CN114786011B - JPEG image compression method, system, equipment and storage medium - Google Patents

Abstract

The invention provides a method, a system, equipment and a storage medium for JPEG image compression, wherein the method comprises the following steps: in response to a current image frame being in a starting frame, encoding the current image using a standard quantization coefficient table; in response to the current image frame not being in the starting frame, calculating a weighted average image data length adjacent to a first predetermined number of frames and calculating an encoding factor according to the weighted average image data length; predicting a bandwidth factor of a next frame according to the change condition of the bandwidth of the adjacent second predetermined number of frames; and determining a quantization parameter of the current image frame through a quantization table according to the relation between the coding factor and the bandwidth factor, and updating the quantization parameter to a quantization table corresponding to the next frame. The invention aims at optimizing the coding process frame by frame when the system bandwidth changes and the image characteristics change, so that the coded image is always in the highest allowable image quality.

Description

A method, system, device and storage medium for JPEG image compression

technical field

The present invention relates to the field of chip design, more specifically, to a method, system, device and storage medium for JPEG image compression.

Background technique

JPEG video image compression is a commonly used international standard for video image compression, which is used to compress continuous tone still images (including grayscale images and color images). JPEG is the abbreviation of Joint Photographic Experts Group (Joint Photographic Experts Group), the purpose of this standard is to support various applications based on continuous tone still image compression. The image to be compressed can be in any color space, and the user can adjust the compression ratio so that the compression effect can reach or approach the top compression performance in the industry, and has good resolution and restoration quality. Therefore, when a large number of images need to be stored and transmitted, JPEG image compression is very necessary.

As shown in Figure 1, it is a classic JPEG image compression flow chart, mainly including color mode conversion, DCT (discrete cosine transform), quantization, Z-arrangement, run-length encoding, Huffman encoding, and data packaging. Color mode conversion is to convert RGB color mode to YCbCr color mode. DCT is to process the entire image according to 8X8 small blocks, and the three color channels of each small block are respectively DCTed. In this process, the image data input according to the row and column needs to be divided into several 8X8 small blocks, and then sequentially DCT. The DCT process consumes the most resources, has the greatest delay, and is the most difficult to implement, which largely determines the performance of the entire algorithm.

In the actual technical application process, such a situation is often encountered, the video image is sent to the subsequent stage or other equipment after JPEG compression, but the bandwidth of the actual physical channel to be sent is fixed, and other channels need to be sent in this bandwidth Data (the bandwidth occupied by data is also changing at any time), and the priority of these data may be higher than that of video images, which will cause the actual bandwidth allocated to video images to change, so images are prone to freeze or blur . In the existing technology, the following two methods are generally used: 1. Compression processing is performed according to the minimum bandwidth that may be allocated to video images; 2. When the bandwidth changes, the compression rate of each frame is fixedly increased to ensure a stable frame rate. Shortcomings of prior art: 1, this method is comparatively simple, and realization difficulty is little, but can reduce image quality greatly, and average bandwidth utilization rate is also lower simultaneously; 2, although this method can guarantee frame rate stability, promptly video image does not Stuttering, but severely degrades image quality.

Contents of the invention

In view of this, the purpose of the embodiments of the present invention is to propose a method, system, computer equipment and computer-readable storage medium for JPEG image compression. The present invention analyzes the encoding characteristics of the image frame by frame and calculates the quantization coefficient when the external bandwidth changes. , and then optimize the quantization coefficient table frame by frame, and improve the image quality as much as possible while ensuring that the image is not stuck.

Based on the above purpose, an aspect of the embodiments of the present invention provides a method for compressing a JPEG image, including the following steps: in response to the current image frame being at the start frame, encoding the current image using a standard quantization coefficient table; in response to The current image frame is not in the starting frame, calculate the weighted average image data length adjacent to the first predetermined number of frames, and calculate the encoding factor according to the weighted average image data length; predict the next according to the bandwidth change of the adjacent second predetermined number of frames a bandwidth factor of a frame; and determining the quantization parameter of the current image frame through a quantization table according to the relationship between the coding factor and the bandwidth factor, and updating the quantization parameter into the quantization table corresponding to the next frame.

In some implementations, the calculating the weighted average image data length of frames adjacent to the first predetermined number includes: performing weighted average calculation on the encoded image length of each frame in the frames adjacent to the first predetermined number.

In some embodiments, the calculating the encoding factor according to the weighted average image data length includes: determining the standard encoded frame length according to the image resolution and pixel depth, and determining the frame length after encoding according to the weighted average image data length and the standard encoded frame length. The ratio of the frame lengths determines the coding factor.

In some embodiments, the predicting the bandwidth factor of the next frame according to the change of the bandwidth of the frames adjacent to the second predetermined number includes: respectively calculating the average bandwidth of the frames adjacent to the second predetermined number, and calculating according to the average bandwidth a gradient value; and calculating a predicted value of the bandwidth of the next frame according to the gradient value and the average bandwidth of the latest frame, and calculating a bandwidth factor of the next frame according to the predicted value.

In some implementations, the calculating the bandwidth factor of the next frame according to the predicted value includes: determining the standard bandwidth according to the image resolution, pixel depth and frame rate, and determining according to the ratio of the predicted value to the standard bandwidth The bandwidth factor for the next frame.

In some implementations, said respectively calculating the average bandwidth of the adjacent second predetermined number of frames includes: calculating the time mark point of each frame according to the original frame rate of the image and the frame start position, and recording the corresponding time mark point according to the time mark point bandwidth, and take the average of all bandwidths as the average bandwidth of the current frame.

In some embodiments, the determining the quantization parameter of the current image frame through the quantization table according to the relationship between the coding factor and the bandwidth factor includes: responding to the coding factor being less than or equal to the bandwidth factor, according to the The quantization table determines the luminance and chroma of the current image frame; and in response to the encoding factor being greater than the bandwidth factor, determines the luminance and chrominance of the current image frame according to the ratio between the encoding factor and the bandwidth factor Spend.

Another aspect of the embodiments of the present invention provides a JPEG image compression system, including: an encoding module configured to encode the current image using a standard quantization coefficient table in response to the fact that the current image frame is in the initial frame; The first calculation module is configured to calculate the weighted average image data length adjacent to the first predetermined number of frames in response to the current image frame not being in the initial frame, and calculate the encoding factor according to the weighted average image data length; the second calculation module , configured to predict the bandwidth factor of the next frame according to the variation of the bandwidth adjacent to the second predetermined number of frames; and an execution module configured to determine the current The quantization parameter of the image frame is updated to the quantization table corresponding to the next frame.

In some implementations, the first calculation module is configured to: perform weighted average calculation on the encoded image lengths of each frame in the adjacent first predetermined number of frames.

In some implementations, the first calculation module is configured to: determine the standard coded frame length according to image resolution and pixel depth, and determine according to the ratio of the weighted average image data length to the standard coded frame length coding factor.

In some implementations, the second calculation module is configured to: respectively calculate the average bandwidth of the frames adjacent to the second predetermined number of frames, and calculate a gradient value according to the average bandwidth; and calculate the gradient value according to the gradient value and the latest frame The average bandwidth of the next frame is calculated to predict the bandwidth of the next frame, and the bandwidth factor of the next frame is calculated according to the predicted value.

In some implementations, the second calculation module is configured to: determine the standard bandwidth according to the image resolution, pixel depth and frame rate, and determine the bandwidth factor of the next frame according to the ratio of the predicted value to the standard bandwidth .

In some implementations, the second calculation module is configured to: calculate the time mark point of each frame according to the original frame rate of the image and the frame start position, record the corresponding bandwidth according to the time mark point, and store all bandwidth The average value of is used as the average bandwidth of the current frame.

In another aspect of the embodiments of the present invention, there is also provided a computer device, including: at least one processor; and a memory, the memory stores computer instructions executable on the processor, and the instructions are executed by the The steps of the above method are realized when the processor executes.

In yet another aspect of the embodiments of the present invention, a computer-readable storage medium is also provided, and the computer-readable storage medium stores a computer program for implementing the above method steps when executed by a processor.

The present invention has the following beneficial technical effects: when the external bandwidth changes, the encoding characteristics of the image are analyzed frame by frame, the quantization coefficient is calculated, and the quantization coefficient table is optimized frame by frame, so as to improve the image quality as much as possible while ensuring that the image is not stuck.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention, and those skilled in the art can obtain other embodiments according to these drawings without any creative effort.

Fig. 1 is a flow chart of JPEG image compression in the prior art;

Fig. 2 is the schematic diagram of the embodiment of the method for JPEG image compression provided by the present invention;

Fig. 3 is the flowchart of the embodiment of the method for JPEG image compression provided by the present invention;

Fig. 4 is a brightness standard quantization coefficient table;

Fig. 5 is the schematic diagram of the embodiment of the system of JPEG image compression provided by the present invention;

Fig. 6 is the hardware structural representation of the embodiment of the computer equipment of JPEG image compression that the present invention provides;

FIG. 7 is a schematic diagram of an embodiment of a computer storage medium for JPEG image compression provided by the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are to distinguish two entities with the same name but different parameters or parameters that are not the same, see "first" and "second" It is only for the convenience of expression, and should not be construed as a limitation on the embodiments of the present invention, which will not be described one by one in the subsequent embodiments.

According to the first aspect of the embodiments of the present invention, an embodiment of a method for compressing a JPEG image is proposed. FIG. 2 is a schematic diagram of an embodiment of a method for compressing a JPEG image provided by the present invention. As shown in Figure 2, the embodiment of the present invention includes the following steps:

S1. In response to the fact that the current image frame is in the initial frame, encode the current image using a standard quantization coefficient table;

S2. In response to the fact that the current image frame is not in the initial frame, calculate a weighted average image data length adjacent to the first predetermined number of frames, and calculate a coding factor according to the weighted average image data length;

S3. Predict the bandwidth factor of the next frame according to the change of the bandwidth of the adjacent second predetermined number of frames; and

S4. Determine the quantization parameter of the current image frame through the quantization table according to the relationship between the encoding factor and the bandwidth factor, and update the quantization parameter into the quantization table corresponding to the next frame.

The essence of the quantization process is the process of optimizing the 8×8 coefficient matrix generated after the discrete cosine transform. Since human eyes are not sensitive to high-frequency components, the purpose of reducing the amount of data can be achieved by retaining a small amount or removing high-frequency parts of the 8×8 coefficient matrix. The actual purpose of the quantization process is to reduce the magnitude values of the non-zero frequency component coefficients and to increase the number of zero-valued frequency component coefficients. The actual implementation process of the quantization process is to divide each coefficient value of the 8×8 coefficient matrix generated by the discrete cosine transform by the constant corresponding to the coefficient value (these coefficients are combined together to form the quantization parameter table), and round the obtained quotient value After rounding, the quantized coefficient value is obtained. The quantization process is a lossy process, and the high-frequency components of the quantized coefficient matrix are basically close to 0. The quantization parameter table can be produced through the standard quantization coefficient table and quantization step size, and the selection of the quantization step size can change the compression rate and precision of the entire encoder. The larger the quantization step size, the higher the compression rate of the obtained code stream, and the greater loss of image detail information; otherwise, the obtained code stream compression ratio will be relatively low, but more image detail information can be retained. Therefore, it is possible to control the output stream state of the encoder by adjusting the value of the quantization step. Compared with color difference, human eyes are more sensitive to brightness, so two quantization tables are often used in the quantization process: brightness quantization table and color difference quantization table.

The principle of Huffman coding is to first count the probability of occurrence of each pixel value in the image, and then correspond each pixel value with each codeword one by one according to the probability of each pixel value, assign a shorter codeword to the pixel value with a high probability of occurrence, and A longer codeword is assigned to pixel values with low occurrence probability, thereby further compressing the data.

FIG. 3 is a flowchart of an embodiment of a method for compressing a JPEG image provided by the present invention, and the embodiment of the present invention will be described according to FIG. 3 .

In response to the fact that the current image frame is the initial frame, the current image is encoded using a standard quantization coefficient table. In the embodiment of the present invention, the starting frame refers to the first 6 frames of images when the encoding of the video image is just started. When encoding these frames, it is not necessary to consider the impact of external bandwidth, and the standard quantization coefficient table is used for encoding. Figure 4 is a table of brightness standard quantization coefficients.

In response to the fact that the current image frame is not in the initial frame, calculate the weighted average image data length of adjacent first predetermined number of frames, and calculate the encoding factor according to the weighted average image data length.

In some implementations, the calculating the weighted average image data length of frames adjacent to the first predetermined number includes: performing weighted average calculation on the encoded image length of each frame in the frames adjacent to the first predetermined number.

In some embodiments, the calculating the encoding factor according to the weighted average image data length includes: determining the standard encoded frame length according to the image resolution and pixel depth, and determining the frame length after encoding according to the weighted average image data length and the standard encoded frame length. The ratio of the frame lengths determines the coding factor.

When the beginning of the image frame is detected, the coded frame count frame_cnt is set to 0, and when valid data is output after huffman encoding, the counter starts to accumulate. When the end of the frame is detected, frame_cnt is registered as frame_cnt_reg. In the first 1-5 frames, the encoded image length is registered as frame_cnt_reg_1, frame_cnt_reg_2, frame_cnt_reg_3, frame_cnt_reg_4 and frame_cnt_reg_5.

When the encoded image length frame_cnt_reg_6 of the sixth frame is obtained, the time-weighted average image data length frame_ave is calculated. frame_ave=(6*frame_cnt_reg_6+4*frame_cnt_reg_5+2*frame_cnt_reg_4+2*frame_cnt_reg_3+frame_cnt_reg_2+frame_cnt_reg_1)/16. When obtaining the encoded image length of the 7th frame, assign its value to frame_cnt_reg_6, assign the previous frame_cnt_reg_5 value to frame_cnt_reg_4, and so on, to obtain the image length of the nearest 6 frames, and then calculate frame_ave according to the same formula.

Calculate the encoding factor Ta, Ta=frame_ave/frame_std. Among them, frame_std is the frame length after standard encoding, which is related to image resolution and pixel depth. When the video image specification is determined, this value is a fixed value.

The bandwidth factor of the next frame is predicted according to the variation of the bandwidth of the adjacent second predetermined number of frames.

In some embodiments, the predicting the bandwidth factor of the next frame according to the change of the bandwidth of the frames adjacent to the second predetermined number includes: respectively calculating the average bandwidth of the frames adjacent to the second predetermined number, and calculating according to the average bandwidth a gradient value; and calculating a predicted value of the bandwidth of the next frame according to the gradient value and the average bandwidth of the latest frame, and calculating a bandwidth factor of the next frame according to the predicted value.

In some implementations, the calculating the bandwidth factor of the next frame according to the predicted value includes: determining the standard bandwidth according to the image resolution, pixel depth and frame rate, and determining according to the ratio of the predicted value to the standard bandwidth The bandwidth factor for the next frame.

In some implementations, said respectively calculating the average bandwidth of the adjacent second predetermined number of frames includes: calculating the time mark point of each frame according to the original frame rate of the image and the frame start position, and recording the corresponding time mark point according to the time mark point bandwidth, and take the average of all bandwidths as the average bandwidth of the current frame.

When calculating the bandwidth factor, calculate and predict the available bandwidth of the next frame based on the bandwidth gradient of the adjacent 3 frames, and finally calculate the bandwidth factor of the next frame. Therefore, in essence, the bandwidth factor is a predictive value, which is based on the changes in the available bandwidth of the previous 3 frames to predict the next frame. In the design and operation of the actual chip system, the change of the bandwidth has time correlation, so there is a solid theoretical support for using this method. Specific steps are as follows:

Computes the average bandwidth Band_ave granted per image frame. The bandwidth granted to the image refers to the bandwidth allocated by the jpeg compressed data stream in the entire bus system. In the bus architecture of the SOC system, under the influence of many factors such as priority settings and actual data bandwidth, the allocated bandwidth of different master-slave devices changes in real time. Some bus systems can provide the bandwidth Band_i of each channel of data in real time. , and others need to be calculated by themselves according to relevant agreements.

First, calculate the time mark points T1, T2, and T3 of 3 groups of each frame, and calculate according to the original frame rate of the image and the frame start position. The time of the frame start position is T1, the time of the end position of the frame is T3, and the time of the middle position of the frame It is T2=T1+1/(frame*2), and frame is the frame rate. Second, record the corresponding bandwidth Band_i at the time mark point, and register it, and name it Band_T1, Band_T2, and Band_T3. Finally, calculate Band_ave=(Band_T1+ Band_T2+Band_T3)/3. The same method calculates and records the average bandwidth of the last 3 consecutive frames, and records them as Band_ave_1, Band_ave_2 and Band_ave_3. Calculate the gradient value grad=(Band_ave_3-Band_ave_2)+(Band_ave_2- Band_ave_1). Calculate the predicted value of the bandwidth of the next frame Band_p=Band_ave_1+grad. Calculate the bandwidth factor Tb=Band_p/Band_std. Among them, Band_std is the standard bandwidth, that is, the maximum bandwidth occupied under the current image specification, which is related to image resolution, pixel depth, and frame rate. When the video image specification is determined, this value is a fixed value.

Determine the quantization parameter of the current image frame through a quantization table according to the relationship between the encoding factor and the bandwidth factor, and update the quantization parameter into a corresponding quantization table of the next frame.

In some embodiments, the determining the quantization parameter of the current image frame through the quantization table according to the relationship between the coding factor and the bandwidth factor includes: responding to the coding factor being less than or equal to the bandwidth factor, according to the The quantization table determines the luminance and chroma of the current image frame; and in response to the encoding factor being greater than the bandwidth factor, determines the luminance and chrominance of the current image frame according to the ratio between the encoding factor and the bandwidth factor Spend.

The JPEG protocol stipulates a standard luminance and chroma quantization parameter table [Q_s] (essentially an 8*8 matrix), and the calculation process of the quantization parameter table here, the calculation method of luminance and chrominance is the same, and will not be introduced separately . When T1/(T2)<1 or =1, [Q]=[Q_s]; when T1/(T2)>1, [Q]=[Q_s]*T1/(T2), where, [Q] Indicates luminance or chroma.

The calculated quantization parameter table is updated to the quantization table of the next frame image encoding, and the corresponding division operation is performed to complete the quantization calculation. It should be noted that the bandwidth factor, encoding factor, and quantization parameter table are all calculated at the end of each frame, and this quantization table is used as the quantization parameter table for the next frame during quantization processing.

The embodiment of the present invention proposes a high-performance adaptive JPEG compression design and implementation method, which can optimize the encoding process frame by frame when system bandwidth changes and image characteristics change, so that the encoded image is always at the highest allowable image quality.

It should be pointed out that the various steps in the various embodiments of the above-mentioned JPEG image compression method can be intersected, replaced, added, and deleted. Therefore, these reasonable permutations and combinations should also belong to the JPEG image compression method. protection scope of the present invention and should not be limited to the embodiments.

Based on the above purpose, a second aspect of the embodiments of the present invention proposes a JPEG image compression system. As shown in FIG. 5 , the system 200 includes the following modules: an encoding module configured to encode the current image using a standard quantization coefficient table in response to the current image frame being in the initial frame; a first calculation module configured to respond to When the current image frame is not in the initial frame, calculate the weighted average image data length adjacent to the first predetermined number of frames, and calculate the encoding factor according to the weighted average image data length; the second calculation module is configured for adjacent second predetermined The change of the bandwidth of the number of frames predicts the bandwidth factor of the next frame; and the execution module is configured to determine the quantization parameter of the current image frame through the quantization table according to the relationship between the coding factor and the bandwidth factor, and the obtained The above quantization parameters are updated to the quantization table corresponding to the next frame.

In some implementations, the first calculation module is configured to: perform weighted average calculation on the encoded image lengths of each frame in the adjacent first predetermined number of frames.

In some implementations, the first calculation module is configured to: determine the standard coded frame length according to image resolution and pixel depth, and determine according to the ratio of the weighted average image data length to the standard coded frame length coding factor.

In some implementations, the second calculation module is configured to: respectively calculate the average bandwidth of the frames adjacent to the second predetermined number of frames, and calculate a gradient value according to the average bandwidth; and calculate the gradient value according to the gradient value and the latest frame The average bandwidth of the next frame is calculated to predict the bandwidth of the next frame, and the bandwidth factor of the next frame is calculated according to the predicted value.

In some implementations, the second calculation module is configured to: determine the standard bandwidth according to the image resolution, pixel depth and frame rate, and determine the bandwidth factor of the next frame according to the ratio of the predicted value to the standard bandwidth .

In some implementations, the second calculation module is configured to: calculate the time mark point of each frame according to the original frame rate of the image and the frame start position, record the corresponding bandwidth according to the time mark point, and store all bandwidth The average value of is used as the average bandwidth of the current frame.

In some embodiments, the execution module is configured to: determine the brightness and chrominance of the current image frame according to the quantization table in response to the encoding factor being less than or equal to the bandwidth factor; and in response to the The encoding factor is greater than the bandwidth factor, and the brightness and chrominance of the current image frame are determined according to a ratio between the encoding factor and the bandwidth factor.

Based on the above purpose, a third aspect of the embodiments of the present invention proposes a computer device, including: at least one processor; and a memory, the memory stores computer instructions that can run on the processor, and the instructions are executed by the processor to The following steps are implemented: S1, in response to the current image frame being in the initial frame, encoding the current image using a standard quantization coefficient table; S2, in response to the current image frame not being in the initial frame, calculating the adjacent first predetermined number of frames Weighted average image data length, and calculate the encoding factor according to the weighted average image data length; S3, predict the bandwidth factor of the next frame according to the change of the bandwidth of the adjacent second predetermined number of frames; and S4, according to the encoding factor and The relationship between the bandwidth factors determines the quantization parameter of the current image frame through the quantization table, and updates the quantization parameter to the corresponding quantization table of the next frame.

In some implementations, the calculating the weighted average image data length of frames adjacent to the first predetermined number includes: performing weighted average calculation on the encoded image length of each frame in the frames adjacent to the first predetermined number.

In some embodiments, the calculating the encoding factor according to the weighted average image data length includes: determining the standard encoded frame length according to the image resolution and pixel depth, and determining the frame length after encoding according to the weighted average image data length and the standard encoded frame length. The ratio of the frame lengths determines the coding factor.

In some embodiments, the predicting the bandwidth factor of the next frame according to the change of the bandwidth of the frames adjacent to the second predetermined number includes: respectively calculating the average bandwidth of the frames adjacent to the second predetermined number, and calculating according to the average bandwidth a gradient value; and calculating a predicted value of the bandwidth of the next frame according to the gradient value and the average bandwidth of the latest frame, and calculating a bandwidth factor of the next frame according to the predicted value.

In some implementations, the calculating the bandwidth factor of the next frame according to the predicted value includes: determining the standard bandwidth according to the image resolution, pixel depth and frame rate, and determining according to the ratio of the predicted value to the standard bandwidth The bandwidth factor for the next frame.

In some implementations, said respectively calculating the average bandwidth of the adjacent second predetermined number of frames includes: calculating the time mark point of each frame according to the original frame rate of the image and the frame start position, and recording the corresponding time mark point according to the time mark point bandwidth, and take the average of all bandwidths as the average bandwidth of the current frame.

In some embodiments, the determining the quantization parameter of the current image frame through the quantization table according to the relationship between the coding factor and the bandwidth factor includes: responding to the coding factor being less than or equal to the bandwidth factor, according to the The quantization table determines the luminance and chroma of the current image frame; and in response to the encoding factor being greater than the bandwidth factor, determines the luminance and chrominance of the current image frame according to the ratio between the encoding factor and the bandwidth factor Spend.

As shown in FIG. 6 , it is a schematic diagram of the hardware structure of an embodiment of the above-mentioned JPEG image compression computer device provided by the present invention.

Taking the device shown in FIG. 6 as an example, the device includes a processor 301 and a memory 302 .

The processor 301 and the memory 302 may be connected through a bus or in other ways, and connection through a bus is taken as an example in FIG. 6 .

The memory 302, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs and modules, such as the method corresponding to the JPEG image compression method in the embodiment of the present application Program instructions/modules. The processor 301 executes various functional applications and data processing of the server by running the non-volatile software programs, instructions and modules stored in the memory 302, that is, the method for realizing JPEG image compression.

The memory 302 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application program required by at least one function; the data storage area may store data created by using a JPEG image compression method, and the like. In addition, the memory 302 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid-state storage devices. In some embodiments, the memory 302 may optionally include memory that is remotely located relative to the processor 301, and these remote memories may be connected to the local module through a network. Examples of the aforementioned networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

Computer instructions 303 corresponding to one or more JPEG image compression methods are stored in the memory 302, and when executed by the processor 301, the JPEG image compression method in any of the above method embodiments is executed.

Any one embodiment of the computer device that executes the above-mentioned JPEG image compression method can achieve the same or similar effects as any of the above-mentioned method embodiments corresponding thereto.

The present invention also provides a computer-readable storage medium, which stores a computer program for executing the JPEG image compression method when executed by a processor.

As shown in FIG. 7 , it is a schematic diagram of an embodiment of the above-mentioned JPEG image compression computer storage medium provided by the present invention. Taking the computer storage medium shown in FIG. 7 as an example, the computer readable storage medium 401 stores a computer program 402 for executing the above method when executed by a processor.

Finally, it should be noted that those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented through computer programs to instruct related hardware to complete, and the program of the JPEG image compression method can be stored in a computer-readable When the program is executed, the program may include the processes of the embodiments of the above-mentioned methods. Wherein, the storage medium of the program may be a magnetic disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM). The foregoing computer program embodiments can achieve the same or similar effects as any of the foregoing method embodiments corresponding thereto.

The above are the exemplary embodiments disclosed in the present invention, but it should be noted that various changes and modifications can be made without departing from the scope of the disclosed embodiments of the present invention defined in the claims. The functions, steps and/or actions of the method claims in accordance with the disclosed embodiments described herein need not be performed in any particular order. In addition, although the elements disclosed in the embodiments of the present invention may be described or required in an individual form, they may also be understood as a plurality unless explicitly limited to a singular number.

It should be understood that as used herein, the singular form "a" and "an" are intended to include the plural forms as well, unless the context clearly supports an exception. It should also be understood that "and/or" as used herein is meant to include any and all possible combinations of one or more of the associated listed items.

The serial numbers of the embodiments disclosed in the above-mentioned embodiments of the present invention are only for description, and do not represent the advantages and disadvantages of the embodiments.

Those of ordinary skill in the art can understand that all or part of the steps for implementing the above-mentioned embodiments can be completed by hardware, or can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. The above-mentioned The storage medium may be a read-only memory, a magnetic disk or an optical disk, and the like.

Those of ordinary skill in the art should understand that: the discussion of any of the above embodiments is exemplary only, and is not intended to imply that the disclosed scope (including claims) of the embodiments of the present invention is limited to these examples; under the idea of the embodiments of the present invention , the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the above embodiments of the present invention, which are not provided in details for the sake of brevity. Therefore, within the spirit and principle of the embodiments of the present invention, any omissions, modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the embodiments of the present invention.

Claims (14)

1. a method for JPEG image compression, is characterized in that, comprises the steps: In response to the fact that the current image frame is the initial frame, encoding the current image using a standard quantization coefficient table; In response to the fact that the current image frame is not in the initial frame, calculating a weighted average image data length adjacent to the first predetermined number of frames, and calculating a coding factor according to the weighted average image data length; Predicting the bandwidth factor of the next frame based on the variation of the bandwidth adjacent to the second predetermined number of frames; and Determine the quantization parameter of the current image frame through the quantization table according to the relationship between the coding factor and the bandwidth factor, and update the quantization parameter into the quantization table corresponding to the next frame; The determining the quantization parameter of the current image frame through the quantization table according to the relationship between the encoding factor and the bandwidth factor includes: determining luma and chrominance of the current image frame according to the quantization table in response to the encoding factor being less than or equal to the bandwidth factor; and In response to the encoding factor being greater than the bandwidth factor, determining the brightness and chrominance of the current image frame according to a ratio between the encoding factor and the bandwidth factor. 2. The method according to claim 1, wherein said calculating the weighted average image data length adjacent to the first predetermined number of frames comprises: Perform weighted average calculation on the encoded image lengths of each frame in the adjacent first predetermined number of frames. 3. method according to claim 1, is characterized in that, described calculating coding factor according to described weighted average image data length comprises: The standard coded frame length is determined according to the image resolution and pixel depth, and the coding factor is determined according to the ratio of the weighted average image data length to the standard coded frame length. 4. The method according to claim 1, wherein said predicting the bandwidth factor of the next frame according to the variation of the bandwidth of the adjacent second predetermined number of frames comprises: respectively calculating the average bandwidth of the adjacent second predetermined number of frames, and calculating a gradient value according to the average bandwidth; and Calculate the predicted value of the bandwidth of the next frame according to the gradient value and the average bandwidth of the latest frame, and calculate the bandwidth factor of the next frame according to the predicted value. 5. The method according to claim 4, wherein said calculating the bandwidth factor of the next frame according to the predicted value comprises: Determine the standard bandwidth according to the image resolution, pixel depth and frame rate, and determine the bandwidth factor of the next frame according to the ratio of the predicted value to the standard bandwidth. 6. The method according to claim 4, wherein said calculating the average bandwidth of said adjacent second predetermined number of frames respectively comprises: Calculate the time mark point of each frame according to the original frame rate of the image and the frame start position, record the corresponding bandwidth according to the time mark point, and use the average value of all bandwidths as the average bandwidth of the current frame. 7. A system for JPEG image compression, comprising: An encoding module configured to encode the current image using a standard quantization coefficient table in response to the fact that the current image frame is in the initial frame; The first calculation module is configured to calculate the weighted average image data length of adjacent first predetermined number of frames in response to the current image frame not being in the initial frame, and calculate the encoding factor according to the weighted average image data length; The second calculation module is configured to predict the bandwidth factor of the next frame according to the change of the bandwidth adjacent to the second predetermined number of frames; and An execution module configured to determine the quantization parameter of the current image frame through a quantization table according to the relationship between the encoding factor and the bandwidth factor, and update the quantization parameter to the quantization table corresponding to the next frame; The determining the quantization parameter of the current image frame through the quantization table according to the relationship between the encoding factor and the bandwidth factor includes: determining luma and chrominance of the current image frame according to the quantization table in response to the encoding factor being less than or equal to the bandwidth factor; and In response to the encoding factor being greater than the bandwidth factor, determining the brightness and chrominance of the current image frame according to a ratio between the encoding factor and the bandwidth factor. 8. The system according to claim 7, wherein the first calculation module is configured to: Perform weighted average calculation on the encoded image lengths of each frame in the adjacent first predetermined number of frames. 9. The system according to claim 7, wherein the first computing module is configured to: The standard coded frame length is determined according to the image resolution and pixel depth, and the coding factor is determined according to the ratio of the weighted average image data length to the standard coded frame length. 10. The system of claim 7, wherein the second computing module is configured to: respectively calculating the average bandwidth of the adjacent second predetermined number of frames, and calculating a gradient value according to the average bandwidth; and Calculate the predicted value of the bandwidth of the next frame according to the gradient value and the average bandwidth of the latest frame, and calculate the bandwidth factor of the next frame according to the predicted value. 11. The system of claim 10, wherein the second calculation module is configured to: Determine the standard bandwidth according to the image resolution, pixel depth and frame rate, and determine the bandwidth factor of the next frame according to the ratio of the predicted value to the standard bandwidth. 12. The system of claim 10, wherein the second calculation module is configured to: Calculate the time mark point of each frame according to the original frame rate of the image and the frame start position, record the corresponding bandwidth according to the time mark point, and use the average value of all bandwidths as the average bandwidth of the current frame. 13. A computer device, comprising: at least one processor; and A memory, the memory stores computer instructions operable on the processor, and when the instructions are executed by the processor, the steps of the method according to any one of claims 1-6 are implemented. 14. A computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, wherein, when the computer program is executed by a processor, the steps of the method according to any one of claims 1-6 are implemented.

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