CN109756736B

CN109756736B - SAO mode decision method, device, electronic equipment and readable storage medium

Info

Publication number: CN109756736B
Application number: CN201711058757.6A
Authority: CN
Inventors: 范娟婷; 张贤国; 朱政; 张二丽; 金星
Original assignee: Beijing Kingsoft Cloud Network Technology Co Ltd; Beijing Kingsoft Cloud Technology Co Ltd
Current assignee: Beijing Kingsoft Cloud Network Technology Co Ltd; Beijing Kingsoft Cloud Technology Co Ltd
Priority date: 2017-11-01
Filing date: 2017-11-01
Publication date: 2021-02-12
Anticipated expiration: 2037-11-01
Also published as: WO2019085942A1; CN109756736A

Abstract

The embodiment of the invention provides an SAO mode decision method, an SAO mode decision device, electronic equipment and a readable storage medium, wherein the method comprises the following steps: the method comprises the steps of performing pixel compensation on a current Coding Tree Unit (CTU) in a merging mode, determining an optimal merging mode and a first rate-distortion cost C1 of the current CTU in the optimal merging mode, obtaining a sample adaptive compensation SAO parameter of the current CTU based on the optimal merging mode under the condition that C1 is smaller than a preset first threshold, performing pixel compensation on the current CTU in an EO mode under the condition that C1 is not smaller than the first threshold, obtaining a second rate-distortion cost C2, determining the SAO parameter of the current CTU according to C2 and C1, and further completing SAO mode decision of the current CTU. By applying the SAO mode decision method provided by the embodiment of the invention, the coding efficiency can be improved.

Description

SAO mode decision method, device, electronic equipment and readable storage medium

Technical Field

The present invention relates to the field of video coding technologies, and in particular, to an SAO mode decision method, an apparatus, an electronic device, and a computer-readable storage medium.

Background

SAO (Sample Adaptive Offset, Sample Adaptive compensation) is a novel in-loop filtering technique proposed in High Efficiency Video Coding (HEVC) and aims to increase pixel compensation and reduce distortion between an original image and a reconstructed image on the premise of reducing compression performance as much as possible, thereby improving visual quality of a compressed Video.

In order to obtain better coding performance, it is necessary to select appropriate SAO parameters in the video coding process, and the SAO parameters mainly include: SAO type, offset value set, and merge mode, the selection process of SAO parameters is also referred to as SAO mode decision process. Wherein, the SAO types comprise: skip mode, EO (Edge Offset) mode, and BO (Band Offset) mode.

Since a CTU (Coding Tree Unit) includes a luma Coding Tree block and a plurality of chroma Coding Tree blocks, in the prior art, SAO mode decision needs to be made on the luma Coding Tree block and the chroma Coding Tree block in the CTU, which includes the following specific processes:

firstly, pixel compensation is carried out on a luminance coding tree block and a chrominance coding tree block under three modes, namely a skip mode, an EO mode and a BO mode, so that the minimum rate distortion cost of a CTU under the three modes is recorded as J1, if J1 is smaller than the optimal coding cost J0 of the CTU, J0 is set to be equal to J1, and SAO parameters of the CTU are generated. Then, pixel compensation is carried out on the luminance coding tree block and the chrominance coding tree block respectively in the merging mode, the rate distortion cost of the CTU is obtained and recorded as J2, if J2 is smaller than J0, J0 is set to be equal to J2, and the SAO parameter of the CTU is updated.

It can be seen from the above that, in the prior art, the process of making the SAO mode decision is complex, and the coding time is increased, resulting in low coding efficiency.

Disclosure of Invention

Embodiments of the present invention provide an SAO mode decision method, an apparatus, an electronic device, and a computer-readable storage medium, so as to improve coding efficiency. The specific technical scheme is as follows:

in a first aspect, to achieve the above object, an embodiment of the present invention discloses an SAO mode decision method, where the method includes:

performing pixel compensation on a current Coding Tree Unit (CTU) in a merging mode, and determining an optimal merging mode and a first rate-distortion cost C1 of the current CTU in the optimal merging mode;

under the condition that C1 is smaller than a preset first threshold, obtaining a sample adaptive compensation (SAO) parameter of the current CTU based on the optimal merging mode;

under the condition that C1 is not less than the first threshold, performing pixel compensation on the current CTU in an EO mode to obtain a second rate-distortion cost C2;

according to C2 and C1, determining SAO parameters of the current CTU, and further completing SAO mode decision of the current CTU.

Optionally, the performing pixel compensation on the current coding tree unit CTU in the merging mode, and determining an optimal merging mode and a first rate-distortion cost C1 of the current CTU in the optimal merging mode include:

setting a target threshold value C0 as a preset second threshold value, wherein the second threshold value is a value greater than the first threshold value;

performing pixel compensation on the current CTU in a leftward merging mode to obtain a third rate-distortion cost C3;

in the case where C3 is smaller than C0, the leftward merging mode is determined as the optimal merging mode, and C0 is updated to C3;

determining that the first rate-distortion cost C1 of the current CTU is equal to C3 in the optimal merge mode if C0 is less than a preset third threshold, wherein the third threshold is a value less than the second threshold;

under the condition that C0 is not less than the third threshold, performing pixel compensation on the current CTU in an upward merging mode to obtain a fourth rate-distortion cost C4;

in case C4 is less than C0, determining an upward merge mode as an optimal merge mode, and a first rate-distortion cost C1 of the current CTU in the optimal merge mode is equal to C4;

in case C4 is not less than C0, performing the pixel compensation of the current CTU in EO mode in case C1 is not less than the first threshold, obtaining a second rate-distortion cost C2.

Optionally, the preset second threshold is: a current best coding cost of the current CTU.

Optionally, the performing pixel compensation on the current CTU in the EO mode includes:

and under the EO mode, carrying out pixel compensation on the current CTU according to an offset value set obtained by a preset pixel row interval and/or a preset pixel column interval.

Optionally, before performing pixel compensation on the current coding tree unit CTU in the merge mode, determining an optimal merge mode and a first rate-distortion cost C1 of the current CTU in the optimal merge mode, the method further includes:

judging whether the current CTU is the first CTU in the video frame;

if not, executing the steps of performing pixel compensation on the current CTU in the merging mode, determining an optimal merging mode and a first rate-distortion cost C1 of the current CTU in the optimal merging mode;

and if so, directly carrying out pixel compensation on the current CTU in the EO mode, and obtaining the SAO parameter of the current CTU based on the EO mode.

Optionally, the directly performing pixel compensation on the current CTU in the EO mode includes:

selecting part or all of EO types from various preset EO types of the EO mode;

respectively carrying out pixel compensation on the current CTU under the selected EO types to obtain the rate-distortion cost of the current CTU under each selected EO type;

and determining the pixel compensation result corresponding to the rate distortion cost with the minimum value in the obtained rate distortion costs as the pixel compensation result of the current CTU in the EO mode.

Optionally, the directly performing pixel compensation on the current CTU in the EO mode, and obtaining an SAO parameter of the current CTU based on the EO mode includes:

performing pixel compensation on the current CTU in an EO mode to obtain a fifth rate-distortion cost C5;

judging whether C5 is smaller than the current optimal coding cost of the current CTU;

if not, ending the SAO mode decision of the current CTU, and skipping the SAO mode decisions of other CTUs in the video frame where the current CTU is located;

if so, obtaining the SAO parameter of the current CTU based on the EO mode.

Optionally, the determining the SAO parameter of the current CTU according to C2 and C1 includes:

if C2 is less than C1, obtaining SAO parameters of the current CTU based on the EO mode;

if C2 is not less than C1, obtaining SAO parameters of the current CTU based on the optimal merge mode.

In a second aspect, to achieve the above object, an embodiment of the present invention further discloses an SAO mode decision device, where the SAO mode decision device includes:

a mode determining module, configured to perform pixel compensation on a current CTU in a merging mode, and determine an optimal merging mode and a first rate-distortion cost C1 of the current CTU in the optimal merging mode;

the first judgment module is used for judging whether C1 is smaller than a preset first threshold value, and if so, the first parameter obtaining module is triggered; if not, triggering a rate distortion cost obtaining module;

the first parameter obtaining module is configured to obtain an SAO parameter of the current CTU based on the optimal merging mode;

the rate distortion cost obtaining module is configured to perform pixel compensation on the current CTU in the EO mode to obtain a second rate distortion cost C2;

a second parameter obtaining module, configured to determine, according to C2 and C1, an SAO parameter of the current CTU, so as to complete an SAO mode decision of the current CTU.

Optionally, the mode determining module includes: the optimal merging mode determining module comprises a threshold determining sub-module, a first rate-distortion cost obtaining sub-module, a first judging sub-module, an optimal merging mode determining sub-module, a second judging sub-module, a first rate-distortion cost determining sub-module, a second rate-distortion cost obtaining sub-module, a third judging sub-module and a second rate-distortion cost determining sub-module;

the threshold determination submodule is used for setting a target threshold value C0 as a preset second threshold value, wherein the second threshold value is a value greater than the first threshold value;

the first rate-distortion cost obtaining submodule is configured to perform pixel compensation on the current CTU in a left merging mode to obtain a third rate-distortion cost C3;

the first judgment submodule is used for judging whether C3 is smaller than C0, and if so, triggering the optimal merging mode determination submodule; if not, triggering the second judgment submodule;

the optimal merging mode determining submodule is used for determining the leftward merging mode as the optimal merging mode, and C0 is updated to C3;

the second judgment submodule is configured to judge whether C0 is smaller than a preset third threshold, and if so, trigger the first rate-distortion cost determination submodule; if not, triggering the second rate-distortion cost obtaining submodule;

the first rate-distortion cost determination sub-module is configured to determine that a first rate-distortion cost C1 of the current CTU in the optimal merge mode is equal to C3, where the third threshold is a value smaller than the second threshold;

the second rate-distortion cost obtaining sub-module is configured to perform pixel compensation on the current CTU in an upward merging mode to obtain a fourth rate-distortion cost C4;

the third judging submodule is used for judging whether C4 is smaller than C0, and if so, triggering the second rate-distortion cost determining submodule; if not, triggering the rate distortion cost obtaining module;

the second rate-distortion cost determination submodule is used for determining the upward merging mode as the optimal merging mode, and the first rate-distortion cost C1 of the current CTU in the optimal merging mode is equal to C4.

Optionally, the rate-distortion cost obtaining module is specifically configured to:

Optionally, the apparatus further comprises: a second judgment module and a third parameter obtaining module;

the second judging module is used for judging whether the current CTU is the first CTU in the video frame, and if so, triggering the mode determining module; if not, triggering the third parameter obtaining module;

the third parameter obtaining module is configured to directly perform pixel compensation on the current CTU in the EO mode, and obtain an SAO parameter of the current CTU based on the EO mode.

Optionally, the third parameter obtaining module is specifically configured to select a part of or all EO types from each preset EO type of the EO mode;

Optionally, the third parameter obtaining module includes: a third rate-distortion cost obtaining submodule, a fourth judging submodule, a skipping submodule and a first parameter obtaining submodule;

the third rate-distortion cost obtaining sub-module is configured to perform pixel compensation on the current CTU in the EO mode to obtain a fifth rate-distortion cost C5;

the fourth judgment submodule is used for judging whether C5 is smaller than the current optimal coding cost of the current CTU, and if not, the skipping submodule is triggered; if yes, triggering the first parameter obtaining submodule;

the skipping submodule is used for ending the SAO mode decision of the current CTU and skipping the SAO mode decision of other CTUs in the video frame where the current CTU is located;

the first parameter obtaining submodule is used for obtaining the SAO parameter of the current CTU based on the EO mode.

Optionally, the second parameter obtaining module includes: a fifth judgment submodule, a second parameter obtaining submodule and a third parameter obtaining submodule;

the fifth judgment submodule is used for judging whether C2 is smaller than C1, and if so, triggering the second parameter obtaining submodule; if not, triggering the third parameter obtaining submodule;

the second parameter obtaining submodule is used for obtaining the SAO parameter of the current CTU based on the EO mode;

and the third parameter obtaining submodule is used for obtaining the SAO parameter of the current CTU based on the optimal merging mode.

In yet another aspect of the present invention, there is also provided an electronic device, comprising a processor and a memory;

a memory for storing a computer program;

and the processor is used for realizing any SAO mode decision method when executing the program stored in the memory.

In yet another aspect of the present invention, there is also provided a computer-readable storage medium having stored therein instructions, which when run on a computer, cause the computer to perform any of the SAO mode decision methods described above.

In yet another aspect of the present invention, there is also provided a computer program product including instructions, which when run on a computer, causes the computer to perform any of the SAO mode decision methods described above.

The SAO mode decision method, the apparatus, the electronic device, and the computer-readable storage medium according to embodiments of the present invention may perform pixel compensation on a current CTU in a merge mode, determine an optimal merge mode and a first rate-distortion cost C1 of the current CTU in the optimal merge mode, when C1 is smaller than a preset first threshold, may directly skip an EO mode to determine a SAO parameter of the current CTU, and when C1 is not smaller than the first threshold, determine the SAO parameter of the current CTU according to a second rate-distortion cost C2 and C1 obtained by performing pixel compensation on the current CTU in the EO mode. Therefore, the EO mode can be skipped when the first rate-distortion cost C1 meets the condition by applying the embodiment of the invention, so that the coding time can be saved, and the coding efficiency can be improved.

Of course, it is not necessary for any product or method of practicing the invention to achieve all of the above-described advantages at the same time.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a general framework diagram of a video codec corresponding to the latest video coding standard HEVC;

fig. 2 is a frame diagram of an SAO encoding terminal interface in HEVC, which is the latest video encoding standard;

fig. 3 is a block diagram of a SAO decoder interface in HEVC, which is the latest video coding standard;

fig. 4 is a schematic diagram of four different sets of adjacent pixels for EO mode in SAO within the latest video coding standard HEVC;

fig. 5 is a schematic diagram of merge modes in SAO within the latest video coding standard HEVC;

FIG. 6 is a flow chart illustrating an SAO mode decision method;

fig. 7 is a first flowchart of an SAO mode decision method according to an embodiment of the present invention;

fig. 8 is a second flowchart of an SAO mode decision method according to an embodiment of the present invention;

fig. 9 is a third flowchart illustrating an SAO mode decision method according to an embodiment of the present invention;

FIG. 10 is a schematic flow chart of obtaining the SAO parameter of the current CTU directly in the EO mode according to the embodiment of the present invention;

FIG. 11 is a flowchart illustrating the determination of SAO parameters of the current CTU according to C2 and C1 according to an embodiment of the present invention;

fig. 12 is a schematic diagram illustrating a first structure of an SAO mode decision device according to an embodiment of the present invention;

fig. 13 is a schematic diagram illustrating a second structure of an SAO mode decision device according to an embodiment of the present invention;

fig. 14 is a schematic structural diagram of an SAO mode decision device according to a third embodiment of the present disclosure;

fig. 15 is a schematic structural diagram of a third parameter obtaining module according to an embodiment of the present invention;

fig. 16 is a schematic structural diagram of a second parameter obtaining module according to an embodiment of the present invention;

fig. 17 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

First, the technical terms related to the present application will be described with reference to a sample adaptive compensation SAO mode decision method in the prior art.

Video compression, also known as video coding, aims to eliminate redundant information existing between video images. To date, various video coding standards have been established successively by standardization organizations at home and abroad, and the mainstream video coding standard adopts a hybrid coding framework of 'prediction and transformation based on blocks'. Referring to fig. 1, fig. 1 is a general frame diagram of a video codec corresponding to the latest HEVC, and an input video signal is processed by coding techniques such as block structure division, prediction, transformation, quantization, entropy coding, and the like, and then a bitstream is output.

Generally, a Video encoder divides a Video frame into blocks for encoding, for example, an h.264/AVC (Advanced Video Coding) Video encoding standard divides the Video frame into 16 × 16 Macroblocks (MBs) with equal sizes and without covering each other, and HEVC divides the Video frame into Coding Tree Units (CTUs) with uniform sizes, where the CTUs may be set in an encoder configuration file and generally adopt 64 × 64 sizes. The CTU may be divided into Coding Units (CUs) of different sizes, and coded in units of CUs. And then dividing the CU into different Prediction Units (PUs) by taking the CU as a reference, performing Prediction by taking the PU as a Unit to obtain a Prediction block, performing difference between the Prediction block and the original PU to obtain a Prediction residual block, performing transformation on the Prediction residual block to obtain a transformation coefficient block, forming a one-dimensional array in a specific scanning mode, inputting the array into a quantizer to perform scalar quantization, inputting the quantized coefficient into an entropy coder to perform coding, and outputting a coding bit stream. The encoded video reconstructed block is used as a reference block for subsequent video blocks, so that the subsequent video blocks can obtain more accurate prediction blocks by inter/intra prediction. And a certain error may exist between the original video block and a reconstructed block obtained after prediction, transformation, quantization, inverse quantization and inverse transformation, that is, the obtained reconstructed block has distortion. And deblocking filtering (De-block Filter, DF), SAO and the like can effectively reduce the distortion of the reconstructed block and further improve the subjective/objective quality of the coded video.

Referring to fig. 2, fig. 2 is a frame diagram of an SAO encoding terminal interface in HEVC of the latest video encoding standard, which includes inputting video frame block data and intermediate data after deblocking filtering, and outputting final reconstructed block data (which may be used as a reference block for encoding a subsequent encoding block) and SAO parameters (which need to be encoded by an entropy encoder into a code stream and input to a decoding terminal), where the encoding SAO parameters also need a certain encoding bit. For the decoder, referring to fig. 3, fig. 3 is a frame diagram of an SAO decoder interface in HEVC, which is a latest video coding standard, and inputs deblock-filtered data of reconstructed block data and SAO information decoded by an entropy decoder, and outputs a final reconstructed signal (which is input to a reference frame list buffer for reference of a subsequent video frame). Therefore, the SAO should balance the quality of the finally compressed video and the compression performance to select an appropriate SAO parameter, and the selection process of the SAO parameter is also called as the SAO mode decision process.

The SAO parameters mainly include the SAO type, the offset value set, and the merge mode. The SAO types include three types, i.e., a skip mode, an EO mode, and a BO mode. The offset value set is a set of offset values calculated according to the relationship between the current pixel in the luminance coding tree block or the chrominance coding tree block and the value of the corresponding pixel in the original image in the EO/BO mode. The calculated offset value is applied to the corresponding pixel to achieve pixel compensation of the luminance coding tree block or the chrominance coding tree block, i.e. to reduce distortion of the reconstructed block. Specifically, the relationship between the value of SAO _ type _ idx and the corresponding SAO type in table 1 can be identified by the value of SAO _ type _ idx.

TABLE 1

sao_type_idx	SAO type
		0	Skip mode
1	BO mode
		2	EO mode

The EO mode is a process of calculating an offset value according to a relationship between a current pixel and its neighboring pixels in the luma coding tree block or the chroma coding tree block, and applying the calculated offset value to the current pixel, and the EO mode specifically operates as follows: the current pixel is divided into five different types according to table 2, and table 2 shows the corresponding relationship between the class number of the current pixel and the relationship between the current pixel and its neighboring pixels.

TABLE 2

Category numbering	Condition
		1	c<a&&c<b
2	(c<a&&c＝＝b)\|\|(c＝＝a&&c<b)
		3	(c>a&&c＝＝b)\|\|(c＝＝a&&c>b)
4	c>a&&c>b
		0	Other cases

Referring to fig. 4, fig. 4 is a schematic diagram of four different groups of adjacent pixels of an EO mode in an SAO within the latest video coding standard HEVC. a. b denotes a neighboring pixel and c denotes a current pixel. If "other conditions" are met, i.e., the pixel belongs to the "0" th class, then no offset value will be applied to the current pixel c of that class; if the other four conditions are satisfied, then it is the current of each categoryPixel c is assigned an offset value that is added to the current pixel c. The offset value is a positive integer for the class 1 and class 2 current pixels and a negative integer for the class 3 and class 4 current pixels to avoid an increase in coded bits due to coding sign bits. The specific operation mode of the offset value calculation is as follows: calculating the average value R of all pixels in each category after dividing the luminance coding tree block or the chrominance coding tree block into 5 categories before SAO mode decision₁And the mean value S of all the pixels in each category after the pixels of the luminance coding tree block or the chrominance coding tree block of the original image are divided into 5 categories₁The offset value for this class is (S)₁-R₁). The offset values of each class constitute a set of offset values for the EO mode.

The BO mode is a process of classifying all pixels according to the value sizes of all pixels within a luminance coding tree block or a chrominance coding tree block, setting an offset value for each class of pixels, and then applying the offset value to the corresponding class of pixels. The specific operation mode is as follows: all pixels are divided into 32 non-interleaved bands (bands), i.e. each band contains pixels with corresponding 8 pixel values, like a statistical histogram, and the 1 st band contains a range of pixel values belonging to 0,7]The 2 nd band contains the pixel values in the range of [8,15 ]]And so on, the 32 nd range of values with included pixels belongs to [248,255 ]]The pixel of (2). For each band a corresponding offset value is determined, which is applied to the pixels belonging to that band. Selects 4 bands in which the pixel distribution is most concentrated within the CTU, and transmits the start positions of the 4 bands and corresponding offset values to the decoding end. The calculation method of the offset value is as follows: calculating average value R of all pixels in each band after dividing a luminance coding tree block or a chrominance coding tree block into 32 bands before SAO mode decision₂And the average value S of all pixels in each band after the pixels of the luminance coding tree block or the chrominance coding tree block of the original image are divided into 32 bands₂The offset value of the band is (S)₂-R₂). The offset value of each band constitutes a set of offset values for the BO mode.

Referring to fig. 5, fig. 5 is a schematic diagram of a merge mode in SAO within the latest video coding standard HEVC. As shown in fig. 5, the merge mode (including the upward merge mode and the leftward merge mode) refers to SAO parameters of the CTU pointed by the arrow used by the current CTU. An upward merge mode, that is, the current CTU uses the SAO parameter of the CTU above the current CTU; left merge mode, i.e. the current CTU uses the SAO parameter of the left CTU of the current CTU

A CTU usually includes a luma coding tree block and several chroma coding tree blocks, so performing SAO mode decision on the CTU requires performing SAO mode decision on the luma coding tree block and the chroma coding tree block, respectively.

Referring to fig. 6, fig. 6 is a flowchart illustrating an SAO mode decision method.

First, an SAO type decision is made for the CTU. The method comprises the steps of firstly, determining the SAO type of a brightness coding tree block, namely selecting one of three SAO types with the minimum rate distortion cost to generate the SAO parameter of the brightness coding block, and calculating to obtain the rate distortion cost of the corresponding brightness coding block. And secondly, if the CTU has chrominance components, generating SAO parameters of chrominance coding tree blocks in the same mode, and if the CTU has a plurality of chrominance components, requiring a plurality of chrominance coding tree blocks to respectively perform mode decision, generating corresponding SAO parameters, and calculating to obtain the rate-distortion cost of corresponding chrominance coding blocks. Rate-distortion cost, i.e. coding cost, is a measure for evaluating coding performance based on rate-distortion theory in video coding.

Then, the rate-distortion cost of the CTU after SAO usage (i.e., the sum of the rate-distortion cost of the luma coded tree block and the rate-distortion cost of the chroma coded tree block) J1 is calculated. At this time, if one of the luma coded tree block and the chroma coded tree block does not adopt the skip mode and J1 is less than the optimal CTU coding cost J0 before SAO is used, the current SAO parameters (including the SAO type and the offset value set of the luma coded tree block and the SAO type and the offset value set of the chroma coded tree block) need to be stored, and J0 is set to be equal to J1; otherwise, directly entering the next step.

And thirdly, selecting the SAO merging mode for the CTU. And sequentially calculating the rate-distortion cost J2 of the CTU in the leftward merging mode and the rate-distortion cost J3 of the CTU in the upward merging mode according to the leftward merging mode and the upward merging mode. And if the rate-distortion cost of the CTU obtained in the current step is less than the current J0, updating the SAO parameters of the CTU to the corresponding merging mode (namely an upward merging mode or a leftward merging mode), and setting J0 to be equal to the corresponding rate-distortion cost (namely J2 or J3).

Finally, if the J1 obtained by the SAO type decision is not less than the J0, and the rate-distortion cost obtained by each step in the SAO merging mode selection process is not less than the J0 at the current step, the SAO mode decision is skipped for the CTU.

It can be seen from the above that the SAO mode decision process is complex, the coding time and the amount of calculation are increased, and the coding efficiency is not high.

The present invention will be described in detail with reference to specific examples.

Fig. 7 is a first flowchart of an SAO mode decision method according to an embodiment of the present invention, including:

s701: and performing pixel compensation on the current coding tree unit CTU in the merging mode, and determining the optimal merging mode and a first rate-distortion cost C1 of the current CTU in the optimal merging mode.

In this embodiment, the merge mode may include a leftward merge mode and an upward merge mode.

Pixel compensation can be performed on the current CTU in the left combining mode and the upward combining mode respectively to obtain a rate-distortion cost of the current CTU in the left combining mode and a rate-distortion cost of the current CTU in the upward combining mode, the magnitudes of the rate-distortion costs of the current CTU in the two different combining modes are compared, the combining mode with the smaller rate-distortion cost is determined as the combining mode to be selected (i.e., the optimal combining mode), and the rate-distortion cost of the current CTU in the combining mode is taken as the first rate-distortion cost C1.

It should be noted that, according to the introduction of the SAO mode decision method in the prior art, it can be known that the CTU is pixel compensated, that is, the luminance coding tree block and the chrominance coding tree block included in the CTU are pixel compensated. Similarly, the CTUs mentioned in the following embodiments all represent the luma coding tree block and the chroma coding tree block included therein. Reference to processing a CTU means to perform corresponding processing on a luma coded tree block included in the CTU and to perform corresponding processing on a chroma coded tree block included in the CTU. The rate-distortion costs of the CTUs mentioned each represent the sum of the rate-distortion cost of the luma coding tree block comprised by the CTU and the rate-distortion cost of the chroma coding tree block comprised by the CTU.

S702: judging whether C1 is smaller than a preset first threshold value, if so, executing S703; if not, S704 is performed.

The first threshold may be set empirically by a technician, or may be the optimal coding cost of the current CTU before using SAO.

S703: and obtaining a sample adaptive compensation SAO parameter of the current CTU based on the optimal merging mode.

As a result of a large number of experiments, in the SAO mode decision process, the probability of finally selecting the merging mode is very high, and therefore, in this embodiment, when C1 is smaller than the preset first threshold, after determining the merging mode of the current CTU (i.e., the optimal merging mode), the SAO type decision step may be skipped, and the SAO parameters of the current CTU (the SAO parameters of the CTU above the current CTU or the SAO parameters of the CTU to the left of the current CTU) are obtained according to the optimal merging mode (the upward merging mode or the leftward merging mode).

The SAO parameters include a SAO type and a set of offset values of the CTU above the current CTU or a SAO type and a set of offset values of the CTU to the left of the current CTU.

S704: and performing pixel compensation on the current CTU in the EO mode to obtain a second rate distortion cost C2.

In this embodiment, when C1 is not less than the first threshold, pixel compensation may be performed on the current CTU by using each EO type of the EO mode, and a rate-distortion cost of the current CTU, which is obtained by performing pixel compensation on the current CTU by using each EO type, is calculated, and the calculated minimum rate-distortion cost is used as the second rate-distortion cost.

S705: according to C2 and C1, the SAO parameters of the current CTU are determined.

In this embodiment, when C2 is less than C1, the SAO parameter of the current CTU may be obtained based on the EO mode, and when C2 is not less than C1, the SAO parameter of the current CTU may be obtained based on the optimal merge mode corresponding to C1.

As can be seen from the above description, in the scheme provided in the embodiment of the present invention, when C1 is smaller than the preset first threshold, the EO mode decision step may be skipped, and the SAO parameter of the current CTU is directly obtained based on the optimal merge mode, so that the coding time can be saved, and the coding efficiency can be improved.

In an embodiment of the present invention, referring to fig. 8, fig. 8 is a second flowchart of an SAO mode decision method provided by the embodiment of the present invention, in which pixel compensation is performed on a current CTU in a merging mode, and an optimal merging mode and a first rate-distortion cost C1 of the current CTU in the optimal merging mode are determined (S701), including:

s7011: the target threshold C0 is set to a preset second threshold.

Wherein the second threshold is a value greater than the first threshold.

In one implementation, the second threshold may be an optimal coding cost before the current CTU does not make the SAO mode decision. Setting C0 as a variable quantity in the selection of merge mode, the initial value of C0 is equal to the second predetermined threshold.

S7012: and performing pixel compensation on the current CTU in the left merging mode to obtain a third rate-distortion cost C3.

And obtaining the SAO type (EO mode or BO mode or skip mode) and the offset value set (no offset value set exists in the skip mode) of the CTU on the left of the current CTU, performing pixel compensation on the current CTU by using the obtained SAO type and the offset value set, and calculating and obtaining the rate-distortion cost C3 of the current CTU under the action of the SAO type and the offset value set according to the compensation result.

In particular, the method for pixel compensation of the current CTU by using the SAO type and the offset value set may refer to the specific operation steps of the EO mode and the BO mode described above.

S7013: judging whether C3 is less than C0, if yes, executing S7014; if not, S7015 is directly performed.

S7014: the leftward merge mode is determined as the optimal merge mode, and C0 is updated to C3.

And the rate-distortion cost obtained by the current CTU in the left merging mode is less than the optimal coding cost of the current CTU, the current CTU is determined to be capable of selecting the left merging mode (the optimal merging mode), and the value of C0 is updated to the value of a third rate-distortion cost C3.

S7015: judging whether C0 is smaller than a preset third threshold value, if so, executing S7016; if not, S7017 is performed.

Wherein the third threshold is a value smaller than the second threshold.

If the third rate distortion cost C3 is less than C0 as determined in S7013, the value of C0 is equal to the third rate distortion cost C3; if the third rate-distortion cost C3 is not less than C0 as determined in S7013, the value of C0 is equal to the second threshold.

I.e., whether C3 is less than a preset third threshold or whether the second threshold is less than the third threshold.

Obviously, the second threshold is not less than the third threshold, and for the case that the third rate-distortion cost C3 is not less than C0, it can be directly determined that S7017 is performed next.

S7016: it is determined that the first rate-distortion cost C1 of the current CTU in the optimal merge mode is equal to C3.

According to S7015, when the value of C0 is equal to the third rate-distortion cost C3, the selection process of the upward merging mode is skipped, the optimal merging mode of the current CTU is determined to be the leftward merging mode, and the first rate-distortion cost C1 of the current CTU is equal to the third rate-distortion cost C3 of the current CTU in the leftward merging mode.

S7017: pixel compensation is performed on the current CTU in the up-merge mode to obtain a fourth rate-distortion cost C4.

According to S7015, the value of C0 at this time is equal to the second threshold or C3.

And obtaining an SAO type (EO mode or BO mode or skip mode) and an offset value set of the CTU above the current CTU, performing pixel compensation on the current CTU by using the obtained SAO type and offset value set, and calculating and obtaining a rate-distortion cost C4 of the current CTU under the action of the SAO type and the offset value according to a compensation result.

S7018: judging whether C4 is less than C0, if yes, executing S7019; if not, S702 is executed.

S7019: the upward merging mode is determined as the optimal merging mode, and the first rate-distortion cost C1 of the current CTU in the optimal merging mode is equal to the fourth rate-distortion cost C4.

And the rate-distortion cost C4 obtained by the current CTU in the upward merging mode is less than the current C0 (equal to the second threshold or the third rate-distortion cost C3), and the current CTU is determined to be capable of selecting the upward merging mode (the optimal merging mode), wherein the first rate-distortion cost C1 of the current CTU is equal to the rate-distortion cost C4 of the current CTU in the upward merging mode.

As can be seen from the above description, in the case that C0 is smaller than the preset third threshold, the scheme provided in the embodiment of the present invention determines that the first rate-distortion cost C1 of the current CTU in the optimal merge mode is equal to C3, that is, the selection process of the upward merge mode can be directly skipped. The coding time can be saved, and the coding efficiency is improved.

In a specific embodiment of the present invention, the second threshold is the current best coding cost of the current CTU.

As can be seen from the above, in the scheme provided in the embodiment of the present invention, the second threshold is set as the current optimal coding cost of the current CTU, and is used as the threshold initially determined in the merging mode selection process, and the merging mode can be accurately selected by using the threshold, so that the coding efficiency is improved.

In one embodiment of the present invention, pixel compensation of the current CTU in EO mode includes:

In one implementation, pixels within a luma coding tree block and/or a chroma coding block may be sampled in an interlaced manner when computing the set of offset values. Among the sampled pixels, the offset value of the pixel of the same category is calculated for the pixels belonging to the category.

When sampling pixels in a luminance coding tree block and/or a chrominance coding block, if a mode of sampling every other line is adopted, the calculation amount can be reduced by half when calculating an offset value; if sampling is performed every three rows, the amount of calculation can be reduced by three quarters when calculating the offset value. The invention does not limit the interval mode adopted during sampling, and the specific interval mode can be determined by balancing the calculation amount and the coding cost.

Specifically, the method for calculating the offset value may refer to the specific operation steps for obtaining the set of offset values in the EO mode.

As can be seen from the above description, according to the scheme provided by the embodiment of the present invention, the offset value set is calculated according to the preset pixel row interval and/or the preset pixel column interval, so that the calculation amount can be reduced, and the encoding efficiency can be improved.

In an embodiment of the present invention, referring to fig. 9, fig. 9 is a third flowchart illustrating an SAO mode decision method provided by the embodiment of the present invention, including:

s901: judging whether the current CTU is the first CTU in the video frame, if so, executing S902; if not, S903 is executed.

The first CTU in a video frame, there is no upper CTU and no left CTU. Therefore, the CTU does not select the merge mode, and its SAO mode decision process includes only SAO type decisions. And under the condition that both the EO mode and the BO mode exist, the probability that the CTU selects the EO mode is extremely high, and the EO mode can reflect the direct relation of adjacent pixels. Therefore, the step of BO mode to reduce the decision of SAO type can be directly omitted, thereby reducing the computational cost.

S902: and directly carrying out pixel compensation on the current CTU in the EO mode, and obtaining the SAO parameter of the current CTU based on the EO mode.

For the first CTU in the video frame, since it will not select the merge mode, the merge mode decision process can be skipped, and pixel compensation can be directly performed on it in the EO mode to obtain the parameters of SAO.

The method of pixel compensation in the EO mode can refer to the specific operation steps of the EO mode.

S903: and performing pixel compensation on the current CTU in the merging mode, and determining the optimal merging mode and a first rate-distortion cost C1 of the current CTU in the optimal merging mode.

S904: judging whether C1 is smaller than a preset first threshold value, if so, executing S905; if not, S906 is performed. S905: and obtaining the SAO parameter of the current CTU based on the optimal merging mode.

S906: and performing pixel compensation on the current CTU in the EO mode to obtain a second rate distortion cost C2.

S907: according to C2 and C1, the SAO parameters of the current CTU are determined.

Wherein, S903 to S907 are the same as S701 to S705 described above, and are not described herein again.

As can be seen from the above description, according to the scheme provided in the embodiment of the present invention, for the first CTU in the video frame, the merging mode decision process can be skipped, and the pixel compensation is directly performed on the first CTU in the EO mode to obtain the parameter of the SAO, so that the calculation cost is reduced, and the coding efficiency is improved.

In a specific embodiment of the present invention, the pixel compensation of the current CTU directly in the EO mode may include:

selecting part or all EO types from all preset EO types of the EO mode, respectively carrying out pixel compensation on the current CTU under the selected EO types to obtain rate distortion cost of the current CTU under each selected EO type, and determining a pixel compensation result corresponding to the rate distortion cost with the minimum value in the obtained rate distortion cost as a pixel compensation result of the current CTU under the EO mode.

As can be seen from the description of the prior art, four types of EO types are included in the EO pattern. In one implementation, any one or a combination of several types can be selected from the four types as the EO type to be selected. Based on the obtained EO types to be selected, pixel compensation is performed on the current CTU under each EO type to be selected, so that the rate distortion cost of the current CTU under each EO type can be obtained. And determining the EO type to be selected with the minimum rate distortion cost as the EO type of the current EO mode, and obtaining the pixel compensation result of the current CTU under the EO type.

The present application recommends using the first EO type and the second EO type in fig. 4 as candidate EO types, but the candidate EO types are not limited, and may be determined by balancing the calculation amount and the coding cost.

Specifically, the method for performing pixel compensation on the current CTU under each EO type to be selected may refer to the specific operation steps of the EO mode.

As can be seen from the above, in the scheme provided by the embodiment of the present invention, part or all of EO types may be selected from the preset EO types in the EO mode as EO types to be selected, so that the calculation amount of the EO type determination step can be reduced, and the coding efficiency is further improved.

In an embodiment of the present invention, referring to fig. 10, fig. 10 is a schematic flowchart of a process of directly obtaining SAO parameters of a current CTU in an EO mode according to an embodiment of the present invention, where pixel compensation is directly performed on the current CTU in the EO mode, and the obtaining SAO parameters of the current CTU based on the EO mode (S902), includes:

s9021: and performing pixel compensation on the current CTU in the EO mode to obtain a fifth rate-distortion cost C5.

The first CTU in a video frame, there is no upper CTU and no left CTU. Therefore, the CTU does not have a merge mode, and its SAO mode decision process includes only SAO type decisions. And under the condition that both the EO mode and the BO mode exist, the probability of selecting the BO mode by the CTU is smaller, and the EO mode can reflect the direct relation of adjacent pixels. Therefore, the BO mode can be directly ignored, and the CTU is pixel-compensated only in the EO mode, resulting in the fifth rate-distortion cost C5.

S9022: judging whether C5 is smaller than the current optimal coding cost of the current CTU, if not, executing S9023; if so, S9024 is executed.

S9023: and ending the SAO mode decision of the current CTU, and skipping the SAO mode decisions of other CTUs in the video frame where the current CTU is positioned.

S9024: the SAO parameter of the current CTU is obtained based on the EO mode.

C5 is not less than the current best coding cost of the current CTU, i.e. the rate-distortion cost after SAO mode decision is increased for the CTU, therefore, it is determined that the CTU skips SAO mode decision.

The probability of selecting the merging mode in the SAO mode decision process is very high, and if all CTUs in the current video frame adopt the merging mode, the first CTU determines the SAO parameters of all CTUs in the video frame where the first CTU is located. Therefore, if the first CTU skips the SAO mode decision, it is determined that all CTUs in the video frame where the first CTU is located skip the SAO mode decision.

As can be seen from the above description, according to the scheme provided in the embodiment of the present invention, when it is determined that the first CTU in the video frame is the skip SAO mode decision, the SAO mode decisions of all CTUs in the video frame are skipped, so that the amount of calculation in the SAO mode decision process is reduced, and the coding efficiency is further improved.

In an embodiment of the present invention, referring to fig. 11, fig. 11 is a flowchart illustrating a process of determining SAO parameters of a current CTU according to C2 and C1 according to an embodiment of the present invention, wherein determining SAO parameters of the current CTU according to C2 and C1 (S705), including:

s7051: judging whether C2 is less than C1, if yes, executing S7052; if not, S7053 is performed.

S7052: the SAO parameter of the current CTU is obtained based on the EO mode.

S7053: and obtaining the SAO parameter of the current CTU based on the optimal merging mode.

C1 at this time may be equal to the second threshold, possibly also equal to C3, and possibly also equal to C4.

If C2 is smaller than C1, that is, the rate-distortion cost in the optimal merge mode obtained by the merge mode is greater than the rate-distortion cost in the EO mode, it may be determined that the SAO parameter of the current CTU is the SAO parameter obtained based on the EO mode.

If C2 is not less than C1, that is, the rate-distortion cost in the optimal merge mode obtained by the merge mode is less than the rate-distortion cost in the EO mode, it may be determined that the SAO parameter of the current CTU is the SAO parameter obtained based on the optimal merge mode.

Wherein, when C1 is equal to the second threshold, it may be determined that the current CTU is a skip SAO mode decision; when C1 is equal to C3, it may be determined that the SAO parameter of the current CTU is the SAO parameter obtained in the left merge mode; when C1 is equal to C4, it may be determined that the SAO parameter of the current CTU is the SAO parameter obtained in the upward merge mode.

As can be seen from the above description, the scheme provided by the embodiment of the present invention may directly determine the SAO parameter of the current CTU according to the value of C1 based on the size relationship between C2 and C1.

Corresponding to the above method embodiment, referring to fig. 12, fig. 12 is a schematic structural diagram of a SAO mode decision device provided in an embodiment of the present invention, including: a mode determining module 1201, a first judging module 1202, a first parameter obtaining module 1203, a rate-distortion cost obtaining module 1204 and a second parameter obtaining module 1205.

A mode determining module 1201, configured to perform pixel compensation on the current coding tree unit CTU in the merging mode, and determine an optimal merging mode and a first rate-distortion cost C1 of the current CTU in the optimal merging mode;

a first determining module 1202, configured to determine whether C1 is smaller than a preset first threshold, and if so, trigger a first parameter obtaining module 1203; if not, triggering a rate distortion cost obtaining module 1204;

a first parameter obtaining module 1203, configured to obtain a sample adaptive compensation SAO parameter of the current CTU based on the optimal merging mode;

a rate distortion cost obtaining module 1204, configured to perform pixel compensation on the current CTU in the EO mode to obtain a second rate distortion cost C2;

a second parameter obtaining module 1205, configured to determine an SAO parameter of the current CTU according to C2 and C1, so as to complete an SAO mode decision of the current CTU.

In an embodiment of the present invention, referring to fig. 13, fig. 13 is a schematic diagram of a second structure of an SAO mode decision device provided in the embodiment of the present invention, where a mode determining module 1201 includes: a threshold value determining submodule 12011, a first rate-distortion cost obtaining submodule 12012, a first judging submodule 12013, an optimal merging mode determining submodule 12014, a second judging submodule 12015, a first rate-distortion cost determining submodule 12016, a second rate-distortion cost obtaining submodule 12017, a third judging submodule 12018 and a second rate-distortion cost determining submodule 12019.

A threshold determination submodule 12011, configured to set the target threshold C0 to a preset second threshold, where the second threshold is a value greater than the first threshold;

a first rate-distortion cost obtaining sub-module 12012, configured to perform pixel compensation on the current CTU in the left merging mode, so as to obtain a third rate-distortion cost C3;

a first judgment submodule 12013, configured to judge whether C3 is smaller than C0, and if so, trigger the optimal merge mode determination submodule 12014; if not, triggering a second judgment submodule 12015;

an optimal merge mode determination submodule 12014 configured to determine the left merge mode as the optimal merge mode, and update C0 to C3;

a second determining submodule 12015, configured to determine whether C0 is smaller than a preset third threshold, and if so, trigger the first rate-distortion cost determining submodule 12016; if not, a second rate-distortion cost obtaining sub-module 12017 is triggered;

a first rate-distortion cost determination submodule 12016, configured to determine that the first rate-distortion cost C1 of the current CTU in the optimal merge mode is equal to C3, where the third threshold is a value smaller than the second threshold;

a second rate-distortion cost obtaining sub-module 12017, configured to perform pixel compensation on the current CTU in the upward merging mode, to obtain a fourth rate-distortion cost C4;

a third determining submodule 12018, configured to determine whether C4 is smaller than C0, and if so, trigger the second rate-distortion cost determining submodule 12019; if not, the first judgment module 1202 is triggered;

the second rate-distortion cost determination submodule 12019 is configured to determine the upward merge mode as the optimal merge mode, and the first rate-distortion cost C1 of the current CTU in the optimal merge mode is equal to C4.

In an embodiment of the present invention, the preset second threshold is: the current best coding cost of the current CTU.

In an embodiment of the present invention, the rate-distortion cost obtaining module is further configured to:

In an embodiment of the present invention, referring to fig. 14, fig. 14 is a schematic structural diagram of a third structure of an SAO mode decision device provided in the embodiment of the present invention, where the device may further include: a second determination module 1206 and a third parameter obtaining module 1207;

a second judging module 1206, configured to judge whether the current CTU is the first CTU in the video frame, and if not, trigger the mode determining module 1201; if yes, a third parameter obtaining module 1207 is triggered;

a third parameter obtaining module 1207, configured to directly perform pixel compensation on the current CTU in the EO mode, and obtain an SAO parameter of the current CTU based on the EO mode.

For the first CTU in the video frame, the merging mode decision process can be skipped, and pixel compensation is directly performed on the first CTU in the EO mode to obtain the parameters of the SAO, thereby reducing the calculation cost and improving the coding efficiency.

In an embodiment of the invention, the third parameter obtaining module 1207 may be further configured to select some or all EO types from the preset EO types in the EO mode;

respectively carrying out pixel compensation on the current CTU under the selected EO types to obtain the rate distortion cost of the current CTU under each selected EO type;

In an embodiment of the present invention, referring to fig. 15, fig. 15 is a schematic structural diagram of a third parameter obtaining module according to an embodiment of the present invention, where the third parameter obtaining module 1207 includes: a third rate-distortion cost obtaining submodule 12071, a fourth decision submodule 12072, a skip submodule 12073, and a first parameter obtaining submodule 12074.

A third rate-distortion cost obtaining sub-module 12071, configured to perform pixel compensation on the current CTU in the EO mode, and obtain a fifth rate-distortion cost C5;

a fourth judgment submodule 12072, configured to judge whether C5 is smaller than the current optimal coding cost of the current CTU, and if not, trigger the skip submodule 12073; if so, the first parameter obtaining sub-module 12074 is triggered;

skipping submodule 12073 for ending the SAO mode decision of the current CTU and skipping the SAO mode decision of other CTUs in the video frame where the current CTU is located;

a first parameter obtaining sub-module 12074 for obtaining SAO parameters of the current CTU based on the EO mode.

In an embodiment of the present invention, referring to fig. 16, fig. 16 is a schematic structural diagram of a second parameter obtaining module provided in the embodiment of the present invention, where the second parameter obtaining module 1205 includes: a fifth judgment submodule 12051, a second parameter obtaining submodule 12052, and a third parameter obtaining submodule 12053;

a fifth judgment submodule 12051, configured to judge whether C2 is smaller than C1, and if so, trigger the second parameter obtaining submodule 12052; if not, a third parameter obtaining sub-module 12053 is triggered;

a second parameter obtaining submodule 12052, configured to obtain an SAO parameter of the current CTU based on the EO mode;

a third parameter obtaining submodule 12053, configured to obtain SAO parameters of the current CTU based on the optimal merging mode.

An embodiment of the present invention also provides an electronic device, as shown in fig. 17, including a processor 1701 and a memory 1702;

a memory 1701 for storing a computer program;

the processor 1702 is configured to implement the SAO mode decision method provided by the embodiment of the present invention when executing the program stored in the memory 1701.

Specifically, the SAO mode decision method includes:

performing pixel compensation on the current CTU in the merging mode, and determining an optimal merging mode and a first rate-distortion cost C1 of the current CTU in the optimal merging mode;

under the condition that C1 is smaller than a preset first threshold value, obtaining an SAO parameter of the current CTU based on the optimal merging mode;

under the condition that C1 is not less than a first threshold, performing pixel compensation on the current CTU in an EO mode to obtain a second rate-distortion cost C2;

and determining the SAO parameters of the current CTU according to the C2 and the C1, and further finishing the SAO mode decision of the current CTU.

It should be noted that other implementation manners of the SAO mode decision method are partially the same as those of the foregoing method embodiments, and are not described herein again.

The Memory mentioned in the above electronic device may include a Random Access Memory (RAM), and may also include a non-volatile Memory (non-volatile Memory), such as at least one disk Memory. Optionally, the memory may also be at least one memory device located remotely from the processor.

The Processor may be a general-purpose Processor, and includes a Central Processing Unit (CPU), a Network Processor (NP), and the like; the Integrated Circuit may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, a discrete Gate or transistor logic device, or a discrete hardware component.

The electronic device provided by the embodiment of the invention can skip the EO mode when the first rate-distortion cost C1 meets the condition in the SAO mode decision making process, thereby saving the coding time and improving the coding efficiency.

An embodiment of the present invention further provides a computer-readable storage medium, where instructions are stored in the computer-readable storage medium, and when the instructions are executed on a computer, the computer is enabled to execute the SAO mode decision method provided in the embodiment of the present invention.

Specifically, the SAO mode decision method includes:

By operating the instructions stored in the computer-readable storage medium provided by the embodiment of the invention, in the process of making the SAO mode decision, the EO mode can be skipped when the first rate-distortion cost C1 meets the condition, so that the coding time can be saved, and the coding efficiency can be improved.

Embodiments of the present invention further provide a computer program product including instructions, which when run on a computer, enable the computer to execute the SAO mode decision method provided by embodiments of the present invention.

Specifically, the SAO mode decision method includes:

By operating the computer program product provided by the embodiment of the invention, in the SAO mode decision process, the EO mode can be skipped when the first rate-distortion cost C1 meets the condition, so that the coding time can be saved, and the coding efficiency can be improved.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website site, computer, server, or data center to another website site, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the apparatus, the electronic device, the computer-readable storage medium, and the computer program product embodiments, since they are substantially similar to the method embodiments, the description is relatively simple, and for the relevant points, reference may be made to the partial description of the method embodiments.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. A SAO mode decision method, comprising:

determining the SAO parameters of the current CTU according to C2 and C1, and further completing the SAO mode decision of the current CTU;

the pixel compensation of the current coding tree unit CTU in the merge mode, determining the optimal merge mode and the first rate-distortion cost C1 of the current CTU in the optimal merge mode, includes:

2. The method of claim 1,

the preset second threshold is as follows: a current best coding cost of the current CTU.

3. The method according to any of claims 1-2, wherein said pixel compensating said current CTU in EO mode comprises:

4. The method according to any of claims 1-2, further comprising, before said pixel compensating a current Coding Tree Unit (CTU) in a merge mode, determining an optimal merge mode and a first rate-distortion cost (C1) of the current CTU in the optimal merge mode:

judging whether the current CTU is the first CTU in the video frame;

5. The method of claim 4, wherein the pixel compensating the current CTU directly in EO mode comprises:

selecting part or all of EO types from various preset EO types of the EO mode;

6. The method as claimed in claim 4, wherein the pixel compensating the current CTU directly in EO mode and obtaining SAO parameters of the current CTU based on EO mode comprises:

if so, obtaining the SAO parameter of the current CTU based on the EO mode.

7. The method according to any of claims 1-2, wherein the determining the SAO parameter of the current CTU according to C2 and C1 comprises:

8. An SAO mode decision apparatus, the apparatus comprising:

a second parameter obtaining module, configured to determine, according to C2 and C1, an SAO parameter of the current CTU, so as to complete an SAO mode decision of the current CTU;

the mode determination module includes: the optimal merging mode determining module comprises a threshold determining sub-module, a first rate-distortion cost obtaining sub-module, a first judging sub-module, an optimal merging mode determining sub-module, a second judging sub-module, a first rate-distortion cost determining sub-module, a second rate-distortion cost obtaining sub-module, a third judging sub-module and a second rate-distortion cost determining sub-module;

9. The apparatus of claim 8,

10. The apparatus according to any of claims 8-9, wherein the rate-distortion cost obtaining module is specifically configured to:

11. The apparatus according to any one of claims 8-9, further comprising: a second judgment module and a third parameter obtaining module;

12. The apparatus according to claim 11, wherein the third parameter obtaining module is specifically configured to select some or all EO types from respective preset EO types of an EO pattern;

13. The apparatus of claim 11, wherein the third parameter obtaining module comprises: a third rate-distortion cost obtaining submodule, a fourth judging submodule, a skipping submodule and a first parameter obtaining submodule;

14. The apparatus according to any one of claims 8-9, wherein the second parameter obtaining module comprises: a fifth judgment submodule, a second parameter obtaining submodule and a third parameter obtaining submodule;

15. An electronic device comprising a processor and a memory, wherein,

the memory is used for storing a computer program;

the processor, when executing the program stored in the memory, implementing the method steps of any of claims 1-7.

16. A computer-readable storage medium, characterized in that a computer program is stored in the computer-readable storage medium, which computer program, when being executed by a processor, carries out the method steps of any one of claims 1 to 7.