each maximum encoding unit using information on the encoding depth and the encoding mode for each maximum encoding unit .

The decoding step may further include a step of searching for a position of each of the maximum encoding units based on the addresses of the maximum encoding unit according to the raster scan order.

The decoding step may further include searching for a position of each minimum encoding unit based on a minimum encoding unit index according to a zigzag scan order for each maximum encoding unit.

The decoding step may further include a step of searching for a position of each minimum encoding unit based on a minimum encoding unit index according to a raster scan order for each maximum encoding unit.

The decoding step may further include the step of converting indexes according to the zigzag scanning order of each minimum coding unit and indexes according to the raster scanning order for each maximum coding unit.

The position of the maximum coding unit according to an exemplary embodiment may be represented by a pixel position at the upper left of the maximum coding unit relative to a pixel position at the upper left of the image picture.

The position of the minimum coding unit according to an exemplary embodiment may be represented by the pixel position of the upper left corner of the minimum coding unit relative to the pixel position of the upper left corner of the maximum coding unit.

The decoding step may refer to the neighbor information by searching the availability of the neighbor information considering the scan order of the maximum encoding unit, the prediction unit, and the minimum encoding unit.

The decoding step according to an exemplary embodiment may further include searching for the availability of the maximum encoding unit.

According to one embodiment, when the maximum coding unit is not included in the current picture in the decoding unit, the maximum coding unit is not included in the current slice, and the case where the address of the maximum coding unit is later than the address of the current maximum coding unit , The data of the maximum encoding unit can be used.

The decoding step according to an exemplary embodiment may further include retrieving the availability of the depth-dependent encoding unit within the maximum encoding unit.

If the maximum encoding unit is not included in the current picture in the decoding step according to an embodiment of the present invention and the maximum encoding unit is not included in the current slice, the address of the maximum encoding unit is less than the address of the current maximum encoding unit And the index in accordance with the zigzag scanning order of the minimum coding unit in the upper left of the coding unit for depth is one of the cases where the index according to the zigzag scanning order of the current minimum coding unit is one of the depth coding Data in units can be used.

The decoding step according to an exemplary embodiment may further include searching for a maximum encoding unit neighboring the current maximum encoding unit and an availability.

The maximum coding unit neighboring the current maximum coding unit in the decoding step according to an exemplary embodiment may include a left maximum coding unit, an uppermost coding unit, a right uppermost coding unit, and a left uppermost coding unit Or the like.

According to an exemplary embodiment, the decoding step may further include searching for the availability of the minimum encoding unit neighboring to the current prediction unit included in the current maximum encoding unit and the neighboring minimum encoding unit.

According to an exemplary embodiment, the minimum coding unit neighboring the current prediction unit may be a left minimum coding unit, an uppermost minimum coding unit, a right uppermost minimum coding unit, a left uppermost minimum coding unit, and a left lower minimum coding unit And may include at least one.

According to one embodiment, the decoding step may further include searching for a location of a boundary neighboring the current maximum encoding unit and an availability of the neighboring boundary.

According to an exemplary embodiment, the boundary adjacent to the current maximum encoding unit includes at least one of a left maximum encoding unit, an uppermost encoding unit, a right uppermost encoding unit, and a left uppermost encoding unit of the current maximum encoding unit can do.

According to one embodiment, for the minimum coding unit, at least one of information on a coding unit for each depth, information about division into a prediction unit of the coding unit for each depth, and information on a prediction mode of the prediction unit May be set.

The decoding step according to an exemplary embodiment may further include searching for the availability of a depth encoding unit or a prediction unit including the minimum encoding unit based on the encoding information of the minimum encoding unit.

According to an embodiment, the maximum encoding unit includes at least one encoding unit, and in the first encoding unit and the second encoding unit neighboring to each other, the first encoding unit is positioned in a subordinate to the second encoding unit If the first encoding unit is higher than the second encoding unit according to the zigzag scan order, the first encoding unit may be referred to for decoding the second encoding unit.

According to an exemplary embodiment, when the first encoding unit is adjacent to the lower left end of the second encoding unit, the first encoding unit may be referred to for decoding the second encoding unit.

According to an embodiment, when the first encoding unit is adjacent to the lower left end of the second encoding unit, the right boundary of the first encoding unit may be referred to for decoding the second encoding unit.

According to an aspect of the present invention, there is provided a video encoding method including: dividing a current picture into at least one maximum encoding unit that is a maximum-size encoding unit; Encoding the at least one divided area in which the area of the maximum encoding unit is divided for each depth, based on a depth that increases as the number of times of dividing the area of the maximum encoding unit increases, Determining a depth at which the result is to be output; And encoding and outputting image data encoded with one coding depth determined for each of the maximum coding units and information on the coding depth and coding mode and outputting the coded image data and the raster scanning order between the at least one maximum coding units, May be encoded in consideration of a zigzag scan order between at least one depth-dependent encoding units included in the maximum encoding unit.

The video encoding method according to an exemplary embodiment may refer to neighbor information including a data unit located at the lower left of the current data unit for encoding the video data of the current data unit.

The neighbor information according to an embodiment may include a left maximum coding unit, an uppermost maximum coding unit, a right uppermost coding unit and a left uppermost coding unit of the current maximum coding unit. In addition, the neighbor information may include a left minimum coding unit, an uppermost minimum coding unit, a right uppermost minimum coding unit, a left uppermost minimum coding unit, and a lower left minimum coding unit of the current prediction unit. The neighbor information may include a boundary of a left lower coding unit of a current prediction unit.

In the video encoding method according to an embodiment, the maximum encoding unit includes at least one encoding unit, and in a neighboring first encoding unit and a second encoding unit, a first encoding unit The second encoding unit may be referred to as neighbor information of the second encoding unit if the first encoding unit is higher than the second encoding unit in a zigzag scan order. And the first encoding unit may be positioned adjacent to the lower left end of the second encoding unit.

According to an aspect of the present invention, there is provided a video decoding apparatus including: a receiving unit for receiving and parsing a bitstream of encoded video; An extraction unit for extracting coded image data of a current picture allocated to a maximum encoding unit which is a maximum size encoding unit and information on the encoding depth and encoding mode; And decoding the image data encoded by the maximum encoding unit based on information on the encoding depth and encoding mode of the maximum encoding unit in consideration of the raster scan order of the maximum encoding unit and the zigzag scan order of the depth encoding unit Wherein the maximum encoding unit includes a depth encoding unit according to at least one depth, and as the depth from the lowest depth increases, the depth encoding unit from the maximum encoding unit, which is the lowest depth, .

A video encoding apparatus according to an embodiment of the present invention includes: a maximum encoding unit division unit that divides a current picture into at least one maximum encoding unit, which is a maximum-size encoding unit; Encoding the at least one divided area in which the area of the maximum encoding unit is divided for each depth, based on a depth that increases as the number of times of dividing the area of the maximum encoding unit increases, An encoding depth determination unit for determining a depth at which a result is output; And an output unit for encoding image data encoded at one encoding depth determined for each of the maximum encoding units and encoding depth and encoding mode information, and outputting the encoded image data, wherein a raster scan order between the at least one maximum encoding units, And the zigzag scanning order between at least one depth-dependent coding units included in the maximum coding unit of the coding unit.

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

The present invention discloses a computer-readable recording medium on which a program for implementing a video encoding method 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 illustrates a video encoding apparatus that refers to neighbor information according to an embodiment of the present invention.
15 illustrates a video decoding apparatus that refers to neighbor information according to an embodiment of the present invention.
16 illustrates a raster scan sequence of a maximum encoding unit according to an embodiment of the present invention.
17 illustrates a raster scan sequence of a minimum encoding unit according to an embodiment of the present invention.
FIG. 18 shows a zigzag scanning order of coding units according to depths according to an embodiment of the present invention.
FIG. 19 illustrates the maximum encoding units neighboring the current maximum encoding unit according to an embodiment of the present invention.
FIG. 20 shows an existing macroblock according to the raster scanning scheme.
Figure 21 shows a current prediction unit according to a zigzag scan sequence, in accordance with an embodiment of the present invention.
Figure 22 illustrates the minimum encoding units neighboring the current prediction unit, in accordance with an embodiment of the present invention.
23 illustrates a method of predicting a motion vector using neighbor information according to an embodiment of the present invention.
24 illustrates an interpolation method using neighbor information according to an embodiment of the present invention.
25 illustrates a video decoding method that refers to neighbor information according to an embodiment of the present invention.
26 illustrates a video encoding method that refers to neighbor information according to an embodiment of the present invention.

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 FIGS. 1 to 26. Referring to FIGS. 1 to 14, 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 26, Coding and video decoding of video referring to neighbor information will be described below in consideration of a data scanning order according to the present invention.

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 division unit 110 may 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 image data may be a result of encoding residual data of the image.

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 a video decoding unit based on an encoding unit according to an embodiment of the present invention.

The bitstream 505 passes through the parsing unit 510 and the encoded image data to be decoded and the encoding-related information necessary for decoding are parsed. The encoded image 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 the 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 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 coding 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, a 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 determining 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, video coding and video decoding referring to neighbor information in consideration of a data scanning order according to an embodiment of the present invention will be described with reference to FIGS. 14 to 26. FIG.

14 illustrates a video encoding apparatus that refers to neighbor information according to an embodiment of the present invention.

The video encoding apparatus 1400 according to one embodiment includes a maximum encoding unit division unit 1410, a coding depth determination unit 1420, and an output unit 1450. The output unit 1450 includes an encoded image data output unit 1430 and an encoded information output unit 1440. The video encoding apparatus 1400 according to the embodiment has the same configuration as the video encoding apparatus 100 described above with reference to FIG. However, features for coding by referring to neighbor information in consideration of a data scan order according to an embodiment will be described in detail below.

According to an embodiment, the maximum coding unit division unit 1410 divides the current picture based on the maximum coding unit which is a coding unit of the maximum size for the current picture of the picture, and the coding depth determination unit 1420 divides the current picture by the maximum coding unit The image data is encoded in the depth-dependent coding unit, and the depth at which the smallest coding error occurs is selected to determine the coding depth.

According to one embodiment, the encoding order for the largest encoding unit considers the raster scan order. The coding units of the hierarchical depth in the maximum coding unit can be scanned in the zigzag scanning order among the depth coding units of the same depth by depth. In addition, the encoding order of the minimum encoding unit in the maximum encoding unit may follow the zigzag scan order or the raster scan order.

The image data output unit 1430, which is encoded according to an embodiment, outputs a bit stream of image data of the maximum encoding unit encoded based on the encoding depth. The encoding information output unit 1440 encodes and outputs information on the depth encoding mode for each maximum encoding unit.

The video encoding apparatus 1400 according to an exemplary embodiment may refer to neighbor information of a current data unit for encoding image data of a current data unit. For example, neighbor information such as a current maximum encoding unit, a current encoding depth encoding unit, or a neighboring maximum encoding unit and a neighboring depth encoding unit may be referred to for predictive encoding of the current prediction unit.

Specifically, the neighbor information may include a left maximum coding unit, an uppermost coding unit, a right uppermost coding unit and a left uppermost coding unit of the current maximum coding unit. In addition, the neighbor information may include information such as a left minimum coding unit, an uppermost minimum coding unit, a right uppermost minimum coding unit, a left uppermost minimum coding unit and a lower left minimum coding unit of the current prediction unit.

Also, a portion of the data unit, rather than the entire data unit, may be referred to as neighbor information. For example, it may include the right boundary of the maximum encoding unit located at the lower left of the current prediction unit.

Since the data unit located at the lower left of the current data unit is a subordinate to the current data unit according to the raster scan order, it can not be referred to for coding the current macroblock in the macroblock-based coding scheme according to the raster scanning order. However, in the present invention, the maximum encoding unit only follows the raster scan order, and the minimum encoding units and data units in the maximum encoding unit can be scanned along the zigzag scan order, and thus can be referred to as neighbor information.

15 illustrates a video decoding apparatus that refers to neighbor information according to an embodiment of the present invention.

The video decoding apparatus 1500 according to an embodiment includes a receiving unit 1501, an extracting unit 1505, and a video data decoding unit 1530. The extraction unit 1505 includes an image data acquisition unit 1510 and an encoding information extraction unit 1520. The configurations of the video decoding apparatus 1500 are corresponding to those of the video decoding apparatus 200 described above with reference to FIG. However, a feature of decrypting data in consideration of a data scanning order according to an embodiment will be described below with reference to the video decoding apparatus 1500. [

The receiving unit 1501 receives and parses a bitstream of the encoded video, and the extracting unit 1505 extracts various encoded information from the parsed bitstream. The image data obtaining unit 1510 can obtain the image data encoded by the maximum encoding unit from the parsed bitstream. The encoding information extracting unit 1520 extracts, from the parsed bit stream, information on the encoding depth and the encoding mode for each maximum encoding unit from the header for the current picture.

The image data decoding unit 1530 decodes the encoded 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 recover the current picture, And the zigzag scan order of the depth-coded units.

Neighbor information can be referenced for decoding of the current data unit. For example, a motion vector of a neighboring prediction unit may be referred to for inter prediction of a current prediction unit. As another example, for intra prediction of the current prediction unit, the pixel value of the data unit neighboring the pixel value of the current prediction unit may be referred to.

The image data decoding unit 1530 can retrieve the location of a neighboring data unit that can be referred to for decoding of the current data unit and the availability of neighboring data units. Accordingly, the image data decoding unit 1530 searches the availability of the neighbor information considering the raster scan order of the maximum encoding unit and the prediction unit, the zigzag scan order of the minimum encoding unit, or the raster scan order Neighbor information can be referred to.

The image data decoding unit 1530 according to an exemplary embodiment may search for a position of a data unit according to a scan order. For example, the position of each maximum encoding unit can be retrieved based on the maximum encoding unit address according to the raster scan order.

In addition, the position of the minimum encoding unit in the maximum encoding unit can be retrieved based on the minimum encoding unit index according to the zigzag scan order. The position of each minimum encoding unit may be retrieved based on the index of the minimum encoding unit according to the raster scan order within the maximum encoding unit. The index according to the zigzag scanning order of the minimum coding unit within the maximum coding unit and the index according to the raster scanning order may be mutually converted.

The position of the maximum encoding unit may be represented by the pixel position of the upper left corner of the current maximum encoding unit relative to the pixel position of the upper left corner of the current picture. The position of the minimum encoding unit may be represented by the position of the upper left pixel of the current minimum encoding unit relative to the pixel position of the upper left corner of the maximum encoding unit.

The image data decoding unit 1530 according to an exemplary embodiment may search for a maximum encoding unit neighboring the current maximum encoding unit and an availability. The maximum coding unit neighboring the current maximum coding unit may include at least one of a left maximum coding unit, an uppermost coding unit, a right uppermost coding unit and a left uppermost coding unit of the current maximum coding unit.

In addition, the image data decoding unit 1530 according to an exemplary embodiment may retrieve the availability of a neighboring minimum encoding unit and a neighboring minimum encoding unit adjacent to a current prediction unit included in the current maximum encoding unit. The minimum coding unit neighboring the current prediction unit may include at least one of a left minimum coding unit, an uppermost minimum coding unit, a right uppermost minimum coding unit, a left uppermost minimum coding unit and a lower left minimum coding unit of the current prediction unit .

In addition, the image data decoding unit 1530 according to an exemplary embodiment may search for the availability of neighboring boundaries and neighboring boundaries of the current prediction unit. The boundary adjacent to the current maximum encoding unit may include a boundary of at least one of a left data unit, an upper data unit, a right upper data unit, a left upper data unit, and a lower left data unit of the current prediction unit.

The image data decoding unit 1530 according to an exemplary embodiment can search for the availability of a depth encoding unit or a prediction unit including the minimum encoding unit based on the encoding information of the minimum encoding unit. Accordingly, the location or availability of a prediction unit, a data unit for each depth, a maximum encoding unit, etc. neighboring the current data unit can be retrieved using the encoding information of the minimum encoding unit neighboring the current data unit.

According to the raster scan order, at the time of scanning the current maximum encoding unit, the maximum encoding unit located on the left side or the maximum encoding unit located on the upper side is already decoded, but the maximum encoding unit located on the right side or the maximum encoding unit located on the lower side Units are not yet decoded.

In order to compare an existing macroblock with a hierarchical data unit according to an embodiment, it is assumed that a maximum encoding unit includes at least one macroblock. For example, assume that the first macroblock and the second macroblock are included in the same maximum coding unit, and the first macroblock is located adjacent to the lower left of the second macroblock.

According to the raster scan order, the first macro block is rearranged from the second macro block, and according to the zigzag scan order, the first macro block is higher than the second macro block. In the conventional encoding scheme, the first macro block, which is a rearranged macroblock, is decoded later than the second macro block according to the raster scan method, so that the information of the first macro block can not be referred to by the second macro block. Meanwhile, the video encoding apparatus 1400 according to an embodiment may refer to the first macro block as neighbor information of the second macro block to perform the second decoding of the second macro block.

Since the video encoding apparatus 1400 and the video decoding apparatus 1500 according to the embodiment use a raster scan method as well as a zigzag scan method for each hierarchical encoding unit, a wide range of neighbor information can be used have.

16 illustrates a raster scan sequence of a maximum encoding unit according to an embodiment of the present invention.

According to one embodiment, the maximum encoding unit 1610 is scanned from the left end to the right end of the picture 1600 and from top to bottom according to the raster scan order. Therefore, according to the raster scanning order, at the time of scanning the current maximum encoding unit, the maximum encoding unit located on the left side or the maximum encoding unit located on the upper side is already scanned, but the maximum encoding unit located on the right side The maximum encoding unit is not yet scanned.

The video decoding apparatus 1500 according to an embodiment can know the position of the current maximum encoding unit according to the raster scan order if the address of the current maximum encoding unit, the size of the largest encoding unit, and the size of the picture are known. At this time, the position of the current maximum encoding unit is a distance from the left upper end of the picture to the upper left end of the current maximum encoding unit, and may be expressed as a pixel position at the upper left of the current maximum encoding unit relative to the pixel position at the upper left of the picture have.

Referring to FIG. 9, a scanning order of partial data units of depth-based coding units will be described. Depending on the depths 0, 1, ..., d-1, the partial data units of the depth-coded units are in raster scan order. For example, in the case of depth 0, partial data units of index 0, 1 are scanned in the index order in the partition type 914 having the size 2N_0xN_0 and the partition type 916 having the size N_0x2N_0. In the partition type 918 of size N_0xN_0, the partial data units of indexes 0, 1, 2, and 3 can be scanned in the index order.

The video data decoding unit 1530 of the video decoding apparatus 1500 according to an exemplary embodiment may search for a position of a partial data unit for each depth encoding unit. Knowing the index of the current partial data unit, the size of the partial data unit, and the size of the current coding unit in the current depth coding unit, the position of the current partial data unit according to the raster scanning order can be known.

Here, the position of the current partial data unit is the distance from the upper left corner of the current depth data unit to the upper left corner of the current partial data unit, and the left side of the current partial data unit relative to the upper left pixel position of the current depth data unit Can be represented by the pixel position at the top.

According to one embodiment, the minimum encoding units in the largest encoding unit may be scanned according to a zigzag scan order or a raster scan order. Thus, for the minimum encoding unit, an index based on the zigzag scan order and an index based on the raster scan order can be defined. Hereinafter, FIG. 17 shows the minimum encoding unit according to the raster scan order, and FIG. 18 shows the minimum encoding unit according to the zigzag scan order.

17 illustrates a raster scan sequence of a minimum encoding unit according to an embodiment of the present invention.

According to one embodiment, the minimum encoding unit 1710 is scanned from the left end to the right end of the maximum encoding unit 1700 and from top to bottom according to the raster scan order. That is, starting from the uppermost coding unit, the lower bits are scanned in the order of the minimum coding units of index 0, 1, 2, 3, 4, 5, 6 and 7 from the left end to the right end, , 10, 11, 12, 13, 14, and 15, and then down to the lower level and scanned in the order of the minimum encoding units of indices 16, 17, 18,

The video data decoding unit 1530 of the video decoding apparatus 1500 according to the embodiment can search for the position of the minimum encoding unit in the maximum encoding unit. Knowing the index of the current minimum encoding unit, the size of the minimum encoding unit, and the size of the largest encoding unit according to the raster scan order, the position of the minimum encoding unit according to the raster scan order can be known.

The position of the minimum encoding unit is a distance from the upper left of the current maximum encoding unit to the upper left end of the current minimum encoding unit and is a distance from the upper left pixel of the current minimum encoding unit relative to the pixel position of the upper left corner of the current maximum encoding unit Position.

FIG. 18 shows a zigzag scanning order of coding units according to depths according to an embodiment of the present invention.

The depth-dependent encoding units of the same depth are scanned in a zigzag scan order. For example, the maximum coding unit 1800 has a depth of 0, and the minimum coding unit 1810 has a depth of 3. The four minimum encoding units can be grouped and scanned in a zigzag scan order. That is, the minimum coding units of index 0, 1, 2 and 3 are scanned in zigzag order, and the minimum coding units of index 4, 5, 6 and 7 are scanned in zigzag order.

In addition, the group of the minimum encoding units having indexes 0, 1, 2, and 3 is the encoding unit of depth 2. Therefore, the first group including the minimum coding units having indices 0, 1, 2, and 3, the second group including the minimum coding units having indices 4, 5, 6, and 7, and the second group including indices 8, 9, 10, The fourth group including the minimum encoding units of indexes 12, 13, 14, and 15 may be scanned in zigzag order as the encoding units of depth 2, respectively.

Similarly, for a depth 1 coding unit that includes four coding units of depth 2, the coding units of four depth 1 can be scanned in a zigzag order.

The video data decoding unit 1530 of the video decoding apparatus 1500 according to the embodiment can search for the position of the minimum encoding unit in the maximum encoding unit. Knowing the index of the current minimum encoding unit, the size of the minimum encoding unit, and the size of the maximum encoding unit according to the zigzag scan order, the position of the minimum encoding unit according to the zigzag scan order can be known.

The position of the minimum encoding unit is a distance from the upper left of the current maximum encoding unit to the upper left end of the current minimum encoding unit and is a distance from the upper left pixel of the current minimum encoding unit relative to the pixel position of the upper left corner of the current maximum encoding unit Position.

The image data decoding unit 1530 of the video decoding apparatus 1500 according to the embodiment can convert the index according to the zigzag scanning order of the minimum coding unit and the index according to the raster scanning order within the maximum coding unit. For the conversion of the index according to the zigzag scanning order of the minimum coding unit and the index according to the raster scanning order, the size, current depth and maximum depth of the maximum coding unit can be considered.

FIG. 19 illustrates the maximum encoding units neighboring the current maximum encoding unit according to an embodiment of the present invention.

The video encoding apparatus 1400 according to an exemplary embodiment may refer to a neighboring maximum encoding unit for encoding based on a maximum encoding unit. In addition, the video decoding apparatus 1500 may refer to a neighboring maximum encoding unit for decoding based on a maximum encoding unit.

The left maximum coding unit 1910, the uppermost coding unit 1920, the right uppermost coding unit 1930 and the upper left uppermost coding unit 1940 are referred to as neighboring maximum coding units of the current maximum coding unit 1900 . Since the maximum encoding unit conforms to the raster scan scheme, the maximum encoding unit located on the right side of the current maximum encoding unit 1900 and the maximum encoding units located on the lower end can not be referred to as neighbor information.

The video data decoding unit 1530 of the video decoding apparatus 1500 according to an exemplary embodiment may search for an address and availability of a neighboring maximum encoding unit. The address of the neighboring maximum encoding unit may be represented by a position relative to the address of the current maximum encoding unit.

The image data decoding unit 1530 according to an exemplary embodiment may retrieve the availability for each maximum encoding unit. (i) when the maximum encoding unit is included in the current picture, (ii) when the maximum encoding unit is not included in the current slice, and (iii) when the address of the maximum encoding unit is later than the address of the current maximum encoding unit , The data of the maximum encoding unit can be retrieved as available.

FIG. 20 shows an existing macroblock according to the raster scanning scheme.

Existing codecs such as H.264 use macroblock units with a maximum size of 16x16. The neighboring macroblocks of the same picture 2000 may be referred to for decoding the current macroblock 2010. However, since the macroblocks are decoded according to the raster scan order, the macroblock 2020 located at the lower left is not yet decoded It can not be referred to by the current macroblock 2010. Hereinafter, when the data unit has not yet been decoded and can not be referred to by the current encoding unit, it is defined that the corresponding data unit is unavailable.

Figure 21 shows a current prediction unit according to a zigzag scan sequence, in accordance with an embodiment of the present invention.

Since the existing encoding method scans a macroblock according to a raster scan method, information of a first macroblock, which is a rearrangement, can not be referred to by the second macroblock. Meanwhile, the video encoding apparatus 1400 according to an exemplary embodiment may refer to the first macro block as neighbor information of the second macro block to encode the second macro block.

Taking picture 2100 as an example, a maximum encoding unit of size 64x64 is decoded in a zigzag scan order between depth-dependent encoding units 2110, 2120, 2130, and 2140 of depth 1, and depth- The depth-dependent coding units 2142, 2144, 2146, and 2148 of depth 2 in the bitstream 2 are also scanned in the zigzag order.

According to the zigzag scanning order, the depth-by-depth coding unit 2150 of depth 1 is decoded and then the depth-by-depth coding unit 2150 of depth 1 is decoded. The decoding of the depth-first coding unit 2150 of depth 1 proceeds in the order of depth-level coding units 2152, 2154 and 2156 of depth 2. [ Since the depth-dependent coding unit 2144 of depth 2 exists at the lower left of the depth-level coding unit 2156 of depth 2, it is already decoded in the zigzag scanning order. Therefore, as the neighbor information of the depth-level coding unit 2156 of depth 2 Can be referenced.

The macroblocks in the raster scan mode are decoded at a later position than the block 2156 in the scan order. Therefore, block 2156 can not refer to the information in block 2144.

Figure 22 illustrates the minimum encoding units neighboring the current prediction unit, in accordance with an embodiment of the present invention.

There are maximum coding units 2210, 2220, and 2230 of depth 0, and a size 2240 of the minimum coding unit is set to a depth 3. The neighbor information of the current prediction unit 2250 of the current maximum encoding unit 2210 indicates an external minimum encoding unit neighboring the minimum encoding unit in the current prediction unit 2250.

For example, the left neighbor information, the upper neighbor information, and the upper left neighbor information of the current prediction unit 2250 are respectively allocated to the minimum encoding unit 2256 located at the left side of the minimum encoding unit 2256 located at the upper left in the current prediction unit 2250, A unit 2262, a minimum encoding unit 2260 located at the upper end, and a minimum encoding unit 2266 located at the upper left end.

The upper right neighbor information of the current prediction unit 2250 indicates the minimum encoding unit 2264 positioned at the right upper end of the minimum encoding unit 2254 located at the upper right of the current prediction unit 2250. The lower left neighbor information of the current prediction unit 2250 indicates the minimum encoding unit 2268 positioned at the lower left of the minimum encoding unit 2256 located at the lower left in the current prediction unit 2250.

The video data decoding unit 1530 of the video decoding apparatus 1500 according to an exemplary embodiment may search for the location and availability of a minimum encoding unit or a maximum encoding unit neighboring the current prediction unit. The address of the neighboring minimum encoding unit or the position of the maximum encoding unit may be represented by the index of the minimum encoding unit neighboring the current prediction unit and the address of the maximum encoding unit including the neighboring minimum encoding unit.

(i) when the maximum encoding unit is included in the current picture, (ii) when the maximum encoding unit is not included in the current slice, (iii) when the address of the maximum encoding unit is later than the address of the current maximum encoding unit, and and iv) the case where the index according to the zigzag scanning order of the minimum coding unit at the upper left of the coding unit for each depth is one of the following order than the index according to the zigzag scanning order of the current minimum coding unit, Can be searched for available.

The index of the minimum coding unit located at the upper left of the current prediction unit, the index of the minimum coding unit located at the upper right corner of the current prediction unit, or the index of the minimum coding unit located at the lower left of the current prediction unit And information on the division type information and the current depth is needed. Also, if the size of all the partial data units is not the same, an index of the partial data unit for the current prediction unit is needed.

23 illustrates a method of predicting a motion vector using neighbor information according to an embodiment of the present invention.

The video coding apparatus 1400 and the video decoding apparatus 1500 according to an embodiment may refer to a motion vector of a prediction unit neighboring the current prediction unit when motion prediction is performed according to the inter mode .

That is, in order to predict the motion information of the current prediction unit 2300, motion information MV_A 2310, MV_B 2320, MV_C 2330, MV_D 2340, and MV_E 2350 of neighboring prediction units are referred to . The motion information MV_A 2310, MV_B 2320, MV_C 2330, MV_D 2340 and MV_E 2350 are allocated to the left, upper, right, upper left, and lower left neighbor of the current prediction unit 2300 Information. The motion information MV_A 2310, MV_B 2320, MV_C 2330, MV_D 2340 and MV_E 2350 can be retrieved using the encoding information of the minimum encoding unit of the prediction unit.

24 illustrates an interpolation method using neighbor information according to an embodiment of the present invention.

The video encoding apparatus 1400 and the video decoding apparatus 1500 according to an embodiment may refer to a pixel value on a boundary of a prediction unit neighboring a current prediction unit when prediction encoding according to the intra mode is performed .

That is, in order to predict the pixel value of the current prediction unit 2400, pixel values on the boundary of neighboring data units, i.e., the context pixels 2410 and 2420, can be referred to and used. Of these, the context pixel 2430 is neighbor information located at the lower left of the current prediction unit 2400.

The existing codec based on the macroblock unit according to the raster scanning order can not use the neighbor information located at the lower left of the current macroblock, i.e., the motion information MV_E (2350) or the context pixel (2430) as neighbor information.

However, since the video encoding apparatus 1400 and the video decoding apparatus 1500 according to the embodiment encode or decode encoding units of depth according to the hierarchical depth according to the zigzag scanning order, Neighbor information located at the lower end may be referred to. Accordingly, the video coding apparatus 1400 and the video decoding apparatus 1500 according to an embodiment check the availability of the lower left neighbor information of the current prediction unit, and if available, Information can be referred to in the encoding or decoding of the current prediction unit.

25 illustrates a video encoding method that refers to neighbor information according to an embodiment of the present invention.

In step 2510, the current picture is divided into at least one maximum encoding unit which is a maximum-size encoding unit.

In step 2520, the image data is encoded for each maximum encoding unit based on the depth-dependent encoding unit that is hierarchically reduced as the depth increases, so that at least one encoding depth is determined. The image data is encoded in consideration of the raster scan order between the maximum encoding units and the zigzag scan order between the depth encoding units included in each maximum encoding unit. In addition, it is possible to encode by referring to the available neighbor information considering the scan order between data units.

In step 2530, the image data and the coding depth and coding mode information encoded with one coding depth are coded and output for each maximum coding unit.

26 illustrates a video encoding method that refers to neighbor information according to an embodiment of the present invention.

In step 2610, the bitstream for the encoded video is received and parsed. The encoded image data of the current picture allocated to the maximum encoding unit, which is the encoding unit of the maximum size, is obtained from the bitstream parsed in step 2620, and information on the encoding depth and encoding mode for each maximum encoding unit is extracted.

In step 2530, the image data encoded per the maximum encoding unit is decoded in consideration of the raster scan order of the maximum encoding unit and the zigzag scan order of the depth encoding units. The position of the maximum coding unit according to the raster scanning order and the position of the coding unit according to the zigzag scanning order can be searched and the index according to the zigzag scanning order of the minimum coding unit and the index according to the raster scanning order can be mutually converted have.

The availability of the neighbor information is retrieved in consideration of the scan order of various hierarchical data units such as the raster scan order of the maximum encoding unit or the prediction unit, the zigzag scan order of the minimum encoding unit, or the raster scan order, Neighbor information can be referenced. The neighbor information according to an exemplary embodiment may include information on a data unit positioned at the lower left of the current data unit.

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 may be a magnetic storage medium such as a ROM, a floppy disk, a hard disk, etc., an optical reading medium such as a CD-ROM or a DVD and a carrier wave such as the Internet Lt; / RTI > transmission).

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 (1)

Video coding method and apparatus considering the scanning order of hierarchical coding units, video decoding method and apparatus

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