WO2024104506A1

WO2024104506A1 - Filtering method, device, and storage medium

Info

Publication number: WO2024104506A1
Application number: PCT/CN2024/072131
Authority: WO
Inventors: 魏亮; 陈方栋; 王莉; 武晓阳
Original assignee: 杭州海康威视数字技术股份有限公司
Priority date: 2022-11-14
Filing date: 2024-01-12
Publication date: 2024-05-23
Also published as: CN118042164A

Abstract

The present invention belongs to the technical field of image processing. Disclosed are a filtering method, a device, and a storage medium. The method of the present invention comprises: determining a filtering policy corresponding to the current filter unit, and a permission area where the current filter unit is located; according to the permission level of the permission area, determining the permission level of a sample in the current filter unit; according to the permission level of the sample, classifying the sample in the current filter unit; and according to the filtering policy and the classification result, executing a corresponding filtering operation on the current filter unit. According to a filtering policy, different filtering operations are executed on samples of different permission levels in each permission area, such that constrained filtering operations are performed on the permission area, thereby improving the subjective and objective quality of an image.

Description

Filtering method, device and storage medium

Technical Field

The present invention relates to the field of image processing technology, and in particular to a filtering method, device and storage medium.

Background technique

Different areas in the encoded image have different permissions, which can be a confidentiality level or other access permission level. Users with the highest permissions can see the correct content of all areas. Users with the lowest permissions can only see the correct content of areas equal to their own permissions, and cannot see the correct content of areas with higher permissions than their own. For example, these high-authority areas present mosaic or obscured content to low-authority users. One application scenario of permission areas is to present correct images of different ranges to users with different permissions. In principle, users with higher permissions see a larger range of correct images and a smaller range of obscured images.

Existing solutions do not filter the permission area, which will affect the subjective and objective quality of the image.

The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art.

Summary of the invention

The main purpose of the present invention is to provide a filtering method, device and storage medium, aiming to solve the technical problem that the prior art does not filter the permission area, which affects the subjective and objective quality of the image.

To achieve the above object, the present invention provides a filtering method, which comprises the following steps:

Determine the filtering strategy corresponding to the current filtering unit and the authority area in which it is located, wherein the authority area is an image area in the image with an authority level;

Determining the permission level of the samples in the current filtering unit according to the permission level of the permission area;

Classifying the samples in the current filtering unit according to the permission level of the samples;

A corresponding filtering operation is performed on the current filtering unit according to the filtering strategy and the classification result.

Optionally, the filtering strategy is determined by flag information parsed from a bitstream, and the flag information is used for transmission at a sequence level, an image level, a slice level, a tile level, or a filtering unit level.

Optionally, the permission region includes at least one filtering unit, the current filtering unit is allowed to span multiple permission regions, and the filtering unit includes at least one sample;

The determining the permission level of the sample in the current filtering unit according to the permission level of the permission area includes:

The permission level of the sample in the current filtering unit is consistent with the permission area where the sample is located.

Optionally, the current filtering unit is a basic unit in the filtering process and different filtering units are allowed to perform different filtering operations;

The performing corresponding filtering operations on the current filtering unit according to the filtering strategy and the classification result includes:

Not performing a filtering operation on a first sample in the current filtering unit, and performing a filtering operation on a second sample in the current filtering unit;

or,

Performing a filtering operation on all samples in the current filtering unit;

or,

No filtering operation is performed on all samples in the current filtering unit.

Optionally, the first sample is a non-filterable sample, and the second sample is a filterable sample.

Optionally, performing a filtering operation on all samples in the current filtering unit includes:

Converting the non-filterable samples in the current filtering unit into filterable samples by deriving information of a reference block or a reference sample, and performing a filtering operation on all filterable samples, wherein the information of the derived reference block or the reference sample is derived from available blocks or available samples in and around the permission area, or is derived from preset information;

The available blocks or available samples are blocks or samples that have authority lower than or equal to authority of the non-filterable samples and have been decoded or encoded.

Optionally, at least one of the following is included:

Taking samples in the current filtering unit that require reference block information during filtering and for which at least one reference block is unavailable as unfilterable samples;

Taking samples in the current filtering unit that require reference samples during filtering and for which at least one reference sample is unavailable as unfilterable samples;

The samples in the current filtering unit that require reference samples in the filtering process and for which all reference samples are unavailable are regarded as unfilterable samples; or

Samples that require reference samples in the filtering process within the current filtering unit and whose proportion of unavailable reference samples among all reference samples is greater than or equal to a preset value are regarded as unfilterable samples.

Optionally, the filtering method further includes:

Determine whether the samples in the current filtering unit need to use reference block information during the filtering process according to a preset filtering mode;

Whether the reference block is available is determined by the authority of the sample and the authority of the reference block.

Optionally, the reference block is a block required for making a filtering decision and/or implementing a filtering operation, the reference block includes at least one sample, and the authority of the reference block is the highest authority of all samples in the reference block.

Optionally, the determining whether the reference block is available based on the permission of the sample and the permission of the reference block includes:

If the authority of the reference block is lower than or equal to the authority of the sample and at least one of the following preset conditions is met, it is determined that the reference block is available;

The preset conditions include:

The reference block has been decoded or encoded;

The reference block and the sample are located in the same Slice or Tile; or

The reference block and the sample are located in different slices or tiles, and filtering is allowed on the boundary of the slice or tile.

Optionally, if the authority of the reference block is lower than or equal to the authority of the sample and at least one of the following preset conditions is met, after determining that the reference block is available, the method further includes:

Derived reference block information by using decoded blocks or coded blocks with authority lower than or equal to that of the sample around the unavailable reference block, and/or, derived reference block information by using preset information;

The information of the unavailable reference block is replaced by the derived reference block information so that the unavailable reference block is converted is the available reference block.

Optionally, the filtering method further includes:

Acquire a reference sample corresponding to any sample in the current filtering unit according to a preset filtering method;

Whether the reference sample is available is determined by comparing the permissions of the sample and the permissions of the reference sample.

Optionally, the reference samples are samples required for making filtering decisions and/or implementing filtering operations.

Optionally, judging whether the reference sample is available by comparing the permission of the sample with the permission of the reference sample includes:

If the authority of the reference sample is lower than or equal to the authority of the sample and at least one of the following preset conditions is met, it is determined that the reference sample is available;

The preset conditions include:

The reference sample has been decoded or encoded;

The reference sample and the sample are located in the same Slice or Tile; or

The reference sample and the sample are located in different slices or tiles, and filtering is allowed on the boundary of the slice or tile.

Optionally, if the authority of the reference sample is lower than or equal to the authority of the sample and at least one of the following preset conditions is met, after determining that the reference sample is available, the method further includes:

The reference sample information is derived by using decoded samples or encoded samples with authority lower than or equal to that of the sample around the unavailable reference sample, and/or the reference sample information is derived by using preset information;

The information of the unavailable reference sample is replaced by the derived reference sample information, so that the unavailable reference sample is converted into an available reference sample.

Optionally, the preset filtering mode includes at least one of the following:

Deblocking filtering;

Sample adaptive compensation;

Enhanced sample point adaptive compensation;

Adaptive compensation across component samples; or

Adaptive loop filtering.

In addition, to achieve the above objectives, the present invention also proposes a filtering device, which includes: a memory, a processor, and a filtering program stored in the memory and running on the processor, and the filtering program is configured to implement the filtering method described above.

In addition, to achieve the above-mentioned purpose, the present invention further proposes a storage medium, on which a filtering program is stored, and when the filtering program is executed by a processor, the filtering method as described above is implemented.

In addition, to achieve the above object, the present invention further provides a filtering device, the filtering device comprising:

An acquisition module, used to determine the filtering strategy corresponding to the current filtering unit and the authority area in which it is located, wherein the authority area is an image area in the image with an authority level;

an identification module, configured to determine the permission level of the sample in the current filtering unit according to the permission level of the permission area;

A classification module, used for classifying the samples in the current filtering unit according to the permission level of the samples;

A filtering module is used to perform corresponding filtering operations on the current filtering unit according to the filtering strategy and the classification result.

The present invention determines the filtering strategy corresponding to the current filtering unit and the authority area in which it is located; determines the authority level of samples in the current filtering unit according to the authority level of the authority area; classifies the samples in the current filtering unit according to the authority level of the samples; performs corresponding filtering operations on the current filtering unit according to the filtering strategy and the classification result, and performs different filtering operations on samples of different authority levels in each authority area according to the filtering strategy, thereby realizing constrained filtering operations on the authority area and improving the subjective and objective quality of the image.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a filtering device in a hardware operating environment according to an embodiment of the present invention;

FIG2 is a schematic diagram of a flow chart of a first embodiment of a filtering method according to the present invention;

FIG3 is a schematic diagram of a video coding framework structure in an embodiment of a filtering method of the present invention;

FIG4 is a schematic diagram of a flow chart of a second embodiment of a filtering method according to the present invention;

FIG5 is a schematic diagram of reference samples of a deblocking filtering method in an embodiment of a filtering method of the present invention;

FIG6 is a schematic diagram of vertical boundaries and horizontal boundaries corresponding to a deblocking filtering method in an embodiment of a filtering method of the present invention;

FIG7 is a schematic diagram of a reference sample of a sample point adaptive compensation method in an embodiment of a filtering method of the present invention;

FIG8 is a schematic diagram of a reference block of a sample adaptive compensation method in an embodiment of a filtering method of the present invention;

FIG9 is a schematic diagram of reference samples in an enhanced sample adaptive compensation method in an embodiment of a filtering method of the present invention;

FIG10 is a schematic diagram of reference samples in an adaptive compensation method across component samples in an embodiment of a filtering method of the present invention;

FIG11 is a schematic diagram of a reference sample of an adaptive loop filtering method in an embodiment of a filtering method of the present invention;

FIG12 is a schematic diagram of another reference sample of an adaptive loop filtering method in an embodiment of a filtering method of the present invention;

FIG13 is a schematic flow chart of a third embodiment of a filtering method according to the present invention;

FIG. 14 is a structural block diagram of the first embodiment of the filtering device of the present invention.

The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings.

Detailed ways

It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

Refer to FIG. 1 , which is a schematic diagram of the structure of a filtering device in a hardware operating environment according to an embodiment of the present invention.

As shown in FIG1 , the filtering device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), an input unit such as a keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a wireless fidelity (Wireless-Fidelity, Wi-Fi) interface). The memory 1005 may be a high-speed random access memory (Random Access Memory, RAM) memory, or a stable non-volatile memory (Non-Volatile Memory, NVM), such as a disk memory. The memory 1005 may also be a storage device independent of the aforementioned processor 1001.

Those skilled in the art will appreciate that the structure shown in FIG. 1 does not constitute a limitation on the filtering device, and may include more or fewer components than shown in the figure, or a combination of certain components, or a different arrangement of components.

As shown in FIG. 1 , the memory 1005 as a storage medium may include an operating system, a network communication module, a user interface module, and a filtering program.

In the filtering device shown in Figure 1, the network interface 1004 is mainly used for data communication with the network server; the user interface 1003 is mainly used for data interaction with the user; the processor 1001 and the memory 1005 in the filtering device of the present invention can be set in the filtering device, and the filtering device calls the filtering program stored in the memory 1005 through the processor 1001, and executes the filtering method provided by the embodiment of the present invention.

Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings need to be determined by their explanation in the specific embodiment or further combined with the context of the specific embodiment.

It should be understood that, although the terms first, second, third, etc. may be used to describe various information in this article, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this article, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein can be interpreted as "at the time of..." or "when..." or "in response to determination". Furthermore, as used in this article, the singular forms "one", "one" and "the" are intended to also include plural forms, unless there is an opposite indication in the context. It should be further understood that the terms "comprising", "including" indicate that there are the described features, steps, operations, elements, components, projects, kinds, and/or groups, but do not exclude the existence, occurrence or addition of one or more other features, steps, operations, elements, components, projects, kinds, and/or groups. The terms "or", "and/or", "including at least one of the following" etc. used in this application can be interpreted as inclusive, or mean any one or any combination. For example, “comprising at least one of the following: A, B, C” means “any of the following: A; B; C; A and B; A and C; B and C; A and B and C”, and for another example, “A, B or C” or “A, B and/or C” means “any of the following: A; B; C; A and B; A and C; B and C; A and B and C”. An exception to this definition will only occur when a combination of elements, functions, steps or operations are inherently mutually exclusive in some manner.

It should be understood that, although the various steps in the flowchart in the embodiment of the present application are displayed in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and it can be performed in other orders. Moreover, at least a portion of the steps in the figure may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and their execution order is not necessarily performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

It should be noted that in this article, step codes such as S10 and S20 are used for the purpose of expressing the corresponding content more clearly and concisely, and do not constitute a substantial limitation on the sequence. When implementing the step, those skilled in the art may execute S20 first and then S10, etc., but these should all be within the scope of protection of this application.

It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

An embodiment of the present invention provides a filtering method. Referring to Figure 2, Figure 2 is a flow chart of a first embodiment of a filtering method of the present invention. The filtering method can be applied to a decoding method flow for processing video data, and can also be applied to an encoding method flow for processing video data.

In this embodiment, the filtering method includes the following steps:

Step S10: Determine the filtering strategy and the authority area corresponding to the current filtering unit, where the authority area is an image area with an authority level in the image.

The execution subject of this embodiment may be a filtering device, and the filtering device may be implemented in various forms. For example, the filtering device described in this application may include mobile terminals or intelligent terminals such as tablet computers, laptop computers, PDAs, cameras, and fixed terminal devices such as desktop computers. These devices all have image processing functions, and the filtering device will be used as an example for explanation in the subsequent description.

Referring to FIG3 , it is a video coding framework, which includes prediction, transformation, quantization, entropy coding and filtering modules, wherein: the prediction module includes intra-frame prediction and inter-frame prediction, intra-frame prediction is to use the reconstructed pixels around the current block for prediction to remove spatial redundancy; inter-frame prediction is to use the reconstructed pixels on the time domain reference frame for prediction to remove temporal redundancy. The transformation module linearly maps the residual information in the spatial domain to the transformation domain (such as the frequency domain), with the goal of making the energy more concentrated and removing the frequency domain correlation of the signal. The theoretical transformation matrix is reversible and will not cause signal loss. The quantization module is a "many-to-one" mapping process, which is irreversible and will cause signal loss; the advantage is that it can greatly reduce the value range of the signal, so that the encoder can use a small number of symbols to give a good approximation of the original signal, thereby improving the compression rate. The entropy coding module is a lossless coding method based on the principle of information entropy, which converts a series of element symbols used to represent the video sequence (such as transform coefficients and mode information, etc.) into a binary code stream to remove the statistical redundancy of these video element symbols. The filtering module will enhance the reconstructed image with the goal of making the reconstructed image closer to the original image, while reducing the impact of blocking and ringing effects and improving the quality of the reconstructed image.

In an optional embodiment, the filtering operation in this embodiment is for filtering operations of encoded images, and different areas in the encoded image have different permissions, which can be a confidentiality level or other access permission level. For users with the highest permissions, the correct content of all areas can be seen. For users with the lowest permissions, they can only see the correct content of areas equal to their own permissions, and cannot see the correct content of areas with higher permissions than their own. For example, these high-authority areas present mosaic or obscured content to low-authority users. One application scenario of permission areas is to present correct images of different ranges to users with different permissions. Users with higher permissions see a larger range of correct images and a smaller range of obscured images.

However, the current filtering method does not filter samples within the permission area, which will greatly affect the subjective and objective quality of the image. In order to solve the above technical problems, in this embodiment, according to the filtering operation and the permission level of the permission area, a constrained filtering operation is performed on the permission areas of different permission levels. For example, there is no restriction on filtering in high-authority areas because the surrounding reference sample information can be obtained; for filtering in low-authority areas, if the reference sample is not available (for example, the reference sample is located in the high-authority area), a constrained filtering operation is required.

In this embodiment, when filtering an image, filtering is performed using a filtering unit as the basic unit in the filtering process. When filtering, each filtering unit may be filtered in sequence, or multiple filtering units may be filtered simultaneously. Each filtering unit corresponds to an image sub-region in the image. In contrast, a permission region is an image region with permission levels. For a single image, the image has multiple filtering units and multiple permission regions. There is no corresponding relationship between the number of filtering units and the number of permission regions. A permission region may contain multiple filtering units. For example, permission region X may contain one filtering unit A. It may also include two filter units A and B. Furthermore, a filter unit may also be located in multiple different authority areas, for example, filter unit C may be located in authority area X, or may span authority areas X and Y at the same time.

The filtering unit divides the image into multiple image areas in the horizontal and vertical directions. In this embodiment, the image can also be divided into a chroma component and a luminance component according to chroma and luminance, and the filtering units contained in these two components are corresponding. A filtering unit can include the above two components, and a component can also include multiple filtering units. In this embodiment, the filtering process of the entire image is explained using the filtering unit as an example. In this embodiment, the number and size of the filtering units divided by a single image, as well as the number and size of the authority areas can be set accordingly according to the actual image processing requirements, and this is not limited in this embodiment.

In an optional embodiment, when filtering the filter unit, it is performed according to the corresponding filtering strategy, and each filter unit can be allowed to execute different filtering strategies. Taking the current filter unit as an example, the filtering strategy executed by the current filter unit can be the same as the filtering strategy of other filter units, or it can be different from the filtering strategy of other filter units. In this embodiment, the filtering strategy is determined by the flag information, and the flag information can be transmitted at the sequence level (or SPS (Sequence Parameter Set) level), or the image level (or PPS (Picture Parameter Set) level or frame level), or Slice level, or Tile level, or filter unit level (or CTU (Coding Tree Unit)/CTB/LCU (Largest Coding Unit)/LCB (Largest Coding Block) level). The flag information is parsed from the bitstream, and the filtering strategy corresponding to each filter unit can be determined based on the parsed flag information. The level of the filtering strategy can also be patch level. Among them, the syntax used to manage or control several images can be called sequence level; the syntax used to manage or control a single frame image can be called image level; the syntax used to manage or control a parallel unit (i.e., an image area) including several coding units can be called slice level, tile level, or patch level; the syntax used to manage or control a maximum coding unit can be called LCU level; the syntax used to manage or control a filtering unit can be called filtering unit level. A filtering unit can include multiple maximum coding units, and a maximum coding unit can also include multiple filtering units.

Step S20: Determine the permission level of the samples in the current filtering unit according to the permission level of the permission area.

In an optional embodiment, each filtering unit includes at least one sample, which is a chromaticity sample or a brightness sample of a pixel. The authority level of each sample in the filtering unit is determined by the authority level of the authority area in which the filtering unit is located. The authority level may be a confidentiality level or other access permission level.

Since the filter unit in this embodiment can be in one permission area or in multiple permission areas at the same time, the permission levels of each sample in the filter unit are not all the same. In this embodiment, the above two situations are described separately. For the first situation, that is, when the filter unit is in one permission area, in this case, all samples in the filter unit are also in the permission area. At this time, the permission level of each sample in the filter unit is consistent with the permission level of the permission area. For example, when the current filter unit is in permission area X, the permission level of all samples in the current filter unit is the permission level of permission area X. For the second situation, that is, when the filter unit is in multiple permission areas, in this case, the samples in the filter unit are also in different permission areas accordingly, and the permission of the samples in the filter unit is consistent with the permission level of the permission area. For example, when the current filter unit is in permission areas X and Y at the same time, at this time, part of the samples in the current filter unit are in permission area X, and the other part of the samples are in permission area Y. The permission level of the samples in permission area X is the permission level of permission area X, and the permission level of the samples in permission area Y is the permission level of permission area Y.

Step S30: Classify the samples in the current filtering unit according to the authority levels of the samples.

In an optional embodiment, after determining the authority level of each sample in the current filtering unit, in this embodiment, all samples in the current filtering unit can be classified according to the authority level of each sample. In this embodiment, all samples in the current filtering unit can be divided into first samples and second samples according to the authority level of each sample. Second, samples, the specific process of classifying the samples in the current filtering unit in this embodiment can be implemented as follows.

An implementation method is provided in this embodiment, specifically, samples with high authority levels and samples with low authority levels in the current filtering unit can be determined according to the authority levels of each sample, and all samples in the current filtering unit are classified according to the authority levels of the samples. Optionally, samples with high authority levels can be used as first samples, and samples with low authority levels can be used as second samples.

Another implementation method is further provided in the present embodiment, specifically, reference block information needs to be used in the filtering process within the current filtering unit, and the permission level of the sample is compared with the permission level of the reference block, and all samples in the current filtering unit are classified based on the comparison result. Optionally, samples with a permission level lower than or equal to the permission level of the reference block can be used as the first sample, and samples with a permission level higher than the permission level of the reference block can be used as the second sample.

Another implementation method is further provided in the present embodiment, specifically, a reference sample is required during the filtering process in the current filtering unit, and the permission level of the sample is compared with the permission level of the reference sample, and all samples in the current filtering unit are classified based on the comparison result. Optionally, a sample with an permission level lower than or equal to the permission level of the reference sample can be used as the first sample, and a sample with an permission level higher than the permission level of the reference sample can be used as the second sample.

The above-mentioned methods are only examples. In the actual filtering process, other methods besides the above-mentioned methods may be selected, which is not limited in this embodiment.

In an optional embodiment, the first sample may be a non-filterable sample, and the second sample may be a filterable sample.

Step S40: performing corresponding filtering operations on the current filtering unit according to the filtering strategy and the classification result.

In an optional embodiment, in this embodiment, all samples in the current filtering unit can be divided into filterable samples and non-filterable samples according to the permission level of each sample, wherein the filterable samples are samples that can be directly filtered, and the non-filterable samples are samples that cannot be directly filtered.

In an optional embodiment, the flag information parsed from the bitstream is used to determine the filtering strategy corresponding to the current filtering unit, and the authority level is used to classify the samples in the current filtering unit. Due to the different classification of samples in the filtering unit, even if two filtering units have the same filtering strategy, the results after performing the filtering operation may be different. For example, assuming that the filtering strategy is partial filtering, the partial filtering strategy is to not perform the filtering operation on the first sample (that is, the non-filterable sample) in the filtering unit, and perform the filtering operation on the second sample (that is, the filterable sample) in the filtering unit. Due to the different classification of samples in the filtering unit, the number of the first sample and the second sample in each filtering unit is also different, so the final filtering result is also different.

In an optional embodiment, the filtering strategy includes at least three methods: full filtering, partial filtering, and no filtering. Based on the classification result of the samples, it can be determined that the samples of the current filtering unit at least include the situation where there is at least one unfilterable sample and/or at least one filterable sample. Among them, full filtering means that when there is at least one filterable sample, all samples in the current filtering unit are filtered, partial filtering means that no filtering operation is performed on the unfilterable samples in the current filtering unit, and filtering operation is performed on the filterable samples, and no filtering means that when there is at least one unfilterable sample, no filtering operation is performed on all samples of the current filtering unit.

In an optional embodiment, a preset filtering method is adopted when filtering the samples. The preset filtering method in this embodiment includes at least one of deblocking filtering, sample adaptive compensation, enhanced sample adaptive compensation, cross-component sample adaptive compensation and adaptive loop filtering. Then, the samples are filtered in the corresponding manner. Different from the existing method that does not perform filtering operations on samples in the permission area, in this embodiment, Based on the preset filtering method, the filtering operation is performed in combination with the permission level of the samples in the permission area, thereby realizing constrained filtering of permission areas with different permission levels, thereby improving the subjective and objective quality of the image.

This embodiment determines the filtering strategy corresponding to the current filtering unit and the permission area it is in; determines the permission level of samples in the current filtering unit according to the permission level of the permission area; classifies the samples in the current filtering unit according to the permission level of the samples; performs corresponding filtering operations on the current filtering unit according to the filtering strategy and the classification results, and performs different filtering operations on samples of different permission levels in each permission area according to the filtering strategy, thereby realizing constrained filtering operations on the permission area and improving the subjective and objective quality of the image.

Refer to FIG. 4 , which is a flow chart of a second embodiment of a filtering method according to the present invention.

Based on the above first embodiment, the filtering method of this embodiment further includes:

Step S301: samples in the current filtering unit that need to use reference block information during filtering and for which at least one reference block is unavailable are regarded as unfilterable samples.

In an optional embodiment, in this embodiment, filterable samples and non-filterable samples in the current filtering unit can be judged based on information related to the reference block. Specifically, for a certain sample in the current filtering unit, it is first necessary to determine whether the sample needs to use reference block information during the filtering process. If the reference block information is needed, it is further determined whether there is at least one reference block that is unavailable. If the above two conditions are met at the same time, it can be determined that the sample is a non-filterable sample. Among them, the reference block is a block required for making filtering decisions and/or implementing filtering operations. On the contrary, if the reference block information is not used; or if the reference block information is used and all reference block information is available, it is impossible to directly determine whether the sample is filterable, and it is necessary to further determine whether the sample is filterable based on the situation of the reference sample.

In an optional embodiment, whether reference block information needs to be used in the filtering process for samples in the current filtering unit can be determined according to a preset filtering method in this embodiment, wherein the preset filtering method includes at least one of deblocking filtering, sample adaptive compensation, enhanced sample adaptive compensation, cross-component sample adaptive compensation, and adaptive loop filtering.

In this embodiment, the preset filtering method is first used as the deblocking filter for explanation. Referring to FIG5 , according to the deblocking filtering method, the P blocks and Q blocks on both sides of the boundary are required when calculating the boundary strength. The coding information of the reference block is used in the deblocking filtering process, including the prediction method, non-zero transform coefficients, reference images, and motion vectors. When this filtering method is used to filter the sample, the sample will use the reference block information, and the two reference blocks required are the P block and the Q block.

In this embodiment, the preset filtering mode is further described as the filtering mode of sample adaptive compensation. The filtering mode of sample adaptive compensation includes a variety of different modes, such as boundary compensation, sideband compensation and parameter fusion. Taking the parameter fusion mode as an example, referring to FIG8 , the parameter fusion mode means that for a SAO (Sample Adaptive Offset) filter unit, its SAO parameters directly use the SAO parameters of the adjacent filter unit (left or top), and its reference block is the SAO filter unit on the left or top. A, B, and C all represent SAO filter units. When block C makes SAO parameter decisions, there are three situations: (a) directly use the parameters of block A; (b) directly use the parameters of block B; (c) select parameters different from block A and block B by analyzing the characteristics of its own pixel block. When this filtering mode is used to filter the sample, the sample will use the reference block information, and when block C makes SAO parameter decisions as an example, the two reference blocks required are block A and block B. The above are examples for explaining whether reference block information is needed for different filtering methods. In specific implementations, whether reference block information is needed for samples during filtering may also be determined in other ways, which is not limited in this embodiment.

In an optional embodiment, in this embodiment, whether the reference block required by the sample is available can be further determined by the permission of the sample and the permission of the reference block. Specifically, for a sample in the current filtering unit, it is necessary to obtain the permission of the sample and the permission of the reference block required by the sample. The corresponding permission can be determined by the permission area where the sample is located. The reference block also includes multiple samples, and the permission of the reference block is the permission of all samples in the reference block. The highest authority of the reference block. For example, there are samples Q, W and E in the reference block. Assuming that sample Q has the highest authority, the authority of the reference block is consistent with that of sample Q. Then compare the authority of the reference block with that of the sample. If the authority of the reference block is lower than or equal to that of the sample, further determine whether the following preset conditions are met. The preset condition may be that the reference block has been decoded or encoded, that is, for the encoding end, it is also necessary to ensure that the reference block has been encoded, or for the decoding end, it is also necessary to ensure that the reference block has been decoded. The preset condition may also be that the reference block and the sample are located in the same Slice or Tile. The preset condition may also be that the reference block and the sample are located in different Slices or Tiles, and filtering of the boundaries of the Slices or Tiles is allowed. If the judgment condition of the authority level and any one of the preset conditions are met at the same time, the reference block is deemed to be available.

In an optional embodiment, after determining that the reference block is unavailable, the information of the unavailable reference block may be replaced by the derived reference block information, thereby converting the unavailable reference block into an available reference block. In this embodiment, an implementation method is provided for the derived reference block information, specifically, for the encoding end, the reference block information is derived by the encoded blocks around the unavailable reference block, and for the decoding end, the reference block information is derived by the decoded blocks around the unavailable reference block, and it should be emphasized that since the authority of the unavailable reference block is usually higher than the authority of the sample, the authority of these decoded blocks or encoded blocks in this embodiment needs to be lower than or equal to the authority of the sample.

This embodiment also provides another implementation method, which is to derive reference block information through preset information, wherein the preset information includes default filtering parameters, prediction methods, non-zero transform coefficients, reference images, motion vectors and other information.

Step S302: taking samples in the current filtering unit that require reference samples during the filtering process and for which at least one reference sample is unavailable as unfilterable samples.

Step S303: taking samples in the current filtering unit that require reference samples during the filtering process and for which all reference samples are unavailable as unfilterable samples.

Step S304: samples that require reference samples in the filtering process within the current filtering unit and whose proportion of unavailable reference samples among all reference samples is greater than or equal to a preset value are regarded as unfilterable samples.

In an optional embodiment, in this embodiment, filterable samples and non-filterable samples in the current filtering unit may also be judged based on reference sample information, wherein the reference samples are samples required for making filtering decisions and/or implementing filtering operations.

In an optional embodiment, for a certain sample in the current filtering unit, it is necessary to first obtain a reference sample of the sample. After determining the reference sample, it is further determined whether the reference sample is available. Finally, based on the judgment result of whether the reference sample is available, it is determined whether the sample is an unfilterable sample. The specific judgment process can be implemented as follows.

This embodiment provides an implementation method, when it is determined that a reference sample needs to be used and at least one reference sample is unavailable, the sample is identified as an unfilterable sample. For example, the reference samples corresponding to the sample S in the current filtering unit are S1, S2, and S3, and if at least one of S1, S2, and S3 is an unavailable reference sample, the sample S can be identified as an unfilterable sample.

This embodiment provides another implementation method, when it is determined that a reference sample needs to be used and all reference samples are unavailable, the sample is identified as an unfilterable sample. For example, the reference samples corresponding to the sample S in the current filtering unit are S1, S2 and S3, and assuming that S1, S2 and S3 are all unavailable reference samples, the sample S can be identified as an unfilterable sample.

This embodiment provides another implementation method. When it is determined that a reference sample needs to be used and the proportion of unavailable reference samples is greater than or equal to a preset value, the sample is considered to be an unfilterable sample. For example, the reference samples corresponding to the sample S in the current filtering unit are S1, S2, and S3. Assuming that S1 and S2 are unavailable reference samples and S3 is an available reference sample, it can be calculated that the proportion of unavailable reference samples is 2/3. Assuming that the preset value of the proportion is 50%, then By determining that the proportion of unavailable reference samples is greater than a preset value, it can be determined that sample S is an unfilterable sample. The preset value can be set accordingly according to actual filtering requirements, which is not limited in this embodiment.

Furthermore, in this embodiment, the reference sample corresponding to the sample may be determined based on different preset filtering methods. In this embodiment, examples are further provided for various filtering methods.

In an optional embodiment, the deblocking filter is described in a filtering manner. The deblocking filter module needs to process the 8x8 block boundaries in all PU (Prediction Unit) and TU (Transform Unit) boundaries, including two links: filtering decision and filtering operation. First, a filtering decision is made to obtain the filtering strength (no filtering, weak filtering or strong filtering) and filtering parameters of the boundary. Then the filtering operation is performed, that is, the pixels are corrected accordingly according to the selected filtering strength and filtering parameters. The deblocking filter algorithm has the ability to adapt to different video contents and different encoding parameters, that is, different block boundaries are adaptively selected whether to filter and the filtering strength. For example, strong filtering is performed on the discontinuous boundaries of the smooth area, and weak filtering or no filtering is performed on the texture-rich area. In addition, at the slice level, the filtering parameters (i.e., β and tc) are allowed to be adjusted according to the individual characteristics of different video sequences, that is, the filtering parameters are fine-tuned by adding offset values, so that the filtering strength can be increased or decreased, the decoded video quality can be optimized, and better results can be obtained than the default values. It is worth noting that although the minimum unit of deblocking filtering is the 8x8 block boundary, the 8x8 block boundary is actually divided into two parts for independent deblocking filtering, as shown in Figures 5 and 6, the vertical boundary is based on 8x4 as the basic unit, and the horizontal boundary is based on 4x8 as the basic unit. Further take the deblocking filtering method of the vertical boundary as an example for explanation, as shown in Figure 5, for this filtering method, the reference sample can be the sample required in the filtering process, that is, the reference sample is the sample required for calculating the boundary strength and implementing the filtering operation. Specifically, according to different filtering operations, such as strong brightness filtering, weak brightness filtering and chroma filtering, the reference sample can be all or part of the samples in Figure 5. Further, the deblocking filter can also be operated on the horizontal boundary, and the deblocking filter of the horizontal boundary is shown in Figure 6. Similarly, according to different filtering operations, the reference sample can be all or part of the samples of the P block and Q block in Figure 6.

In an optional embodiment, the sample adaptive compensation is described in a filtering manner. Sample adaptive compensation uses CTB (Coding Tree Block) as the basic unit. By selecting a suitable classifier to classify the reconstructed pixels into categories, and then using different compensation values for pixels of different categories, the subjective and objective quality of the video can be effectively improved. SAO includes two major types of compensation forms, namely edge compensation (Edge Offset, EO) and sideband compensation (Band Offset, BO). In addition, in order to save the bit rate of encoding parameters, parameter fusion technology is also introduced. Boundary compensation technology is to classify the current pixel by comparing the size of the current pixel value with the adjacent pixel value, and then compensate the same value for the same type of pixels. The compensation values of different types of pixels can be different. According to the position difference of the selected adjacent pixels, the boundary compensation is divided into 4 modes: horizontal direction (EO_0), vertical direction (EO_1), 135 degree direction (EO_2) and 45 degree direction (EO_3), as shown in Figure 7, where c represents the current pixel, and a and b represent adjacent pixels. Referring to FIG7 , for this filtering method, a preset number of samples around any sample in the current filtering unit can be used as reference samples. As shown in FIG7 , the reference samples are two samples around the current sample. For example, if c is the current sample, a and b are reference samples. Furthermore, the sideband compensation is classified according to the pixel intensity value, and the pixel range is equally divided into 32 sidebands. Each sideband is compensated according to its own characteristics, and the same compensation value is used for the same sideband. For example, for an 8-bit image, the pixel value range is [0,255], which is divided into 32 sidebands, each sideband contains 8 pixel values, and the index range of the sideband is [0,31]. The parameter fusion mode means that for a CTB, its SAO parameters directly use the SAO parameters of the adjacent block (left or top), and this mode does not involve reference samples. See the reference block acquisition process described above.

In an optional embodiment, the enhanced sample adaptive compensation is described in a filtering manner. When the enhanced sample adaptive compensation method is adopted, for the luminance sample, all pixels are first divided into C1 and C2 categories according to two dimensions, and then the categories of the two dimensions are Cartesian product to obtain the final classification result Ct = C1 × C2. For the chrominance sample, only the second dimension is used for classification (ie C2), and the final classification result Ct is obtained by table lookup. Each category of samples has an offset value, which is transmitted in the bitstream. ESAO also supports image-level control The switch and LCU (Largest Coding Unit) level control switch. For the C1 category of the first dimension, the classification template is shown in Figure 9. For the current pixel, the initial category is set to cx = 0, and then the size is compared with the surrounding 8 pixels from left to right and from top to bottom. If the surrounding pixels are larger than the current pixel, cx is increased by 1; otherwise, cx is reduced by 1 (the second method is that cx remains unchanged). After the traversal is completed, the final category of the current pixel is obtained. It can be seen that the value range of cx is [-8,8] (the second method is [0,8]), so C1 = 17 (the second method is 9). Which of the two methods is used is determined by the encoder, and the identification information is transmitted in the image header. Figure 9 Classification template of C1 category For the C2 category of the second dimension, the pixel values in the range of [0, (1<<bitdepth)-1] are evenly divided into C2 categories according to the size interval. The size of C2 is determined by the encoder and transmitted in the image header. Suppose the current pixel value is y, then the classification formula is cy=(y*C2)>>bitdepth, where cy is a specific category between [0,C2]. Referring to FIG9, for this filtering method, a preset number of samples around any sample in the current filtering unit can also be used as reference samples. As shown in FIG9, the reference samples are the 8 samples around the current sample. For example, the shaded portion in FIG9 is the current sample, and the 8 non-shaded portions around the shaded portion are the reference samples of the current sample.

In an optional embodiment, the adaptive compensation of cross-component samples is described in a filtering manner. Adaptive compensation of cross-component samples is to classify the current chrominance sample according to the corresponding luminance sample value, and then superimpose an offset value according to the category. This technology only supports the BO (Band Offset) classification method. Specifically, the value range of the luminance sample is evenly divided into BandNum strips, each strip is a category, and the strip category into which the luminance sample value corresponding to the current chrominance sample falls is used as the category of the current chrominance sample, and then the chrominance sample is superimposed with the offset value corresponding to the category. Referring to Figure 10, for this filtering method, a preset number of samples around any sample in the current filtering unit can also be used as reference samples. In this filtering method, the sample and the reference sample are in different components. For example, the reference sample of the current chrominance sample is one of the surrounding 9 luminance samples. As shown in Figure 10, c is the current chrominance sample, 0 to 8 are the surrounding 9 luminance samples, and a luminance sample is selected from these 9 luminance samples as the reference sample of the current chrominance sample.

In an optional embodiment, adaptive loop filtering is described in a filtering manner. In adaptive loop filtering, for the luminance component, a frame of image is divided into 4x4 coefficient areas (as shown in FIG. 14 ), and the pixels in the same coefficient area use the same set of filter coefficients. According to the scanning order of the coefficient area, two adjacent coefficient areas can be merged into a new area, and the merged area can continue to be merged with its adjacent area until the entire frame of image is a coefficient area. Therefore, the number of filter coefficient groups of a frame of image is equal to the number of merged coefficient areas, and the value range is [1,16]. The number of filter coefficient groups of this frame of image (i.e., the number of merged coefficient areas), the size of each area (i.e., each merged area contains several original coefficient areas), and each set of filter coefficients need to be transmitted in the code stream. For the chrominance component, a frame of image uses a filter (i.e., the entire frame of image corresponds to a coefficient area and a set of filter coefficients), and the Cb and Cr components have their own filters. Referring to Figures 11 and 12, the shape of the adaptive loop filter is shown in Figure 11, and the shape of the enhanced adaptive loop filter is shown in Figure 12. For this filtering method, the surrounding samples within the filter coverage range, which are centered on the current sample, can be used as reference samples. Figures 11 and 12 show the surrounding samples within the filter coverage range, i.e., reference samples. The filter coverage range can be set based on different standards, which is not limited in this embodiment.

After determining the reference sample, in this embodiment, the permission of the sample and the permission of the reference sample can be used to further determine whether the reference sample required by the sample is available. Specifically, for a certain sample in the current filtering unit, it is necessary to obtain the permission of the sample and the permission of the reference sample required by the sample. The corresponding permission can be determined by the permission area where the sample is located and the permission area where the reference sample is located. Then, the permission of the reference sample is compared with the permission of the sample. If the permission of the reference sample is lower than or equal to the permission of the sample, it is further determined whether the following preset conditions are met. The preset condition can be that the reference sample has been decoded or encoded, that is, for the encoding end, it is also necessary to ensure that the reference sample has been encoded, or for the decoding end, it is also necessary to ensure that the reference sample has been decoded. The preset condition can also be that the reference sample and the sample are located in the same Slice or Tile. The preset condition can also be that the reference sample and the sample are located in different Slices or Tiles, and filtering is allowed on the boundaries of the Slice or Tile. If the judgment condition of the authority level and any one of the preset conditions are met at the same time, the reference sample is deemed to be available.

Furthermore, in this embodiment, after determining that the reference sample is unavailable, the information of the unavailable reference sample can be replaced by the derived reference sample information, thereby converting the unavailable reference sample into an available reference sample. In this embodiment, an implementation method is provided for the derived reference sample information, specifically, for the encoding end, the reference sample information is derived by the encoded samples around the unavailable reference sample, and for the decoding end, the reference sample information is derived by the decoded samples around the unavailable reference sample, and it should be emphasized that, since the authority of the unavailable reference sample is usually higher than the authority of the sample, in this embodiment, the authority of these decoded samples or encoded samples needs to be lower than or equal to the authority of the sample.

This embodiment also provides another implementation manner, which is to derive reference sample information through preset information, wherein the preset information includes a default sample value.

This embodiment classifies the unfilterable samples and filterable samples in the current filtering unit through reference block information or reference sample information, and can also convert unavailable reference blocks or unavailable reference samples into available reference blocks or available reference samples. The above method can accurately identify the unfilterable samples and filterable samples, and then execute the corresponding filtering strategy, which can effectively improve the subjective and objective quality of the image.

Refer to FIG. 13 , which is a flow chart of a second embodiment of a filtering method according to the present invention.

Step S401: Do not perform a filtering operation on a first sample in the current filtering unit, and perform a filtering operation on a second sample in the current filtering unit.

The preset filtering method in this embodiment includes at least one of deblocking filtering, sample adaptive compensation, enhanced sample adaptive compensation, cross-component sample adaptive compensation and adaptive loop filtering. The specific process of the filtering operation can be implemented as follows.

In an optional embodiment, when the filtering strategy is partial filtering, no matter how many unfilterable samples and filterable samples there are in the current filtering unit, the filtering operation performed is not to perform the filtering operation on the first sample (unfilterable sample) in the filtering unit, and to perform the filtering operation on the second sample (filterable sample) in the filtering unit. Assuming that there are N unfilterable samples and M filterable samples in the current filtering unit, the filtering operation is not performed on the N unfilterable samples, and the filtering operation is performed on the M filterable samples.

In an optional embodiment, when the filtering strategy is no filtering, in this case, it is necessary to first determine whether there are unfilterable samples in the current filtering unit. If there are unfilterable samples, no filtering operation is performed on all samples in the current filtering unit. Assuming that there are N unfilterable samples and M filterable samples in the current filtering unit, no filtering operation is performed on all samples in the current filtering unit, that is, M+N samples.

In an optional embodiment, when the filtering strategy is full filtering, in this case, it is necessary to first determine whether there are filterable samples in the current filtering unit. If there are filterable samples, the filtering operation is performed on all samples in the current filtering unit. Further, whether there are filterable samples in the current filtering unit includes two situations. The first situation is that all the samples in the current filtering unit are filterable samples. For example, the current filtering unit contains N samples, and these N samples are all filterable samples, then the filtering operation can be performed on these N filterable samples. The second situation is that there are non-filterable samples in the current filtering unit. For this situation, when executing the full filtering strategy, it is necessary to first convert all the non-filterable samples in the current filtering unit into filterable samples, and finally perform the filtering operation on all the filterable samples. For example, the current filtering unit contains N filterable samples and M non-filterable samples. First, convert these M non-filterable samples into M filterable samples, and finally perform the filtering operation on N+M filterable samples.

In an optional embodiment, the non-filterable samples in the current filtering unit can be converted into filterable samples by deriving information of reference blocks or reference samples, wherein the reference blocks refer to adjacent blocks required for sample filtering, and the reference samples refer to surrounding samples required for sample filtering. This embodiment provides an implementation method for obtaining information of derived reference blocks or reference samples, specifically, by using the permission area The available blocks or available samples inside and around the reference block or reference sample are used to derive information of the reference block or reference sample. The available blocks or available samples may be in the same authority area as the non-filterable samples, or may be in different authority areas, which is not limited in this embodiment. Among them, the authority of the available blocks or available samples needs to be lower than or equal to the authority of the non-filterable samples. For the decoding end, the available blocks or available samples are decoded blocks or samples, and for the encoding end, the available blocks or available samples are encoded blocks or samples.

In this embodiment, another implementation method is provided for obtaining the information of the reference block or reference sample, specifically deriving the information of the reference block or reference sample through preset information, wherein the preset information includes default sample values, filtering parameters, prediction methods, non-zero transform coefficients, reference images, motion vectors and other information.

This embodiment performs different filtering operations on samples of different permission levels in each permission area according to the filtering strategy, thereby realizing constrained filtering operations on the permission area and improving the subjective and objective quality of the image.

Refer to FIG. 14 , which is a structural block diagram of a first embodiment of a filtering device according to the present invention.

As shown in FIG14 , the filtering device provided in the embodiment of the present invention includes:

The acquisition module 10 is used to determine the filtering strategy corresponding to the current filtering unit and the authority area in which it is located, where the authority area is an image area with an authority level in the image.

The identification module 20 is used to determine the permission level of the sample in the current filtering unit according to the permission level of the permission area.

The classification module 30 is used to classify the samples in the current filtering unit according to the authority level of the samples.

The filtering module 40 is used to perform corresponding filtering operations on the current filtering unit according to the filtering strategy and the classification result.

In one embodiment, the filtering strategy is determined by flag information parsed from a bitstream, and the flag information is used for transmission at a sequence level, a picture level, a slice level, a tile level, or a filtering unit level.

In one embodiment, the permission region includes at least one filtering unit, the current filtering unit is allowed to span multiple permission regions, and the filtering unit includes at least one sample;

The identification module 20 is further configured to ensure that the authority level of the sample in the current filtering unit is consistent with the authority region where the sample is located.

In one embodiment, the current filtering unit is a basic unit in the filtering process and different filtering units allow different filtering operations to be performed;

The filtering module 40 is further used to not perform a filtering operation on the first sample in the current filtering unit, and to perform a filtering operation on the second sample in the current filtering unit; or to perform a filtering operation on all samples in the current filtering unit; or to not perform a filtering operation on all samples in the current filtering unit.

In one embodiment, the first sample is a non-filterable sample, and the second sample is a filterable sample.

In one embodiment, the filtering module 40 is further configured to convert the non-filterable samples in the current filtering unit into filterable samples by deriving information of reference blocks or reference samples, and perform filtering operations on all filterable samples, wherein the information of the derived reference blocks or reference samples is obtained by obtaining available blocks or samples in and around the permission area. The available block or available sample is derived from the available sample, or is derived through preset information; wherein the available block or available sample is a block or sample whose authority is lower than or equal to the authority of the non-filterable sample and has been decoded or encoded.

In one embodiment, the classification module 30 is further used to treat samples that require reference block information during the filtering process in the current filtering unit and for which at least one reference block is unavailable as unfilterable samples; treat samples that require reference samples during the filtering process in the current filtering unit and for which at least one reference sample is unavailable as unfilterable samples; treat samples that require reference samples during the filtering process in the current filtering unit and for which all reference samples are unavailable as unfilterable samples; and treat samples that require reference samples during the filtering process in the current filtering unit and for which the proportion of unavailable reference samples in all reference samples is greater than or equal to a preset value as unfilterable samples.

In one embodiment, the classification module 30 is further used to determine whether the samples in the current filtering unit need to use reference block information during the filtering process according to a preset filtering method; and to determine whether the reference block is available based on the permissions of the samples and the permissions of the reference block.

In one embodiment, the reference block is a block required for making filtering decisions and/or implementing filtering operations, the reference block includes at least one sample, and the authority of the reference block is the highest authority of all samples in the reference block.

In one embodiment, the classification module 30 is further used to determine that the reference block is available if the authority of the reference block is lower than or equal to the authority of the sample and at least one of the following preset conditions is met; the preset conditions include: the reference block has been decoded or encoded; the reference block and the sample are located in the same Slice or Tile; the reference block and the sample are located in different Slices or Tiles, and filtering of the Slice or Tile boundary is allowed.

In one embodiment, the filtering device further comprises a conversion module;

The conversion module is used to derive reference block information through decoded blocks or encoded blocks with authority lower than or equal to the authority of the sample around the unavailable reference block, and/or derive reference block information through preset information; replace the information of the unavailable reference block with the derived reference block information, so that the unavailable reference block is converted into an available reference block.

In one embodiment, the classification module 30 is further used to obtain a reference sample corresponding to any sample in the current filtering unit according to a preset filtering method; and determine whether the reference sample is available based on the authority of the sample and the authority of the reference sample.

In one embodiment, the reference samples are samples required for making filtering decisions and/or performing filtering operations.

In one embodiment, the classification module 30 is further used to determine that the reference sample is available if the authority of the reference sample is lower than or equal to the authority of the sample and at least one of the following preset conditions is met; the preset conditions include: the reference sample has been decoded or encoded; the reference sample and the sample are located in the same Slice or Tile; the reference sample and the sample are located in different Slices or Tiles, and filtering of the Slice or Tile boundaries is allowed.

In one embodiment, the filtering device further comprises a conversion module;

The conversion module is used to derive reference sample information through decoded samples or encoded samples whose authority around the unavailable reference sample is lower than or equal to the authority of the sample, and/or derive reference sample information through preset information; replace the information of the unavailable reference sample with the derived reference sample information, so that the unavailable reference sample is converted into an available reference sample.

In one embodiment, the preset filtering method includes at least one of the following: deblocking filtering; sample adaptive compensation; enhanced sample adaptive compensation; cross-component sample adaptive compensation; adaptive loop filtering.

In addition, to achieve the above objectives, the present invention also proposes a filtering device, which includes: a memory, a processor, and a filtering program stored in the memory and executable on the processor, wherein the filtering program is configured to implement the filtering method described above.

In addition, an embodiment of the present invention further provides a storage medium, wherein a filtering program is stored on the storage medium. When the filtering program is executed by the processor, the steps of the filtering method described above are implemented.

Since the storage medium adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

It should be understood that the above is only an example and does not constitute any limitation on the technical solution of the present invention. In specific applications, technicians in this field can make settings as needed, and the present invention does not limit this.

It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of the present invention. In practical applications, technicians in this field can select part or all of them according to actual needs to achieve the purpose of the present embodiment, and no limitation is made here.

In addition, for technical details that are not described in detail in this embodiment, reference can be made to the filtering method provided in any embodiment of the present invention, and will not be repeated here.

In addition, it should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory (ROM)/RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present invention.

The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

A filtering method, characterized in that the filtering method comprises:

Determine the filtering strategy corresponding to the current filtering unit and the authority area in which it is located, wherein the authority area is an image area in the image with an authority level;

Determining the permission level of the samples in the current filtering unit according to the permission level of the permission area;

Classifying the samples in the current filtering unit according to the permission level of the samples;

A corresponding filtering operation is performed on the current filtering unit according to the filtering strategy and the classification result.
The filtering method according to claim 1 is characterized in that the filtering strategy is determined by flag information parsed from the bitstream, and the flag information is used for transmission at the sequence level, image level, slice level, tile level or filtering unit level.
The filtering method according to claim 1, wherein the permission region includes at least one filtering unit, the current filtering unit is allowed to span multiple permission regions, and the filtering unit includes at least one sample;

The determining the permission level of the sample in the current filtering unit according to the permission level of the permission area includes:

The permission level of the sample in the current filtering unit is consistent with the permission area where the sample is located.
The filtering method according to claim 3, characterized in that the current filtering unit is a basic unit in the filtering process and different filtering units allow different filtering operations to be performed;

The performing corresponding filtering operations on the current filtering unit according to the filtering strategy and the classification result includes:

Not performing a filtering operation on a first sample in the current filtering unit, and performing a filtering operation on a second sample in the current filtering unit;

or,

Performing a filtering operation on all samples in the current filtering unit;

or,

No filtering operation is performed on all samples in the current filtering unit.
The filtering method according to claim 4 is characterized in that the first sample is a non-filterable sample and the second sample is a filterable sample.
The filtering method according to claim 4, characterized in that the performing a filtering operation on all samples in the current filtering unit comprises:

Converting the non-filterable samples in the current filtering unit into filterable samples by deriving information of a reference block or a reference sample, and performing a filtering operation on all filterable samples, wherein the information of the derived reference block or the reference sample is derived from available blocks or available samples in and around the permission area, or is derived from preset information;

The available blocks or available samples are blocks or samples that have authority lower than or equal to authority of the non-filterable samples and have been decoded or encoded.
The filtering method according to claim 5, characterized in that it comprises at least one of the following:

Taking samples in the current filtering unit that require reference block information during filtering and for which at least one reference block is unavailable as unfilterable samples;

Taking samples in the current filtering unit that require reference samples during filtering and for which at least one reference sample is unavailable as unfilterable samples;

The samples in the current filtering unit that require reference samples in the filtering process and for which all reference samples are unavailable are regarded as unfilterable samples; or

The reference samples required in the filtering process of the current filtering unit and not available in all reference samples Samples whose proportion is greater than or equal to the preset value are regarded as non-filterable samples.
The filtering method according to claim 7, characterized in that the filtering method further comprises:

Determine whether the samples in the current filtering unit need to use reference block information during the filtering process according to a preset filtering mode;

Whether the reference block is available is determined by the authority of the sample and the authority of the reference block.
The filtering method as described in claim 8 is characterized in that the reference block is a block required for making filtering decisions and/or implementing filtering operations, the reference block includes at least one sample, and the authority of the reference block is the highest authority of all samples in the reference block.
The filtering method according to claim 8, wherein the determining whether the reference block is available by the authority of the sample and the authority of the reference block comprises:

If the authority of the reference block is lower than or equal to the authority of the sample and at least one of the following preset conditions is met, it is determined that the reference block is available;

The preset conditions include:

The reference block has been decoded or encoded;

The reference block and the sample are located in the same Slice or Tile; or

The reference block and the sample are located in different slices or tiles, and filtering is allowed on the boundary of the slice or tile.
The filtering method according to claim 10, characterized in that if the authority of the reference block is lower than or equal to the authority of the sample and at least one of the following preset conditions is met, after determining that the reference block is available, it also includes:

Derived reference block information by using decoded blocks or coded blocks with authority lower than or equal to that of the sample around the unavailable reference block, and/or, derived reference block information by using preset information;

The information of the unavailable reference block is replaced by the derived reference block information, so that the unavailable reference block is converted into an available reference block.
The filtering method according to claim 7, characterized in that the filtering method further comprises:

Acquire a reference sample corresponding to any sample in the current filtering unit according to a preset filtering method;

Whether the reference sample is available is determined by comparing the permissions of the sample and the permissions of the reference sample.
The filtering method according to claim 12, characterized in that the reference samples are samples required for making filtering decisions and/or implementing filtering operations.
The filtering method according to claim 12, wherein the determining whether the reference sample is available based on the authority of the sample and the authority of the reference sample comprises:

If the authority of the reference sample is lower than or equal to the authority of the sample and at least one of the following preset conditions is met, it is determined that the reference sample is available;

The preset conditions include:

The reference sample has been decoded or encoded;

The reference sample and the sample are located in the same Slice or Tile; or

The reference sample and the sample are located in different slices or tiles, and filtering is allowed on the boundary of the slice or tile.
The filtering method according to claim 14, characterized in that if the authority of the reference sample is lower than or is equal to the authority of the sample, and at least one of the following preset conditions is met, then after determining that the reference sample is available, the method further includes:

The reference sample information is derived by using decoded samples or encoded samples with authority lower than or equal to that of the sample around the unavailable reference sample, and/or the reference sample information is derived by using preset information;

The information of the unavailable reference sample is replaced by the derived reference sample information, so that the unavailable reference sample is converted into an available reference sample.
The filtering method according to claim 8 or 12, characterized in that the preset filtering mode includes at least one of the following:

Deblocking filtering;

Sample adaptive compensation;

Enhanced sample point adaptive compensation;

Adaptive compensation across component samples; or

Adaptive loop filtering.
A filtering device, characterized in that the filtering device comprises: a memory, a processor, and a filtering program stored in the memory and running on the processor, wherein the filtering program is configured to implement the filtering method according to any one of claims 1 to 16.
A storage medium, characterized in that a filtering program is stored on the storage medium, and when the filtering program is executed by a processor, the filtering method according to any one of claims 1 to 16 is implemented.
A filtering device, characterized in that the filtering device comprises:

An acquisition module, used to determine the filtering strategy corresponding to the current filtering unit and the authority area in which it is located, wherein the authority area is an image area in the image with an authority level;

an identification module, configured to determine the permission level of the sample in the current filtering unit according to the permission level of the permission area;

A classification module, used for classifying the samples in the current filtering unit according to the permission level of the samples;

A filtering module is used to perform corresponding filtering operations on the current filtering unit according to the filtering strategy and the classification result.