WO2022012183A1

WO2022012183A1 - Encoding method, encoder and computer readable storage medium

Info

Publication number: WO2022012183A1
Application number: PCT/CN2021/096491
Authority: WO
Inventors: 谭皓
Original assignee: Oppo广东移动通信有限公司
Priority date: 2020-07-17
Filing date: 2021-05-27
Publication date: 2022-01-20
Also published as: CN111866504B; CN111866504A; CN114979640A

Abstract

Disclosed in embodiments of the present application are an encoding method, an encoder and a computer readable storage medium for improving the video quality of an encoded video. The method comprises: when a current frame is a first frame in a video to be encoded, obtaining image information of the current frame in an inter-frame level code rate control process; calculating a complexity accumulation value of the current frame on the basis of the image information of the current frame; performing coded quantization estimation on the current frame on the basis of the complexity accumulation value of the current frame to obtain an initial quantization step length of the current frame; and encoding the current frame on the basis of the initial quantization step length of the current frame to obtain the encoding result of the current frame.

Description

An encoding method, encoder and computer-readable storage medium

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on the Chinese patent application with the application number of 202010693484.8 and the application date of July 17, 2020, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is incorporated herein by reference.

technical field

The present application relates to the field of audio and video encoding, and in particular, to an encoding method, an encoder, and a computer-readable storage medium.

Background technique

Video coding is a video compression technology, which uses the temporal redundancy and spatial redundancy of video information to compress video, which can achieve the purpose of reducing the storage space and network bandwidth occupied by the video. Bit rate control is a key technology in video coding, and its purpose is to optimize the objective quality of the video while ensuring a certain number of bits occupied after video compression. The Quantization Parameter (QP) is a key parameter in the video coding technology, which directly determines the compression degree of the video coding unit, thereby controlling the bit rate and video quality after video coding. In the related art, when setting the initial value of the complexity of the first frame used to calculate the quantization parameter, a fixed value preset manually is usually used as the initial value, which easily causes the QP set when encoding the first frame to be unreasonable, resulting in instant decoding. The bit rate of the Instantaneous Decoding Refresh (IDR) frame is wasted, thereby reducing the video quality of the encoded video.

SUMMARY OF THE INVENTION

The embodiments of the present application are expected to provide an encoding method, an encoder, and a computer-readable storage medium, which can improve the video quality of the encoded video.

The technical solution of the present application is realized as follows:

In a first aspect, an embodiment of the present application provides an encoding method, which is applied to an encoder, including:

When the current frame is the first frame in the video to be encoded, in the inter-frame-level rate control process, the image information of the current frame is acquired;

Calculate the complexity cumulative value of the current frame based on the image information of the current frame;

Based on the cumulative complexity value of the current frame, perform coding and quantization estimation on the current frame to obtain an initial quantization step size of the current frame;

Based on the initial quantization step size of the current frame, the current frame is encoded to obtain an encoding result of the current frame.

In a second aspect, an embodiment of the present application provides an encoder, including: an acquisition part, a calculation part, a quantization part, and an encoding part, wherein,

The acquisition part is configured to acquire image information of the current frame in the inter-frame-level code rate control process when the current frame is the first frame in the video to be encoded;

The calculation part is configured to calculate the complexity cumulative value of the current frame based on the image information of the current frame;

The quantization part is configured to perform coding and quantization estimation on the current frame based on the cumulative complexity value of the current frame to obtain an initial quantization step size of the current frame;

The encoding part is configured to encode the current frame based on the initial quantization step size of the current frame to obtain an encoding result of the current frame.

In a third aspect, an embodiment of the present application provides an encoder, including:

a memory configured to store executable data instructions;

The processor, when configured to execute the executable instructions stored in the memory, implements any of the encoding methods described above.

In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium storing executable instructions configured to cause a processor to execute any of the encoding methods described above.

In a fifth aspect, embodiments of the present application provide a computer program product, where the computer program product includes computer-readable codes, and when the computer-readable codes run in an encoder, processing in the encoder The processor implements the encoding method as described in any of the above.

Embodiments of the present application provide an encoding method, an encoder, and a computer-readable storage medium. The method includes: when the current frame is the first frame in the video to be encoded, in an inter-frame-level rate control process, obtaining the current frame's Image information; based on the image information of the current frame, calculate the cumulative complexity value of the current frame; based on the cumulative complexity value of the current frame, perform coding and quantization estimation on the current frame to obtain the initial quantization step size of the current frame; based on the initial quantization step size of the current frame The quantization step size is used to encode the current frame to obtain the encoding result of the current frame. Through the method in the embodiment of the present application, the complexity accumulation value of the first frame can be evaluated by using the image information of the first frame, and the initial quantization step size, that is, the QP value, is reasonably set based on the complexity accumulation value of the first frame, thereby realizing The QP value can be adaptively adjusted according to the image information of the first frame, so that the video encoding based on the QP value can obtain more accurate encoding results, and finally improve the video quality of the encoded video.

Description of drawings

The accompanying drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate the embodiments in accordance with the present application, and together with the specification, are used to explain the technical solutions of the embodiments of the present application.

Fig. 1 is the coding flow chart of the current X.264 coding system;

2 is a flowchart 1 of an encoding method provided by an embodiment of the present application;

FIG. 3 provides a coding flow chart 1 of an embodiment of the present application;

Fig. 4 is a kind of coding flow chart 2 provided by the embodiment of this application;

FIG. 5 is an implementation manner of a macroblock-level rate control process provided by an embodiment of the present application;

FIG. 6 is another implementation manner of a macroblock-level rate control process provided by an embodiment of the present application;

7 is a second flowchart of an encoding method provided by an embodiment of the present application;

8 is a third flowchart of an encoding method provided by an embodiment of the present application;

FIG. 9 is a fourth flowchart of an encoding method provided by an embodiment of the present application;

10 is a flowchart 5 of an encoding method provided by an embodiment of the present application;

FIG. 11 is a schematic diagram 1 of the composition and structure of an encoder according to an embodiment of the application

FIG. 12 is a second schematic diagram of the composition and structure of an encoder according to an embodiment of the present application.

detailed description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application.

Before further describing the embodiments of the present application in detail, the terms and terms involved in the embodiments of the present application are described, and the terms and terms involved in the embodiments of the present application are suitable for the following explanations.

1) H.264: A highly compressed digital video codec standard.

2) X.264: Open source H.264 video encoding function library.

3) SATD: Sum of Absolute Transformed Difference, the sum of the absolute values of the prediction residuals of the 4×4 blocks of which the residuals are Hardman transformed, is a simple time-frequency transform used to reflect the size of the generated code stream.

4) QP: quantization parameter, that is, the quantization step size. The smaller the value of QP, the smaller the quantization step size, and the higher the quantization accuracy, which means that the amount of data generated may be larger under the same image quality.

5) VBV: Video Buffering Verifier, a video buffering verifier, used to ensure that the output encoded stream does not underflow the buffer at the receiving end.

6) AQ: Adaptive Quantization, adaptive quantization.

7) MB: Macro Block, macro block.

8) RCEQ: Rate-Control Equation, rate control formula, RCEQ establishes a mapping model from motion complexity to quantization step size.

9) PSNR: Peak Signal to Noise Ratio, an objective measurement method for evaluating image quality.

H.264 uses the Lagrangian cost function to control the encoding, which is one of the main reasons for the high coding complexity of H.264. As the application version of H.264, X.264 uses the SATD of the half-precision frame as the QP selection. main basis. The X.264 rate control process is divided into an inter-frame-level rate control process and a macroblock-level rate control process. The allocation of the QP value of each frame is realized by the inter-frame-level rate control, and the The assignment of QP values is implemented by macroblock-level rate control. The X.264 bit rate control process mainly depends on two variables, one is the complexity of the video frame, and the other is the budget of the bit rate. Generally, the higher the complexity of the video frame, the more bits are required for encoding. As shown in FIG. 1 , FIG. 1 is an encoding flow chart of the current X.264 encoding system. After the to-be-encoded video enters the encoding system, it will synchronously enter the inter-frame-level rate control process and the macro-block-level rate control process. During the inter-frame-level rate control process, the lookahead module 100 is configured to provide video frames for the to-be-encoded video. The buffer queue assists in completing more stable bit rate control. The complexity estimation module 101 is configured to estimate the complexity of the current frame in the video to be encoded. Exemplarily, the complexity of the current frame may be the fuzzy complexity; the quantization level The calculation module 103 is configured to calculate the quantization level according to the complexity of the current frame output by the complexity estimation module 101, obtain the quantization proportion corresponding to the current frame, and calculate the code rate factor (ratefactor) provided by the code rate factor calculation module 102. The quantization weight is adjusted to obtain the initial quantization level; the code rate factor calculation module 102 is configured to calculate the complexity accumulation value of the current frame according to the feedback code rate of the coded frame, and then calculate the code according to the complexity accumulation value. The rate factor is provided to the quantization level calculation module 103; the buffer control (VBV) module 104 is configured to adjust the initial quantization level output by the quantization level calculation module 103 based on the size of the buffer area at the receiving end to obtain the quantization level; the quantization level The conversion module 105 is configured to convert the quantization level into an initial quantization step size and provide it to the macroblock-level quantization step size adjustment module 106 . At the same time, the rate control process at the macroblock level is performed synchronously with the rate control process at the inter-frame level, wherein the macroblock calculation module 108 is configured to calculate the macroblock structure of the current frame according to the image content of the current frame ( MBTree); the adaptive quantization module 107 is configured to calculate the average macroblock energy of the current frame according to the macroblock structure and the image content of the current frame, and determine the preset quantization intensity factor corresponding to the average macroblock energy; the macroblock The level quantization step size adjustment 106 is configured to adjust the initial quantization step size of the current frame according to the preset quantization intensity factor to obtain the quantization step size corresponding to the current frame; the encoding module 109 is configured to be configured according to the current frame. The corresponding quantization step size The current frame is long encoded, and the above process continues until all frames in the to-be-encoded video are encoded, and the encoded code stream is output.

It can be seen from the coding method shown in FIG. 1 that at present, in the inter-frame-level code rate control process, the quantization level calculation module 103 needs to obtain the code calculated by the code rate factor calculation module 102 according to the feedback of the coding result of the previous frame. The rate factor is used to adjust the quantization weight calculated by itself to obtain the initial quantization level. However, for the first frame such as IDR frame, the feedback of the encoding result of the previous frame cannot be obtained at the position of the first frame. Therefore, at present, a fixed value is manually set as the initial value of the bit rate factor, and then according to the fixed initial value The initial quantization level of the first frame is calculated by the code rate factor of the value, and then the initial quantization step size, that is, the QP value, is calculated based on the initial quantization level. In this way, the QP value of the first frame cannot be adaptively adjusted according to the complexity, resulting in a waste of bit rate and reducing the quality of the overall video. Further, at present, in the macroblock-level rate control process, the quantization intensity factor calculated in the adaptive quantization module 107 is in a fixed state during the entire video encoding process, but in actual encoding, the video to be encoded is in a fixed state. The video content is constantly changing. If a larger quantization intensity factor is used in the complex area, the quantization step size adjusted according to the larger quantization intensity factor will increase significantly, which will lead to serious problems in the complex area under the condition of low bit rate. blurring, which further degrades the overall video quality.

An embodiment of the present application provides an encoding method, which is applied to an encoder, as shown in Figure 2:

S101. When the current frame is the first frame in the video to be encoded, in the process of inter-frame-level bit rate control, obtain image information of the current frame.

In this embodiment of the present application, for the first frame in the video to be encoded, the encoder first obtains image information of the first frame.

In the embodiment of the present application, the image information includes any one of the average macroblock energy of the first frame, the gradient value of the first frame, the edge information of the first frame, and the histogram information of the first frame.

In some embodiments of the present application, based on the rate control flow shown in FIG. 1 , in the macro-level rate control process, the execution process of the macroblock calculation module 108 is logically prior to the inter-frame-level rate control process , considering that in the process of FIG. 1, without increasing the amount of calculation, the encoder can use the average macroblock energy generated during the execution of the macroblock calculation module 108 as the image information of the current frame to evaluate the average macroblock energy. The accumulated complexity value of the first frame in the video to be encoded is shown in FIG. 3 .

In the embodiment of the present application, the macroblock calculation module 108 in FIG. 3 feeds back the calculated average macroblock energy of the first frame to the rate factor calculation module 102 in the inter-frame-level rate control process, so that the rate factor The calculation module 102 can calculate the code rate factor according to the average macroblock energy of the first frame, and then adjust the initial quantization step size corresponding to the first frame according to the code rate factor.

In other embodiments of the present application, when the image information of the current frame is gradient value, edge information or histogram information, the encoder may, as shown in FIG. information, calculate the gradient value, edge information or histogram information of the current frame, and feed back the gradient value, edge information or histogram information of the current frame to the rate factor calculation module 102, so that the rate factor calculation module 102 can The gradient value, edge information or histogram information of the first frame is used to calculate the bit rate factor, and then the initial quantization step size corresponding to the first frame is adjusted according to the bit rate factor. Exemplarily, the encoder can calculate the grayscale change in the neighborhood of each pixel in the current frame according to the grayscale information in the pixel information, and then calculate the gradient value that can reflect the detail contrast degree and texture change characteristics of the current frame, and use The gradient value is used as the image information of the current frame; in other embodiments, the encoder can further obtain the edge information of the current frame according to the gradient value, and use the edge information as the image information of the current frame, so as to determine the content of the current frame according to the edge information. Identify and analyze; or, the encoder can also calculate the histogram information that can reflect the brightness, brightness, and gradation distribution of the current frame according to the grayscale information in the pixel information, and use the histogram information as the image information of the current frame.

S102. Calculate a complexity cumulative value of the current frame based on the image information of the current frame.

In the embodiment of the present application, the encoder calculates the complexity cumulative value of the current frame based on the image information of the current frame, so that the bit rate factor can be reasonably initialized according to the first frame complexity cumulative value, so that the first frame The quantitative proportions are adjusted.

In the embodiment of the present application, for different types of image information, a corresponding objective function model may be established in advance, the image information of the first frame is used as the input value of the objective function model, and the initial quantization step size is used as the output value of the objective function model to output The initial quantization step size meets the goal of low bit rate, high-quality video applications, and analyzes the pros and cons of the output initial quantization step size through multiple simulation experiments, and fits the initial quantization step size and the image through function fitting information curve, obtain the functional relationship between the initial quantization step size and the image information corresponding to the optimal value of the initial quantization step size, and then according to the functional relationship between the initial quantization step size and the image information, and the initial quantization step size and the image information. Based on the preset functional relationship between the accumulated complexity values, a relationship formula between the image information of the current frame and the accumulated complexity value is derived, and the accumulated complexity value of the current frame is calculated based on the relationship formula.

It can be seen that since the relationship formula between the image information of the current frame and the accumulated complexity value is obtained by curve fitting the initial quantization step size and image information through multiple simulation experiments, the image information of the current frame can be obtained by curve fitting. The calculated cumulative complexity value can better adapt to the real image content of the current frame, thereby ensuring that the bit rate factor calculated according to the cumulative complexity value and the initial quantization step size adjusted according to the bit rate factor are more accurate.

S103. Based on the cumulative complexity value of the current frame, perform coding and quantization estimation on the current frame to obtain an initial quantization step size of the current frame.

In this embodiment of the present application, when the current frame is the first frame, the encoder may calculate the cumulative complexity value of the first frame based on the image information of the first frame.

In this embodiment of the present application, when the current frame is not the first frame, the encoder may calculate the cumulative complexity value of the non-first frame in combination with the encoding result of the previous frame that is not the first frame.

In this embodiment of the present application, the encoder may first estimate the complexity of the current frame through the complexity estimation module, calculate the initial quantization step size of the current frame according to the complexity, and then calculate the first frame according to the accumulated complexity value of the current frame For the corresponding bit rate factor, adjust the quantization weight once according to the bit rate factor to obtain the initial quantization level, and then further adjust the initial quantization level through the cache control module to obtain the quantization level of the current frame. The preset mapping relationship converts the quantization level into the initial quantization step size.

S104 , encoding the current frame based on the initial quantization step size of the current frame to obtain an encoding result of the current frame.

In the embodiment of the present application, after the encoder obtains the initial quantization step size of the current frame, that is, the QP value, the code rate control process at the inter-frame level corresponding to the current frame is completed, and the encoder can continue to go through the macroblock-level code rate control process. The initial quantization step size of the current frame is adjusted to obtain the quantization step size of the current frame.

In some embodiments of the present application, an implementation manner of the macroblock-level rate control process may be as shown in FIG. 5 . In the macroblock-level rate control process 1, the encoder may perform a macroblock energy calculation process, The current frame is divided into a number of different macroblocks according to the image content, and the macroblock energy of each macroblock is calculated according to the pixel value and the square error sum of the pixels in each macroblock, and then the average macroblock of the current frame is obtained. energy. The average macroblock energy obtained in the process of calculating the macroblock energy will, in the adaptive quantization adjustment process, obtain a preset quantization intensity factor corresponding to the average macroblock energy according to the correspondence between the average macroblock energy and the preset quantization intensity factor, and finally In the quantization step size adjustment process, the offset value of the initial quantization step size is obtained by the preset quantization intensity factor, and then the initial quantization step size is adjusted by the offset value of the initial quantization step size to obtain the quantization step size of the current frame.

Under normal circumstances, if the current frame has a lot of dynamics, the corresponding average macroblock energy is higher, and the encoder can select a lower preset quantization strength factor aq_strength value, exemplarily, the selection value is 0.6-0.8 aq_strength in between, in order to retain more high-frequency details and improve the overall video quality; and if there are many static pictures in the current frame, the corresponding average macroblock energy is low, and the encoder can choose a higher aq_strength value, for example Optionally, the encoder can select aq_strength greater than or equal to 1 to prevent the dark part from generating color bands due to insufficient bits. In some embodiments, the above method and process can be implemented by the following code:

In the embodiment of the present application, for the above code, if qp_adj-avg_adj is greater than 0, the QP of the macroblock with large macroblock energy will be adjusted to be larger, so that the larger the final calculated qp_offset, the more blurred the complex area; if qp_adj -avg_adj is less than 0, the larger the strength, the smaller the qp_offset, the smaller the final QP, and the clearer the flat area. Since h->param.rc.f_aq_strength is a fixed aq_strength value set manually, it is difficult to adapt to the video to be encoded. changes in complexity.

In other embodiments of the present application, another implementation manner of the macroblock-level rate control process may be as shown in FIG. 6 . In the macroblock-level rate control process 2, the encoder uses the macroblock energy calculation process The calculated macroblock energy of each macroblock obtains the content complexity of each macroblock through the complexity information calculation process, and according to the preset complexity benchmark, in the complexity benchmark adjustment process, the current frame is based on each macroblock. The content complexity of the macroblock is divided into different regions, and different preset quantization strength factors aq_strength are set in different regions through the adaptive quantization process. Finally, through the quantization step size adjustment process, according to the different preset quantization strengths of each region The factor aq_strength adjusts the offset of the initial quantization step size to obtain the quantization step size corresponding to the area, so as to realize the change of the preset quantization strength factor aq_strength with the complexity of the image, which can reduce the preset quantization strength factor of complex areas and reduce the complexity of The blurring phenomenon of the area is improved, and the adaptability of the preset quantization intensity factor to the video content is improved.

In the embodiment of the present application, after the encoder obtains the quantization step size corresponding to each macroblock in the current frame according to the macro-level quantization step size adjustment module, the encoder can encode the current frame based on the quantization step size to obtain the encoding result of the current frame. Based on the encoding result of the current frame, the encoder performs the encoding of the next frame with the same rate control process until the encoding of the to-be-encoded video is completed.

It can be understood that, in the embodiment of the present application, for the first frame of the video to be encoded, the encoder can obtain the accumulated complexity value corresponding to the first frame based on the image information of the first frame, and then further calculates according to the accumulated complexity value to obtain the first frame. The initial quantization step size of the first frame can be set adaptively according to the complexity of the first frame, so as to avoid the waste of bit rate caused by manually setting the unreasonable initial quantization step size of the first frame, and improve the The quality of the encoded video. Further, in the macroblock-level code rate control process, the encoder can perform preset quantization intensity factor settings for the current frame according to the complexity of the macroblock, so that the current frame can be set according to different preset quantization intensity factors. Appropriate quantization step sizes are calculated respectively for different complexity regions of the image, realizing the self-adaptation of the preset quantization intensity factor with the complexity of the image, improving the clarity of the image, and further improving the quality of the encoded video.

In the following, the encoding method in the embodiment of the present application is further described by taking the average macroblock energy of the first frame as the image information as an example.

In some embodiments of the present application, based on FIG. 2, when the current frame is the first frame in the video to be encoded, in the inter-frame-level rate control process, the encoder in S101 obtains the image information of the current video through S1011- S1012 implementation, as shown in Figure 7:

S1011. In the macroblock-level rate control process, perform macroblock division on the current frame to obtain at least one macroblock.

In the embodiment of the present application, the encoder divides the current frame into macroblocks based on the image content of the current frame through the macroblock calculation module to obtain at least one macroblock.

In some embodiments, at least one macroblock may be in the form of an MB tree.

S1012. Calculate the average macroblock energy of at least one macroblock as image information of the current frame.

In this embodiment of the present application, the encoder may calculate the macroblock energy of each macroblock by using the pixel value and the sum of squared errors in each macroblock of at least one macroblock, and then calculate the macroblock energy of each macroblock according to the macroblock energy of each macroblock. The average macroblock energy of the at least one macroblock is obtained, and the average macroblock energy of the at least one macroblock is used as the image information of the current frame.

It can be understood that, in the embodiment of the present application, the average macroblock energy is used as the image information of the first frame, and the average macroblock energy calculated in the macroblock-level rate control process can be directly used, and additional image processing work is not required. the computational complexity of the encoder.

In some embodiments of the present application, based on FIG. 2 or FIG. 7 , when the current frame is the first frame in the video to be encoded, in the inter-frame-level rate control process, the encoder in S102 is based on the image information of the current frame, Calculating the complexity cumulative value of the current frame can be achieved through S1021-S1022, as shown in Figure 8:

S1021. Perform complexity evaluation on the current frame according to the average macroblock energy, the preset coding bits of the first frame, and at least one preset fitting factor, to obtain the estimated coding complexity of the current frame; at least one preset fitting factor is used for fitting The relationship between the combined average macroblock energy and the initial quantization step size.

In the embodiment of the present application, the encoder performs complexity evaluation on the current frame according to the average macroblock energy, the preset first frame coding bits and at least one preset fitting factor, and the process of obtaining the estimated coding complexity of the current frame may include: Multiply the average macroblock energy by the first fitting factor to obtain the first product result; multiply the preset first frame coded bits by the second fitting factor to obtain the second product result; calculate the first product result minus the second product The difference value of the results, and the difference value and the third fitting factor are added to obtain the estimated coding complexity; wherein, at least one preset fitting factor includes the first fitting factor, the second fitting factor and the third fitting factor. combination factor. As shown in formula (1):

cplxr_zero=s ₁ ×avg_energy-s ₂ ×wanted_bits_window+s ₃ (1)

In the above formula (1), avg_energy is the average macroblock energy of the current frame, that is, the first frame, cplxr_zero is the estimated complexity of the current frame calculated according to the average macroblock energy, s ₁ , s ₂ and s ₃ are at least one The first fitting factor, the second fitting factor and the third fitting factor in the preset fitting factors. Among them, at least one preset fitting factor in the embodiment of the present application is to adjust the relationship between the initial quantization step size and avg_energy through a large number of simulation experiments, so as to meet the low bit rate and high quality video application as the goal, analyze the initial test video The pros and cons of the quantization step size are obtained by fitting the QP-energy function curve corresponding to the initial quantization step size and the average macroblock energy, that is to say, at least one preset fitting factor in formula (1) is a pass function The optimal value obtained by the way of curve fitting. In some embodiments, _{the value of s 1} may be 13000, _{the value of s 2} may be 0.3858, and _{the value of s 3} may be 515000, or it may be calculated by means of function curve fitting according to the actual encoding target Other values are specifically selected according to actual applications, which are not limited in this embodiment of the present application.

In formula (1), wanted_bits_window is the preset first frame encoding bit, which is used to represent the target file size of the encoded frame, that is, the total bit value of the encoded frame. Wanted_bits_window can be obtained by formula (2), as follows:

wanted_bits_window=bitrate/fps (2)

fps in formula (2) is the preset frame rate of the video to be encoded, bitrate represents the encoded bitrate, the bitrate of the first frame is the default value, and the bitrate of the non-first frame is the bitrate corresponding to the previous frame after encoding , so the wanted_bits_window of the first frame is also the default value.

S1022. Calculate the cumulative complexity value of the current frame based on the estimated coding complexity.

In the embodiment of the present application, the encoder calculates the complexity cumulative value of the current frame based on the estimated coding complexity, which may include:

S10221. Acquire the number of macroblocks of at least one macroblock.

S10222. Obtain a complexity cumulative value of the current frame according to the estimated coding complexity, the number of macroblocks of at least one macroblock, and a preset compression parameter.

In the embodiment of the present application, the encoder may perform an update calculation on the cumulative value of the estimated coding complexity according to the macroblock data of at least one macroblock and a preset compression parameter, so as to obtain the complexity update value of the current frame.

In some embodiments, the encoder may obtain the number of macroblocks of at least one macroblock obtained by dividing the macroblock by the macroblock calculation module, and calculate the preset compression parameter power and the preset coefficient to estimate the coding complexity, and The product of the one-half power of the number of macroblocks is the cumulative value of the complexity of the current frame.

Exemplarily, the above calculation process can be shown in formula (3):

cplxr_sum=0.01×cplxr_zero ^qcom ×(mbcount) ^1/2 (3)

In formula (3), qcomp is a preset compression parameter. This parameter is externally adjustable and can take a value between 0 and 1. mbcount is the number of macroblocks of at least one macroblock. cplxr_sum is the accumulated complexity value of the current frame.

In some embodiments, when the current frame is the first frame, the code implementation for the encoder to calculate the complexity cumulative value cplxr_sum of the current frame through S1021-S1022 may be as follows:

...

if(rc->b_abr){//ABR encoding algorithm is used

......

rc->cplxr_sum

＝13000*h->param.avg_energy-0.3858*rcc->wanted_bits_window+515000;//code instruction corresponding to formula (1), where h->param.avg_energy is the average macroblock energy, rcc->wanted_bits_window is the default The first frame coding bit, here, the initial value calculated by the variable rc->cplxr_sum for the first time is the estimated coding complexity of the current frame, that is, cplxr_zero;

rc->cplxr_sum=.01*pow(rc->cplxr_sum,rc->qcompress)*pow(h->mb.i_mb_count,0.5);//The code instruction corresponding to formula (3), through the preset compression parameter rc ->qcompress and the number of macroblocks h->mb.i_mb_count of at least one macroblock, execute the code instruction corresponding to the process of formula (3), update the initial value corresponding to the variable rc->cplxr_sum, and obtain the complexity accumulation of the current frame value;

......

}

...

In the current inter-frame-level rate control process, the calculation method of the complexity cumulative value cplxr_sum of the first frame is shown in formula (4):

cplxr_sum=0.01×(7×10 ⁵ ) ^qcompress ×(mbcount) ^1/2 (4)

The code implementation corresponding to formula (4) is as follows:

...

if(rc->b_abr){

......

rc->cplxr_sum=.01*pow(7.0e5,rc->qcompress)*pow(h->mb.i_mb_count,0.5);//Calculate the first frame ^{by the fixed value 7.0e5 set manually, that is, 7×10 5} The cumulative value of the complexity;

......

}

...

It can be understood that the current inter-frame-level rate control process ^{initializes the complexity cumulative value cplxr_sum of the first frame with a fixed value, such as 7×10 5} , so it cannot be initialized according to the actual complexity of the first frame. Adaptive adjustment of the value, which affects the accuracy of the complexity cumulative value calculated based on the initial value, and then affects the initial quantization step size of the first frame calculated by the inter-frame-level rate control process, reducing the encoded video. quality. In the embodiment of the present application, the estimated coding complexity of the first frame can be obtained by calculating the average macroblock energy of the first frame of video, and then the cumulative complexity value cplxr_sum of the first frame can be obtained by calculating the estimated coding complexity of the first frame, and further The initial quantization step size of the first frame is calculated according to the accumulated complexity value cplxr_sum, which realizes that the initial quantization step size of the first frame calculated by the inter-frame rate control can be adaptively adjusted following the complexity of the first frame, thereby improving the initial quantization of the first frame. The rationality of the step size setting saves the encoding bit rate and improves the encoded video quality.

It should be noted that, in some embodiments of the present application, when the current frame is a non-first frame in the video to be encoded, the encoder may, based on the number of encoded bits of the previous frame corresponding to the current frame, differ from the The quantization parameter is used to accumulate the complexity to obtain the accumulated complexity value of the current frame. That is to say, when the current frame is not the first frame, the encoder can calculate the cumulative complexity value of the current frame according to the encoding result of the previous frame. In some embodiments, the above process can be as shown in formula (5). Show:

In formula (5), bits(i-1) is the actual number of bits obtained from the encoding of the previous frame, qscale_raw(i-1) is the quantized weight value corresponding to the previous frame without adjustment of the bit rate factor, qscale_adj(i- 1) is the initial quantization level corresponding to the previous frame adjusted by the bit rate factor, cplxr_sum(i-1) is the accumulated complexity value corresponding to the previous frame, and cplxr_sum(i) is the accumulated complexity value of the current frame.

It can be understood that the accumulated complexity value of the current frame is an iterative amount, which is gradually accumulated during the encoding process. Therefore, the setting of the accumulated complexity value of the first frame will affect the encoding quality of the entire video. The method in the embodiment of the present application calculates the cumulative complexity value of the first frame by averaging the macroblock energy, so that the cumulative value of the complexity of the first frame can be adaptively adjusted according to the complexity of the first frame, so that the cumulative value of the complexity of the first frame can be adjusted adaptively. The settings are more accurate, thereby improving the quality of the entire video encoding.

In some embodiments of the present application, based on FIG. 8 , the encoder in S103 performs encoding and quantization estimation on the current frame based on the complexity cumulative value of the current frame, and obtaining the initial quantization step size of the current frame can be achieved through S1031-S1034, As shown in Figure 9:

S1031 , estimating the fuzzy complexity of the current frame, and compressing the estimated fuzzy complexity to obtain the complexity of the current frame.

In the embodiment of the present application, the encoder performs sampling filtering on the current frame to obtain a small image with half the original resolution, makes half-pixel precision prediction on the small image, subtracts it from the original image to obtain a residual, and then performs a halves on the residual. Deman transform and absolute sum to obtain SATD, then the fuzzy complexity of the current frame can be obtained according to the weighted average of the SATD values of the current frame and the previous adjacent frames.

In this embodiment of the present application, the estimation of the fuzzy complexity of the current frame by the encoder may be as shown in formula (6) and formula (7), as follows:

BlurCplx=Cplxsum/Cplxcount (6)

In formula (6), BlurCplx represents blur complexity, and the encoder can obtain BlurCplx by weighting the complexity of adjacent coded frames according to formula (6). In formula (6), Cplxsum represents the weighted sum of coding complexity, and Cplxcount represents the weighted sum of coding frame numbers. The calculation methods of Cplxsum and Cplxcount are shown in formula (7). In formula (7), i is the serial number of the frame to be encoded, satd is the sum of absolute values of residuals of the current frame after motion compensation, SATD, the satd of the first frame is a preset value, and the satd of the non-first frame can be calculated according to the time-frequency transformation, which is used to reflect the size of the generated code stream.

In the embodiment of the present application, since the constant quality of the video frame does not mean the use of a constant QP value, according to the visual characteristics of the human eye, it is difficult for the human eye to perceive the loss of details subjectively in a high-complexity scene. The perceptual coding optimization method performs nonlinear compression on the fuzzy complexity of the current frame to reduce the code rate, as shown in formula (8):

rceq=BlurCplx ^(1-qcomp) ,qcomp∈[0,1] (8)

In formula (8), rceq represents the complexity after perceptual coding optimization, which can be used as the quantization weight to evaluate the quantization degree of the current frame; the meaning of qcomp is, when qcomp is equal to 1, the quantization weight of each frame, namely The rceq is the same, and the bits allocated to the flat frame and the complex frame are the same; when qcomp=0, the quantization weight of each frame is proportional to its fuzzy complexity, and finally the QP value of each frame is equal, which is equivalent to turning off this function. Item-aware encoding optimizations.

S1032: Calculate the ratio between the total bit value of the encoded frames in the to-be-encoded video and the accumulated complexity value to obtain the bit rate factor of the current frame.

In the embodiment of the present application, the encoder calculates the ratio between the total bit value of the encoded frames in the to-be-encoded video and the accumulated complexity value as the bit rate factor of the current frame, as shown in formula (9) and formula (10) :

ratefactor=wanted_bits_window/cplxr_sum (9)

In formula (9), ratefactor is the rate factor of the current frame generated by the rate factor calculation module according to the bitrate of the encoded frame.

S1033. Obtain the quantization level of the current frame based on the complexity and the code rate factor.

In this embodiment of the present application, the encoder may first use the ratio of the quantization weight to the bit rate factor as the initial quantization level of the current frame.

In the embodiment of the present application, the encoder can calculate the ratio of the quantization ratio rceq to the code rate factor ratefactor by formula (10), to obtain the initial quantization level of the current frame:

qscale=rceq/ratefactor (10)

In formula (10), qscale is the initial quantization level of the current frame.

In this embodiment of the present application, after obtaining the initial quantization level of the current frame, the encoder may adjust the initial quantization level based on the preset target number of bits to obtain the quantization level of the current frame.

In the embodiment of the present application, the encoder can obtain the quantization of the current frame by calculating the difference between the preset target number of bits and the total bit value generated after the actual encoding of the current frame, and then adjusting the initial quantization level according to the difference. level, so that the size of the generated code stream can be stabilized.

In some embodiments, the preset target number of bits may be the size of the buffer at the receiving end corresponding to the encoded video, and the encoder may adjust the initial quantization level based on the preset target number of bits through the buffer control module to obtain the current frame's Quantization level.

S1034. Convert the quantization level of the current frame into an initial quantization step size based on the mapping relationship between the preset quantization level and the initial quantization step size.

In this embodiment of the present application, the mapping relationship between the preset quantization level and the initial quantization step size may be as shown in formula (11):

In formula (11), a, b, and c are empirical value coefficients. In some embodiments, a can take a value of 12, b can take a value of 6, c can take a value of 0.85, qscale is a quantization level, and QP is The quantization step size converted from the quantization level.

Therefore, after the encoder calculates the quantization level, it can convert the quantization level of the current frame into the initial quantization step size based on the mapping relationship between the preset quantization level and the initial quantization step size.

It can be understood that, for the first frame of the video to be encoded, the complexity cumulative value calculated according to the estimated coding complexity in formula (3) is then used to calculate the bit rate factor in formula (9), and then In formula (10), the initial quantization level is calculated based on the code rate factor, and finally the initial quantization level is converted into an initial quantization step size. That is to say, the accumulated complexity value can play the role of a compression coefficient when calculating the initial quantization step size, that is, the QP value. Because in the embodiment of the present application, the estimated coding complexity of the first frame can be adaptively adjusted according to the average macroblock energy of the first frame, thereby realizing the adaptive adjustment of the accumulated complexity value of the first frame and the initial quantization step size, thereby Improved the quality of the encoded video.

In some embodiments of the present application, based on FIG. 2 or FIG. 7, the encoder in S104 encodes the current frame based on the initial quantization step size of the current frame, and obtaining the encoding result of the current frame can be achieved through S1041-S1044, as shown in the figure 10 shows:

S1041. In the macroblock-level rate control, after dividing the current frame into macroblocks, obtain the content complexity of each macroblock.

In the embodiments of the present application, based on the above S1011-S1012, in the macroblock-level rate control, the encoder divides the current frame into macroblocks, and after obtaining at least one macroblock, it calculates the average macroblock energy of the at least one macroblock. Here, when calculating the average macroblock energy, the encoder needs to first calculate the macroblock energy of each macroblock, and then calculate the average macroblock energy of at least one macroblock. The encoder can acquire the complexity data generated in the process of calculating the energy of the macroblock, that is, in the process of calculating the energy of each macroblock, as the content complexity of each macroblock.

S1042. According to the content complexity of each macroblock and a preset complexity threshold, perform region division on the current frame to obtain at least one region.

In this embodiment of the present application, the encoder first sets a preset complexity threshold. Usually, the preset complexity threshold may be determined according to prior knowledge. Exemplarily, the preset complexity threshold may be between [80000, 85000]. value, preferably, the preset complexity threshold can be 82400.

In this embodiment of the present application, the encoder compares the content complexity of each macroblock with a preset complexity threshold, divides the current frame into regions in units of macroblocks, and divides macroblocks whose complexity is higher than the preset complexity threshold. Blocks and macroblocks whose complexity is lower than a preset complexity threshold are divided into different regions, thereby obtaining at least one region. Wherein, the complexity of each region in at least one region is different.

In some embodiments, the encoder can divide the current frame into a high-complexity region and a low-complexity region by presetting a complexity threshold.

S1043. Determine a preset quantization intensity factor of each area in the at least one area, and adjust the initial quantization step size according to the preset quantization intensity factor corresponding to each area to obtain a quantization step size corresponding to each area.

In this embodiment of the present application, the encoder first determines the area complexity of each area according to the content complexity of the macroblocks included in each area.

In some embodiments, the encoder may calculate the mean value of the content complexity of each macroblock included in each area as the area complexity of each area, or may also calculate the mean value according to other measurement methods, such as variance, etc. The selection is made according to the actual situation, which is not limited in the embodiments of the present application.

In this embodiment of the present application, the encoder determines the preset quantization intensity factor for each region according to the preset correspondence between the region complexity and the preset quantization intensity factor. Wherein, the size of the preset quantization intensity factor is inversely proportional to its corresponding area complexity.

In this embodiment of the present application, the preset quantization strength factor aq_strength may be used to adjust the block effect in the flat area and the blurring effect in the texture area. Among them, the higher the aq_strength, the more high-frequency information in the complex area is reduced, but the improved definition of the flat area also means that the texture is more blurred, conversely, the lower the aq_strength, the more high-frequency information in the complex area is retained, while the The sharpness is reduced, which means that the textured areas are sharper.

In some embodiments, the encoder may divide the current frame into a high-complexity region and a low-complexity region, and set the preset quantization strength factor aq_strength of the high-complexity region to 0.5, and the preset quantization strength of the low-complexity region to be 0.5 The factor aq_strength is 1.0, so that for high-complexity areas with more complex scenes, a lower aq_strength can be used to reduce the blurring phenomenon and improve the overall quality of the encoded video. In some embodiments, the above process can be implemented by the following code:

In the above code, h->param.rc.f_aq_strength_cplx=0.5, indicating that the value of the preset quantization strength factor aq_strength of the high-complexity region is set to 0.5, and frame->s_cplx is the content complexity of each macroblock in the region The obtained area complexity, when the area complexity is greater than the preset complexity threshold of 82400, the encoder can use the preset quantization strength factor aq_strength corresponding to the high complexity area, such as 0.5, to set the high complexity area The initial quantization step long to reduce blurring in highly complex areas.

In the embodiment of the present application, the encoder uses the same method to determine the preset quantization intensity factor set in each region according to the regional complexity of the region, and according to the preset quantization intensity factor respectively set in each region, pair the The initial quantization step size is adjusted to obtain the corresponding quantization step size for each region. That is to say, the quantization step size for quantizing the current frame finally calculated in the embodiment of the present application is at least one quantization step size corresponding to at least one area divided with different complexity in the current frame, so it can be calculated according to the current frame The area complexity of the content scene in the quantization step size is adaptively adjusted.

S1044. According to the quantization step size corresponding to each region, each region of the current frame is encoded to obtain the encoding result of the current frame.

In the embodiment of the present application, the encoder encodes each area of the current frame according to the quantization step size corresponding to each area, and obtains an encoding result of the current frame.

It can be understood that, in the embodiment of the present application, the encoder divides the current frame according to the complexity of the macroblock, so that when adjusting the quantization step size in the process of the macroblock-level rate control, the quantization step size can be adjusted according to the complexity of the current frame. The adaptive adjustment of sub-regions improves the accuracy of the quantization step size, thereby improving the accuracy of the encoded video.

In some embodiments, based on the encoding method provided by the embodiments of the present application, on the X.264 software encoding platform, common standard video data is used as the test sequence, the video resolution is fixedly set to 960*540, and the encoding algorithm adopts the ABR mode , and set the bit rate at a relatively low 1.2Mb/s, and based on this, test the objective PSNR of the encoded video obtained by the current encoding method and the encoded video obtained by the encoding method in the embodiment of the present application. The numerical value and the corresponding rate control situation, the experimental results are shown in Table 1. Table 1 is a comparison of the code rate and PSNR of the encoded video obtained by the encoding method of the current encoding method and the encoding method of the embodiment of the present application, as follows:

Table 1

It can be seen from the comparison data in Table 1 that, compared with the current encoding method, the encoding method of the embodiment of the present application can ensure the ability of the encoder to control the code rate, and will not cause the failure of the code rate control due to the introduction of the algorithm, At the same time, the coding method according to the embodiment of the present application improves the objective quality of PSNR by about 0.145dB on average. From this, it can be concluded that the encoding method provided by the embodiment of the present application can improve the video quality of the encoded video without causing a compression rate burden.

An embodiment of the present application provides an encoder, and FIG. 11 is a schematic structural diagram 1 of an encoder provided by an embodiment of the present application. As shown in FIG. 11 , the encoder 11 includes: an acquisition part 1101 , a calculation part 1102 , and a quantization part part 1103 and encoding part 1104, where,

The acquisition part 1101 is configured to acquire image information of the current frame in the inter-frame-level code rate control process when the current frame is the first frame in the video to be encoded;

The calculating part 1102 is configured to calculate the complexity cumulative value of the current frame based on the image information of the current frame;

The quantization part 1103 is configured to perform coding and quantization estimation on the current frame based on the cumulative complexity value of the current frame to obtain the initial quantization step size of the current frame;

The encoding part 1104 is configured to encode the current frame based on the initial quantization step size of the current frame to obtain an encoding result of the current frame.

In some embodiments, the image information includes any one of the average macroblock energy of the first frame, the gradient value of the first frame, the edge information of the first frame, and the histogram information of the first frame.

In some embodiments, the image information is the average macroblock energy of the first frame, and the calculating part 1102 is further configured to calculate the average macroblock energy according to the average macroblock energy, a preset first frame coding bit and at least one preset The fitting factor evaluates the complexity of the current frame to obtain the estimated coding complexity of the current frame; the at least one preset fitting factor is used to fit the difference between the average macroblock energy and the initial quantization step size The relationship curve between; based on the estimated coding complexity, calculate the complexity cumulative value of the current frame.

In some embodiments, the calculating part 1102 is further configured to multiply the average macroblock energy by a first fitting factor to obtain a first product result; multiply the preset first frame coded bits by a second Fitting factors to obtain a second product result; calculating the difference between the first product result and the second product result, and adding the difference to the third fitting factor to obtain the estimated code complexity; wherein, the at least one preset fitting factor includes the first fitting factor, the second fitting factor, and the third fitting factor.

In some embodiments, the obtaining part 1101 is further configured to perform macroblock division on the current frame during the macroblock-level rate control process to obtain at least one macroblock; calculate the at least one macroblock The average macroblock energy is used as the image information of the current frame.

In some embodiments, the calculating part 1102 is further configured to obtain the number of macroblocks of the at least one macroblock; according to the estimated coding complexity, the number of macroblocks of the at least one macroblock and a preset compression parameter , to obtain the cumulative complexity value of the current frame.

In some embodiments, the calculating part 1102 is further configured to calculate the preset compression parameter as the power of the estimated coding complexity, and compare the calculation result with the preset coefficient and the macro The multiplication of the one-half power of the number of blocks is performed to obtain the cumulative complexity value of the current frame.

In some embodiments, the acquiring part 1101 is further configured to calculate the gradient value, edge information or histogram information of the current frame according to the pixel information contained in the current frame.

In some embodiments, the encoding part 1104 is further configured to obtain the content complexity of each macroblock after dividing the current frame into macroblocks in the macroblock-level rate control; the content complexity of the macroblocks and the preset complexity threshold, the current frame is divided into regions to obtain at least one region; the preset quantization intensity factor of each region in the at least one region is determined, and according to the According to the preset quantization intensity factor corresponding to each area, the initial quantization step size is adjusted to obtain the quantization step size corresponding to each area; according to the quantization step size corresponding to each area, the current frame to encode each region of the current frame to obtain the encoding result of the current frame.

In some embodiments, the encoding part 1104 is further configured to determine the area complexity of each area according to the content complexity of the macroblocks contained in each area; according to the area complexity and the preset The preset corresponding relationship of the quantization intensity factors determines the preset quantization intensity factor of each area; the size of the preset quantization intensity factor is inversely proportional to the complexity of the area.

In some embodiments, the quantization part 1103 is further configured to perform fuzzy complexity estimation on the current frame, and perform compression processing on the estimated fuzzy complexity, so as to calculate the complexity of the current frame ; Calculate the ratio between the total bit value of the encoded frame in the video to be encoded and the cumulative value of the complexity to obtain the code rate factor of the current frame; Based on the complexity and the code rate factor, obtain The quantization level of the current frame; based on the mapping relationship between the preset quantization level and the initial quantization step size, the quantization level of the current frame is converted into the initial quantization step size.

In some embodiments, the quantization part 1103 is further configured to use the ratio of the complexity to the code rate factor as the initial quantization level of the current frame; The initial quantization level is adjusted to obtain the quantization level of the current frame.

In some embodiments, the calculating part 1102 is configured to perform coding and quantization estimation on the current frame based on the accumulated complexity value of the current frame to obtain the initial quantization step size of the current frame , when the current frame is a non-first frame in the video to be encoded, the complexity is accumulated based on the encoded bits of the previous frame corresponding to the current frame and the quantization parameter of the previous frame processing to obtain the cumulative complexity value of the current frame.

In some embodiments, the quantization part 1103 is further configured to calculate the difference between the preset target number of bits and the total bit value generated after encoding the current frame, and according to the difference The initial quantization level is adjusted to obtain the quantization level of the current frame.

In some embodiments, the encoding part 1104 is further configured to calculate the average value of the content complexity of each macroblock included in each region as the region complexity of each region.

In some embodiments, the encoding part 1104 is further configured to obtain the complexity data generated by the macroblock energy calculation process as the content complexity of each macroblock; the macroblock energy calculation process is used to calculate the macroblock energy of each macroblock to obtain the average macroblock energy of at least one macroblock.

It should be noted that the descriptions of the above apparatus embodiments are similar to the descriptions of the above method embodiments, and have similar beneficial effects to the method embodiments. For technical details not disclosed in the device embodiments of the present application, please refer to the descriptions of the method embodiments of the present application for understanding.

It should be noted that, in the embodiments of the present application, if the above-mentioned information display method is implemented in the form of a software function module and sold or used as an independent product, it may also be stored in a computer-readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application can be embodied in the form of software products in essence or in the parts that make contributions to the prior art. The computer software products are stored in a storage medium and include several instructions for A computer device (which may be a terminal, a server, etc.) is caused to execute all or part of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read only memory (Read Only Memory, ROM), a magnetic disk or an optical disk and other media that can store program codes. As such, the embodiments of the present application are not limited to any specific combination of hardware and software.

Correspondingly, the embodiments of the present application further provide a computer program product, where the computer program product includes computer-readable codes, and when the computer-readable codes run in an encoder, a processor in the encoder Execution is used to implement the encoding method provided by the embodiment of the present application.

Correspondingly, the embodiments of the present application further provide a computer-readable storage medium, where computer-executable instructions are stored on the computer-readable storage medium, and the computer-executable instructions are configured to cause the processor to execute the above-mentioned embodiments. Provides the steps of the encoding method.

An embodiment of the present application further provides an encoder. FIG. 12 is a second schematic diagram of the composition and structure of an encoder provided by an embodiment of the present application. As shown in FIG. 12 , the encoder 1200 includes: a memory 1201 configured to store Computer program;

The processor 1202 is configured to implement the steps of the encoding method provided by the above embodiment when executing the computer program stored in the memory 1201;

The encoder 1200 also includes a communication bus 1203; it is configured to connect the memory 1201 and the processor 1202, and realize the connection and communication between the memory 1201 and the processor 1202.

The memory 1201 is configured to store computer programs and applications by the processor 1202, and can also cache data to be processed or processed by the processor 1202 and modules in the encoder (eg, image data, audio data, voice communication data, and video communication data). data), which can be implemented through flash memory (FLASH) or random access memory (Random Access Memory, RAM).

When the processor 1202 executes the program, the steps of any one of the above encoding methods are implemented.

The above-mentioned processor 1202 may be an Application Specific Integrated Circuit (ASIC), a Digital Signal Processor (DSP), a Digital Signal Processing Device (DSPD), a Programmable Logic Device (Programmable Logic Device) At least one of a Logic Device (PLD), a Field Programmable Gate Array (FPGA), a Central Processing Unit (CPU), a controller, a microcontroller, and a microprocessor. It can be understood that the electronic device that implements the function of the above processor may also be other, which is not limited in the embodiment of the present application.

The above-mentioned computer-readable storage medium/memory can be a read-only memory (Read Only Memory, ROM), a programmable read-only memory (Programmable Read-Only Memory, PROM), an erasable programmable read-only memory (Erasable Programmable Read-Only Memory) Memory, EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Magnetic Random Access Memory (FRAM), Flash Memory (Flash Memory), Magnetic Surface Memory, optical disk, or memory such as Compact Disc Read-Only Memory (CD-ROM); it can also be various terminals including one or any combination of the above memories, such as mobile phones, computers, tablet devices, personal digital Assistant etc.

It should be pointed out here that the descriptions of the above storage medium and device embodiments are similar to the descriptions of the above method embodiments, and have similar beneficial effects to the method embodiments. For technical details not disclosed in the embodiments of the storage medium and device of the present application, please refer to the description of the method embodiments of the present application to understand.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other manners. The device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined, or Can be integrated into another system, or some features can be ignored, or not implemented. In addition, the coupling, or direct coupling, or communication connection between the various components shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be electrical, mechanical or other forms. of.

The unit described above as a separate component may or may not be physically separated, and the component displayed as a unit may or may not be a physical unit; it may be located in one place or distributed to multiple network units; Some or all of the units may be selected according to actual needs to achieve the purpose of the solutions of the embodiments of the present application.

In addition, each functional unit in each embodiment of the present application may all be integrated into one processing unit, or each unit may be separately used as a unit, or two or more units may be integrated into one unit; the above integration The unit can be implemented either in the form of hardware or in the form of hardware plus software functional units.

Alternatively, if the above-mentioned integrated units of the present application are implemented in the form of software function modules and sold or used as independent products, they may also be stored in a computer-readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application may be embodied in the form of software products in essence or the parts that contribute to related technologies. The computer software products are stored in a storage medium and include several instructions to make The automatic test line of the device performs all or part of the methods described in the various embodiments of the present application. The aforementioned storage medium includes various media that can store program codes, such as a removable storage device, a ROM, a magnetic disk, or an optical disk.

The above is only the embodiment of the present application, but the protection scope of the present application is not limited to this. Covered within the scope of protection of this application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Industrial Applicability

In this embodiment of the present application, the accumulated complexity value of the first frame can be evaluated by using the image information of the first frame, and the initial quantization step size, that is, the QP value, is reasonably set based on the accumulated complexity value of the first frame, so that the QP value can be reasonably set. Adaptive adjustment is performed according to the image information of the first frame, so that the video encoding based on the QP value can obtain a more accurate encoding result, and finally the video quality of the encoded video is improved. In addition, the current frame is divided into regions by the complexity of the macroblock, so that when the quantization step size is adjusted in the macroblock-level rate control process, the adaptive adjustment of the subregions can be performed according to the complexity of the current frame, which improves the quantization step. long precision, thus improving the precision of the encoded video. According to the experimental comparison data, it can be concluded that the encoding method in the embodiment of the present application can improve the video quality of the encoded video without causing a burden on the compression rate.

Claims

An encoding method, applied to an encoder, comprising:

When the current frame is the first frame in the video to be encoded, in the inter-frame-level rate control process, the image information of the current frame is acquired;

Calculate the complexity cumulative value of the current frame based on the image information of the current frame;

Based on the cumulative complexity value of the current frame, perform coding and quantization estimation on the current frame to obtain an initial quantization step size of the current frame;

Based on the initial quantization step size of the current frame, the current frame is encoded to obtain an encoding result of the current frame.
The method of claim 1, wherein the image information includes any one of the average macroblock energy of the first frame, the gradient value of the first frame, the edge information of the first frame, and the histogram information of the first frame.
The method according to claim 2, wherein the image information is the average macroblock energy of the first frame, and the calculation of the complexity cumulative value of the current frame based on the image information of the current frame, comprising:

The complexity evaluation of the current frame is performed according to the average macroblock energy, the preset coding bits of the first frame and at least one preset fitting factor, so as to obtain the estimated coding complexity of the current frame; the at least one preset coding complexity is obtained. The fitting factor is used to fit the relationship curve between the average macroblock energy and the initial quantization step size;

Based on the estimated coding complexity, a cumulative complexity value of the current frame is calculated.
The method according to claim 3, wherein the current frame is obtained by performing complexity evaluation on the current frame according to the average macroblock energy, preset first frame coding bits and at least one preset fitting factor The estimated coding complexity of , including:

multiplying the average macroblock energy by the first fitting factor to obtain a first product result;

multiplying the preset first frame coding bits by the second fitting factor to obtain a second product result;

Calculate the difference value of the first product result minus the second product result, and add the difference value to the third fitting factor to obtain the estimated coding complexity; wherein, the at least one predictor It is assumed that the fitting factor includes the first fitting factor, the second fitting factor and the third fitting factor.
The method according to claim 3, wherein the acquiring the image information of the current frame comprises:

In the macroblock-level rate control process, the current frame is divided into macroblocks to obtain at least one macroblock;

Calculate the average macroblock energy of the at least one macroblock as image information of the current frame.
The method according to claim 5, wherein the calculating a complexity cumulative value of the current frame based on the estimated coding complexity comprises:

obtaining the number of macroblocks of the at least one macroblock;

The cumulative complexity value of the current frame is obtained according to the estimated coding complexity, the number of macroblocks of the at least one macroblock, and a preset compression parameter.
The method according to claim 6, wherein obtaining the cumulative complexity value of the current frame according to the estimated coding complexity, the number of macroblocks of the at least one macroblock and a preset compression parameter, comprising:

Calculate the preset compression parameter as the power of the estimated coding complexity, and multiply the calculation result with the preset coefficient and the first power of the number of macroblocks to obtain the The accumulated complexity value of the current frame.
The method according to claim 2, wherein the acquiring the image information of the current frame comprises:

According to the pixel information contained in the current frame, the gradient value, edge information or histogram information of the current frame is calculated.
The method according to any one of claims 1-8, wherein the encoding the current frame based on the initial quantization step size of the current frame to obtain an encoding result of the current frame, comprising:

In the macroblock-level code rate control, after the current frame is divided into macroblocks, the content complexity of each macroblock is obtained;

According to the content complexity of each macroblock and the preset complexity threshold, the current frame is divided into regions to obtain at least one region;

Determine a preset quantization intensity factor of each area in the at least one area, and adjust the initial quantization step size according to the preset quantization intensity factor corresponding to each area to obtain the corresponding quantization step size;

According to the quantization step size corresponding to each area, each area of the current frame is encoded to obtain an encoding result of the current frame.
The method of claim 9, wherein the determining a preset quantized intensity factor for each of the at least one region comprises:

Determine the area complexity of each area according to the content complexity of the macroblocks contained in each area;

The preset quantization intensity factor of each area is determined according to the preset correspondence between the area complexity and the preset quantization intensity factor; the size of the preset quantization intensity factor is inversely proportional to the area complexity.
The method according to any one of claims 1-8, wherein the current frame is subjected to coding and quantization estimation based on a complexity cumulative value of the current frame to obtain an initial quantization step size of the current frame, include:

Performing fuzzy complexity estimation on the current frame, and compressing the estimated fuzzy complexity, and calculating the complexity of the current frame;

Calculate the ratio between the total bit value of the encoded frame in the to-be-encoded video and the cumulative complexity value to obtain the bit rate factor of the current frame;

obtaining the quantization level of the current frame based on the complexity and the code rate factor;

Based on the mapping relationship between the preset quantization level and the initial quantization step size, the quantization level of the current frame is converted into the initial quantization step size.
The method according to claim 11, wherein the obtaining the quantization level of the current frame based on the complexity and the code rate factor comprises:

Taking the ratio of the complexity to the code rate factor as the initial quantization level of the current frame;

Based on the preset target number of bits, the initial quantization level is adjusted to obtain the quantization level of the current frame.
The method according to any one of claims 1-8, wherein the coding and quantization estimation is performed on the current frame based on the accumulated complexity value of the current frame, and before the initial quantization step size of the current frame is obtained , the method also includes:

When the current frame is not the first frame in the to-be-encoded video, the complexity is accumulated based on the encoded bits of the previous frame corresponding to the current frame and the quantization parameter of the previous frame , to obtain the cumulative complexity value of the current frame.
The method according to claim 12, wherein adjusting the initial quantization level based on a preset target number of bits to obtain the quantization level of the current frame, comprising:

Calculate the difference between the preset target number of bits and the total bit value generated after encoding the current frame, adjust the initial quantization level according to the difference, and obtain the quantization level of the current frame .
The method according to claim 10, wherein the determining the area complexity of each area according to the content complexity of the macroblock included in each area comprises:

Calculate the mean value of the content complexity of each macroblock included in each area as the area complexity of each area.
The method according to claim 9, wherein the obtaining the content complexity of each macroblock comprises:

Obtain the complexity data generated by the macroblock energy calculation process as the content complexity of each macroblock; the macroblock energy calculation process is used to calculate the macroblock energy of each macroblock to obtain at least one macroblock The average macroblock energy of the block.
An encoder, comprising: an acquisition part, a calculation part, a quantization part and an encoding part, wherein,

The acquisition part is configured to acquire image information of the current frame in the inter-frame-level code rate control process when the current frame is the first frame in the video to be encoded;

The calculation part is configured to calculate the complexity cumulative value of the current frame based on the image information of the current frame;

Described quantization part, is configured to be based on the complexity accumulation value of described current frame, carry out coding quantization estimation to described current frame, obtain the initial quantization step size of described current frame;

The encoding part is configured to encode the current frame based on the initial quantization step size of the current frame to obtain an encoding result of the current frame.
An encoder comprising:

a memory configured to store executable data instructions;

A processor, configured to execute the executable instructions stored in the memory, implements the method of any one of claims 1 to 16.
A computer-readable storage medium storing executable instructions configured to cause a processor, when executed, to implement the method of any one of claims 1 to 16.
A computer program product comprising computer readable code which, when the computer readable code is run in an encoder, executed by a processor in the encoder for implementing claims 1 to 16 The method of any one.