KR102419589B1 - Method and apparatus for deciding boundary filtering strength of deblocking filtering - Google Patents

Abstract

The present invention relates to a method and apparatus for determining boundary filtering strength of deblocking filtering, wherein the method for determining boundary filtering strength according to the present invention includes determining a partition boundary of a PU (Prediction Unit) and boundary filtering strength of deblocking filtering and determining (bS), wherein the boundary filtering strength of the deblocking filtering may be determined based on a partition boundary of the PU.

Description

Method and apparatus for determining boundary filtering strength of deblocking filtering

The present invention relates to a video compression technique, and more particularly, to a deblocking filtering method and apparatus.

Recently, a broadcasting service having a high definition (HD) resolution (1280x1024 or 1920x1080) is expanding not only in Korea but also worldwide.

Accordingly, many users are accustomed to high-resolution and high-definition images, and many institutions are spurring the development of next-generation imaging devices to keep pace with it.

Also, along with HDTV, as interest in Ultra High Definition (UHD), which has a resolution four times higher than that of HDTV, increases, video standardization organizations recognize the need for compression technology for higher resolution and high-definition images.

There is an urgent need for a new standard that can obtain many benefits in terms of frequency band and storage while maintaining the same image quality through higher compression efficiency than H.264/AVC currently used in HDTVs, mobile phones, and Blu-ray players.

Currently, MPEG (Moving Picture Experts Group) and VCEG (Video Coding Experts Group) are jointly developing HEVC (High Efficiency Video Coding), which is a next-generation video codec. It aims to encode with twice the compression efficiency. This can provide not only HD and UHD images, but also 3D broadcasting and high-definition images at lower frequencies than the present in mobile communication networks.

An object of the present invention is to provide a method and apparatus capable of removing or reducing a blocking phenomenon in a video encoding and decoding process.

An object of the present invention is to provide a method and apparatus for determining different boundary filtering strengths according to block characteristics in deblocking filtering performed during image encoding or decoding.

An object of the present invention is to provide a method and apparatus for differently determining boundary filtering strength according to whether a boundary is a PU partition in deblocking filtering.

The present invention provides a method and apparatus for enabling the filtering strength adjustment for PUs having the same motion information by motion information compression by determining the strength of the deblocking filtering according to the characteristics of the block (eg, whether it is a PU partition boundary). intended to provide

An embodiment of the present invention is a method for determining boundary filtering of deblocking filtering, and may determine boundary filtering strength (bS) of deblocking filtering based on a partition type (PU type) of a CU.

In this case, when at least one of the absolute values of the difference between motion vectors is 4 or more, the reference frame in motion compensation is different, or it is a PU partition boundary, the boundary filtering strength (bS) is determined to be 1, while the motion vector When the absolute values of the differences of are all less than 4 and the reference frames in motion compensation are the same and are not PU partition boundaries, the boundary filtering strength bS may be determined to be 0.

The filtering strength bS may be determined in the parsing step. In this case, the determined filtering strength bS may be stored and used in the deblocking filtering process after the entire frame is decoded.

Another embodiment of the present invention is an apparatus for determining boundary filtering of deblocking filtering, comprising: a boundary filtering strength determining unit for determining boundary filtering strength for two adjacent blocks; and a filtering application unit for applying filtering to the pixel values of the two blocks according to the boundary filtering strength output from the boundary filtering strength determining unit.

The boundary filtering strength determiner determines whether at least one block among two adjacent blocks is intra-coded, and when it is determined that both blocks are not intra-coded, at least one of the two blocks is orthogonal. It is determined whether the block has a transform coefficient, and when it is determined that both blocks do not have an orthogonal transform coefficient, at least one of an absolute value of a difference between an x-axis component or a y-axis component of a motion vector with respect to the two blocks. is greater than 4, or whether motion compensation is performed based on another reference frame or PU partition boundary, the absolute values of the difference between the motion vectors are all less than 4 and the motion compensation is based on the same reference frame The boundary filtering strength may be determined by considering whether it is performed and whether it is a PU partition boundary.

In this case, when at least one of the absolute values of the difference between motion vectors is 4 or more, the reference frame in motion compensation is different, or it is a PU partition boundary, the boundary filtering strength (bS) is determined to be 1, while the motion vector When the absolute values of the differences of are all less than 4 and the reference frames in motion compensation are the same and are not PU partition boundaries, the boundary filtering strength bS may be determined to be 0.

The filtering strength bS may be determined by the parsing unit. In this case, the parsing unit may determine and store the filtering strength bS, and the stored filtering strength bS may be used in the deblocking filtering process after the entire frame is decoded.

Another embodiment of the present invention is a deblocking filtering method, wherein the method for determining boundary filtering of deblocking filtering includes parsing from a bitstream, determining a filtering strength (bS) through the parsed information, and decoding a frame and deblocking and filtering the currently decoded frame using the filtering strength (bS) obtained by the parsing unit.

According to the present invention, it is possible to remove or reduce a blocking phenomenon in a video encoding and decoding process.

According to the present invention, in deblocking filtering performed during video encoding or decoding, encoding efficiency can be increased by determining different boundary filtering strengths according to block characteristics.

According to the present invention, in deblocking filtering, the boundary filtering strength can be determined differently depending on whether it is a PU partition boundary.

According to the present invention, by determining the strength of the deblocking filtering according to the characteristics of the block (eg, whether it is a PU partition boundary), it is possible to adjust the filtering strength for PUs having the same motion information by motion information compression. .

1 is a block diagram showing the configuration of an image encoding apparatus according to an embodiment of the present invention.
2 is a block diagram showing the configuration of an image decoding apparatus according to another embodiment of the present invention.
3 is a diagram schematically illustrating compression of spatial motion information and bS set accordingly.
4 is a flowchart schematically illustrating an example of a method of determining bS based on a partition type of a CU.
5 is a diagram schematically illustrating a relationship between a block p and a block q.
6 is a diagram schematically illustrating an example of a method of determining bS of deblocking filtering in a parsing unit.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described concretely with reference to drawings. In describing the embodiments of the present specification, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present specification, the detailed description thereof will be omitted.

When it is said that a component is “connected” or “connected to” another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be In addition, the description of “including” a specific configuration in the present invention does not exclude configurations other than the corresponding configuration, and it means that additional configurations may be included in the practice of the present invention or the scope of the technical spirit of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

In addition, the components shown in the embodiment of the present invention are shown independently to represent different characteristic functions, and it does not mean that each component is made of separate hardware or a single software component. That is, each component is listed as each component for convenience of description, and at least two components of each component are combined to form one component, or one component can be divided into a plurality of components to perform a function, and each Integrated embodiments and separate embodiments of the components are also included in the scope of the present invention without departing from the essence of the present invention.

In addition, some of the components are not essential components for performing essential functions in the present invention, but may be optional components for merely improving performance. The present invention can be implemented by including only essential components to implement the essence of the present invention, except for components used for performance improvement, and a structure including only essential components excluding optional components used for performance improvement Also included in the scope of the present invention.

1 is a block diagram showing the configuration of an image encoding apparatus according to an embodiment of the present invention.

Referring to FIG. 1 , the image encoding apparatus 100 includes a motion prediction unit 111 , a motion compensation unit 112 , an intra prediction unit 120 , a switch 115 , a subtractor 125 , and a transform unit 130 . , a quantizer 140 , an entropy encoder 150 , an inverse quantizer 160 , an inverse transform unit 170 , an adder 175 , a filter unit 180 , and a reference picture buffer 190 .

The image encoding apparatus 100 may encode an input image in an intra mode or an inter mode and output a bitstream. In the intra mode, the switch 115 may be switched to the intra mode, and in the inter mode, the switch 115 may be switched to the inter mode. After calculating a prediction block for an input block of an input image, the image encoding apparatus 100 may encode a residual between the input block and the prediction block.

The intra mode is an intra prediction mode, the inter mode is an inter prediction mode, the intra prediction unit 120 is an intra prediction unit, and the motion prediction unit 111 and the motion compensator 112 are defined as an inter prediction unit. and can be used

In the intra mode, the intra prediction unit 120 may calculate a prediction block by performing spatial prediction using pixel values of an already encoded block around the current block.

In the inter mode, the motion prediction unit 111 may obtain a motion vector by finding a region that best matches the input block in the reference image stored in the reference picture buffer 190 during the motion prediction process. The motion compensator 112 may calculate a prediction block by performing motion compensation using a motion vector.

The subtractor 125 may calculate a residual block based on the difference between the input block and the calculated prediction block. The transform unit 130 may perform transform on the residual block to output a transform coefficient. Here, the transform coefficient may mean a coefficient value calculated by performing transform on the residual block and/or the residual signal. Hereinafter, in the present specification, a quantized transform coefficient level calculated by applying quantization to a transform coefficient may also be referred to as a transform coefficient.

The quantizer 140 may quantize the input transform coefficient according to the quantization parameter to output a quantized transform coefficient level.

The entropy encoding unit 150 may output a bit stream by performing entropy encoding based on the values calculated by the quantization unit 140 or encoding parameter values calculated during the encoding process.

When entropy encoding is applied, a small number of bits are allocated to a symbol having a high probability of occurrence and a large number of bits are allocated to a symbol having a low probability of occurrence to express the symbol, so that bits for symbols to be encoded The size of the column may be reduced. Accordingly, compression performance of image encoding may be improved through entropy encoding. The entropy encoder 150 may use an encoding method such as exponential golomb, Context-Adaptive Variable Length Coding (CAVLC), or Context-Adaptive Binary Arithmetic Coding (CABAC) for entropy encoding.

Since the image encoding apparatus according to the embodiment of FIG. 1 performs inter prediction encoding, that is, inter prediction encoding, the currently encoded image needs to be decoded and stored to be used as a reference image. Accordingly, the quantized coefficients are inverse quantized by the inverse quantization unit 160 and inversely transformed by the inverse transformation unit 170 . The inverse-quantized and inverse-transformed coefficients are added to the prediction block through the adder 175, and a reconstructed block is calculated.

The reconstructed block passes through the filter unit 180, and the filter unit 180 applies at least one of a deblocking filter, a sample adaptive offset (SAO), and an adaptive loop filter (ALF) to the reconstructed block or the reconstructed picture. can do. The reconstructed block passing through the filter unit 180 may be stored in the reference picture buffer 190 .

2 is a block diagram showing the configuration of an image decoding apparatus according to another embodiment of the present invention.

2, the image decoding apparatus 200 includes an entropy decoding unit 210, an inverse quantization unit 220, an inverse transform unit 230, an intra prediction unit 240, a motion compensator 250, an adder ( 255), a filter unit 260 and a reference picture buffer 270 .

The image decoding apparatus 200 may receive a bitstream output from the encoder, perform decoding in an intra mode or an inter mode, and output a reconstructed image, that is, a reconstructed image. In the case of the intra mode, the switch may be switched to the intra mode, and in the case of the inter mode, the switch may be switched to the inter mode. The image decoding apparatus 200 obtains a reconstructed residual block from the received bitstream, calculates a prediction block, and then adds the reconstructed residual block and the prediction block to calculate a reconstructed block, that is, a reconstructed block. .

The entropy decoding unit 210 may entropy-decode the input bitstream according to a probability distribution to calculate symbols including symbols in the form of quantized coefficients. The entropy decoding method is similar to the entropy encoding method described above.

When the entropy decoding method is applied, a small number of bits are allocated to a symbol having a high occurrence probability and a large number of bits are allocated to a symbol having a low occurrence probability to represent the symbol, so that the size of the bit stream for each symbol is can be reduced. Accordingly, the compression performance of image decoding may be improved through the entropy decoding method.

The quantized coefficient is inverse quantized by the inverse quantization unit 220 and inverse transformed by the inverse transformation unit 230 , and as a result of inverse quantization/inverse transformation of the quantized coefficient, a reconstructed residual block may be calculated.

In the intra mode, the intra prediction unit 240 may calculate a prediction block by performing spatial prediction using pixel values of an already decoded block around the current block. In the inter mode, the motion compensator 250 may calculate a prediction block by performing motion compensation using a motion vector and a reference image stored in the reference picture buffer 270 .

The reconstructed residual block and the prediction block may be added through the adder 255 , and the added block may pass through the filter unit 260 . The filter unit 260 may apply at least one of a deblocking filter, SAO, and ALF to a reconstructed block or a reconstructed picture. The filter unit 260 may output a reconstructed image, that is, a reconstructed image. The reconstructed image may be stored in the reference picture buffer 270 and used for inter prediction.

Methods for improving the prediction performance of the encoding/decoding apparatus include a method of increasing the accuracy of an interpolation image and a method of predicting a difference signal. Here, the difference signal is a signal indicating a difference between the original image and the predicted image. In the present invention, "difference signal" may be used instead of "difference signal", "residual block" or "difference block" depending on the context, and those of ordinary skill in the art may affect the spirit and essence of the invention. You will be able to distinguish them within the range not given.

In an embodiment of the present invention, the terms coding unit (CU), prediction unit (PU), and transform unit (TU) may be used as a unit for processing an image.

The coding unit is an image processing unit for performing encoding/decoding, and may include a coding block that is a block-unit set of luminance samples or chrominance samples on which encoding/decoding is performed, and information used for encoding or decoding samples of the coding block.

The prediction unit is an image processing unit for performing prediction, and may include a prediction block that is a block unit set of luminance samples or chrominance samples on which prediction is performed, and information used to predict the samples of the prediction block. A coding block may be divided into a plurality of prediction blocks.

The transformation unit is an image processing unit that performs transformation, and may include a transformation block that is a block-unit set of luminance samples or chrominance samples on which transformation is performed, and information used to transform the samples of the transformation block. The coding block may be divided into a plurality of transform blocks.

Hereinafter, in the embodiments of the present invention, unless otherwise indicated, a block and a unit may be interpreted as having the same meaning.

Also, the current block may refer to a block on which specific image processing is performed, such as a prediction block on which prediction is currently performed, and a coding block on which current encoding is performed. For example, when one coding block is divided into two prediction blocks, a block on which prediction is performed among the divided prediction blocks may be referred to as a current block and used.

An image encoding method and an image decoding method, which will be described later in an embodiment of the present invention, may be performed by each component included in the image encoder and image decoder described above with reference to FIGS. 1 and 2 . The meaning of the constituent part may include not only a hardware meaning but also a software processing unit that may be performed through an algorithm.

Meanwhile, the importance of memory in encoding/decoding is increasing, so that a method of compressing and storing temporal motion information and/or a method of compressing and storing spatial motion information may be used.

Compression of spatial motion information is a method of having only two or one motion information according to depth when a current coding unit (CU) is divided into four PU blocks.

In this case, it may affect the setting of the boundary filtering strength of the deblocking filtering (Boundary Filtering Strength: bS, hereinafter referred to as 'bS' for convenience of description).

3 is a diagram schematically illustrating compression of spatial motion information and bS set accordingly.

In FIG. 3 , a case in which the current CU 300 is divided into two PUs 310 and 320 is described as an example.

Referring to FIG. 3 , when the current CU 300 is divided into a PU0 310 indicated by a partition index PartIdx = 0 and a PU1 320 indicated by a partition index PartIdx = 1, the space Due to dynamic motion information compression, PU0 310 and PU1 320 may have the same motion information.

Therefore, when determining the bS of the deblocking filtering, since the motion information for two PUs, that is, PU0 310 and PU1 320 is the same, the bS of the deblocking filtering may be determined to be '0'.

Since the original two PUs have different motion information, the bS of the deblocking filtering should be set to '1', but the bS of the deblocking filtering is determined as '0', which may affect subjective image quality.

The present invention proposes a method for determining bS of deblocking filtering.

The present invention determines bS differently depending on whether it is a PU partition boundary when deblocking filtering is applied during video encoding or decoding. Therefore, according to the present invention, it is possible to adjust the bS value for PUs having the same motion information by motion information compression.

For example, when determining bS, (1) at least one of the absolute values of difference between motion vectors becomes 4 or more, (2) reference frames in motion compensation are different, or (3) PU partition boundary determines bS In the case of an edge, bS may be determined to be 1.

On the other hand, when (i) the absolute values of the motion vector differences are all less than 4, (ii) the reference frame in motion compensation is the same, and (iii) the PU partition boundary is not, that is, (i), (ii), ( If all iii) is satisfied, bS may be determined to be 0.

According to the present invention, the bS of the deblocking filtering may be determined based on the partition type (PU type) of the CU, or the boundary filtering strength (bS) of the deblocking filtering may be determined and stored in the parsing unit.

Hereinafter, each method will be described in detail with reference to the drawings.

Method based on CU partition type (PU type)

According to an embodiment of the present invention, the bS of deblocking filtering may be determined based on the partition type of the CU, for example, the PU type.

4 is a flowchart schematically illustrating an example of a method of determining bS based on a partition type of a CU.

Referring to FIG. 4 , in order to determine the boundary filtering strength bS, it is first determined whether at least one block among blocks p and q adjacent to each other is intra-coded (S410). Here, that the block p or q is intra-coded or inter-coded may mean that the block p or q is an intra-coded macroblock, a CU, a PU, or a TU, or a block belonging to any one of them.

5 is a diagram schematically illustrating a relationship between a block p and a block q.

Referring to FIG. 5A , when the boundary 500 is a horizontal edge, a block p 510 indicates a block located to the left with respect to the block boundary 500, and a block q 520 indicates a block boundary ( 500) to the right of the block.

Referring to FIG. 5( b ), when the boundary 530 is a vertical edge, the block p 540 represents a block located above the block boundary 530 , and the block q 550 is the block boundary ( 530) indicates a block located below the 530).

As a result of the determination in step S410, if there is one or more intra-coded blocks among blocks p and q, the 'INTRA MODE' step proceeds. On the contrary, when both blocks p and q are inter-coded, the 'inter mode' (INTER MODE)'.

Here, inter encoding is predictive encoding using an image of a reconstructed (reconstructed) frame (picture) different in time from the current frame (picture) as a reference frame (picture), and intra encoding is an image of neighboring blocks within the current frame (picture). It is a predictive encoding using

In the intra mode step, that is, when it is determined that at least one intra-coded block exists among blocks p and q, it is determined whether the boundary between the blocks p and q matches the boundary of the CU ( S440 ).

If the boundary of blocks p and q coincides with the boundary of the CU, bS is determined to be 4. On the other hand, when the boundary between blocks p and q is not the boundary of the CU, bS is determined to be 3.

When bS is 4, the strongest filtering is applied in a subsequent filtering application procedure, and the smaller the bS value, the weaker the filtering strength.

In the inter mode step, that is, when it is determined that both blocks p and q are inter-coded blocks, the boundary between the blocks p and q is the boundary of the TU (Transform Unit), and at least one of the blocks p and q has an orthogonal transform coefficient. It is determined whether or not (S420).

The orthogonal transform coefficient is also referred to as a coded coefficient or a non-zero transform coefficient.

As a result of the determination, if the boundary between the blocks p and q is the boundary of the TU and there is at least one block having an orthogonal transform coefficient, bS is determined to be 2. On the other hand, unless the boundary between the blocks p and q is the boundary of the TU and there is at least one block having an orthogonal transform coefficient, the next step is performed.

In the next step, for blocks p and q, whether the absolute value of the difference between one component of the motion vector, that is, the x-axis component or the y-axis component, is greater than or equal to 4 and/or whether the reference frame in motion compensation is different and/or PU It is determined whether it is a partition boundary (S430).

Here, 'that the reference frames are different' includes both that the reference frames themselves are different and that the number of reference frames is different.

When at least one of the absolute values of the difference between motion vectors is 4 or more, the reference frame in motion compensation is different, or it is a PU partition boundary, bS is determined to be 1.

On the other hand, when the absolute values of the motion vector differences are all less than 4 and the reference frames in motion compensation are the same and are not at the PU partition boundary, bS is determined as 0. bS being 0 indicates that filtering is not performed in the filtering application procedure.

Meanwhile, a method of determining bS may be determined based on various conditions as well as PU partition boundaries. For example, bS may be determined by applying at least one or more of the conditions 1 to 3 below.

1. When the target boundary is a PU partition boundary, bS may be determined to be 1.

2. When the current CU is the maximum depth and the target boundary is the PU partition boundary of the CU, bS may be determined to be 1. Here, the depth of the current CU may be performed when not only the maximum depth but also an arbitrarily determined depth or more.

3. If the boundary between the blocks p and q, which are the target boundary, is the boundary of the TU (Transform Unit), bS is determined as 1.

4. If the current CU has a maximum depth, bS for a boundary (or an inner boundary) is determined as 0.

In addition, various methods for determining bS may be applied.

How the parsing unit determines bS

According to the present invention, the parsing unit of the decoding apparatus may determine bS of deblocking filtering and store the determined bS.

6 is a diagram schematically illustrating an example of a method of determining bS of deblocking filtering in a parsing unit.

Referring to FIG. 6 , the decoder 600 includes a parsing and bS determining unit 610 , a decoding unit 640 , and a deblocking filtering unit 650 .

The parsing and bS determining unit 610 may include a parsing unit 620 and a bS determining unit 630 .

When the bitstream transmitted from the encoder is input to the decoder 600 , the parsing unit 620 parses it to obtain necessary information.

The bS determiner 630 may determine bS based on information obtained by parsing. In this case, the bS determiner 630 may determine bS by the method described with reference to FIG. 4 . Accordingly, the information obtained by parsing in the parsing unit 620 determines whether p is intra-coded, q is intra-coded, whether an edge between p and q is a TU edge, p includes coded coefficients, and q is encoded. information on whether the difference between the components of the motion vector for blocks p and q is equal to or greater than 4, whether the reference frames of p and q are different, and whether the edge between p and q is a PU partition boundary includes

The bS determined by the bS determiner 630 is transmitted to the deblocking filtering unit 650 .

The decoding unit 640 performs decoding based on the parsed information and outputs a reconstructed block. A specific method of generating the reconstructed block is as described with reference to FIG. 2 .

The deblocking filtering unit 650 performs deblocking filtering using the bS determined by the bS determining unit 630 .

The deblocking filter unit 650 may determine an area to which the deblocking filter is applied. Specifically, when the minimum unit to which the deblocking filter is applied is an 8x8 block, the boundary of the block may be derived by considering a horizontal edge and a vertical edge. The deblocking filtering unit 650 may determine whether to filter based on the bS for the boundary of the block or to apply the filtering. The deblocking filtering unit 650 selects a filter to be applied to the edge of the block. Filters can be divided into strong filters and weak filters. The filter may be selected according to a bS value, a quantization parameter, a deblocking filtering parameter, and the like.

Meanwhile, 'applying the deblocking filter to the block edge' here means that the deblocking filter is applied to left and right predetermined samples (eg, predetermined samples in p and q) bordering on the block edge.

In the example of FIG. 6 , each functional unit is configured to clarify the understanding of the present invention, but the present invention is not limited thereto. For example, the parsing and filtering strength determiner 610 may correspond to the entropy decoder of FIG. 2 or may be configured as a separate parsing unit. Also, the deblocking filtering unit 650 may correspond to the filter unit of FIG. 2 . Also, the decoding unit 640 may correspond to the remaining functional units except for the entropy decoding unit and the filter unit in FIG. 2 .

In addition, in FIG. 6 , when bS is determined by the bS determiner 640 but bS is not determined by the parsing unit and is determined by the filtering unit, the filtering unit derives a boundary to which deblocking filtering is applied, After setting bS. Whether to apply deblocking filtering or which deblocking filtering (weak filtering, strong filtering) is to be applied may be determined according to bS and/or other filtering parameters.

In this specification, the present invention has been described using terms such as frame and reference frame, but this is for convenience of description, and (reference) frame can be used in the same meaning as (reference) picture, and in the present invention, frame Note that the technical spirit of the present invention can be equally applied even in the case of replacing with .

In the exemplary system described above, the methods are described on the basis of a flowchart as a series of steps or blocks, however, the present invention is not limited to the order of steps, and some steps may occur in a different order or concurrently with other steps as described above. can In addition, the above-described embodiments include examples of various aspects. Accordingly, it is intended that the present invention cover all other substitutions, modifications and variations falling within the scope of the following claims.

When it is mentioned that one component is "connected" or "connected" to another component in the description of the present invention so far, the other component is directly connected to or connected to the other component. Although there may be, it should be understood that other components may exist between the two components. On the other hand, when it is mentioned that one component is "directly connected" or "directly connected" to another component, it should be understood that no other component exists between the two components.

Claims (2)

determining a block boundary to which a deblocking filter is to be applied;
determining boundary filtering strength for the block boundary; and
applying the deblocking filter to the block boundary based on the boundary filtering strength;
Determining the boundary filtering strength comprises:
determining the boundary filtering strength based on whether the block boundary is a partition boundary of a prediction block and whether the block boundary is a partition boundary of a transform block;
When the depth of the coding block is the maximum depth, filtering is not performed on the inner boundary of the coding block.
determining a block boundary to which a deblocking filter is to be applied;
determining boundary filtering strength for the block boundary; and
applying the deblocking filter to the block boundary based on the boundary filtering strength;
Determining the boundary filtering strength comprises:
determining the boundary filtering strength based on whether the block boundary is a partition boundary of a prediction block and whether the block boundary is a partition boundary of a transform block;
When the depth of the coding block is the maximum depth, filtering is not performed on the inner boundary of the coding block.

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