KR20150021980A - Method for decoding partitioned block in video decoding and recording medium implementing the same - Google Patents

Abstract

Disclosed are a method of encoding a division block in video encoding and a method of decoding a division block in video decoding. An input picture is divided into encoding unit blocks. The encoding unit block is divided into sub-encoding unit blocks. The sub-encoding unit blocks are encoded by selectively using at least one of intra prediction encoding and inter prediction encoding in the encoding unit block or each sub-encoding unit block. A decoding process is performed through a reverse process of the encoding method. When pixel values of an encoding unit block are encoded in video encoding, the flexibility in selecting an encoding mode is improved, and the efficiency of encoding is improved.

Description

TECHNICAL FIELD The present invention relates to a method of decoding a divided block in video decoding and a recording medium implementing the same.

The present invention relates to a method capable of coding an input picture on a block-by-block basis and a method of coding and decoding a divided block using both in-picture and inter-picture prediction coding in video coding and decoding, In addition, in the video coding in which the coding efficiency is further improved by coding the block video signal using a squared or non-squared conversion according to the size of the divided block, And a method of dividing block coding and decoding through intra prediction.

ISO / IEC 14496-10 (MPEG-4 Part 10 Advanced Video Coding) or H.264 and ISO / IEC 14496-10 amendments to video compression coding standard jointly standardized by ISO / IEC and ITU-T. (MPEG-4 Scalable Video Coding) standard, the SMPTE standard VC-1, and the Audio Video Coding Standard (AVS) standard have made many advances in video data compression efficiency.

However, the conventional video coding standards (MPEG-1 Video, MPEG-2 Video, MPEG-4 Part 2 Visual, H.261, H.263, etc.) 16 × 16, 8 × 16, 8 × 8, 8 × 4, 16 × 16, 16 × 16, 16 × 16, 16 × 16, 16 × 16, 16 × 16, and 16 × 16 pixels as compared with the case where the size of a picture to be coded is divided into macroblocks 4 × 8, and 4 × 4 units, performs prediction coding on these sub-blocks, and encodes the block that minimizes cost in terms of rate-distortion cost as an optimal block mode.

By doing so, it is possible to more effectively perform fine motion or complex motion prediction, and significantly reduce the residual signal, thereby greatly improving the compression efficiency.

FIG. 1 is a diagram showing a divided block type of a 16 × 16 macroblock unit block for coding in the conventional H.264 | AVC encoder, and shows seven types of motion prediction block division types used in H.264.

As shown in FIG. 1, a block-based predictive coding scheme divides an input image into 16 × 16 macroblocks and encodes the input image. Particularly, in ISO / IEC 14496-10 (MPEG-4 Advanced Video Coding) or H.264 standard, a block which minimizes the rate-distortion cost by dividing a macroblock into seven sub-blocks is finally selected and predicted And performs encoding.

When the intra-picture coding is performed on the sub-blocks divided for the 16x16 macroblock to be coded, the intra-picture prediction coding is performed with a size of one 16x16 pixel unit for each macroblock, Performs intra-picture prediction coding of 8x8 blocks, or intra-picture prediction coding of 16 4x4 blocks.

Generally, in the low-resolution video coding, the intra-picture prediction coding method has a coding efficiency in terms of reducing the number of cases in the multi-block mode. However, in the high definition (HD) or ultra high definition (UHD) There is a problem. That is, in the case of a super macroblock having a size of 32 × 32 or more that is a 16 × 16 macroblock extended as an encoding unit block, the mode of all divided blocks in the super macroblock is 16 × 16, 8 × 8, or 4 × 4 block based on the same intra-picture prediction, the coding efficiency is lowered.

In other words, in the conventional divided block-based predictive encoding method, it is to be noted that all of the divided blocks are encoded only by intra picture coding or inter picture prediction coding. That is, only one of the intra-picture prediction coding and the intra-picture prediction coding is selected and applied. This is because, by applying only one of intra-picture coding and inter-picture coding, there is a gain in coding efficiency for image or video compression below HD resolution due to simplification of the syntax for expressing the block coding mode. However, In the case of a macroblock, the coding efficiency may be degraded.

The present invention has been conceived to solve the above-described problems, and it is an object of the present invention to provide a method and apparatus for expanding an intra picture or inter picture prediction coding selection scheme for sub- Mode encoding method, and selectively applying a square or non-square transformation kernel according to a block size to a residual signal after motion compensation of a divided block, thereby providing a more efficient predictive encoding method .

Another object of the present invention is to provide a computer readable recording medium on which the above method is implemented.

According to an aspect of the present invention, there is provided a method for coding an input picture by dividing an input picture into coding unit blocks, dividing the coding unit block into sub-blocks, and selecting one of the intra- .

The method may further include a step of selectively applying a variable transform kernal to the residual signal through the coding unit block and the subblock according to a block size, performing quantization on the variable transform kernal, and entropy coding the result have.

One or more block-based de-blocking filters may be selectively applied to the residual signal through the lower block according to the block size and the encoding type.

The size of the encoding unit block may be a square of N * N size, and the encoding unit block may be divided into one or more sub-blocks that are squared or non-squared at an arbitrary size.

When encoding the sub-blocks of square or non-square form using intra-picture prediction coding, one intra-picture prediction coding method among the intra-picture intra prediction coding methods may be selected and encoded.

In case of performing intra-picture prediction coding or inter picture prediction coding on the square or non-square sub-blocks, the quantized transform coefficients selected according to the block size may be scanned to perform entropy coding.

A square transform kernel can be applied to the sub-blocks of the square.

The square transform kernel may be applied to the square sub-block to compare the number of horizontal pixels of the sub-block of the square with the number of vertical pixels to apply a square transform kernel corresponding to a smaller or equal number of pixels.

Square conversion kernel can be applied to the non-square sub-block.

Square conversion kernel is applied to the non-square sub-block, the number of horizontal pixels of the non-square sub-block is compared with the number of vertical pixels to apply a non-square conversion kernel corresponding to the number of pixels smaller or equal .

A divided block coding method in video coding according to another exemplary embodiment of the present invention includes the steps of (a) inputting a picture to be coded, (b) dividing the input bottom into coding unit blocks, (c) Dividing an encoding unit block into sub-blocks, (d) performing intra-picture prediction encoding and inter-picture prediction encoding on the encoding unit block and its sub-blocks, selecting one of the block types, and ) Performing intra-picture prediction coding and / or inter picture prediction coding on the sub-block including the coding unit block using the prediction result of the block type.

(B ') dividing the input picture into coding unit blocks, (c') compressing the picture into unit blocks, and (c ' (D ') initializing a sequence of sub-blocks of an encoding unit block to be encoded on an input screen when the current input screen is an inter-screen prediction, determining whether the current input picture is to be inter- , (e ') selecting a block mode of a coding unit block to be coded, (f') determining whether to perform both intra picture coding and inter picture prediction coding on the selected block mode, (g ') selecting Performing in-picture and inter-picture predictive coding on the selected block mode when both the in-picture and inter-picture predictive coding are performed on the block mode, (h ') performing the in- (I '). If the selected block mode is the final mode, the rate-distortion cost for each block mode is compared to select the last block mode for the encoding unit block, Determining whether the current encoding unit block is the last block in the current input picture, and (k ') determining whether the current encoding unit block is the last block in the current input picture, And repeating the steps (a ') to (j') until the current input screen becomes the final screen.

After the step (c '), if the current input picture is not inter-picture prediction, performing intra-picture prediction coding may be further performed.

After the step (f '), if the intra-picture prediction and the inter-picture prediction coding are not performed for the selected block mode, the inter-picture prediction coding may be performed for the selected block mode.

When the inter-picture prediction coding is performed on the selected block mode after the step (g '), a residual signal is obtained through motion prediction and compensation, the selected block is transformed using the residual signal, , And entropy-encoding the result.

In case of performing intra-picture prediction coding on the selected block mode after the step (g '), a residual signal is obtained through intra-picture prediction coding, the selected block is transformed using the residual signal, And entropy-encoding the result.

And converting the selected block using the residual signal by applying a conversion kernel selectively according to the size of the block.

(A) inputting a bitstream to be decoded, (B) determining whether an input bitstream is an inter-picture prediction, (C) (D) interpolating a slice when the input bitstream is inter-picture prediction, (E) interpreting a unit encoded block in the slice, and Decoding the lower divided block coding mode of the unitary coded block, (G) interpreting whether the lower divided coding block is an inter picture predictive coding block, (H) (I) performing intra prediction decoding when the lower-sub-coded block is intra-picture prediction, (J) (K) constructing the decoding unit block result as slice pixels, and (K) constructing the slice pixel configuration result as a screen. Intra-block prediction and / or inter-picture prediction decoding.

In the step (C), if the unit encoding block is a super macroblock having a size of 16x16 macroblocks or more, the step of decoding the lower divided block encoding mode corresponding to the size to perform intra prediction decoding may be performed.

In step (C), a step of applying intra-picture prediction decoding by applying a de-blocking filter corresponding to the size of the lower sub-block may be performed.

In step (C), the intra-picture prediction decoding may be performed by applying a de-blocking filter according to the size of the lower sub-block.

In the step (F), if the unit encoding block is a super macroblock having a size of 16 × 16 macroblocks or more, decoding the subdivision block encoding mode corresponding to the size may be further included.

In the step (H), the step of decoding the quantized transform coefficients by applying a square or non-square transforming kernel corresponding to the size of the sub-block may be performed to perform intra picture prediction decoding.

In step (H), the step of decoding the encoded quantized transform coefficient by applying an inverse quantization method according to the size of the sub-block and the decoding mode condition of the surrounding decoding block may be performed to perform intra prediction decoding .

In step (H), the inter-picture prediction decoding may be performed by applying a de-blocking filter corresponding to the size of the lower block.

In another embodiment of the present invention, there is provided a computer-readable recording medium on which a program capable of executing the above method by a computer is recorded.

The present invention encodes a pixel value of an encoding unit block in a video encoding, encodes the divided lower block or its sub-block by applying at least one intra-picture prediction encoding and inter-picture prediction encoding, Or inter-picture prediction coding mode so that the coding unit block or the sub-divided block is predictively coded using both intra picture and inter picture prediction, thereby increasing the flexibility of coding mode selection and increasing the coding efficiency .

In addition, in the present invention, in the divided block-based predictive coding, each divided block can apply both intra-picture prediction and inter-picture prediction to the sub-divided blocks underneath, and the variable- The coding efficiency is greatly improved by performing coding by applying a variable block-size transform kernel (Kernel) size.

FIG. 1 is a diagram showing a divided block type of a 16 × 16 macroblock unit block for encoding in a conventional H.264 | AVC encoder; FIG.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a super macro block and a divided block type for intra-picture or inter-picture prediction coding in an encoder according to an embodiment of the present invention.
3 is a flowchart illustrating a divided block coding method in video coding according to an embodiment of the present invention.
FIG. 4 is a flowchart illustrating a method of decoding a bitstream encoded by a split block method of video according to an embodiment of the present invention; FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used for the same reference numerals even though they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 2 is a diagram illustrating a super macroblock unit block and a split block type for intra picture or inter picture prediction coding in an encoder according to an embodiment of the present invention. Referring to FIG. FIG. 2 is a diagram illustrating an example of a super macroblock and a block division type that are larger than a 16 × 16 pixel unit macroblock size applied in an embodiment of the present invention.

 As shown in FIG. 2, the super macroblock is divided into sub-blocks and the intra-picture or inter-picture predictive coding process is performed on each divided block, so that the final coding mode is a mixed mode So that the coding efficiency of the image can be increased very effectively. A block mode that minimizes the rate-distortion cost can be selected and encoded in the actual encoding as shown in Equation (1).

는 모드에 의존적인 라그랑지안 승수이고, MODE는 분할 블록 모드 타입을 나타낸다.Where J _MODE is the rate-distortion function for the block coding mode, s is the original block pixel input to be encoded, r is the reference image pixel input, QP is the quantization parameter,

Is a mode-dependent Lagrangian multiplier, and MODE represents a split block mode type.

In addition, when transform coding is applied to the residual signal of the super macroblock whose size has been increased, a square conversion kernel having a size of 16x16 or more, which is larger than the conventional 4x4 and 8x8, or 16x8, The encoding efficiency can be increased by selectively applying the non-square conversion kernel of size 8x16 or more according to the size of the divided block.

If a square transform kernel of 16x16 or more size is applied to the super macro block, it can be calculated as shown in Equation (2).

Where X denotes an NxN input image signal matrix, A denotes an NxN square transform kernel matrix, and Y denotes a transformation coefficient matrix. If the divided sub-blocks are non-square blocks, the transform is performed as shown in Equation (3).

Here, when the input image signal X is an Mx (M / 2) matrix, A ₁ represents an MxM square transform kernel matrix, A ₂ represents an (M / 2) x (M / 2) square transform kernel matrix, Represents a coefficient matrix.

In one embodiment of the present invention, when a square or non-square kernel transformation is applied, it is preferable to perform a transcoding by applying a kernel equal to or smaller in size than the number of pixels in the horizontal or vertical pixel of the divided block .

3 is a flowchart illustrating a divided block coding method in video coding according to an embodiment of the present invention.

Referring to FIG. 3, first, the sequence of the picture (i) for encoding is initialized (i = 0) (S101). Then, the screen i is input in order for encoding (S102).

Next, the input picture (i) is divided into coding unit blocks (S103). In an embodiment of the present invention, the encoding unit block may be a macroblock or a super macroblock.

Next, it is confirmed whether or not the current picture (i) is to perform inter picture prediction coding (S104). If the current picture (i) is not inter-picture prediction, intraprediction encoding is performed (S105). Otherwise, if the current picture (i) is inter-picture prediction, the coding unit The sequence of the block j is initialized (j = 0) (S106).

Subsequently, the unit block j to be encoded is divided into sub-blocks (S107). Then, the order of the sub-block mode (k) is initialized (k = 0) (S108). One block mode is selected from the sub-block mode (k) (S109).

Whether the in-picture and inter-picture prediction are performed for the sub-block mode to be coded in the coding unit block is checked (S110). When inter-picture prediction and intra-picture prediction are performed, in-picture and inter-picture coding are performed (S111), and if not, inter-picture prediction coding is performed only (S112). Then, the prediction encoding result and the rate-distortion cost value, which are encoding results, are stored (S113).

It is confirmed whether the sub-block mode (k) is the last block mode (S114). If the sub-block mode (k) is not the final block mode, steps S109 to S113 are repeated for the next block mode. On the other hand, if the sub-block mode (k) is the last block mode, the optimal sub-block mode is determined and the corresponding encoding result is finally selected (S115).

Then, it is determined whether the current encoding unit block j is the last block in the current screen (i) (S116). If the current encoding unit block j is not the last block, the next encoding unit block is input and steps S107 to S115 are repeated.

If the encoding unit block j is the last block in the current screen (i) in step S116, it is checked whether the current screen (i) is the final screen (S117). If the current screen (i) is the final screen, the algorithm is terminated. Otherwise, the flow returns to step S102 to input the next screen, and steps S102 to S116 are repeated.

FIG. 4 is a flowchart illustrating a method of decoding a bitstream encoded by a divided block method of a video according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 4, first, the sequence of the screen (i) for decoding is initialized (i = 0) (S201). Then, a screen encoded bitstream i is input in order to decode (S202).

Next, it is confirmed whether the inputted screen bitstream (i) is inter picture prediction coding (S203). In the case where the current screen bitstream i is not inter picture prediction coding, intraframe prediction decoding is performed (S207). Otherwise, when the current input picture bit stream i is inter-picture prediction coding, (j = 0) of the sequence of the slices j to be decoded in the i-th block (S204).

Next, the slice information is analyzed for the input screen bit stream (S205). The sequence of the unit decoding block j to be decoded in each slice in one screen i is initialized (k = 0) (S206). In an embodiment of the present invention, the decoding unit block may be a macroblock or a super macroblock.

Next, after unit encoding block information is analyzed (S208), the order of the sub-block in the unit encoding block is initialized (m = 0) (S209). Thereafter, the encoding mode of the lower divided block in the unit encoding block is decoded (S210). After determining that the sub-block is an inter-picture predictive coding block (S211), the inter-picture predictive decoding is performed if the inter-picture predictive coding block is performed (S213) S212).

Subsequently, the lower divided block pixel value is restored using the lower divided block decoding result (S214). If it is determined in step S215 that the current sub-block m is the last block, the unit decoding block pixel value is constructed in step S216. Otherwise, the sub-sub-block m is decoded in step S210 And performs steps S210 to S214.

If it is determined that the current unit encoding block k is the last unit encoding block (S217), a slice pixel is formed if it is the last unit encoding block (S218). If not, the process returns to S208 and S208 to S216 are performed do. After confirming that the current slice j is the final slice (S219), if the current slice is the last slice, a screen pixel is constructed (S220). Otherwise, steps S205 to S218 are performed. If it is determined that the current screen (i) is the final screen (S221), the process ends if it is the final screen. Otherwise, the process returns to step S202 to input the next screen bitstream and performs steps S202 and S220.

In video coding according to an embodiment of the present invention, an input image is divided into coding unit blocks, a coding unit block is divided into sub-blocks again, and one or more of intra-picture prediction and inter- To perform coding.

By doing so, the coding mode of the coding unit block can be encoded in a mixed manner in the inter-picture prediction mode and the intra-picture prediction sub-block mode, and at the same time, the coding efficiency can be improved by selectively applying the variable kernel conversion according to the divided block.

In addition, video decoding according to an embodiment of the present invention can perform decoding of a compressed bitstream having an improved coding efficiency by performing an inverse process of a coding process.

As another embodiment of the present invention, the sub-divided block coding method in the above-described video coding can be implemented as a computer-readable code on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored.

For example, the computer-readable recording medium includes a ROM, a RAM, a CD-ROM, a magnetic tape, a hard disk, a floppy disk, a removable storage device, a nonvolatile memory, , Optical data storage devices, and the like, as well as carrier waves (for example, transmission over the Internet).

In addition, the computer readable recording medium may be distributed and executed in a computer system connected to a computer communication network, and may be stored and executed as a code readable in a distributed manner.

In the video coding according to the present invention, the intra-picture prediction coding method and / or the inter-picture prediction coding method are described. However, the embodiments are merely illustrative It is not limited. It will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention and the scope of the appended claims.

Claims (6)

Dividing an input video bitstream into decoding unit blocks;
Dividing the decoding unit block into sub-blocks that are not further divided;
Decoding, for each of the sub-blocks not further divided, predictive encoding mode information indicating whether a sub-block is coded in an intra prediction encoding mode or an inter picture prediction encoding mode;
Performing intra-picture prediction or inter-picture prediction decoding on each of the sub-blocks that are not further divided according to the predictive coding mode information; And
Reconstructing each of the sub-blocks that are not further divided using the intra-picture prediction or the inter-picture prediction decoding result for each of the sub-blocks that are not further divided,
And decodes the divided block into a plurality of blocks. The method according to claim 1,
The step of performing intra-picture prediction or inter picture prediction decoding includes:
An intra-picture prediction is performed on the at least one sub-block when the predictive encoding mode of at least one sub-block among the sub-blocks not further divided from the decoded unit block is decoded into the intra-picture prediction mode, and,
And inter-picture prediction is performed on the remaining sub-blocks when the predictive encoding mode of the remaining sub-blocks is decoded in the inter-picture prediction mode from among the sub-blocks not further divided from the decoded unit block A method of decoding a divided block in video decoding. The method according to claim 1,
Wherein dividing the sub-blocks into sub-
Wherein a dividing process is performed in a recursive manner until a prediction coding mode for intra-picture prediction or inter-picture prediction is determined from the decoding unit block to be sub-blocks which are not further divided. Block decoding method. The method of claim 3,
Wherein the subblocks that are not further partitioned further comprise:
Wherein a depth of the sub-block is incremented by one step each time the dividing process is performed from the decoding unit block. 6. The method of claim 5,
Wherein the decoding unit block is a square block having a size larger than 16x16. The method according to claim 6,
And performing inverse transform by using a variable-size conversion kernel equal to or smaller than the sub-block size for each of the sub-blocks that are not further partitioned, in the video decoding, Way.

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