WO2020107449A1

WO2020107449A1 - Coding method, coder and computer storage medium

Info

Publication number: WO2020107449A1
Application number: PCT/CN2018/118701
Authority: WO
Inventors: 周益民; 程学理
Original assignee: Oppo广东移动通信有限公司
Priority date: 2018-11-30
Filing date: 2018-11-30
Publication date: 2020-06-04
Also published as: CN112655207A

Abstract

Provided are a coding method, a coder and a computer storage medium. The method is applied to a coder, and the method comprises: acquiring a performance parameter of a coder at the last moment and a QP value of an image frame to be coded at the last moment (S101); determining, according to a target performance parameter of the coder, variations in performance parameters of the coder at the current moment and the last moment (S102); determining, according to the variations in the performance parameters, the performance parameter of the coder at the last moment, and the QP value of said image frame at the last moment, a QP value of said image frame at the current moment (S103); and coding, according to the QP value of said image frame at the current moment, said image frame at the current moment (S104).

Description

Encoding method, encoder and computer storage medium

Technical field

The embodiments of the present application relate to the technical field of bit rate control in video encoding, and in particular, to an encoding method, an encoder, and a computer storage medium.

Background technique

Video coding, also known as video compression, compresses original video sources with a large amount of time and space redundancy through techniques such as quantization, transformation, and entropy coding to minimize the space or bandwidth required for storage or transmission. With the rapid development of the Internet, the contradiction between people's pursuit of high-definition and ultra-high-definition video and limited network bandwidth has become increasingly prominent. If the quality of video can be guaranteed as much as possible while meeting the demand for limited bandwidth transmission, this will Bring great convenience to people's lives.

Among them, the code rate control is to change the code rate output by the encoder by adjusting the coding parameters, so as to meet the code rate requirements set by the user. For a long time, rate control is the most important technical field in the field of video coding; the core problem of rate control is to establish the relationship model between the rate and the encoding parameters, that is, how to determine the encoding parameters according to the target rate to ensure that the Under certain video quality, the control is stable and the error is small enough.

In the video encoding process, if the code rate control is not performed, then usually the video encoding will be encoded with preset encoding parameters. The number of output bits of each frame of image fluctuates and is not controlled. In practical applications, the source video contains a lot of time and space redundancy. The purpose of encoding is to eliminate these redundancy as much as possible, but usually these redundancy distributions in various video sequences are very uneven or even no. The regularity causes the encoder output bit to fluctuate greatly. In addition, encoders generally use variable-length coding to encode coefficients to save codewords, and variable-length coding designs codewords based on the probability of symbol appearance. The greater the probability of occurrence, the shorter the codeword. Conversely, the smaller the probability of occurrence, the longer the codeword. In addition, since the probability of signal occurrence and change is random, it will also cause the output bit rate of the encoder to change. Because of these uncertainties in the content of the video source, it is impossible to ensure that the actual output bit rate of each frame of image is stable during encoding, nor can it be guaranteed that the output bit rate is completely consistent with the target bit rate. Therefore, bit rate control is particularly important in video coding.

At present, in the existing code rate control technology, in order to ensure the consistency of the output code rate and the target code rate, in H.264, three levels of code rate control at the group level, frame level, and macroblock level are used. When the precision of rate control is high, the rate control at the macroblock level is adopted. The rate control algorithm calculates a set of coding parameters for each macroblock according to the content characteristics of each macroblock, thereby obtaining a more accurate Control effect; on the contrary, the use of image group level or frame level code rate control, in the case of image group level code rate control, the main idea is: calculate the total bit demand of each image group and the bit allocation of the remaining uncoded frames, And determine the actual quantization parameters of each image group. Frame-level bit rate control is a bit more complicated. It mainly adopts different quantization parameter calculation strategies for three different types of frames: I, P, and B. Frame B is not referenced by other frames, and its quantization parameters pass the quantization parameters of adjacent frames. After interpolation, the P frame will be referenced by multiple frames in the future, which has a greater impact, so it needs to be accurately calculated. In H.264, the linear tracking theory is used to calculate two sets of target bits for the current frame, and then the weighted average is calculated to obtain the number of bits allocated to the current frame, and then the linear model is used to predict the MAD complexity of the current frame and bring into the two The second-rate distortion model obtains the quantization parameters of the current frame. For the rate control at the macroblock level, the main idea is similar to the rate control at the frame level. First, the number of allocated bits is predicted, then the MAD is predicted, and finally the quantization parameter of the current macroblock is calculated by the second rate distortion model.

In the high-efficiency video coding standard (HEVC, High Efficiency Video Coding), a three-level rate control mechanism similar to H.264 is also adopted. The core content is to innovatively propose the R-λ relation model, which is used to calculate the Lagrangian multiplier λ, and then directly bring the Lagrangian multiplier λ into an empirical formula to calculate the quantitative parameters.

In the second-generation source coding standard (AVS2, Audio, Video, and Standard 2), a fuzzy logic-based control theory is adopted, and a fuzzy control lookup table is established in advance. In the rate control process, the buffer state is established, and the table is directly looked up to obtain the change of the quantization parameter, and then the quantization parameter used for encoding the next frame is obtained.

The above three rate control algorithms only consider the current state of the encoded frame, and the method of determining the encoding parameters is single and fixed, resulting in poor encoding control accuracy and unstable performance of the encoder output; it can be seen that the existing encoding The encoder's coding method results in poor coding performance due to poor coding control accuracy.

Summary of the invention

In view of this, the embodiments of the present application desire to provide an encoding method, an encoder, and a computer storage medium, which can improve the encoding performance of the encoder when encoding.

The technical solutions of the embodiments of the present application may be implemented as follows:

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

Obtain the performance parameter of the encoder at the last moment and the quantization parameter QP value of the image frame to be encoded at the last moment;

According to the target performance parameter of the encoder, determine the change amount of the performance parameter of the encoder at the current time and the previous time;

Determine the QP value of the image frame to be encoded at the current time according to the change amount of the performance parameter, the performance parameter of the encoder at the previous time and the QP value of the image frame to be encoded at the previous time;

According to the QP value of the image frame to be encoded at the current moment, encode the image frame to be encoded at the current moment.

In a second aspect, an embodiment of the present application provides an encoder. The encoder includes:

A first acquiring unit, configured to acquire the performance parameter of the encoder at the last moment and the quantization parameter QP value of the image frame to be encoded at the last moment;

A first determining unit, configured to determine the change amount of the performance parameter of the encoder at the current time and the previous time according to the target performance parameter of the encoder;

The second determining unit is configured to determine that the image frame to be encoded is based on the change amount of the performance parameter, the performance parameter of the encoder at the previous time, and the QP value of the image frame to be encoded at the previous time QP value at the current moment;

The encoding unit is configured to encode the image frame to be encoded at the current time according to the QP value of the image frame to be encoded at the current time.

In a third aspect, an embodiment of the present application provides an encoder. The encoder includes:

A processor and a storage medium storing instructions executable by the processor, the storage medium relies on the processor to perform operations through a communication bus, and when the instructions are executed by the processor, the first aspect described above is performed Encoding method.

According to a fourth aspect, an embodiment of the present application provides a computer storage medium that stores executable instructions. When the executable instructions are executed by one or more processors, the processor executes the first aspect. The encoding method described.

An embodiment of the present application provides an encoding method, an encoder, and a computer storage medium. The method is applied to an encoder. The method includes: first, acquiring the performance parameters of the encoder at the previous moment and the image frame to be encoded are on the The QP value at a moment, according to the target performance parameter of the encoder, determines the amount of change in the performance parameter of the encoder at the current time and the previous time, so that you can know the amount of change in the performance parameter at the current time and the previous time, and then according to The amount of change in performance parameters, the performance parameter of the encoder at the previous time, and the QP value of the image frame to be encoded at the previous time, determine the QP value of the image frame to be encoded at the current time, that is, the amount of change in the performance parameter, encoding The performance parameter of the device at the previous moment and the QP value of the image frame to be encoded at the previous moment determine the QP value of the image frame to be encoded at the current moment, that is to say, in the embodiment of the present application, the image frame to be encoded is determined The QP value at the current time takes into account the amount of change in the performance parameter at the previous time. Thus, combined with the historical situation of the performance parameter, the QP value of the resulting encoded image frame at the current time is more accurate. Finally, according to the current image frame to be encoded The QP value at the moment, the image frame to be encoded is encoded at the current moment; making the encoding process not only uses the preset encoding parameters, but also considers the amount of change in the encoder performance parameters, which is conducive to improving the performance of the encoding process The control precision of the parameters, thereby improving the encoding performance in the encoding process.

BRIEF DESCRIPTION

1 is a schematic flowchart of an optional encoding method provided by an embodiment of this application;

2 is a schematic flowchart of another optional encoding method provided by an embodiment of the present application;

FIG. 3 is a schematic flowchart of another alternative encoding method provided by an embodiment of the present application;

4 is a schematic flowchart of still another optional connection method provided by an embodiment of the present application;

5 is a schematic flowchart of an alternative example of an encoding method provided by an embodiment of this application;

6 is a schematic flowchart of another optional example of the encoding method provided by the embodiment of the present application;

7 is a schematic flowchart of another optional example of the encoding method provided by the embodiment of the present application;

8 is a simulation diagram of the filling degree of the virtual buffer zone under the AI coding structure provided by the embodiment of the present application;

9 is a simulation diagram of the filling degree of the virtual buffer under the LD coding structure provided by the embodiment of the present application;

10 is a simulation diagram of the filling degree of the virtual buffer under the RA coding structure provided by the embodiment of the present application;

11 is a schematic structural diagram 1 of an encoder provided by an embodiment of the present application;

FIG. 12 is a second structural diagram of an encoder provided by an embodiment of the present application.

detailed description

In order to understand the features and technical contents of the embodiments of the present application in more detail, the implementation of the embodiments of the present application will be described in detail below with reference to the drawings. The accompanying drawings are for reference only and are not intended to limit the embodiments of the present application.

An embodiment of the present application provides an encoding method, which is applied to an encoder. FIG. 1 is a schematic flowchart of an optional encoding method provided by an embodiment of the present application. Referring to FIG. 1, the encoding method may include:

S101: Obtain the performance parameter of the encoder at the last moment and the QP value of the image frame to be encoded at the last moment;

Among them, the performance parameter includes any one of the following: the output rate parameter of the image frame, the output quality parameter of the image frame, or the output time parameter of the image frame.

For example, when the performance parameter is the output rate parameter of the image frame, and the output rate parameter of the image frame is the output bit rate, correspondingly, the target performance parameter is the target output bit rate;

Before S101, the target output bit rate of the encoder is obtained, for example, the target output bit rate of the encoder set by the user is received. It should be noted here that the target output bit rate may also be referred to as the target code rate;

Among them, the target bit rate of the encoder is preset by the user, and the user can set the target bit rate (TBR, Target, BitRate) of the encoder according to their own needs.

Here, it should be noted that the unit of TBR is bits per second (bps, bit per second). In order to generalize the operation process of the coding sequence, the embodiments of the present application may be performed in units of bit per pixel (bpp, bit per pixel) Characterization of the bit rate, so that the target bit rate can be converted into a target bit per pixel (T _bpp , Target bit per pixel), the conversion method of the target bit rate can be calculated by the following formula:

Among them, FPS is the frame rate of the original video, and W and H are the width and height of the original video, respectively.

In this way, the target code rate can be converted into the target bit per pixel, and the target code rate referred to in the embodiments of the present application is expressed by the target bit per pixel.

In S101, after the image frame at the last moment after the encoding is completed, since the actual output bits (RB, Real Bits) are generated after the encoding of each frame, the number of bits generated in the t-th frame is RB _t , which is converted into The bit rate in bpp, expressed in R _t , can be calculated by the following formula:

Where t represents the time, and the output bit rate of the encoder at the previous time can be expressed by the above formula (2); further, the output error e of the encoder at time t can be calculated by the following formula:

e _t = R _t -T _bpp (3)

Among them, R is the encoder output bit rate, T _bpp is the target code rate;

In other words, in addition to acquiring the image frame to be encoded at the current time, it is also necessary to acquire the output bit rate R _{t-1 of the} encoder at the previous time and the QP value of the image frame to be encoded at the previous time.

S102: According to the target performance parameter of the encoder, determine the change amount of the performance parameter of the encoder at the current time and the previous time;

S102 may include: determining the change amount of the output bit rate of the encoder at the current time and the previous time according to the target output bit rate of the encoder.

After receiving the target code rate of the encoder, the output bit rate change ΔR of the encoder at the current time and the previous time can be determined according to the target code rate, then, in order to determine the output of the encoder at the current time and the previous time The amount of change in bit rate ΔR. In an alternative embodiment, FIG. 2 is a schematic flowchart of another alternative encoding method provided by an embodiment of the present application. Referring to FIG. 2, S102 may include:

S201: Obtain the target line of the virtual buffer at the previous moment;

S202: Obtain the target line of the virtual buffer at the current moment;

S203: According to the target line of the virtual buffer at the previous time and the target line of the virtual buffer at the current time, determine the amount of change in the output bit rate of the encoder between the current time and the previous time;

Among them, the virtual buffer is used to record the value of the encoder's output bit rate exceeding the target output bit rate.

In an optional embodiment, S202 may include:

Determine the encoding structure type of the image frame to be encoded at the current moment;

The target line of the virtual buffer at the current moment is determined according to the encoding structure type of the image frame to be encoded at the current moment and the target output bit rate of the encoder.

Specifically, the coding structure of the image frame can be roughly divided into three types, which are the coding structure in the full frame (AI, All Intra), the coding structure in low latency (LD, Low Delay), and the random access (RA, Random) Access) coding structure.

After the coding structure of the image frame to be coded at the current time determined in S201, the target line of the virtual buffer at the previous time and the target line of the virtual buffer at the current time are determined for different coding structures.

In order to simulate the buffer between the encoder and the channel, the embodiment of the present application introduces a virtual buffer, assuming that the traffic flowing into the virtual buffer is the bit rate output by the encoder in real time, and the traffic flowing out of the virtual buffer is the target code rate, So, in this process, it is assumed that the virtual buffer will keep changing dynamically, where the remaining flow of the virtual buffer is called the current virtual buffer fullness (CBF, Current Buffer Fullness); or, because each frame output may exist e _t , causing the bits output by the encoder to exceed the target code rate and stay at the encoding end (the retention number can be a negative value, indicating that the output bit rate of the encoder is less than the target code rate). The filling level of the virtual buffer. Among them, the filling degree of the virtual buffer can be calculated by the following formula:

Among them, t represents the moment, because of the different coding structure, the dynamic change process of CBF has a big difference, usually the number of bits required to encode I frame is the most, P frame is next, and B frame is the least bit.

Then, in order to determine the target line of the virtual buffer at the previous moment and the target line of the virtual buffer at the current moment, in an optional embodiment, according to the encoding structure type of the image frame to be encoded at the current moment and the encoder’s The target code rate, which determines the target line of the virtual buffer at the current moment, may include:

If the coding structure type of the image frame to be coded at the current moment is the AI structure, determine that the target lines of the virtual buffer at the current moment are all zero;

If the coding structure type of the image frame to be coded at the current moment is the LD structure, based on the target output bit rate, the first preset formula is called to determine the target line of the virtual buffer at the current moment;

If the coding structure type of the image frame to be coded at the current moment is the RA structure, the second preset formula is called based on the target output bit rate to determine the target line of the virtual buffer at the current moment.

Specifically, in the AI structure, since all frames are I frames, the output bit rate is relatively stable, and is close to the target bit rate. Therefore, in this coding structure, the ideal goal of rate control is to let the CBF update In the process, it is as close to 0 as possible, so in the AI structure line, the target line of the virtual buffer is always 0, and the target line of the virtual buffer (TBL, Target BitLine) can be expressed by the following formula:

TBL _t = 0 (5)

If the coding structure type of the image frame to be coded at the current moment is the LD structure, the output error e of the encoder is calculated by formula (3):

Use the following formula to calculate the target line of the virtual buffer at the previous moment and the target line of the virtual buffer at the current moment:

Wherein, TBL represents the target line of the virtual buffer, and TFs represents the total number of encoded frames, that is, the above formula (3) and formula (6) are the first preset formulas.

Specifically, for the LD coding structure, the first frame is an I frame, and the output bit rate is often several times or even tens of times the target bit rate, resulting in the CBF will be much higher after encoding the first I frame, and then It is impossible for the P frame to pull this high back to 0 immediately. Even if it can, it will cause the subsequent P frame to be of poor coding quality. When it is referenced, this error will be further amplified, resulting in serious distortion of the entire sequence . In this case, the height of the first I frame slowly drops to 0, which can make the distortion of the subsequent P frame not too large; where the first I frame is the starting frame of a sequence.

Among them, the above formula (6) shows that under the LD structure, the first I-frame can not be controlled without incremental feedback, and its target line is the bit rate error of the first I-frame, and then this decrease is slowly reduced until the end One frame is zeroed.

If the coding structure type of the image frame to be coded at the current moment is the RA structure, the output error e of the encoder is calculated by the above formula (3).

The filling degree CBF of the virtual buffer is calculated by the above formula (4).

Among them, TBL represents the target line of the virtual buffer, IP represents the number of frames contained in each I frame period, subscript I represents the coding sequence of I frames in the current I frame period, I-Picture represents I frames, and Others represents non-I Frame, that is, the above formula (3), formula (4) and formula (7) are the second preset formula.

For the RA structure, the coding structure and the reference structure are slightly more complicated than the LD. I-frames will appear periodically. The sequence of the sequence is inconsistent with the coding order. When referring, there is a backward reference, and some frames There will be cases where it is not referenced. But ignoring these complicated situations, we can simply treat the situation between adjacent I frames as an LD structure.

Among them, the formula (7) indicates that each I frame period is similar to the LD structure, and in the I frame period, the height is slowly reduced to 0. However, it is difficult to achieve almost exactly zero, therefore, the following cycle (non-first cycle) required TBL I frame errors occurring when the end of a cycle before adding, when said CBF _t-1 represents the end of an encoded IP The degree of filling of the virtual buffer, so when encoding the first IP, CBF _t-1 = 0.

In an alternative embodiment, FIG. 3 is a schematic flowchart of another alternative encoding method provided by an embodiment of the present application. Referring to FIG. 3, S203 may include:

S301: Obtain the filling degree of the virtual buffer at the current moment;

S302: Determine the error of the virtual buffer at the previous time according to the filling level of the virtual buffer at the current time and the target line of the virtual buffer at the previous time;

S303: Determine the output error of the encoder at the previous time according to the output bit rate of the encoder at the previous time and the target output bit rate;

S304: According to the error of the virtual buffer at the last moment, the output error of the encoder at the last moment, the target line of the virtual buffer at the last moment, and the target line of the virtual buffer at the current moment, determine the current moment The output bit rate change at any time;

S305: Call the third preset formula to update the filling level of the virtual buffer at the current moment.

In an optional embodiment, S304 may include:

Using the target line of the virtual buffer at the current time, subtract the target line of the virtual buffer at the previous time, subtract the error of the virtual buffer at the previous time, and subtract the output error of the encoder at the previous time, and determine as The encoder outputs the amount of change in the bit rate between the current time and the previous time.

Here, similar to the above formula (3), after having the target line of the virtual buffer and the filling degree of the virtual buffer, the error E of the virtual buffer can be defined, and the error E of the virtual buffer can be calculated by the following formula:

E _t =CBF _t -TBL _t (8)

In this way, the output bit rate R _{t+1 of the} next frame of the encoder can be obtained. This bit rate is used to eliminate the previous error and needs to reach the target line of the virtual buffer. The derivation process is as follows:

According to the above formulas (3), (8) and (9), the change amount ΔR of the output bit rate between two adjacent moments can be obtained:

After calculating ΔR, the third preset formula, formula (4), is called to update the filling level of the current virtual buffer.

Since the process of video encoding is an unpredictable process, formula (10) does not take into account the changes in the past period of time. Therefore, this technical solution adds the cumulative amount of errors in the past period and the past two frames to the theoretical formula. The amount of error change, and it is given a certain weight. As shown in the following formula:

Among them, the above-mentioned a, b and c are empirical weight parameters.

So far, the amount of change ΔR in the output bit rate of the encoder at the previous time and the current time can be determined by the above formula (10) or formula (11).

S103: Determine the QP value of the image frame to be encoded at the current time according to the amount of change in the performance parameter, the performance parameter of the encoder at the previous time, and the QP value of the image frame to be encoded at the previous time;

Specifically, the QP value can be represented by Q, and the Lagrangian multiplier and quantization parameter need to be calculated through ΔR feedback. The key to calculating both is to find the relationship between the connection bit rate, Lagrangian multiplier and quantization parameter. In fact, there are several empirical formulas between R and λ, R and Q, and λ and Q. It is easy to substitute ΔR into the feedback calculation to obtain λ and Q.

In order to determine the QP value of the image frame to be encoded at the current moment, in an alternative embodiment, FIG. 4 is a schematic flowchart of yet another alternative encoding method provided by an embodiment of the present application. Referring to FIG. 4, S104 may include:

S401: Determine the ratio of the Lagrangian multiplier at the current time to the Lagrangian multiplier at the previous time according to the change in the output bit rate and the output bit rate of the encoder at the previous time;

S402: Determine the QP value of the image frame to be encoded at the current time according to the ratio of the Lagrange multiplier at the current time to the Lagrange multiplier at the previous time and the QP value of the image frame to be encoded at the previous time.

Specifically, the R-λ model can be expressed by the following formula:

R＝α·λ ^β (12)

Among them, the above α and β are constants.

Based on the above formula (12), the output bit rate of the encoder at the adjacent time can be obtained:

Divide the two expressions in the above formula (13) to get the following formula:

In an optional embodiment, S401 may include:

Calculate the ratio of the Lagrange multiplier at the current moment to the Lagrange multiplier at the previous moment by the following formula (16);

If the ratio of two λs is defined as η _λ , then η _λ can be expressed by the following formula:

Where t represents the time, λ is the Lagrangian multiplier, R is the encoder output bit rate, ΔR is the amount of bit rate change, and β is the coefficient.

Then, the λ _t+1 Lagrange multiplier at the next moment can be calculated by the following formula:

In an optional embodiment, S402 may include: similar to the process of solving λ, the Q-λ model may be expressed by the following formula:

Q＝a·lnλ+b (18)

Among them, Q represents QP value, a, b are constants.

Subtract the two expressions in formula (19) to obtain the following formula:

By slightly modifying equation (20), the calculation formula of the final quantization parameter QP can be obtained as follows:

Calculate the QP value of the image frame to be encoded at the current moment by formula (21);

In addition, there can be multiple methods for representing Lagrange multipliers and quantization parameters. For example, the following representation methods and analysis processes:

First, through a lot of statistical analysis, the R-Q index model can be obtained:

R＝α·e ^-βQ (22)

Differentiating Q from both sides of formula (22) gives the following formula:

Within a small variation range of QP value, △R≈dR and △Q≈dQ can be taken into the above formula (23) to obtain:

Then, the QP used at the next moment can be expressed as:

Q _t+1 =Q _t +△Q (25)

The following formula can be obtained from the above formula (20):

The above formula (21) can be obtained according to formula (25) and formula (26), so that the QP value of the image frame to be encoded at the current moment can be calculated.

S104: According to the QP value of the image frame to be encoded at the current moment, encode the image frame to be encoded at the current moment.

In this way, the method based on buffer incremental feedback is used to feed back the current buffer filling degree to the change in bit rate, and then output the bit rate R and Lagrange multiplier λ, bit rate and quantization parameter QP through the encoder. Or, the relationship between the Lagrangian multiplier and the quantization parameter adjusts the encoding parameters (the Lagrangian multiplier and the quantization parameter), and the adjusted parameter is used in the current image encoding, thereby achieving the purpose of code rate control.

The following provides an example to describe the encoding method described in the above one or more embodiments.

FIG. 5 is a schematic flowchart of an alternative example of an encoding method provided by an embodiment of the present application. Referring to FIG. 5, the method may include:

S501: Acquire 1 frame of image;

S502: Determine the coding structure type of the image and the QP value assigned by the system to the image;

S503: Enter the sub-process of calculating the QP value in the incremental feedback of the virtual buffer to obtain the QP value of one frame of image;

S504: encode one frame of image with the QP value of one frame of image;

S505: Update the state of the virtual buffer;

S506: Determine whether all encoding is completed; if yes, end encoding; if no, go to S401.

FIG. 6 is a schematic flowchart of another optional example of the encoding method provided by the embodiment of the present application. Referring to FIG. 6, the method for determining the QP value may include:

S601: Determine the target line of the virtual buffer at the previous moment and the target line of the virtual buffer at the current moment according to the above formula (5), formula (6) and formula (7);

S602: Calculate the error of the virtual buffer in the previous frame (last time) according to formula (8);

S603: Calculate the amount of change in the output bit rate of the encoder at the current time and the previous time according to formula (11);

S604: Calculate the change in QP value according to formula (20);

S605: Calculate the QP value of the image frame to be encoded at the current moment according to formula (21).

FIG. 7 is a schematic flowchart of still another optional example of the encoding method provided by the embodiment of the present application. Referring to FIG. 7, the method for determining the filling degree of the virtual buffer (sub-process of virtual buffer status update) may include :

S701: Determine the output error of the encoder of the current frame (the current moment) according to formula (3);

S702: Update the filling level of the current virtual buffer according to formula (4).

In the embodiment of the present application, by accumulating the error of the output bit rate, a virtual buffer is used to construct a control system, and the QP is fed back to adjust the bit rate. Similarly, if the statistical indicators related to the quality error are used to construct a model, the distortion virtual buffer is used to construct a feedback system, and the error model is used as an input to adjust the QP, the purpose of controlling the image quality can be achieved. The statistical index builds a model, establishes the relationship between time error statistics and image quality, and performs QP adjustment in combination with the quality feedback adjustment system, which can achieve the purpose of stable control rate.

FIG. 8 is a simulation diagram of the filling degree of the virtual buffer under the AI coding structure provided by the embodiment of the present application. Referring to FIG. 8, (a), (b), (c), and (d) in FIG. 8 are: The encoding format of the image is the filling level line of the virtual buffer of the four different videos under different target bit rates under the AI encoding structure. Among them, the video name in Figure 8-(a) is City_1280×720_60, and that in Figure 8-(b) The video name is vidyo1_1280×720_60, the video name in Figure 8-(c) is beach_1920×1080_25, and the video name in Figure 8-(d) is pku_girls_3840×2160_50; (a), (b), (c in Figure 8 ) And (d) in each sub-picture, there are four different target code rates, namely T1, T2, T3 and T4; the abscissa of the above Figure 8 is the coding sequence (coding order), the ordinate is the virtual buffer The filling degree of the district.

9 is a simulation diagram of the filling degree of the virtual buffer under the LD coding structure provided by the embodiment of the present application. Referring to FIG. 9, (a), (b), (c) and (d) in FIG. 9 are: The encoding format of the image is the filling level line of the virtual buffer of the four different videos under different target bit rates under the LD encoding structure. Among them, the video name in Figure 9-(a) is City_1280×720_60, and that in Figure 9-(b) The video name is vidyo1_1280×720_60, the video name in Figure 9-(c) is beach_1920×1080_25, and the video name in Figure 9-(d) is pku_girls_3840×2160_50; (a), (b), (c in Figure 9 ) And (d) in each sub-picture, there are four different target code rates, respectively T1, T2, T3 and T4; the abscissa of the above Figure 9 is the coding sequence (coding order), the ordinate is the virtual buffer The filling degree of the district.

FIG. 10 is a simulation diagram of the filling degree of the virtual buffer under the RA coding structure provided by the embodiment of the present application. Referring to FIG. 10, (a), (b), (c), and (d) in FIG. 10 are: The encoding format of the image is the filling level line of the virtual buffer of the four different videos under different target bit rates under the RA encoding structure. Among them, the video name in Figure 10-(a) is City_1280×720_60, and that in Figure 10-(b) The video name is vidyo1_1280×720_60, the video name in Figure 10-(c) is beach_1920×1080_25, and the video name in Figure 10-(d) is pku_girls_3840×2160_50; (a), (b), (c in Figure 8 ) And (d) in each sub-picture, there are four different target bit rates, respectively T1, T2, T3 and T4; the abscissa of the above Figure 10 is the coding sequence (coding order), the ordinate is the virtual buffer The filling degree of the district.

Table 1 below is the control error of different video sources under the AI coding structure for YUV color coding. Among them, the video sources include: UHD, 1080P, WVGA, WQVGA and 720p.

Table 1

Table 2 below shows the control errors of different video sources under the LD coding structure for YUV color coding. Among them, the video sources include: UHD, 1080P, WVGA, WQVGA, and 720p.

Table 2

Table 3 below shows the control errors of different video sources under the RA coding structure for YUV color coding, where the video sources include: UHD, 1080P, WVGA, WQVGA, and 720p.

table 3

An embodiment of the present application provides an encoding method, which is applied to an encoder. The method includes: determining the QP value of the image frame to be encoded at the current time taking into account the amount of change in the performance parameter at the previous time, thus, combining The historical situation of the performance parameters, the QP value of the obtained encoded image frame at the current time is more accurate, and finally, according to the QP value of the image frame to be encoded at the current time, the image frame to be encoded is encoded at the current time; making the encoding process not only Only the preset encoding parameters are used, and the variation of the encoder performance parameters is also taken into consideration. This helps to improve the control accuracy of the performance parameters during the encoding process, thereby improving the encoding performance during the encoding process.

Based on the same inventive concept of the foregoing embodiment, FIG. 11 is a schematic structural diagram 1 of an encoder provided by an embodiment of the present application. Referring to FIG. 11, the encoder 110 may include:

The first acquiring unit 111 is configured to acquire the performance parameter of the encoder at the last moment and the QP value of the image frame to be encoded at the last moment;

The first determining unit 112 is configured to determine the change amount of the performance parameter of the encoder at the current time and the previous time according to the target performance parameter of the encoder;

The second determining unit 113 is configured to determine the QP value of the image frame to be encoded at the current time according to the change amount of the performance parameter, the performance parameter of the encoder at the previous time, and the QP value of the image frame to be encoded at the previous time;

The encoding unit 114 is configured to encode the image frame to be encoded at the current time according to the QP value of the image frame to be encoded at the current time.

In the above solution, the performance parameter includes any one of the following: the output rate parameter of the image frame, the output quality parameter of the image frame, or the output time parameter of the image frame.

In the above solution, when the performance parameter is the output rate parameter of the image frame, and the output rate parameter of the image frame is the output bit rate, correspondingly, the target performance parameter is the target output bit rate;

The first determining unit 112 is specifically configured to: according to the target output bit rate of the encoder, determine the amount of change in the output bit rate of the encoder at the current time and the previous time.

In the above solution, the first determining unit 112 includes:

The first obtaining subunit is used to obtain the target line of the virtual buffer at the previous moment;

The second obtaining subunit is used to obtain the target line of the virtual buffer at the current moment;

The first determining subunit is used to determine the amount of change in the output bit rate of the encoder between the current time and the previous time according to the target line of the virtual buffer at the previous time and the target line of the virtual buffer at the current time;

In the above solution, the second acquisition subunit includes:

The second determining subunit is used to determine the encoding structure type of the image frame to be encoded at the current moment;

The third determining subunit is used to determine the target line of the virtual buffer at the current time according to the encoding structure type of the image frame to be encoded at the current time and the target output bit rate of the encoder.

In the above solution, the third determining subunit is specifically used for:

If the coding structure type of the image frame to be coded at the current moment is the AI structure within the full frame, determine that the target line of the virtual buffer at the current moment is all zero;

If the encoding structure type of the image frame to be encoded at the current moment is a low-latency LD structure, based on the target output bit rate, the first preset formula is called to determine the target line of the virtual buffer at the current moment;

If the coding structure type of the image frame to be coded at the current moment is a random access RA structure, the second preset formula is called based on the target output bit rate to determine the target line of the virtual buffer at the current moment.

In the above solution, the first determining subunit includes:

The third obtaining subunit is used to obtain the filling degree of the virtual buffer at the current moment;

The fourth determining subunit is used to determine the error of the virtual buffer at the previous time according to the filling level of the virtual buffer at the current time and the target line of the virtual buffer at the previous time;

The fifth determining subunit is used to determine the output error of the encoder at the last moment according to the output bit rate of the encoder at the last moment and the target output bit rate;

The sixth determining subunit is used to determine the encoder based on the error of the virtual buffer at the previous time, the output error of the encoder at the previous time, the target line of the virtual buffer at the previous time and the target line of the virtual buffer at the current time Output the amount of change in bit rate between the current time and the previous time;

The update subunit is used to call the third preset formula to update the filling degree of the virtual buffer at the current moment.

In the above solution, the sixth determining subunit is specifically used for:

In the above solution, when the performance parameter is the output parameter of the image frame, and the output rate parameter of the image frame is the output bit rate, correspondingly, the target performance parameter is the target output bit rate;

The second determining unit 113 is specifically used for:

The QP value of the image frame to be encoded at the current time is determined according to the change amount of the output bit rate, the output bit rate of the encoder at the previous time, and the QP value of the image frame to be encoded at the previous time.

In the above solution, the second determining unit 113 includes:

The seventh determining subunit is used to determine the ratio of the Lagrangian multiplier at the current time to the Lagrangian multiplier at the previous time according to the output bit rate change and the output bit rate of the encoder at the previous time ;

The eighth determination subunit is used to determine the image frame to be encoded based on the ratio of the Lagrange multiplier at the current time to the Lagrange multiplier at the previous time and the QP value of the image frame to be encoded at the previous time QP value at the current moment.

In the above solution, the seventh determining subunit is specifically used for:

Calculate the ratio of the Lagrange multiplier at the current moment to the Lagrange multiplier at the previous moment by the following formula:

Where t represents the time, λ is the Lagrangian multiplier, R is the encoder output bit rate, ΔR is the change in output bit rate, and β is the coefficient.

In the above solution, the eighth determining subunit is specifically used for:

Calculate the QP value of the image frame to be encoded at the current moment by the following formula:

Among them, t represents time, Q represents QP value, λ is Lagrange multiplier, a is constant.

Understandably, in this embodiment, the "unit" may be a part of a circuit, a part of a processor, a part of a program or software, etc. Of course, it may also be a module or non-modular.

In addition, each component unit in this embodiment may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit. The above integrated unit can be implemented in the form of hardware or software function module.

If the integrated unit is implemented in the form of a software function module and is not sold or used as an independent product, it may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this embodiment essentially or It is said that part of the contribution to the existing technology or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions to make a computer device (may It is a personal computer, a server, or a network device, etc.) or a processor (processor) that performs all or part of the steps of the method described in this embodiment. The foregoing storage media include various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (Read Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk, or an optical disk.

FIG. 12 is a second structural diagram of an encoder provided by an embodiment of the present application. As shown in FIG. 12, an encoder 120 is provided by an embodiment of the present application.

It includes a processor 121 and a storage medium 122 that stores instructions executable by the processor 121. The storage medium 122 relies on the processor 121 to perform operations through the communication bus 123. When the instructions are executed by the processor 121, the encoding method of Embodiment 1 above is performed.

It should be noted that, in actual application, various components in the terminal are coupled together through the communication bus 123. It can be understood that the communication bus 123 is used to implement connection communication between these components. The communication bus 123 includes a power bus, a control bus, and a status signal bus in addition to the data bus. However, for the sake of clarity, various buses are marked as communication buses 123 in FIG. 12.

An embodiment of the present application provides a computer storage medium that stores executable instructions, and when the executable instructions are executed by one or more processors, the processor executes the one or more embodiments described above Encoding method.

It can be understood that the memory in the embodiments of the present application may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Among them, the non-volatile memory may be read-only memory (Read-Only Memory, ROM), programmable read-only memory (Programmable ROM, PROM), erasable programmable read-only memory (Erasable PROM, EPROM), electronically Erasable programmable read only memory (Electrically, EPROM, EEPROM) or flash memory. The volatile memory may be a random access memory (Random Access Memory, RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (Static RAM, SRAM), dynamic random access memory (Dynamic RAM, DRAM), synchronous dynamic random access memory (Synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (Double Data Rate SDRAM, DDRSDRAM), enhanced synchronous dynamic random access memory (Enhanced SDRAM, ESDRAM), synchronous connection dynamic random access memory (Synchlink DRAM, SLDRAM) And direct memory bus random access memory (Direct Rambus RAM, DRRAM). The memories of the systems and methods described herein are intended to include, but are not limited to these and any other suitable types of memories.

The processor may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method may be completed by an integrated logic circuit of hardware in the processor or instructions in the form of software. The above-mentioned processor may be a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), an existing programmable gate array (Field Programmable Gate Array, FPGA), or other available Programming logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps, and logical block diagrams disclosed in the embodiments of the present application may be implemented or executed. The general-purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in conjunction with the embodiments of the present application may be directly embodied and executed by a hardware decoding processor, or may be executed and completed by a combination of hardware and software modules in the decoding processor. The software module may be located in a mature storage medium in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, and registers. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

It can be understood that the embodiments described herein may be implemented in hardware, software, firmware, middleware, microcode, or a combination thereof. For hardware implementation, the processing unit can be implemented in one or more application specific integrated circuits (Application Specific Integrated Circuits, ASIC), digital signal processor (Digital Signal Processing, DSP), digital signal processing device (DSP Device, DSPD), programmable Logic device (Programmable Logic Device, PLD), field-programmable gate array (Field-Programmable Gate Array, FPGA), general-purpose processor, controller, microcontroller, microprocessor, others used to perform the functions described in this application Electronic unit or its combination.

For software implementation, the techniques described herein may be implemented through modules (eg, procedures, functions, etc.) that perform the functions described herein. The software codes can be stored in the memory and executed by the processor. The memory may be implemented in the processor or external to the processor.

It should be noted that in this article, the terms "include", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, It also includes other elements that are not explicitly listed, or include elements inherent to such processes, methods, objects, or devices. Without more restrictions, the element defined by the sentence "include one..." does not exclude that there are other identical elements in the process, method, article or device that includes the element.

The sequence numbers of the above embodiments of the present application are for description only, and do not represent the advantages and disadvantages of the embodiments.

Through the description of the above embodiments, those skilled in the art can clearly understand that the methods in the above embodiments can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware, but in many cases the former is better Implementation. Based on this understanding, the technical solutions of the present application can be embodied in the form of software products in essence or part of contributions to the existing technology, and the computer software products are stored in a storage medium (such as ROM/RAM, magnetic disk, The CD-ROM includes several instructions to enable a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the embodiments of the present application.

The embodiments of the present application have been described above with reference to the drawings, but the present application is not limited to the above-mentioned specific implementations. The above-mentioned specific implementations are only schematic, not limiting, and those of ordinary skill in the art Under the inspiration of this application, there are many forms that can be made without departing from the scope of the application and the scope of the claims, all of which fall within the protection of this application.

Industrial applicability

In the embodiment of the present application, when determining the QP value of the image frame to be encoded at the current time, the variation amount of the performance parameter at the previous time is taken into consideration. In this way, combined with the historical situation of the performance parameter, the obtained QP value of the encoded image frame at the current time is obtained More accurate. Finally, according to the QP value of the image frame to be encoded at the current time, the image frame to be encoded is encoded at the current time; making the encoding process not only uses the preset encoding parameters, but also takes into account the encoder performance parameters. The amount of change, in this way, is conducive to improving the control accuracy of the performance parameter during the encoding process, thereby improving the encoding performance during the encoding process.

Claims

An encoding method, wherein the method is applied to an encoder, the method includes:

Obtain the performance parameter of the encoder at the last moment and the quantization parameter QP value of the image frame to be encoded at the last moment;

According to the target performance parameter of the encoder, determine the change amount of the performance parameter of the encoder at the current time and the previous time;

Determine the QP value of the image frame to be encoded at the current time according to the change amount of the performance parameter, the performance parameter of the encoder at the previous time and the QP value of the image frame to be encoded at the previous time;

According to the QP value of the image frame to be encoded at the current moment, encode the image frame to be encoded at the current moment.
The method according to claim 1, wherein, when the performance parameter is an output rate parameter of an image frame, and the output rate parameter of the image frame is an output bit rate, correspondingly, the target performance parameter is a target Output bit rate;

The determining, according to the target performance parameter of the encoder, the amount of change in the performance parameter of the encoder at the current time and the previous time includes:

According to the target output bit rate of the encoder, the change amount of the output bit rate of the encoder at the current time and the previous time is determined.
The method according to claim 2, wherein the determining the amount of change in the output bit rate of the encoder at the current time and the previous time according to the target output bit rate of the encoder includes:

Get the target line of the virtual buffer at the last moment;

Get the target line of the virtual buffer at the current moment;

According to the target line of the virtual buffer at the previous time and the target line of the virtual buffer at the current time, determine the amount of change in the output bit rate of the encoder between the current time and the previous time;

Wherein, the virtual buffer is used to record a value that the output bit rate of the encoder exceeds the target output bit rate.
The method according to claim 3, wherein the acquiring the target line of the virtual buffer at the current moment comprises:

Determine the encoding structure type of the image frame to be encoded at the current moment;

The target line of the virtual buffer at the current moment is determined according to the coding structure type of the image frame to be encoded at the current moment and the target output bit rate of the encoder.
The method according to claim 4, wherein the determining the target line of the virtual buffer at the current moment according to the encoding structure type of the image frame to be encoded at the current moment and the target output bit rate of the encoder includes:

If the coding structure type of the image frame to be coded at the current moment is an AI structure within a full frame, determine that the target lines of the virtual buffer at the current moment are all zero;

If the coding structure type of the image frame to be coded at the current moment is a low-latency LD structure, based on the target output bit rate, the first preset formula is called to determine the target line of the virtual buffer at the current moment;

If the encoding structure type of the image frame to be encoded at the current moment is a random access RA structure, based on the target output bit rate, a second preset formula is called to determine the target line of the virtual buffer at the current moment.
The method according to claim 4, wherein the determining the amount of change in the output bit rate of the encoder at the current time and the previous time based on the virtual buffer target line at the previous time and the virtual buffer target line at the current time, include:

Get the filling level of the virtual buffer at the current moment;

According to the filling degree of the virtual buffer at the current moment and the target line of the virtual buffer at the last moment, determine the error of the virtual buffer at the last moment;

Determine the output error of the encoder at the previous time according to the output bit rate of the encoder at the previous time and the target output bit rate;

According to the error of the virtual buffer at the previous time, the output error of the encoder at the previous time, the target line of the virtual buffer at the previous time and the target line of the virtual buffer at the current time, determine that the encoder is at the current time and The output bit rate change at the last moment;

Call the third preset formula to update the filling level of the virtual buffer at the current moment.
The method according to claim 6, wherein the error based on the virtual buffer at the previous time, the output error of the encoder at the previous time, the target line of the virtual buffer at the previous time, and the virtual buffer at the current time Target line to determine the output bit rate change of the encoder at the current time and the previous time, including:

Using the target line of the virtual buffer at the current time, minus the target line of the virtual buffer at the previous time, minus the error of the virtual buffer at the previous time, and the value obtained by subtracting the output error of the encoder at the previous time, It is determined as the amount of change in the output bit rate of the encoder at the current time and the previous time.
The method according to claim 1, wherein, when the performance parameter is an output parameter of an image frame, and the output rate parameter of the image frame is an output bit rate, correspondingly, the target performance parameter is the target output bit rate;

Correspondingly, according to the change amount of the performance parameter, the performance parameter of the encoder at the last moment and the QP value of the image frame to be encoded at the last moment, it is determined that the image frame to be encoded is at the current moment QP values, including:

Determine the QP value of the image frame to be encoded at the current time according to the change amount of the output bit rate, the output bit rate of the encoder at the previous time and the QP value of the image frame to be encoded at the previous time .
The method according to claim 8, wherein the change according to the output bit rate, the output bit rate of the encoder at the last moment, and the QP value of the image frame to be encoded at the last moment, Determining the QP value of the image frame to be encoded at the current moment includes:

Determine the ratio of the Lagrangian multiplier at the current time to the Lagrangian multiplier at the previous time according to the amount of change in the output bit rate and the output bit rate of the encoder at the previous time;

According to the ratio of the Lagrange multiplier at the current time to the Lagrange multiplier at the previous time, and the QP value of the image frame to be encoded at the previous time, determine the QP value.
The method according to claim 9, wherein the Lagrange multiplier at the current time and the previous time are determined according to the amount of change in the output bit rate and the output bit rate of the encoder at the previous time In the ratio of the Lagrange multiplier of, calculate the ratio of the Lagrange multiplier at the current time to the Lagrange multiplier at the previous time by the following formula:

Where t represents the time, λ is the Lagrangian multiplier, R is the output bit rate of the encoder, ΔR is the amount of change in the output bit rate, and β is the coefficient.
The method according to claim 9, wherein the ratio of the Lagrangian multiplier at the current time to the Lagrangian multiplier at the previous time, and the QP of the image frame to be coded at the previous time Value, determine the QP value of the image frame to be encoded at the current time, and calculate the QP value of the image frame to be encoded at the current time by the following formula:

Among them, t represents time, Q represents QP value, λ is Lagrange multiplier, a is constant.
An encoder, wherein the encoder includes:

A first acquiring unit, configured to acquire the performance parameter of the encoder at the last moment and the quantization parameter QP value of the image frame to be encoded at the last moment;

A first determining unit, configured to determine the change amount of the performance parameter of the encoder at the current time and the previous time according to the target performance parameter of the encoder;

The second determining unit is configured to determine that the image frame to be encoded is based on the change amount of the performance parameter, the performance parameter of the encoder at the previous time, and the QP value of the image frame to be encoded at the previous time QP value at the current moment;

The encoding unit is configured to encode the image frame to be encoded at the current time according to the QP value of the image frame to be encoded at the current time.
The encoder according to claim 12, wherein, when the performance parameter is an output rate parameter of an image frame, and the output rate parameter of the image frame is an output bit rate, correspondingly, the target performance parameter is Target output bit rate;

The first determining unit is specifically configured to: according to the target output bit rate of the encoder, determine the amount of change in the output bit rate of the encoder at the current time and the previous time.
The encoder according to claim 13, wherein the first determining unit includes:

The first obtaining subunit is used to obtain the target line of the virtual buffer at the previous moment;

The second obtaining subunit is used to obtain the target line of the virtual buffer at the current moment;

The first determining subunit is used to determine the change amount of the output bit rate of the encoder between the current time and the previous time according to the target line of the virtual buffer at the previous time and the target line of the virtual buffer at the current time;

Wherein, the virtual buffer is used to record a value that the output bit rate of the encoder exceeds the target output bit rate.
The encoder according to claim 14, wherein the second acquisition subunit includes:

A second determining subunit, configured to determine the encoding structure type of the image frame to be encoded at the current moment;

The third determining subunit is used to determine the target line of the virtual buffer at the current moment according to the encoding structure type of the image frame to be encoded at the current moment and the target output bit rate of the encoder.
The encoder according to claim 15, wherein the third determining subunit is specifically used for:

If the coding structure type of the image frame to be coded at the current moment is an AI structure within a full frame, determine that the target lines of the virtual buffer at the current moment are all zero;

If the coding structure type of the image frame to be coded at the current moment is a low-latency LD structure, based on the target output bit rate, the first preset formula is called to determine the target line of the virtual buffer at the current moment;

If the encoding structure type of the image frame to be encoded at the current moment is a random access RA structure, based on the target output bit rate, a second preset formula is called to determine the target line of the virtual buffer at the current moment.
The encoder according to claim 14, wherein the first determining subunit includes:

The third obtaining subunit is used to obtain the filling degree of the virtual buffer at the current moment;

The fourth determining subunit is used to determine the error of the virtual buffer at the previous time according to the filling level of the virtual buffer at the current time and the target line of the virtual buffer at the previous time;

A fifth determining subunit, configured to determine the output error of the encoder at the previous time according to the output bit rate of the encoder at the previous time and the target output bit rate;

The sixth determining subunit is used to determine the error of the virtual buffer at the previous time, the output error of the encoder at the previous time, the target line of the virtual buffer at the previous time and the target line of the virtual buffer at the current time The encoder outputs the amount of change in the bit rate at the current time and the previous time;

The update subunit is used to call the third preset formula to update the filling degree of the virtual buffer at the current moment.
The encoder according to claim 17, wherein the sixth determining subunit is specifically used for:

Using the target line of the virtual buffer at the current time, minus the target line of the virtual buffer at the previous time, minus the error of the virtual buffer at the previous time, and the value obtained by subtracting the output error of the encoder at the previous time, It is determined as the amount of change in the output bit rate of the encoder at the current time and the previous time.
The encoder according to claim 12, wherein, when the performance parameter is an output parameter of an image frame, and the output rate parameter of the image frame is an output bit rate, correspondingly, the target performance parameter is the target output bit rate ;

The second determining unit is specifically used for:

Determine the QP value of the image frame to be encoded at the current time according to the change amount of the output bit rate, the output bit rate of the encoder at the previous time and the QP value of the image frame to be encoded at the previous time .
The encoder according to claim 19, wherein the second determining unit includes:

The seventh determining subunit is used to determine the Lagrangian multiplier at the current time and the Lagrangian at the previous time according to the change amount of the output bit rate and the output bit rate of the encoder at the previous time Ratio of multipliers;

The eighth determining subunit is used to determine the ratio of the Lagrange multiplier at the current time to the Lagrange multiplier at the previous time and the QP value of the image frame to be encoded at the previous time QP value of the image frame to be encoded at the current moment.
The encoder according to claim 20, wherein the seventh determining subunit is specifically used for:

Calculate the ratio of the Lagrange multiplier at the current moment to the Lagrange multiplier at the previous moment by the following formula:

Where t represents the time, λ is the Lagrangian multiplier, R is the output bit rate of the encoder, ΔR is the amount of change in the output bit rate, and β is the coefficient.
The encoder according to claim 20, wherein the eighth determining subunit is specifically used for:

The QP value of the image frame to be encoded at the current moment is calculated by the following formula:

Among them, t represents time, Q represents QP value, λ is Lagrange multiplier, a is constant.
An encoder, wherein the encoder includes:

A processor and a storage medium storing instructions executable by the processor, the storage medium relies on the processor to perform operations through a communication bus, and when the instructions are executed by the processor, the foregoing claims 1 to 11. The encoding method according to any one of the items.
A computer storage medium, wherein executable instructions are stored, and when the executable instructions are executed by one or more processors, the processor executes any one of claims 1 to 11 Encoding method.