KR20220074835A - Apparatus and method for encoding and decoding to image of ultra high definition resoutltion - Google Patents

Abstract

An encoding apparatus and method, and a decoding apparatus and method using intra prediction encoding are provided. The encoding apparatus generates a prediction block of a current block according to any one of a plurality of predefined methods for generating prediction blocks, and entropy-encodes at least one of encoding information and residual blocks according to whether the residual blocks are encoded into a bitstream. can be printed out.

Description

Apparatus and method for encoding ultra-high-resolution video, and apparatus and method for decoding

The present invention relates to a technique for lowering computational complexity and improving encoding efficiency during intra prediction encoding in an ultra-high-resolution image.

Broadcasting services having high definition (HD) resolutions such as 1280×1024 and 1920×1080 are expanding not only in Korea but also worldwide. Accordingly, users are demanding higher resolution and higher quality content, such as 4K (3840×2160) and 8K (7680×4320), in order to view more realistic images.

The number of pixels of a 4K image is four times the size of an HD image, and the number of pixels of an 8K (7680x4320) image is 16 times the size of an HD image. Accordingly, 4K and 8K images can express more delicate and natural images compared to images with HD resolution. In general, H.264/AVC (MPEG-4 Part 10 Advanced Video Coding) is used to encode a 4K or 8K video.

As such, as the resolution of an image increases, the spatial correlation between pixels may be greatly increased.

1 is a diagram comparing the number of pixels used to express a part of an image for each resolution.

In FIG. 1, when the number of pixels used to express a part of an image is 4 at 480×270 resolution higher than QVGA (352×288) resolution, 960×540 resolution and FULL HDTV (1920×1080) express a part of the image The number of pixels used for this is 9 and 25, respectively. And, in 4K (3840×2160) resolution, the number of pixels is 100, and in 8K (7680×4320) resolution, a part of the image is expressed by the number of 361 pixels. As such, in the 4K and 8K resolution images, the number of pixels used to express a portion of a specific image increases excessively. In other words, images of 4K and 8K resolution have a very high correlation between pixels than images of HD resolution or less. In particular, in an image or a portion of an image that is not complex and has a flat characteristic, the correlation between pixels is further increased.

As such, when intra prediction is performed on an ultra-high-resolution image with very high correlation between pixels, such as 4K or 8K, the pixel value of the current block can be almost predicted using only the pixel values of the neighboring blocks. Accordingly, when the correlation between pixels is high, the process of encoding and decoding the residual block increases computational complexity and reduces encoding efficiency.

Accordingly, when encoding and decoding an ultra-high-resolution image having a high correlation between pixels, there is a need for an encoding and decoding technique capable of improving encoding efficiency while reducing computational complexity.

The present invention provides an encoding apparatus and method, and a decoding apparatus and method capable of reducing computational complexity due to intra prediction encoding for an ultra-high resolution image having high inter-pixel correlation.

In addition, the present invention provides an encoding apparatus and method, and a decoding apparatus and method capable of improving encoding efficiency by performing encoding and decoding using a prediction block having the highest encoding efficiency among a plurality of prediction blocks.

An encoding apparatus according to an embodiment of the present invention includes an intra prediction unit generating a prediction block of a current block based on a reference image, and a subtraction unit generating a residual block based on a difference between the current block and the generated prediction block. , an encoding information generator generating encoding information indicating whether the residual blocks are encoded based on whether the residual blocks are encoded, and entropy encoding at least one of the residual blocks and the encoding information based on the encoding information. It may include an entropy encoder.

Also, when the encoding information includes information indicating that the residual block is not encoded, the entropy encoding unit may generate a bitstream by encoding only the encoding information.

Also, the intra prediction unit may generate the prediction block using any one of a plurality of prediction block generation methods.

Also, the intra prediction unit may generate a plurality of prediction blocks of the current block according to a method of generating a plurality of prediction blocks.

Also, the intra prediction unit may generate one or more prediction blocks of the current block based on a prediction block generation method used to generate prediction blocks of each of the reconstructed neighboring blocks.

In addition, it may include a prediction block selector that selects any one of the generated prediction blocks of the plurality of current blocks.

An encoding method according to an embodiment of the present invention includes generating a prediction block of a current block based on a reference image, generating a residual block through a difference between the current block and the generated prediction block, and the residual block generating encoding information indicating whether the residual block is encoded based on whether the residual block is encoded; transforming and quantizing the residual block based on the encoding information; and the residual block and the residual block based on the encoding information. The method may include entropy encoding at least one of the encoding information.

Also, in the entropy encoding, since the encoding information includes information indicating that the residual block is not encoded, only the encoding information may be encoded to generate a bitstream.

In addition, the generating of the prediction block may include generating a plurality of prediction blocks of the current block according to a method of generating a plurality of prediction blocks.

In addition, the generating of the prediction block may include generating one or more prediction blocks of the current block based on a prediction block generation method used when generating the prediction blocks of each of the reconstructed neighboring blocks.

The method may further include selecting one of the generated prediction blocks of the current block with the best encoding efficiency.

A decoding apparatus according to an embodiment of the present invention includes an entropy decoding unit that extracts encoded encoding information from a bitstream and decodes the encoded encoding information, and a screen for generating a prediction block of a current block using a restored neighboring block and an adder for reconstructing a current block using at least one of an inner prediction unit, a residual block reconstructed based on the decoded encoding information, and a prediction block of the generated current block.

Also, since the encoding information includes information indicating that the residual block is not encoded, the adder may reconstruct the current block using only the prediction block of the current block.

A decoding method according to an embodiment of the present invention includes extracting at least one of encoded encoding information and prediction block selection information from a bitstream, decoding the extracted encoding information and prediction block selection information, and a restored surrounding generating prediction blocks of the current block using the block, selecting any one of the generated prediction blocks of the current block based on the decoded prediction block selection information, and based on the decoded encoding information The method may include reconstructing a current block by using at least one of a reconstructed residual block and a prediction block of the selected current block.

According to the present invention, it is possible to reduce computational complexity by outputting a bitstream using only the prediction block of the current block during intra prediction encoding of an ultra-high resolution image with high correlation between pixels.

According to the present invention, by performing encoding and decoding using a prediction block having the highest encoding efficiency among a plurality of prediction blocks, encoding efficiency can be improved.

1 is a diagram comparing the number of pixels used to express a part of an image for each resolution.
2 is a diagram illustrating a configuration of an encoding apparatus according to an embodiment of the present invention.
3 is a diagram illustrating an overall configuration of an encoding apparatus according to an embodiment of the present invention.
4 is a flowchart provided to explain an operation of an encoding apparatus according to an embodiment of the present invention.
5 is a block diagram illustrating the configuration of a decoding apparatus according to an embodiment of the present invention.
6 is a diagram illustrating an overall configuration of an encoding apparatus according to an embodiment of the present invention.
7 is a flowchart provided to explain an operation of a decoding apparatus according to an embodiment of the present invention.
8 is a diagram illustrating a configuration of an encoding apparatus according to an embodiment of the present invention.
9 is a flowchart provided to explain an operation of an encoding apparatus according to an embodiment of the present invention.
10 is a block diagram illustrating the configuration of a decoding apparatus according to an embodiment of the present invention.
11 is a flowchart provided to explain an operation of a decoding apparatus according to an embodiment of the present invention.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited or limited by the examples. Also, like reference numerals in each figure denote like members.

2 is a diagram illustrating a configuration of an encoding apparatus according to an embodiment of the present invention.

In FIG. 2 , an input image may be processed as a coding unit having a size of 16×16 pixels horizontally and vertically. In this case, the encoding apparatus may output a bitstream generated through intra prediction encoding or inter prediction encoding. First, an intra prediction encoding process will be described with reference to FIG. 2 , and an inter prediction encoding process will be described later with reference to FIG. 3 .

Referring to FIG. 2 , the encoding apparatus 200 includes an intra prediction unit 210 , a reference image buffer 220 , a subtraction unit 230 , an encoding information generation unit 240 , a transform and quantization unit 250 , and entropy encoding. It may include a unit 260 , an inverse quantization and inverse transform unit 270 , and an adder 280 .

The intra prediction unit 210 may generate a prediction block of the current block based on the reference image stored in the reference image buffer 220 . In this case, when using a neighboring block reconstructed as a reference image, the intra prediction unit 210 uses any one of a plurality of predefined methods for generating prediction blocks and pixel values of neighboring blocks spatially adjacent to the current block. A predictive block of a block can be generated.

For example, (1) the intra prediction unit 210 may generate a prediction block of the current block by directly copying (padding) pixels of a neighboring block adjacent to the current block. In this case, the pixels copied (padded) to the current block may vary according to the predicted direction, and the predicted direction information may be encoded and included in the bitstream. In other words, the intra prediction unit 210 may generate the prediction block of the current block by using the H.264/AVC intra prediction method.

As another example, (2) the intra prediction unit 210 determines the prediction direction based on the similarity between the current block and the neighboring block, and copies pixels of the neighboring block according to the determined prediction direction to generate the prediction block of the current block. can In other words, the intra prediction unit 210 selects a neighboring block located in the determined prediction direction from among a plurality of neighboring blocks adjacent to the current block, and copies pixels of the selected neighboring block to generate a prediction block of the current block. can

As another example, (3) the intra prediction unit 210 may extract a block most similar to the current block through matching in the current picture area on which encoding has been performed. And, the intra prediction unit 210 may generate a prediction block of the current block by using the extracted block. In this case, information on the difference between the current block and the prediction block of the current block may be included in the bitstream.

As another example, (4) the intra prediction unit 210 may search for a shape most similar to a neighboring block in a current picture area on which encoding has been performed, and generate a block surrounded by the found shape as a prediction block of the current block.

As another example, (5) the intra prediction unit 210 may generate a prediction block of the current block by mixing a plurality of predefined methods for generating prediction blocks. In this case, the intra prediction unit 210 may generate a prediction block using an average value of prediction blocks generated using a plurality of prediction block generation methods. In addition, the prediction block may be generated by the sum of weights according to each of the plurality of prediction block generation methods.

The subtractor 230 may generate a residual block by subtracting the current block and the prediction block of the current block.

The encoding information generator 240 may generate encoding information based on whether the residual block is encoded. For example, a degree of similarity between a current block and a prediction block of the current block may be used to determine whether to encode the residual block or not.

When the similarity between the current block and the prediction block of the current block is used, the encoding information generator 240 uses Sum of Absolute Differences ( SAD ), Sum of Absolute Transformed Differences ( SATD ), sum of squared difference (SSD), etc. Thus, the degree of similarity between the current block and the prediction block of the current block may be calculated. In addition, the encoding information generator 240 may generate encoding information based on the calculated similarity. Here, the encoding information may include information indicating whether to encode the residual block or not.

For example, when the similarity between the current block and the prediction block of the current block is equal to or greater than a preset reference similarity, the encoding information generator 240 may generate encoding information including information indicating that residual blocks are not encoded.

As another example, when the similarity between the current block and the prediction block of the current block is less than the reference similarity, the encoding information generator 240 may generate encoding information including information indicating that the residual block is encoded.

Then, the transform and quantization unit 250 may transform and quantize the residual block based on the encoding information. In addition, the entropy encoder 260 may generate a bitstream by entropy-encoding at least one of the encoding information and the residual block based on the encoding information.

For example, when the encoding information includes information indicating that the residual block is not encoded, the transform and quantization unit 250 may not transform and quantize the residual block. Then, the entropy encoding unit 260 may generate a bitstream by entropy encoding only the encoding information without the residual block. Accordingly, computational complexity and encoding time for transforming and quantizing the residual block may be reduced. As such, when the encoding information includes information indicating that residual blocks are not encoded, the generated bitstream may include encoded encoding information.

As another example, when the encoding information includes information indicating that the residual block is encoded, the transform and quantization unit 250 may transform and quantize the residual block. Then, the entropy encoder 260 may entropy-encode the transformed and quantized residual blocks and entropy-encode the encoding information. In addition, the entropy encoder 260 may generate a bitstream by mixing the encoded residual block and the encoded encoding information. As such, when the encoding information includes information indicating that the residual block is encoded, the generated bitstream may include both the encoded residual block and the encoded encoding information.

In this case, the transform and quantization unit 250 may differently perform transform and quantization on the residual block according to the intra prediction encoding mode.

For example, when 16×16 intra prediction coding is used, the transform and quantization unit 250 transforms the residual block to generate a transform coefficient, collects only DC coefficients from among the generated transform coefficients, and performs Hadamard transform again. can be performed. Then, the entropy encoder 260 may entropy-encode only the Hadamard-transformed DC coefficient and output it as a bitstream.

As another example, when 8×8 and 4×4 intra prediction encoding modes other than 16×16 are used, the transform and quantization unit 250 transforms the residual block to generate a transform coefficient, and the generated transform A quantized coefficient may be generated by quantizing a coefficient according to a quantization parameter. Then, the entropy encoder 260 may entropy-encode the generated quantization coefficients according to a probability distribution and output them as a bitstream.

The inverse quantization and inverse transform unit 270 may decode the residual block by inverse quantizing and inverse transforming the quantization coefficient output from the transform and quantization unit 250 .

Then, the adder 280 may reconstruct the current block by adding the decoded residual block and the prediction block of the current block. Then, the reference image buffer 220 may store the restored current block.

As such, as the reconstructed current block is stored in the reference image buffer 220 , the neighboring blocks restored in the previous step may be stored in the reference image buffer 220 as a reference image. Then, when the encoding information includes information indicating that residual blocks are not encoded, the reconstructed neighboring blocks stored in the reference image buffer 220 are blocks reconstructed using only the prediction blocks of the neighboring blocks. And, when the encoding information includes information indicating that residual blocks are encoded, the reconstructed neighboring blocks stored in the reference image buffer 220 are blocks reconstructed using the residual blocks and prediction blocks of the neighboring blocks. Accordingly, the intra prediction unit 210 uses the neighboring block reconstructed using only the prediction block of the neighboring block according to the encoding information, or the neighboring block reconstructed using the reconstructed residual block and the prediction block of the neighboring block. A predictive block of a block can be generated.

In FIG. 2 above, a configuration for performing intra prediction encoding on an input image has been described for convenience of explanation. Hereinafter, a configuration for performing both intra prediction encoding and inter prediction encoding will be described with reference to FIG. 3 . decide to do

3 is a diagram illustrating an overall configuration of an encoding apparatus according to an embodiment of the present invention.

In FIG. 3, the components mentioned while describing the operation of FIG. 2 are substantially the same, and thus the overlapping description will be omitted. The encoding apparatus 300 of FIG. 3 may further include a motion prediction unit 310 , a motion compensation unit 320 , and a deblocking unit 350 in the encoding apparatus 200 of FIG. 2 .

The motion prediction unit 310 uses various motion estimation algorithms such as Block Matching Algorithm (BMA), Phase Correlation, and HSBMA to find a region that best matches the current block among reference images to calculate a motion vector. have

Then, the motion compensator 320 may generate a prediction block of the current block by performing motion compensation using the calculated motion vector. As such, the encoding apparatus according to an embodiment of the present invention may perform inter prediction encoding through motion prediction and compensation. Then, the subtractor 330 may generate a residual block by subtracting the current block from the prediction block of the current block generated through inter prediction encoding or intra prediction encoding.

The adder 340 may reconstruct the current block by using at least one of a prediction block of the current block and a reconstructed residual block. And, the reconstructed residual block may be stored in the reference image buffer.

For example, when the residual block is not transformed and quantized in the transform and quantization unit, the adder 304 may reconstruct the current block only from the prediction block of the current block. As another example, when the residual block is transformed and quantized by the transform and quantization unit, the adder 304 may reconstruct the current block by adding the prediction block of the current block and the reconstructed residual block.

Then, the deblocking unit 340 may remove a blocking artifact from the restored current block using the deblocking filter and store it in the reference image buffer.

In FIG. 3 , inter prediction encoding is divided into 16×16, 16×8, 8×16, and 8×8 inter prediction encoding modes, and the 8×8 inter prediction encoding mode is again 8×8, 8×4. , 4×8, and 4×4 inter-prediction encoding modes.

4 is a flowchart provided to explain an operation of an encoding apparatus according to an embodiment of the present invention.

First, in operation 410 , the intra prediction unit 210 may generate a prediction block of a current block based on a reference image.

For example, the intra prediction unit 210 may generate the prediction block of the current block by using any one of a plurality of predefined methods for generating prediction blocks. Here, a reconstructed neighboring block may be used as the reference image. In this case, the reconstructed neighboring block may be reconstructed using only the prediction block of the neighboring block or a block reconstructed using the prediction block of the neighboring block and the decoded residual block. Then, the intra prediction unit 210 may generate a prediction block of the current block by using the reconstructed neighboring block.

Next, in operation 420 , the subtractor 230 may generate a residual block by subtracting the current block and the prediction block of the current block.

In operation 430, the encoding information generator 240 may generate encoding information based on whether the residual blocks are encoded. In this case, whether the residual block is encoded may be determined based on a degree of similarity between the current block and the prediction block of the current block.

For example, when using the similarity, the encoding information generating unit 240 uses a sum of absolute differences (SAD), a sum of absolute transformed differences (SATD), a sum of squared difference (SSD), etc. Similarity between prediction blocks can be calculated. In addition, the encoding information generator 240 may generate encoding information based on the calculated similarity.

In this case, when the calculated similarity is equal to or greater than the reference similarity, the encoding information generator 240 may generate encoding information to include information indicating that residual blocks are not encoded. And, when the calculated similarity is less than the reference similarity, the encoding information generator 240 may generate encoding information to include information indicating that the residual block is encoded.

Next, in operation 440 , the transform and quantization unit 250 may transform and quantize the residual block based on the encoding information.

In this case, when the encoding information includes information indicating that the residual block is encoded, the transform and quantization unit 250 may transform and quantize the residual block.

And, when the encoding information includes information indicating that the residual block is not encoded, the transform and quantization unit 250 may not transform and quantize the residual block.

Then, in operation 450 , the entropy encoder 260 may entropy-encode at least one of the transformed and quantized residual blocks and encoding information and output them as a bitstream.

For example, when the residual block is transformed and quantized based on the encoding information, the entropy encoder 260 may entropy-encode the transformed and quantized residual block and entropy-encode the encoding information. In addition, the entropy encoder 260 may transmit a bitstream generated by mixing the encoded residual block and encoding information to the decoding apparatus.

As another example, when the residual block is not transformed and quantized based on the encoding information, the entropy encoding unit 260 may entropy-encode only the encoding information without the residual block and output it as a bitstream.

5 is a block diagram illustrating the configuration of a decoding apparatus according to an embodiment of the present invention.

Referring to FIG. 5 , the decoding apparatus 500 includes an intra prediction unit 510 , a reference image buffer 520 , an entropy decoding unit 530 , an inverse quantization and inverse transformation unit 540 , and an adder 550 . can do.

The intra prediction unit 510 may generate a prediction block of the current block based on the reference image. In this case, the intra prediction unit 520 may generate the prediction block of the current block by using any one of a plurality of predefined methods for generating prediction blocks. Here, since the predefined method of generating a plurality of prediction blocks has already been described in the intra prediction unit 210 of FIG. 2 , the overlapping description will be omitted.

For example, the intra prediction unit 510 may generate a prediction block of the current block using the reconstructed neighboring blocks stored in the reference image buffer 520 . In this case, depending on whether the residual block is encoded, the reconstructed neighboring block may be reconstructed using only the prediction block of the neighboring block or a block reconstructed using the prediction block of the neighboring block and the decoded residual block.

The entropy decoding unit 530 may demultiplex the bitstream to extract encoded encoding information, and entropy-decode the encoded encoding information.

In this case, when the encoding information includes information indicating that residual blocks are encoded, the entropy decoder 530 may extract the encoded residual blocks as well as the encoded encoding information while demultiplexing the bitstream. In addition, the entropy decoding unit 530 may decode the coded encoding information and decode the coded residual block.

And, when the encoding information includes information indicating that residual blocks are not encoded, the entropy decoder 530 may extract the encoded encoding information while demultiplexing the bitstream. That is, when the encoding information includes information indicating that residual blocks are not encoded, the encoded residual blocks may not be included in the bitstream. Accordingly, the entropy decoding unit 530 may entropy-decode only the encoded encoding information.

The inverse quantization and inverse transform unit 540 may decode the residual block by inverse quantizing and inverse transforming the residual block based on the decoded encoding information.

For example, when the encoding information includes information indicating that the residual block is encoded, the inverse quantization and inverse transform unit 540 inverse quantizes the encoded residual block using variable length decoding according to a probability distribution to obtain a quantization coefficient. can be printed out. In this case, the output quantization coefficient may include only DC coefficient information or both DC coefficient information and AC coefficient information.

As another example, when the encoding information includes information indicating that residual blocks are not encoded, the inverse quantization and inverse transform unit 540 may not operate because there is no encoded residual block extracted from the bitstream. In other words, the inverse quantization and inverse transform unit 540 may operate only when the coded residual block is included in the bitstream.

The adder 550 may reconstruct the current block using at least one of a residual block decoded based on the encoding information and a prediction block of the current block.

For example, when the encoding information includes information indicating that the residual block is encoded, the adder 550 may reconstruct the current block by adding the reconstructed residual block and the prediction block of the current block.

As another example, when the encoding information includes information indicating that the residual block is not encoded, the adder 550 may reconstruct the current block using only the prediction block of the current block generated by the intra prediction unit 510 . .

The reference image buffer 520 may store the reconstructed current block.

6 is a diagram illustrating an overall configuration of an encoding apparatus according to an embodiment of the present invention.

Since the components mentioned while explaining the operation of FIG. 6 in FIG. 5 are substantially the same, the overlapping description will be omitted. The decoding apparatus 600 of FIG. 6 may further include a motion compensation unit 610 and a deblocking unit 620 in the encoding apparatus 500 of FIG. 5 .

The motion compensator 610 may perform motion compensation on a reference image by using a motion vector extracted from a bitstream through entropy decoding. In addition, the motion compensator 610 may generate a prediction block of the current block through motion compensation.

The deblocking unit 620 may output a reconstructed image by removing the blocking phenomenon from the reconstructed current block. And, the restored image may be stored in the reference image buffer.

7 is a flowchart provided to explain an operation of a decoding apparatus according to an embodiment of the present invention.

First, in operation 710 , the intra prediction unit 510 may generate a prediction block of a current block by using a reference image.

For example, the intra prediction unit 510 may generate a prediction block of the current block using the reconstructed neighboring blocks stored in the reference image buffer 520 . In this case, the intra prediction unit 510 may generate the prediction block of the current block according to any one of a plurality of predefined prediction block generation methods, as already described in the intra prediction unit 210 of FIG. 2 . have.

Next, in operation 720 , the entropy decoder 530 may demultiplex the bitstream to extract encoded information.

In operation 730, the entropy decoding unit 530 may entropy-decode the encoded encoding information. Here, the encoding information may include information indicating that residual blocks are encoded or information indicating that residual blocks are not encoded.

In this case, when the encoding information includes information indicating that the residual block is encoded, the entropy decoding unit 530 may extract the encoded residual block from the bitstream and perform entropy-decoding.

Next, in operation 740 , the inverse quantization and inverse transform unit 540 may inverse quantize and inverse transform the residual block based on the decoded encoding information.

For example, when the encoding information includes information indicating that the residual block is encoded, the inverse quantization and inverse transform unit 540 inverse quantizes the encoded residual block and inversely transforms it to reconstruct the residual block.

As another example, when the encoding information includes information indicating that residual blocks are not encoded, the inverse quantization and inverse transform unit 540 may omit the operation because there is no residual block extracted from the bitstream. In other words, the inverse quantization and inverse transform unit 540 may operate only when the coded residual block is included in the bitstream. Accordingly, the computational complexity of the decoding apparatus may be reduced, and the decoding time may be shortened.

In operation 750, the adder 550 may reconstruct the current block based on at least one of a prediction block of the current block and a reconstructed residual block.

For example, when the encoding information includes information indicating that the residual block is encoded, the adder 550 may reconstruct the current block by adding the prediction block of the current block and the reconstructed residual block. Then, the current block that is the image of the present application may be displayed.

As another example, when the encoding information includes information indicating that the residual block is not encoded, the adder 550 may reconstruct the current block using only the prediction block of the current block. In other words, the reconstructed image may consist of only the prediction blocks of the current block.

The configuration for generating the prediction block of the current block by using any one of a plurality of predefined prediction block generation has been described above with reference to FIGS. 2 to 7 . In particular, the configuration of the encoding and decoding apparatus according to an embodiment of the present invention for reconstructing the current block using only the prediction block of the current block based on whether the residual block is encoded has been described.

Hereinafter, a plurality of prediction blocks of the current block are generated according to a method for generating a prediction block used when generating a prediction block of a neighboring block or a plurality of predefined methods for generating prediction blocks, and any one of the prediction blocks of the current block is selected. Thus, a configuration for performing encoding and decoding will be described.

8 is a diagram illustrating a configuration of an encoding apparatus according to an embodiment of the present invention.

FIG. 8 further includes a prediction block selector in the encoding apparatus of FIG. 2 , and the operation of the intra prediction unit is different from the intra prediction unit of FIG. 2 . Accordingly, among the components of FIG. 8 , the names overlapping those of FIG. 2 will be omitted, and descriptions will be made focusing on the prediction block selection unit and the intra prediction unit.

Referring to FIG. 8 , the encoding apparatus 800 includes an intra prediction unit 810 , a reference image buffer 820 , a prediction block selection unit 830 , a subtraction unit 840 , an encoding information generation unit 850 , a transform and It may include a quantization unit 860 , an entropy encoding unit 870 , an inverse quantization and inverse transform unit 880 , and an adder 890 .

The intra prediction unit 810 may generate one or more prediction blocks of the current block by using the reference image stored in the reference image buffer 820 . In this case, the intra prediction unit 810 is used when generating a plurality of prediction block generation methods predefined based on the number of prediction block generation methods used when generating prediction blocks of neighboring blocks or generating prediction blocks of each of the reconstructed neighboring blocks. A prediction block of the current block may be generated according to the predicted block generation method.

For example, when the prediction block generation methods used in generating the prediction blocks of the neighboring blocks are all the same, the intra prediction unit 810 generates the prediction block of the current block according to the prediction block generation method of the neighboring blocks used in the same way. can In other words, when prediction blocks of neighboring blocks are generated according to intra prediction 1, the intra prediction unit 810 may generate a prediction block of the current block by using a reference image according to intra prediction 1. Then, the prediction block selector 830 may output the generated prediction block of the current block as it is because there is one prediction block of the generated current block.

As another example, when there are two or less methods of generating prediction blocks used when generating prediction blocks of neighboring blocks, the intra prediction unit 810 may generate two current prediction blocks according to methods of generating prediction blocks of neighboring blocks. A predictive block of a block can be generated.

Then, the prediction block selector 830 may select a prediction block with good encoding efficiency from among the prediction blocks of the two current blocks. For example, the prediction block selector 830 may select a prediction block having good encoding efficiency by using the similarity between the prediction block of the current block and the current block, rate-distortion cost, and the like. In addition, the prediction block selector 830 may generate prediction block selection information including information indicating a prediction block generation method used when generating the prediction block of the selected current block. In this case, the prediction block selector 830 may calculate the similarity using SAD, SSD, SATD, or the like.

As another example, when there are three or more methods for generating prediction blocks used to generate prediction blocks of neighboring blocks, the intra prediction unit 810 generates a plurality of prediction blocks of the current block according to a plurality of predefined methods for generating prediction blocks. Dogs can be created For example, when the prediction block generation methods of (1) to (5) described in the intra prediction unit 210 of FIG. 2 are predefined, the intra prediction unit 810 generates five predefined prediction blocks. Five prediction blocks of the current block may be generated using the methods. In other words, in the case of three or more, the intra prediction unit 810 generates the prediction blocks of the current block using a plurality of predefined prediction block generation methods instead of the prediction block generation method used when generating the prediction blocks of the neighboring blocks. can

Then, the prediction block selector 830 may select any one of the prediction blocks of the current block having the best encoding efficiency. In addition, the prediction block selector 830 may generate prediction block selection information including information indicating a prediction block generation method used when generating the prediction block of the selected current block.

The adder 840 may generate a residual block by subtracting the current block from the prediction block of the selected current block.

The encoding information generator 850 may generate encoding information based on whether the residual block is encoded. For example, a degree of similarity between a current block and a prediction block of the current block may be used to determine whether to encode the residual block or not. Here, the encoding information may include information indicating whether to encode the residual block or not.

The transform and quantization unit 860 may transform and quantize the residual block based on the encoding information.

The entropy encoding unit 870 may entropy-encode at least one of encoding information, prediction block selection information, and residual blocks and output them as a bitstream. For example, when the residual block is not encoded, the entropy encoder 870 may entropy-encode the encoding information and the prediction block selection information to output the encoded information as a bitstream. In addition, when the residual block is encoded, the encoding information, the prediction block selection information, and the residual block may be entropy-encoded and output as a bitstream.

The inverse quantization and inverse transform unit 880 may restore the residual block by inverse quantizing and inverse transforming the transformed and quantized residual block.

The adder 890 may reconstruct the current block by adding the residual block reconstructed based on the encoding information and the prediction block of the selected current block. Then, the reference image buffer 820 may store the reconstructed current block. In this case, when the residual block is not encoded, the adder 890 may reconstruct the current block only from the prediction block of the selected current block.

9 is a flowchart provided to explain an operation of an encoding apparatus according to an embodiment of the present invention.

First, in operation 910 , the prediction block generator 810 may generate one or more prediction blocks of a current block by using a reference image.

For example, the intra prediction unit 810 may generate the prediction block of the current block according to the prediction block generation method used when generating the prediction block of each of the reconstructed neighboring blocks.

As another example, the intra prediction unit 810 may generate a plurality of prediction blocks of the current block according to a predefined method for generating a plurality of prediction blocks based on the number of methods for generating prediction blocks used when generating prediction blocks of neighboring blocks. can

Next, in operation 920 , the prediction block selector 820 may select any one of the prediction blocks of the current block as the plurality of prediction blocks of the current block are generated. In this case, the prediction block selector 820 may select a prediction block having the best encoding efficiency from among the prediction blocks of the plurality of current blocks.

For example, when using the similarity between the current block and the generated prediction block of the current block, the prediction block selector 820 may determine that the higher the similarity, the better the encoding efficiency. Accordingly, the prediction block selector 820 may select a prediction block having the highest similarity among prediction blocks of the current block.

As another example, the prediction block selector 820 may select the prediction block having the best encoding efficiency by using the rate-distortion cost.

In operation 930, the subtractor 840 may generate a residual block by subtracting the prediction block and the current block of the selected current block.

Next, in operation 940 , the encoding information generator 850 may generate encoding information based on whether the residual block is encoded.

In operation 950, the transform and quantization unit 860 may transform and quantize the residual block based on the encoding information.

Next, in operation 960 , the entropy encoder 870 may entropy-encode at least one of encoding information, prediction block selection information, and residual blocks based on the encoding information.

For example, when the residual block is encoded, the entropy encoding unit 870 entropy-encodes each of the encoding information, the prediction block selection information, and the transformed and quantized residual blocks, the encoded encoding information, the encoded prediction block selection information, and The encoded residual blocks may be mixed and output as a bitstream.

10 is a block diagram illustrating the configuration of a decoding apparatus according to an embodiment of the present invention.

The decoding apparatus 1000 of FIG. 10 may further include a prediction block selector 1050 in the encoding apparatus 400 of FIG. 4 . Accordingly, since the components mentioned while describing the operation of FIG. 4 in FIG. 10 are substantially the same, the overlapping description will be omitted.

Referring to FIG. 10 , the decoding apparatus 1000 includes an intra prediction unit 1010 , a reference image buffer 1020 , an entropy decoding unit 1030 , an inverse quantization and inverse transformation unit 1040 , and an adder 1060 . can do.

The intra prediction unit 1010 may generate a prediction block of the current block based on the reference image stored in the reference image buffer 1020 .

For example, the intra prediction unit 810 may generate the prediction block of the current block according to the prediction block generation method used when generating the prediction block of each of the reconstructed neighboring blocks.

As another example, the intra prediction unit 810 may generate a plurality of prediction blocks of the current block according to a predefined method for generating a plurality of prediction blocks based on the number of methods for generating prediction blocks used when generating prediction blocks of neighboring blocks. can Here, as the method for generating the plurality of prediction blocks, the predefined methods of generating the prediction blocks (1) to (5) described in the intra prediction unit 210 of FIG. 2 may be used.

The entropy decoder 1030 may demultiplex the bitstream to extract at least one of encoded encoding information, encoded residual blocks, and encoded prediction block selection information. In addition, the entropy decoding unit 1030 may entropy-decode the encoded encoding information, the encoded residual block, and the encoded prediction block selection information.

For example, since the encoding information includes information indicating that residual blocks are not encoded, the entropy decoder 1030 may entropy-decode only the encoded encoding information and the encoded prediction block selection information.

As another example, since the encoding information includes information indicating that the residual block is encoded, the entropy decoding unit 1030 may entropy-decode all of the encoded encoding information, the encoded residual block, and the encoded prediction block selection information. .

The prediction block selector 1050 may select any one of one or more prediction blocks generated based on prediction block selection information.

The inverse quantization and inverse transform unit 1040 may inverse quantize and inverse transform the encoded residual block based on the encoding information.

As an example, since the encoding information includes information indicating that the residual block is encoded, the inverse quantization and inverse transform unit 1040 may inverse quantize the encoded residual block and then inversely transform it to reconstruct the residual block. In this case, since the encoding information includes information indicating that residual blocks are not encoded, the inverse quantization and inverse transform unit 1040 may omit the operation.

The adder 1060 may reconstruct the current block by using at least one of a reconstructed residual block and a prediction block of the selected current block.

For example, if the residual block is reconstructed as the encoding information includes information indicating that the residual block is encoded, the adder 1060 may reconstruct the current block by adding the reconstructed residual block and the prediction block of the selected current block. have.

As another example, when the operation of the inverse quantization and inverse transform unit is omitted because the encoding information includes information indicating that the residual block is not encoded, the adder 1060 may reconstruct the current block only from the prediction block of the selected current block. . Then, a reconstructed image composed of only the prediction blocks of the current block may be displayed.

In addition, the reference image buffer 1020 may store the restored current block.

11 is a flowchart provided to explain an operation of a decoding apparatus according to an embodiment of the present invention.

First, in operation 1110, the intra prediction unit 1030 may generate one or more prediction blocks of the current block.

For example, the intra prediction unit 810 may generate the prediction block of the current block according to the prediction block generation method used when generating the prediction block of each of the reconstructed neighboring blocks.

As another example, the intra prediction unit 810 may generate a plurality of prediction blocks of the current block according to a predefined method for generating a plurality of prediction blocks based on the number of methods for generating prediction blocks used when generating prediction blocks of neighboring blocks. can

Next, in step 1120, the entropy decoding unit 1030 demultiplexes the bitstream to extract the encoded encoding information and the encoded prediction block selection information, and entropy-encodes the encoded encoding information and the encoded prediction block selection information. have.

In this case, when the encoding information includes information indicating that residual blocks are encoded, the entropy decoding unit 1030 may extract the encoded residual blocks from the bitstream through demultiplexing and entropy-decode them.

Then, in operation 1130 , the inverse quantization and inverse transform unit 1040 may reconstruct the residual block by inverse quantizing and inverse transforming the coded residual block.

Next, in operation 1140 , the prediction block selector 1050 may select any one of prediction blocks of one or more current blocks based on prediction block selection information.

In operation 1150, the adder 1060 may reconstruct the current block using at least one of a prediction block and a reconstructed residual block of the selected current block. Then, the reference image buffer 1020 may store the restored current block.

For example, when the operation of the inverse quantization and inverse transform unit 1040 is omitted because the encoding information includes information indicating that the residual block is not encoded, the adder 1060 converts the current block to only the prediction block of the selected current block. can be restored In other words, since the coded residual block is not included in the bitstream, there is no reconstructed residual block. Accordingly, the reconstructed image may consist of only the prediction blocks of the current block selected based on the prediction block selection information.

As another example, when the residual block is reconstructed as the encoding information includes information indicating that the residual block is encoded, the adder 1060 may reconstruct the current block by adding the prediction block of the selected current block and the reconstructed residual block. have.

As described above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited to the above embodiments, and various modifications and variations from these descriptions can be made by those skilled in the art to which the present invention pertains. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the following claims as well as the claims and equivalents.

210: prediction unit in the screen
220: reference image buffer
230: subtraction unit
240: encoding information generating unit
250: transform and quantization unit
260: entropy encoding unit
270: inverse quantization and inverse transform unit
280: added part

Claims (25)

performing prediction on the current block; and
generating a bitstream including information on transformed and quantized residual blocks based on the prediction
including,
The transformed and quantized residual block information is generated based on a residual block that is a difference between the current block and the prediction block;
In decoding the current block using the bitstream, a prediction block for the current block is generated according to a method for generating a prediction block for the current block, and the method for generating a prediction block for the current block It is determined based on a plurality of prediction block generation methods of a plurality of neighboring blocks,
In decoding the current block, the plurality of prediction block generation methods of the plurality of neighboring blocks are prediction block generation methods respectively used when generating the plurality of prediction blocks of the plurality of neighboring blocks. According to claim 1,
The bitstream includes selection information,
A method of generating a prediction block for the current block is determined based on the selection information,
The selection information indicates a prediction block generation method used for generation of the prediction block of the current block. 3. The method of claim 2,
The selection information is an encoding method indicating a prediction block generation method used for generation of the prediction block of the current block among the plurality of prediction block generation methods. 3. The method of claim 2,
In decoding the current block, as the selection information indicates one prediction block generation method among the plurality of prediction block generation methods, the prediction block of the current block is generated by the one prediction block generation method encoding method. 3. The method of claim 2,
In decoding of the current block, a method of generating a prediction block of a block adjacent to the current block specified by the selection information is used as a method of generating a prediction block for the current block. According to claim 1,
In the decoding of the current block, the method for generating the prediction block for the current block is determined based on the number of different values for the method for generating the prediction block used for the predictions for the neighboring blocks. According to claim 1,
In the decoding of the current block, the prediction for the current block is an intra prediction. According to claim 1,
In the decoding of the current block, the prediction for the current block is a prediction using a specified decoded block as the prediction block for the current block. A computer-readable recording medium storing the bitstream generated by the encoding method of claim 1. generating a prediction block by performing prediction on the current block; and
generating a reconstructed block for the current block using the residual block and the prediction block
including,
The prediction block is generated according to a method of generating a prediction block for the current block,
The method of generating a prediction block for the current block is determined based on methods of generating a plurality of prediction blocks of a plurality of neighboring blocks of the current block,
The methods for generating a plurality of prediction blocks of the plurality of neighboring blocks are prediction block generation methods respectively used when generating the plurality of prediction blocks of the plurality of neighboring blocks. 11. The method of claim 10,
Selection information is extracted from the bitstream,
A method of generating a prediction block for the current block is determined based on the selection information,
The selection information indicates a prediction block generation method used for generation of the prediction block of the current block. 12. The method of claim 11,
The selection information indicates a prediction block generation method used for generation of the prediction block of the current block among the plurality of prediction block generation methods. 12. The method of claim 11,
A decoding method in which the prediction block of the current block is generated by the one prediction block generation method as the selection information indicates one prediction block generation method among the plurality of prediction block generation methods. 12. The method of claim 11,
A decoding method in which a prediction block generation method of a block adjacent to the current block specified by the selection information is used as a prediction block generation method for the current block. 11. The method of claim 10,
The method for generating the prediction block for the current block is determined based on the number of different values for the method for generating the prediction block used for the predictions for the neighboring blocks. 11. The method of claim 10,
The prediction for the current block is an intra prediction. 11. The method of claim 10,
The prediction for the current block is a prediction using a specified decoded block as the prediction block for the current block. A computer-readable recording medium for storing a bitstream for decoding an image,
The bitstream is
Information on Transformed and Quantized Difference Blocks
including,
In the decoding, a residual block is generated based on the transformed and quantized residual block, a reconstructed block for the current block is generated based on the residual block and a prediction block for the current block, and the prediction block is generated according to a method for generating a prediction block for the current block, and the method for generating a prediction block for the current block is determined based on methods for generating a plurality of prediction blocks of a plurality of neighboring blocks of the current block,
In the decoding, the methods for generating a plurality of prediction blocks of the plurality of neighboring blocks are prediction block generation methods respectively used when generating the plurality of prediction blocks of the plurality of neighboring blocks.
In the decoding, a method for generating a prediction block for the current block is determined based on the selection information. 19. The method of claim 18,
The bitstream is
Optional information
further comprising,
A method of generating a prediction block for the current block is determined based on the selection information,
The selection information is a computer-readable recording medium indicating a prediction block generation method used for generation of the prediction block of the current block. 20. The method of claim 19,
The selection information is a computer-readable recording medium indicating a prediction block generation method used for generation of the prediction block of the current block among the plurality of prediction block generation methods. 20. The method of claim 19,
In the decoding, as the selection information indicates one prediction block generation method among the plurality of prediction block generation methods, a computer readable prediction block of the current block is generated by the one prediction block generation method recording medium. 20. The method of claim 19,
In the decoding, a method of generating a predictive block of a block adjacent to the current block specified by the selection information is used as a method of generating a predictive block for the current block. 19. The method of claim 18,
In the decoding, the method for generating the prediction block for the current block is determined based on the number of different values for the method for generating the prediction block used for the predictions for the neighboring blocks. 19. The method of claim 18,
In the decoding, the prediction for the current block is an intra prediction. 19. The method of claim 18,
In the decoding, the prediction for the current block is a prediction using a specified decoded block as the prediction block for the current block.

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