CN114666584A - A coding method, device, equipment and medium based on high frequency zero setting - Google Patents

Abstract

The invention discloses an encoding method, device, equipment and medium based on high-frequency zero-setting. The present invention performs filtering processing on the co-located block at the corresponding position of the original image according to the position information, obtains the texture complexity parameter, and obtains the resolution of the current encoded image. Determine the scaling factor according to the resolution and the resolution threshold, calculate according to the scaling factor and texture complexity parameters, obtain the weight coefficient of the current coding block, determine the high frequency coefficient threshold according to the weight coefficient and size information, and express the position greater than the high The brightness channel of the frequency domain coefficient of the frequency coefficient threshold is zeroed, which can reduce the brightness information of the complex texture area, thereby helping to reduce the code rate and improve the coding efficiency without changing the visual effect of the human eye. The present invention can be widely used in coding. technical field.

Description

A coding method, device, equipment and medium based on high frequency zero setting

technical field

The present invention relates to the field of coding, in particular to a coding method, device, equipment and medium based on high-frequency zero-setting.

Background technique

The video encoder in the existing AVS3 video coding standard transforms the pixel domain residual information obtained in the upper-level coding module into the frequency domain through the transform module to obtain the frequency domain coefficients, and then the frequency domain coefficient products are simplified and expressed through the quantization module. To the lower encoding module for subsequent encoding. Nowadays, in order to use fewer bits to show the same video visual effect, in the AVS3 video coding standard, the quantization coefficient of the frequency coefficient is changed according to the texture information of the picture in the pixel domain, which will lead to quantization in the simple texture area (flat area). The range becomes smaller, resulting in a smaller step size for the quantized value, which requires more bits to encode the region, or the quantization range becomes larger in a complex texture area, resulting in a larger step size for the quantized value , only a small number of bits are used to encode this area, but the visual effect has no obvious change, and the balance between the visual presentation effect and the coding efficiency is still unable to be accurately controlled.

SUMMARY OF THE INVENTION

In view of this, in order to solve the above-mentioned technical problems, the purpose of the present invention is to provide an encoding method, apparatus, device and medium based on high-frequency zero-setting.

The technical solution adopted in the embodiment of the present invention is:

A coding method based on high frequency zeroing, comprising:

Obtain the position information and size information of the current coding block in the current coded image and the position representation of the frequency domain coefficients of the transform module;

Perform filtering processing on the co-located block at the corresponding position of the original image according to the position information to obtain a texture complexity parameter;

acquiring the resolution of the currently encoded image, and determining a scaling factor according to the resolution and a resolution threshold;

Calculate according to the scaling coefficient and the texture complexity parameter to obtain the weight coefficient of the current coding block;

A high frequency coefficient threshold is determined according to the weight coefficient and the size information, and the luminance channel whose position represents a frequency domain coefficient larger than the high frequency coefficient threshold is zeroed.

Further, performing filtering processing on the co-located block at the corresponding position of the original image according to the position information to obtain a texture complexity parameter, including:

High-pass filtering is performed on the co-located block at the corresponding position of the original image by the Laplacian operator to obtain a texture complexity parameter; the texture complexity parameter is a pixel matrix.

Further, determining the scaling factor according to the resolution and the resolution threshold includes:

The ratio of the resolution to the resolution threshold is calculated to obtain a scaling factor.

Further, the calculation according to the scaling coefficient and the texture complexity parameter to obtain the weight coefficient of the current coding block includes:

According to the texture complexity parameter and the size information, a normalized high-pass coefficient is calculated; the normalized high-pass coefficient represents the activity level of the current coding block;

According to the normalized high-pass coefficient and the scaling coefficient, the weight coefficient of the current coding block is obtained by calculating a preset function.

Further, the size information includes height and width, and the high-frequency coefficient threshold is determined according to the weight coefficient and the size information, including:

Calculate the first product of the height and the weight coefficient to obtain a high-frequency height threshold;

Calculate the second product of the width and the weight coefficient to obtain a high-frequency width threshold;

The high frequency coefficient threshold includes the high frequency height threshold and the high frequency height threshold.

Further, the position representation includes a height representation and a width representation, and performing zero-setting processing on the luminance channel of the frequency domain coefficient whose position representation is greater than the high-frequency coefficient threshold includes:

When the height representation is larger than the high-frequency height threshold or the width representation is larger than the high-frequency width threshold, zeroing is performed on the luminance channel of the frequency domain coefficient corresponding to the position representation.

Further, the method also includes:

The cost function of the current coding block is modified according to the weight coefficient.

An embodiment of the present invention also provides an encoding device based on high-frequency zero-setting, including:

an acquisition module for acquiring the position information, size information and the position representation of the frequency domain coefficients of the transform module in the currently encoded image;

a filtering module, configured to perform filtering processing on the co-located block at the corresponding position of the original image according to the position information to obtain a texture complexity parameter;

a determining module, configured to acquire the resolution of the currently encoded image, and determine a scaling factor according to the resolution and a resolution threshold;

a weighting module, configured to calculate according to the scaling factor and the texture complexity parameter to obtain the weighting factor of the current coding block;

A zero-setting module, configured to determine a high-frequency coefficient threshold according to the weight coefficient and the size information, and perform zero-setting processing on the luminance channel whose position represents a frequency domain coefficient greater than the high-frequency coefficient threshold.

An embodiment of the present invention further provides an electronic device, the electronic device includes a processor and a memory, and the memory stores at least one instruction, at least a piece of program, a code set or an instruction set, the at least one instruction, the at least one A program, the code set or the instruction set is loaded and executed by the processor to implement the method.

An embodiment of the present invention further provides a computer-readable storage medium, where at least one instruction, at least one piece of program, code set or instruction set is stored in the storage medium, the at least one instruction, the at least one piece of program, the code A set or set of instructions is loaded and executed by a processor to implement the method.

The beneficial effects of the present invention are: by obtaining the position information and size information of the current coding block in the current coded image and the position representation of the frequency domain coefficients of the transform module, and filtering the co-located blocks corresponding to the original image according to the position information, the texture is obtained. Complexity parameter, obtain the resolution of the current coded image, and determine the scaling factor according to the resolution and the resolution threshold, calculate according to the scaling factor and the texture complexity parameter, and obtain the weight coefficient of the current coding block, which is determined according to the weight coefficient and size information The high-frequency coefficient threshold is used to determine a high-frequency coefficient threshold that is more in line with the human visual system. Since the human eye is not sensitive to the distortion of the complex texture area, it is relatively sensitive to the change of the flat area, and at the same time, the brightness information is in the video stream. Therefore, zeroing the luminance channel of the frequency domain coefficient whose position represents the frequency domain coefficient greater than the high frequency coefficient threshold can reduce the luminance information of the complex texture area, which is beneficial to reduce the bit rate and improve the coding efficiency without changing almost Human visual effects.

Description of drawings

Fig. 1 is the step flow diagram of the coding method based on high frequency zeroing of the present invention;

FIG. 2 is a schematic diagram of a Laplacian operator according to a specific embodiment of the present invention.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only The embodiments are part of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the scope of protection of the present application.

The terms "first", "second", "third" and "fourth" in the description and claims of the present application and the drawings are used to distinguish different objects, rather than to describe a specific order . Furthermore, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes unlisted steps or units, or optionally also includes For other steps or units inherent to these processes, methods, products or devices.

Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor a separate or alternative embodiment that is mutually exclusive of other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

As shown in FIG. 1 , an embodiment of the present invention provides an encoding method based on high-frequency zero-setting, including but not limited to being applied to the AVS3 video encoding standard, including steps S100-S600:

S100. Acquire position information, size information of the current coding block, and position representations of frequency domain coefficients of the transform module.

In the embodiment of the present invention, the position information of the current coding block in the current coded image is obtained through the transformation module. The size information includes the height H and width W of the current coding block; the transform module has multiple frequency domain coefficients, and each frequency domain coefficient has a corresponding position representation (x, y), where x is the width representation and y is the height express.

S200. Perform filtering processing on the co-located block at the corresponding position of the original image according to the position information to obtain a texture complexity parameter.

Optionally, the original information of the current coded image and the position information of the current coded block are passed to the high-pass filter, and the co-located block of the corresponding position in the original image is determined according to the position information, as shown in FIG. High-pass filtering is performed by a 9-tap Laplacian operator, and the pixel values of the resulting image after high-pass filtering are added to obtain the texture complexity parameter. It should be noted that the texture complexity parameter is the pixel matrix of the co-located block after the high-pass filtering process.

S300. Acquire the resolution of the currently encoded image, and determine the scaling factor according to the resolution and the resolution threshold.

Optionally, the resolution threshold may be adjusted according to the actual situation. In this embodiment of the present invention, a resolution with a resolution threshold of 4k is used as an example. Specifically, after obtaining the resolution of the currently encoded image, the ratio of the resolution of the current encoded image to the resolution of 4k is calculated, so as to obtain the scaling factor.

S400. Calculate according to the scaling coefficient and the texture complexity parameter to obtain the weight coefficient of the current coding block.

Optionally, step S400 includes steps S410-S420:

S410. Calculate a normalized high-pass coefficient according to the texture complexity parameter and size information.

It should be noted that the normalized high-pass coefficient represents the degree of activity of the current coding block, and is also referred to as an activity parameter. Specifically, the normalized high-pass coefficient can be obtained by calculating the ratio of the texture complexity parameter to the size information.

S420. According to the normalized high-pass coefficient and the scaling coefficient, calculate and obtain the weight coefficient of the current coding block through a preset function.

It should be noted that the weight coefficient w' is a guide parameter for zeroing the high frequency components of the current coding block in the frequency domain. Specifically, the calculation formula of the weight coefficient w' is:

Among them, G is a normalized high-pass coefficient, S is a scaling coefficient, and a is a preset empirical value constant.

S500. Determine a high-frequency coefficient threshold according to the weight coefficient and size information, and perform zero-setting processing on a luminance channel whose position represents a frequency-domain coefficient greater than the high-frequency coefficient threshold.

In this embodiment of the present invention, the high-frequency coefficient threshold includes a high-frequency height threshold Th_h and a high-frequency width threshold Th_w.

Optionally, determining the high-frequency coefficient threshold according to the weight coefficient and size information in step S500 includes steps S510-S520:

S510. Calculate the first product of the height and the weight coefficient to obtain a high-frequency height threshold.

Specifically, the calculation formula of the high-frequency height threshold Th_h is: Th_h=H×w'.

S520. Calculate the second product of the width and the weight coefficient to obtain a high-frequency width threshold.

Specifically, the calculation formula of the high frequency width threshold Th_w is: Th_w=W×w'.

In this embodiment of the present invention, in step S500, zeroing is performed on the luminance channel whose position represents the frequency domain coefficient greater than the high frequency coefficient threshold, including step S530:

S530. When the height indicates that the height is greater than the high-frequency height threshold or the width indicates that the width is greater than the high-frequency width threshold, perform zero-setting processing on the luminance channel of the corresponding frequency domain coefficient of the position.

It should be noted that each frequency domain coefficient contains a luminance channel and a chrominance channel. In this embodiment of the present invention, when the height y>the high-frequency height threshold Th_h or the width x>the high-frequency width threshold Th_w, the luminance channel of the frequency domain coefficient corresponding to the position representing (x, y) is zeroed, and for For the chrominance channel, the chrominance channel of the frequency domain coefficient is not processed. This is because the number of bits occupied by the chrominance channel will not be particularly high, but if the frequency domain of the chrominance is also zeroed, the color will be changed. offset, so only the luma channel is processed here and the chroma channel remains unchanged. It should be noted that, in other embodiments, corresponding processing may also be performed on the chrominance channel.

S600. Modify the cost function of the current coding block according to the weight coefficient.

It should be noted that since high-frequency zeroing will introduce additional distortion to the current coding block, this operation will cause other coding blocks in the subsequent coding steps to use the cost function to obtain the accuracy of the optimal solution, which will lead to mismatches. accurate question. However, if the problem of inaccurate matching between the current coding block and the subsequent coding block is not solved, distortion and matching errors will gradually accumulate, and eventually the visual effect of the subsequent image will become poor. At the same time, due to the introduction of distortion, the encoder will More bits are required to encode subsequent video images, which will eventually lead to poor visual effects, but the number of bits required for encoding does not drop but rises. Therefore, in the embodiment of the present invention, the cost function of the current coding block is modified to suppress the negative influence caused by the introduced distortion.

Specifically, the cost function is:

J=D+λ×R

Among them, J is the cost of the cost function, D is the distortion, λ is the coefficient passed from other coding modules of the encoder, and R is the number of bits encoded by the current coding block. In this embodiment of the present invention, in order to ensure that subsequent coding blocks match On the accurate reference block, the weight coefficient w' is used to modify and adjust λ to obtain a new λ value, namely λ_n, so as to update the cost function, which is beneficial to ensure the matching accuracy of subsequent coding blocks, specifically:

λ_n=w’×λ+b

Among them, λ_n is the modified λ parameter, and b is the preset constant value.

The updated cost function J' is:

J'=D+λ_n×R

Optionally, after the above-mentioned step S600 is completed, the new frequency domain coefficient (new frequency domain coefficient) frequency domain coefficient after high-frequency zeroing is passed to the quantization module for quantization, and the numerical value within a certain range is used in this range. The lowest value of , it is assumed that the value range of the frequency coefficient before quantization is 1 to 100. After quantization, the coefficients whose value is between 1 and 10 are represented by 1, that is, the quantization is 1; the value is between 11 and 20. The coefficients of are all represented by 11, that is, quantized to 11, and so on; so as to continue to complete the subsequent encoding process.

In this embodiment of the present invention, a new coding module is added between the existing transform module and the quantization module, which is used to implement a coding method based on high-frequency zero-setting. The threshold of the high-frequency coefficient is determined by determining the weight coefficient. The relationship between the thresholds performs high-frequency zeroing of the brightness channel, reducing the brightness information of the complex texture area without making any changes to the brightness information of the flat area. The complexity of the entire zeroing scheme is lower and the number of bits used for encoding is less. A video with little or no difference in subjective quality to the human eye. In addition, due to the reduction of high-frequency components, the calculation amount of the subsequent quantization module is reduced, and the reduced calculation amount is less than that of the newly introduced module in most test videos. The final result is that the encoding time is even shorter. A small decrease.

An embodiment of the present invention also provides an encoding device based on high-frequency zero-setting, including:

an acquisition module for acquiring the position information, size information and the position representation of the frequency domain coefficients of the transform module in the currently encoded image;

The filtering module is used for filtering the co-located block corresponding to the original image according to the position information to obtain the texture complexity parameter;

A determination module, used to obtain the resolution of the currently encoded image, and determine the scaling factor according to the resolution and the resolution threshold;

The weight module is used to calculate according to the scaling coefficient and texture complexity parameter to obtain the weight coefficient of the current coding block;

The zero-setting module is used to determine the high-frequency coefficient threshold according to the weight coefficient and the size information, and perform zero-setting processing on the luminance channel whose position represents the frequency domain coefficient greater than the high-frequency coefficient threshold.

The contents in the above method embodiments are all applicable to the present device embodiments, the specific functions implemented by the present device embodiments are the same as the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

An embodiment of the present invention further provides an electronic device, the electronic device includes a processor and a memory, and the memory stores at least one instruction, at least one program, code set or instruction set, at least one instruction, at least one program, code set or instruction set The set is loaded and executed by the processor to implement the high frequency zeroing based encoding method of the previous embodiment. The electronic devices in the embodiments of the present invention include but are not limited to terminals such as mobile phones, tablet computers, and computers.

The contents in the above method embodiments are all applicable to the present device embodiments, the specific functions implemented by the present device embodiments are the same as the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

Embodiments of the present invention further provide a computer-readable storage medium, where at least one instruction, at least one piece of program, code set or instruction set is stored in the storage medium, and at least one instruction, at least one piece of program, code set or instruction set is loaded by a processor And execute to realize the encoding method based on high frequency zeroing in the foregoing embodiment.

Embodiments of the present invention further provide a computer program product or computer program, where the computer program product or computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the encoding method based on high-frequency zeroing of the foregoing embodiments.

The terms "first", "second", "third", "fourth", etc. (if any) in the description of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It is to be understood that data so used may be interchanged under appropriate circumstances so that the embodiments of the application described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having" and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

It should be understood that, in this application, "at least one (item)" refers to one or more, and "a plurality" refers to two or more. "And/or" is used to describe the relationship between related objects, indicating that there can be three kinds of relationships, for example, "A and/or B" can mean: only A, only B, and both A and B exist , where A and B can be singular or plural. The character "/" generally indicates that the associated objects are an "or" relationship. "At least one item(s) below" or similar expressions thereof refer to any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (a) of a, b or c, can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c" ", where a, b, c can be single or multiple.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of units is only a logical function division. In actual implementation, there may be other division methods, for example, multiple units or components may be combined or integrated. to another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms. Units described as separate components may or may not be physically separated, and components shown as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment. In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.

The integrated unit, if implemented as a software functional unit and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the present application can be embodied in the form of software products in essence, or the parts that contribute to the prior art, or all or part of the technical solutions, and the computer software products are stored in a storage medium , including multiple instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, Read-Only Memory (ROM for short), Random Access Memory (RAM for short), magnetic disk or CD, etc. that can store programs medium.

Above, the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the above-mentioned embodiments, those of ordinary skill in the art should understand that: it can still be used for the above-mentioned implementations The technical solutions described in the examples are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions in the embodiments of the present application.

Claims (10)

1. a coding method based on high frequency zeroing, is characterized in that, comprises: Obtain the position information and size information of the current coding block in the current coded image and the position representation of the frequency domain coefficients of the transform module; Perform filtering processing on the co-located block at the corresponding position of the original image according to the position information to obtain a texture complexity parameter; acquiring the resolution of the currently encoded image, and determining a scaling factor according to the resolution and a resolution threshold; Calculate according to the scaling coefficient and the texture complexity parameter to obtain the weight coefficient of the current coding block; A high frequency coefficient threshold is determined according to the weight coefficient and the size information, and the luminance channel whose position represents a frequency domain coefficient larger than the high frequency coefficient threshold is zeroed. 2. The coding method based on high-frequency zeroing according to claim 1, wherein the filtering process is performed on the co-located block at the corresponding position of the original image according to the position information to obtain a texture complexity parameter, comprising: A high-pass filtering process is performed on the co-located block at the corresponding position of the original image by the Laplacian operator to obtain a texture complexity parameter; the texture complexity parameter is a pixel matrix. 3. The encoding method based on high-frequency zeroing according to claim 1, wherein: determining the scaling factor according to the resolution and the resolution threshold, comprising: The ratio of the resolution to the resolution threshold is calculated to obtain a scaling factor. 4. The encoding method based on high frequency zeroing according to any one of claims 1 to 3, wherein the calculation is performed according to the scaling coefficient and the texture complexity parameter to obtain the encoding of the current encoding block. Weighting factors, including: According to the texture complexity parameter and the size information, a normalized high-pass coefficient is calculated; the normalized high-pass coefficient represents the activity level of the current coding block; According to the normalized high-pass coefficient and the scaling coefficient, the weight coefficient of the current coding block is obtained by calculating a preset function. 5. The encoding method based on high-frequency zeroing according to claim 1, wherein: the size information includes height and width, and determining a high-frequency coefficient threshold according to the weight coefficient and the size information, comprising: Calculate the first product of the height and the weight coefficient to obtain a high-frequency height threshold; Calculate the second product of the width and the weight coefficient to obtain a high-frequency width threshold; The high frequency coefficient threshold includes the high frequency height threshold and the high frequency height threshold. 6 . The encoding method based on high frequency zeroing according to claim 5 , wherein the position representation includes a height representation and a width representation, and the position representation is a frequency domain coefficient larger than the high frequency coefficient threshold. 7 . The brightness channel of the zero is zeroed, including: When the height representation is larger than the high-frequency height threshold or the width representation is larger than the high-frequency width threshold, zeroing is performed on the luminance channel of the frequency domain coefficient corresponding to the position representation. 7. The encoding method based on high frequency zeroing according to claim 1, wherein the method further comprises: The cost function of the current coding block is modified according to the weight coefficient. 8. An encoding device based on high-frequency zero-setting, characterized in that, comprising: an acquisition module for acquiring the position information, size information and the position representation of the frequency domain coefficients of the transform module in the currently encoded image; a filtering module, configured to perform filtering processing on the co-located block at the corresponding position of the original image according to the position information to obtain a texture complexity parameter; a determining module, configured to acquire the resolution of the currently encoded image, and determine a scaling factor according to the resolution and a resolution threshold; a weighting module, configured to calculate according to the scaling factor and the texture complexity parameter to obtain the weighting factor of the current coding block; A zero-setting module, configured to determine a high-frequency coefficient threshold according to the weight coefficient and the size information, and perform zero-setting processing on the luminance channel whose position represents a frequency domain coefficient greater than the high-frequency coefficient threshold. 9. An electronic device, characterized in that the electronic device comprises a processor and a memory, and the memory stores at least one instruction, at least a piece of program, a code set or an instruction set, the at least one instruction, the at least one A program, the code set or the instruction set is loaded and executed by the processor to implement the method of any of claims 1-7. 10. A computer-readable storage medium, wherein the storage medium stores at least one instruction, at least one piece of program, code set or instruction set, the at least one instruction, the at least one piece of program, the code A set or set of instructions is loaded and executed by a processor to implement the method of any of claims 1-7.

Images