WO2020140636A1

WO2020140636A1 - Watermark embedding and extracting methods and apparatuses, and terminal device and medium

Info

Publication number: WO2020140636A1
Application number: PCT/CN2019/118688
Authority: WO
Inventors: 朱照华; 王健宗
Original assignee: 平安科技（深圳）有限公司
Priority date: 2019-01-04
Filing date: 2019-11-15
Publication date: 2020-07-09
Also published as: CN109784006A

Abstract

Watermark embedding and extracting methods and apparatuses, and a terminal device and a medium. The watermark embedding method comprises: determining degree of a polynomial function to be constructed according to a preset number of copies of division of watermark information, selecting multiple numerical values as coefficients of items in the polynomial function, and constructing the polynomial function, wherein a function value of the polynomial function when the independent variable is zero is a decimal representation value of the watermark information (S101); selecting multiple real values as elements to form a real number set, wherein the number of the elements in the real number set is equal to the preset number of copies of division (S102); respectively substituting the elements in the real number set into the polynomial function, and calculating and saving function values corresponding to the elements (S103); embedding the elements in the real number set into a target file, wherein the elements and the function values corresponding to the elements are used for extracting the watermark information (S104). According to the method, the attack resistance of a watermark can be enhanced, so that the content of the watermark can be completely extracted from the target file after the target file undergoes major changes.

Description

Watermark embedding and extracting method, device, terminal equipment and medium

This application requires the priority of the Chinese patent application filed on January 04, 2019, with the application number 201910008098.8 and the invention titled "A watermark embedding and extraction method and terminal device", the entire content of which is incorporated by reference in In this application.

Technical field

The present application relates to the field of computer technology, and in particular, to a method, device, terminal device, and medium for embedding and extracting watermarks.

Background technique

Copyright protection has always been one of the issues that people have focused on since the digital age. In today’s era of emphasis on data and resource sharing, any data uploaded to the Internet has the risk of being stolen and tampered by a third party, even if these The issuer of the data and resources explained the right to use the data when publishing the data, but the unauthorized use of third-party data cannot prove its true owner, so explore good methods for copyright protection It is an important research direction in the field of data security, especially in the field of music copyright protection, which is now more and more concerned.

Digital watermarking technology is a powerful copyright protection method. At present, existing watermarking technologies can be divided into two categories. The first category is visible watermarking technology. As the name implies, visible watermarking can be seen by third parties, although it can To a certain extent, the file is protected, but its own existence is prone to malicious third-party attacks, and sometimes the visible watermark will destroy the original characteristics of the data, such as pictures, audio, and visible watermarks in the document will more or less affect Its visual or auditory effect; the other is the invisible watermarking technology. This watermarking technology is difficult to find its existence except for the embedder, so it can provide better data protection than visible watermarking, and Does not affect the original characteristics of the data. However, the files embedded with invisible watermark information are currently less resistant to attacks, and it is difficult to recover the watermark when subjected to attack operations such as secondary encoding and audio interception.

technical problem

In view of this, the embodiments of the present application provide a method, device, terminal device and medium for embedding and extracting watermarks, to solve the problem that the file embedded with invisible watermark information has a poor ability to resist attacks.

Technical solution

A first aspect of an embodiment of the present application provides a watermark embedding method, including:

Determine the number of polynomial functions to be constructed according to the preset number of divisions of the watermark information, and select multiple values as coefficients of each item in the polynomial function to construct the polynomial function; when the independent variable takes zero The function value is the decimal representation of the watermark information;

Selecting multiple real values as elements to form a real number set; the number of elements in the real number set is equal to the preset number of divisions;

Substitute each element in the real number set into the polynomial function, calculate and save the function value corresponding to each element;

Each element in the set of real numbers is embedded in the target file; each element and the function value corresponding to each element are used to extract the watermark information.

A second aspect of the embodiments of the present application provides a watermark extraction method, including:

Extracting at least a preset number of elements embedded in the target file from the target file;

Obtaining a function value corresponding to the at least a preset number of elements saved during the watermark information embedding process;

Determining a polynomial function in the process of embedding watermark information according to the at least a preset number of elements and a function value corresponding to the at least a preset number of elements;

The watermark information embedded in the target file is determined according to the function value of the polynomial function when the argument is zero.

A third aspect of the embodiments of the present application provides a watermark embedding device, including:

A first construction module, used to determine the number of polynomial functions to be constructed according to the preset number of divided watermark information, and select multiple values as coefficients of each item in the polynomial function to construct the polynomial function; the polynomial The function value of the function when the argument is zero is the decimal representation of the watermark information;

The second building module is used to select multiple real values as elements to form a real number set; the number of elements in the real number set is equal to the preset number of divisions;

A storage module, used to substitute each element in the real number set into the polynomial function, and calculate and save the function value corresponding to each element;

The embedding module is used to embed each element in the real number set into the target file; each element and the function value corresponding to each element are used to extract the watermark information.

A fourth aspect of the embodiments of the present application provides a watermark extraction device, including:

An extraction module, configured to extract at least a preset number of elements embedded in the target file from the target file;

An obtaining module, configured to obtain a function value corresponding to the at least a preset number of elements saved during the watermark information embedding process;

A first processing module, configured to determine a polynomial function in the process of embedding watermark information according to the at least a preset number of elements and a function value corresponding to the at least a preset number of elements;

The second processing module is used to determine the watermark information embedded in the target file according to the function value of the polynomial function when the argument is zero.

A fifth aspect of the embodiments of the present application provides a terminal device including a memory and a processor, and the memory stores computer-readable instructions that can run on the processor, and the processor executes the computer When reading the instruction, the watermark embedding method in the first aspect or the watermark extraction method in the second aspect is implemented.

A sixth aspect of the embodiments of the present application provides a computer-readable storage medium that stores computer-readable instructions, characterized in that the computer-readable instructions are implemented when executed by at least one processor The watermark embedding method in the first aspect, or implementing the watermark extraction method in the second aspect.

Beneficial effect

The embodiment of the present application constructs a polynomial function and a real number set, where the function value of the polynomial function when the argument is zero is the decimal representation value of the watermark information; embed each element in the real number set into the target file, calculate and save the correspondence of each element The value of the function is used to extract the watermark information and realize the embedding of the watermark information, which can enhance the ability of the watermark to resist attacks, so that the watermark content can be completely extracted from the target file after undergoing large changes.

BRIEF DESCRIPTION

In order to more clearly explain the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings used in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only for the application In some embodiments, for those of ordinary skill in the art, without paying creative labor, other drawings may be obtained based on these drawings.

FIG. 1 is an implementation flowchart of a watermark embedding method provided by an embodiment of the present application;

2 is an implementation flowchart of embedding each element in a real number set into a target file in the watermark embedding method provided by an embodiment of the present application;

3 is a flowchart of an implementation of a musical note instruction in which a binary value corresponding to each element in a real number set is embedded in a MIDI file in the watermark embedding method provided by an embodiment of the present application;

FIG. 4 is an implementation flowchart of a watermark extraction method provided by an embodiment of the present application;

FIG. 5 is an implementation flowchart of extracting at least a preset number of elements embedded in the target file from the target file in the watermark extraction method provided by an embodiment of the present application;

6 is a schematic diagram of a watermark embedding device provided by an embodiment of the present application;

7 is a schematic diagram of a watermark extraction device provided by an embodiment of the present application;

8 is a schematic diagram of a terminal device provided by an embodiment of the present application.

Embodiments of the invention

In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are proposed to thoroughly understand the embodiments of the present application. However, those skilled in the art should understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details hindering the description of the present application.

In order to explain the technical solutions described in the present application, the following will be described with specific embodiments.

In this embodiment, the execution subject of the watermark embedding method and the execution subject of the watermark extraction method may be the same terminal device or different terminal devices, which is not limited herein. For example, a watermark embedding method may be executed on the first terminal device to embed the target file, and a watermark extraction method may be executed on the first terminal device to perform the watermark extraction on the target file; or the watermark embedding method may be executed on the first terminal device Embed the watermark of the target file, and execute the watermark extraction method on the second terminal device to extract the watermark of the target file.

For ease of explanation, take MIDI files for watermark embedding and watermark extraction as an example. First, make a definition of the parameters that need to be explained: define A = {a1, a2, ..., aLA} as the note instruction information stored in the MIDI file, including note-on and note-off Command, LA is the number of note commands in the MIDI file. In a note instruction, there are usually two parts of information that can be used for watermark embedding, namely the velocity field v and the time identification field d, where the length of the velocity field is 8 bits, the length of the time identification field is uncertain; the watermark needs to be embedded Information W={wi=0 or 1|i=1, 2,... LW}, LW is the length of the watermark information.

Music content is organized in the form of MIDI commands in MIDI format files. For a note, the corresponding MIDI commands contain the following information: channel number (MIDI), pitch (pitch), velocity (velocity) ), event type (event) and duration (delta). In these messages, the content of the channel number and event type fields are strictly related to MIDI encoding. If it is modified, it may cause encoding errors; the pitch field reflects the sound we can hear in the music. This field in MIDI The basic unit is a semitone, so the modification of this field will have a greater impact on the final music effect; the basic units of the two fields of velocity and duration are very small, and minor modifications to these two fields are generally in the It is not perceivable on human ears, so these two fields are more suitable for watermark embedding.

FIG. 1 is an implementation flowchart of a watermark embedding method provided by an embodiment of the present application, and the details are as follows:

S101: Determine the number of polynomial functions to be constructed according to the preset number of divisions of the watermark information, and select multiple values as coefficients of each item in the polynomial function to construct the polynomial function; the polynomial function is taken from the independent variable The function value at zero is the decimal representation of the watermark information.

In this embodiment, the preset number of divided watermark information can be obtained first. The preset division number of the watermark information refers to the number of copies into which the watermark information is divided. The preset division number can be set randomly or according to other rules, which is not limited herein. There is a relationship between the preset number of divided watermark information and the number of polynomial functions to be constructed. The number of times the polynomial function to be constructed can be determined according to the relationship and the preset number of divided watermark information. It is possible to select multiple values as coefficients of each item in the polynomial function according to a preset selection rule or randomly. The preset selection rule can be determined according to actual needs and is not limited herein. The polynomial function is used as a watermark information splitter to decompose the watermark information.

S102. Select multiple real values as elements to form a set of real numbers. The number of elements in the real number set is equal to the preset divided number.

In this embodiment, multiple real values can be randomly selected as elements within a preset value range to form a set of real numbers. The number of elements in the real number set is equal to the preset number of divided watermark information. For example, if the preset number of divided watermark information is 12, then 12 real values can be randomly selected to form a real number set, that is, the real number set contains 12 elements, and each element is a real value. The elements in the real number set are used for embedding in the target file to achieve watermark embedding.

Optionally, the degree of the polynomial function is k-1, and the total number of elements in the set of real numbers is u, where u=2k-1; k is an integer greater than 1.

In this embodiment, the number u of the watermark information divided first may be randomly determined, where u>1, and then a k-1 degree polynomial function f(x) is randomly constructed, so that f(0)=b, b is The watermark information represents the value in decimal, which can be calculated by the following formula:

Among them, W={wi=0 or 1|i=1, 2,... LW} is the watermark information to be embedded, and LW is the length of the watermark information.

S103: Substitute each element in the real number set into the polynomial function, and calculate and save the function value corresponding to each element.

In this embodiment, each element in the set of real numbers can be used as the value of the unknown quantity of the polynomial function, which is substituted into the polynomial function to calculate the function value of the corresponding polynomial function and save these function values.

Optionally, the set of real numbers is X={x ₁ , x ₂ ,..., x _u },

Where u is the total number of elements in the real number set; lw is the data length of the watermark information; p is the embedding parameter.

In this embodiment, p is an embedding parameter, which is determined by the actual parameter selected in the embedding process, and is expressed as the number of bits of the element embedded in each note instruction information of the target file, and its value may be 2 by default. In addition, in the real number set X, each element is different from each other.

Among them, the reason for setting such a value range is to ensure that all the values of xi have the same length after being converted into binary, so as to facilitate the extraction operation of the watermark. Values outside this range can also be selected in principle, but if selected, additional information is required to record the location information of each watermark, and the extraction process is more cumbersome. For this reason, the value of xi is restricted within this range.

The value range of the elements in the real set is determined by the embedded parameters and the length of the watermark information, which can make the elements in the real set have the same length after being converted into binary, which is convenient for determining the length of the elements in the extraction process and facilitating the extraction operation of the elements.

S104: Embed each element in the real number set into the target file; each element and the function value corresponding to each element are used to extract the watermark information.

For example, for each element xi in the set X, calculate its corresponding value in f(x) and write Y={y1, y2, ..., yu}. For each element xi in the set X, embed it in the MIDI file, and for each element yi in the set Y, it can be recorded in the local storage or server for extracting the watermark information.

In the process of extracting watermark information, each element can be extracted from the target file, and then the polynomial function in the embedding process is determined according to the function value corresponding to each element and each element recorded, and then the watermark information is determined according to the polynomial function to realize the watermark information. extract.

As an embodiment of the present application, the target file is a MIDI file. As shown in FIG. 2, S104 may include:

S201. Convert each element in the real number set to a corresponding binary value.

S202: Embed the binary values corresponding to the elements in the real number set into the note instructions in the MIDI file in sequence according to the time order of the note instructions in the MIDI file.

In this embodiment, the elements in the real number set X can be embedded in order according to the time order of the note instructions in the MIDI file. Here, each element in the real number set X is converted from real values to binary data and then embedded.

As an embodiment of the present application, the note instruction includes a velocity parameter and/or a time identification parameter; as shown in FIG. 3, S202 may include:

S301: Determine the bit value corresponding to the velocity parameter and/or the time identification parameter in each note instruction according to the chronological order of the note instructions in the MIDI file; wherein, the bit number value is a binary value corresponding to each element in the real number set One digit of

S302. Replace the last bit value of the velocity parameter and/or time identification parameter in each note instruction with the corresponding bit value.

In this embodiment, for each note instruction ai in the MIDI file, the embedding process of the watermark information in it can be divided into two parts:

For the velocity parameter v, modify the last bit parameter v8 in its binary representation, the specific modification process is

Where o _j represents the value of the watermark bit to be embedded at this position.

For the time marker parameter d, it is modified in the same way as the force parameter. The specific modification process is

Where o _j represents the value of the watermark bit to be embedded at this position, and dj represents the binary value of the last bit of the time identification parameter.

As an example to illustrate the embedding process, suppose a MIDI note command has a velocity parameter value of 94 and a time stamp parameter value of 1024, and the corresponding binary data are '01011110' and '10000000000', respectively. If '10' is embedded in this note instruction, the embedded parameters become 95 (01011111) and 1024 (10000000000).

This embodiment replaces the last bit value of the velocity parameter and/or time identification parameter in each note command with the corresponding bit value. This embedding method modifies the carrier less, which is convenient for embedding, and embeds the watermarked file Basically, it will not be noticed by human ears, and it will not affect the auditory effect of the listener on the MIDI file because of the embedded watermark.

FIG. 4 is an implementation flowchart of a watermark extraction method provided by an embodiment of the present application, and the details are as follows:

S401: Extract at least a preset number of elements embedded in the target file from the target file.

In this embodiment, during the watermark extraction process, at least a preset number of elements may be extracted from the target file. Among them, the watermark extraction method provided in this embodiment requires only a part of embedded elements to perform extraction, where the preset number is the minimum number of elements required for successful extraction of the watermark, and below the preset number, the watermark extraction fails. The preset number can be determined according to the total number of embedded elements.

Optionally, the total number of elements embedded in the target file is u, and the preset number is k, where u=2k-1; k is an integer greater than 1.

In this embodiment, the value of the preset number k can be determined from the total number of elements embedded in the target file according to the relationship u=2k-1.

As an embodiment of the present application, the target file is a MIDI file, and the note instructions of the MIDI file include velocity parameters and/or time identification parameters; as shown in FIG. 5, S401 may include:

S501, extract the last digit of the velocity parameter of each note instruction in the MIDI file to form a first sequence; and/or, extract the last digit of the duration parameter of each note instruction in the MIDI file to form a second sequence .

For example, you can extract the last digit of the velocity parameter of each note command in the MIDI file and combine it into a string of binary codes m1; extract the last digit of the duration parameter of each note command in the MIDI file, combine A series of binary sequences m2 are generated.

S502: Divide the first sequence and/or the second sequence according to the data length information in the process of embedding the watermark information to obtain each element embedded in the target file.

In this embodiment, the data length information in the process of embedding the watermark information may include the total number u of elements embedded in the target file, the data length lw of the watermark information, and the embedding parameter p. The data length of each element may be determined according to the data length information in the watermark information embedding process, and then the first sequence and/or the second sequence may be divided.

For example, taking a MIDI file as an example, you can sequentially extract the elements embedded in the note instruction information, and then according to the element length formula

Each element in the real number set X is obtained. Among them, the relevant information p and u used to calculate the element length are determined in the embedding process and are recorded in the local memory or server for auxiliary extraction. Each element can be obtained by dividing data according to the divided element length in m1 and m2.

S503: Select a preset number of elements from each element embedded in the target file.

In this embodiment, a preset number of elements may be randomly selected from each element embedded in the target file, or a preset number of elements may be selected according to a certain rule, which is not limited herein.

S402. Acquire a function value corresponding to the at least a preset number of elements saved during the watermark information embedding process.

In this embodiment, the function value corresponding to each element calculated during the watermark information embedding process can be stored in the local memory or the server's database, and at least a preset number can be obtained from the local memory or server during the watermark extraction process The function value corresponding to the element of.

For example, select k elements {x1, x2, ..., xk} among the divided elements and find their corresponding function values {y1, y2, ..., yk} locally or on the server.

S403: Determine a polynomial function in the process of embedding watermark information according to the at least a preset number of elements and a function value corresponding to the at least a preset number of elements.

In this embodiment, the polynomial function used as the resolver during the embedding of the watermark information may be determined according to at least a preset number of elements and a function value corresponding to at least the preset number of elements.

Optionally, the polynomial function in the process of embedding the watermark information may be determined according to the at least a preset number of elements, a function value corresponding to the at least a preset number of elements, and a Lagrange difference formula.

S404: Determine the watermark information embedded in the target file according to the function value of the polynomial function when the argument is zero.

For example, you can use the formula

Formula for calculating polynomial function, where

Finally, the binary form of the constant term restored to the polynomial function formula is the binary value of the watermark information.

In this embodiment of the present application, at least a preset number of elements embedded in the target file are extracted from the target file, and the embedding in the watermark information is determined according to at least the preset number of elements and the function value corresponding to at least the preset number of elements. The polynomial function in the process, and then determine the watermark information embedded in the target file according to the polynomial function, to achieve the extraction of watermark information. According to the embodiment of the present application, the watermark information can be extracted based on at least a predetermined number of elements, without requiring all elements, and the ability of the watermark to resist attacks can be enhanced, so that the target file can still be intact after being subjected to large changes Extracts the content of the watermark.

The embodiment of the present application adopts a MIDI file adaptive watermark embedding method based on the Shamir algorithm, which mainly uses the masking effect of human hearing to watermark the partially redundant code fields and the partially controlled sound information code fields in the MIDI file format coding Embedding, while using the Shamir algorithm to share the watermark in the encoding field of different notes in the MIDI file to enhance the ability of the watermark to resist attacks, so that it can still extract the watermark content from the carrier file after undergoing major changes. The advantages are:

1) The watermark of this method is an invisible watermark, so this method has good invisibility, and malicious third parties cannot judge the existence of the watermark by hearing, so it can provide better copyright protection to some extent.

2) This method disperses and embeds the watermark information into each part of the MIDI music file, and only part of the information can complete the extraction of the watermark information, so even if the file embedded with the watermark information is intercepted or lost due to secondary encoding Part of the information, we can still restore the watermark. The watermark has strong robustness and can resist common attacks, such as secondary encoding, audio interception and other attack operations, so it has good practicality.

It should be understood that the size of the sequence numbers of the steps in the above embodiments does not mean the order of execution, and the execution order of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

Corresponding to the watermark embedding method described in the above embodiment, FIG. 6 shows a schematic diagram of the watermark embedding apparatus provided by the embodiment of the present application. For ease of explanation, only parts related to this embodiment are shown.

Referring to FIG. 6, the device includes a first building module 61, a second building module 62, a storage module 63 and an embedding module 64.

The first construction module 61 is used to determine the number of polynomial functions to be constructed according to the preset number of divided watermark information, and select multiple values as coefficients of each item in the polynomial function to construct the polynomial function; The function value of the polynomial function when the argument is zero is the decimal representation value of the watermark information.

The second building module 62 is configured to select multiple real values as elements to form a real number set; the number of elements in the real number set is equal to the preset number of divisions.

The storage module 63 is configured to substitute each element in the real number set into the polynomial function, and calculate and save the function value corresponding to each element.

The embedding module 64 is configured to embed each element in the real number set into the target file; the each element and the function value corresponding to each element are used to extract the watermark information.

Optionally, the target file is a MIDI file, and the embedding module 64 is used to:

Convert each element in the real number set to a corresponding binary value;

The binary values corresponding to the elements in the real number set are sequentially embedded into the note instructions in the MIDI file according to the chronological order of the note instructions in the MIDI file.

Optionally, the note instructions include velocity parameters and/or time identification parameters; the embedding module 64 is used to:

Determine the bit value corresponding to the velocity parameter and/or time identification parameter in each note instruction according to the chronological order of the note instructions in the MIDI file; wherein the bit number value is one of the binary values corresponding to each element in the real number set Digit value

Replace the last digit of the velocity parameter and/or time identification parameter in each note command with the corresponding digit value.

Corresponding to the watermark extraction method described in the above embodiment, FIG. 7 shows a schematic diagram of a watermark extraction device provided by an embodiment of the present application. For ease of explanation, only parts related to this embodiment are shown.

Referring to FIG. 7, the device includes an extraction module 71, an acquisition module 72, a first processing module 73 and a second processing module 74.

The extraction module 71 is configured to extract at least a preset number of elements embedded in the target file from the target file.

The obtaining module 72 is configured to obtain the function value corresponding to the at least a preset number of elements saved during the watermark information embedding process.

The first processing module 73 is configured to determine a polynomial function in the process of embedding watermark information according to the at least a preset number of elements and a function value corresponding to the at least a preset number of elements.

The second processing module 74 is configured to determine the watermark information embedded in the target file according to the function value of the polynomial function when the argument is zero.

Optionally, the target file is a MIDI file, and the note instructions of the MIDI file include velocity parameters and/or time identification parameters; the extraction module 71 is used to:

Extract the last digit of the velocity parameter of each note command in the MIDI file to form the first sequence; and/or extract the last digit of the duration parameter of each note command in the MIDI file to form the second sequence;

Divide the first sequence and/or the second sequence according to the data length information in the process of embedding the watermark information to obtain each element embedded in the target file;

Select a preset number of elements from each element embedded in the target file.

Optionally, the first processing module 73 is used to:

The polynomial function in the process of embedding the watermark information is determined according to the at least a preset number of elements, a function value corresponding to the at least a preset number of elements, and a Lagrange difference formula.

8 is a schematic diagram of a terminal device provided by an embodiment of the present application. As shown in FIG. 8, the terminal device 8 of this embodiment includes: a processor 80, a memory 81, and computer-readable instructions 82 stored in the memory 81 and executable on the processor 80, such as programs. When the processor 80 executes the computer-readable instruction 82, the steps in the above watermark embedding method embodiment are implemented, for example, steps 101 to 104 shown in FIG. 1, and/or the steps in the above watermark extraction method embodiment are implemented, For example, steps 401 to 404 shown in FIG. 4. Alternatively, when the processor 80 executes the computer-readable instructions 82, the functions of the modules/units in the foregoing device embodiments are realized, for example, the functions of the modules 61 to 64 shown in FIG. 6, and/or the modules shown in FIG. 71 to 74 functions.

Exemplarily, the computer-readable instructions 82 may be divided into one or more modules/units, the one or more modules/units are stored in the memory 81, and executed by the processor 80, To complete this application. The one or more modules/units may be a series of computer-readable instruction instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer-readable instructions 82 in the terminal device 8.

The terminal device 8 may be a computing device such as a desktop computer, a notebook, a palmtop computer and a cloud server. The terminal device may include, but is not limited to, a processor 80 and a memory 81. Those skilled in the art may understand that FIG. 8 is only an example of the terminal device 8 and does not constitute a limitation on the terminal device 8, and may include more or fewer components than those illustrated, or a combination of certain components, or different components. For example, the terminal device may further include an input and output device, a network access device, a bus, a display, and so on.

The so-called processor 80 may be a central processing unit (Central Processing Unit, CPU), or other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), Ready-made programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 81 may be an internal storage unit of the terminal device 8, such as a hard disk or a memory of the terminal device 8. The memory 81 may also be an external storage device of the terminal device 8, such as a plug-in hard disk equipped on the terminal device 8, a smart memory card (Smart, Media, Card, SMC), and a secure digital (SD) Cards, flash cards, etc. Further, the memory 81 may also include both an internal storage unit of the terminal device 8 and an external storage device. The memory 81 is used to store the computer-readable instructions and other programs and data required by the terminal device. The memory 81 can also be used to temporarily store data that has been or will be output.

Those skilled in the art can clearly understand that, for convenience and conciseness of description, only the above-mentioned division of each functional unit and module is used as an example for illustration. In practical applications, the above-mentioned functions may be allocated by different functional units, Module completion means that the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments 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 may use hardware It can also be implemented in the form of software functional units. In addition, the specific names of the functional units and modules are only for the purpose of distinguishing each other, and are not intended to limit the protection scope of the present application. For the specific working processes of the units and modules in the above system, reference may be made to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

In the above embodiments, the description of each embodiment has its own emphasis. For a part that is not detailed or recorded in an embodiment, you can refer to the related descriptions of other embodiments.

Those of ordinary skill in the art may realize that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on the specific application of the technical solution and design constraints. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

In the embodiments provided in this application, it should be understood that the disclosed device/terminal device and method may be implemented in other ways. For example, the device/terminal device embodiments described above are only schematic. For example, the division of the module or unit is only a logical function division, and in actual implementation, there may be another division manner, such as multiple units Or components can be combined or integrated into another system, or some features can be ignored or not implemented. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place or may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of 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 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 unit.

A person of ordinary skill in the art may understand that all or part of the process in the method of the foregoing embodiments may be completed by instructing relevant hardware through computer-readable instructions, and the computer-readable instructions may be stored in a non-volatile computer In a readable storage medium, when the computer-readable instructions are executed, they may include the processes of the foregoing method embodiments. Wherein, any reference to the memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and/or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous chain (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

The above-mentioned embodiments are only used to illustrate the technical solutions of the present application, not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still implement the foregoing The technical solutions described in the examples are modified, or some of the technical features are equivalently replaced; and these modifications or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present application. Within the scope of protection of this application.

Claims

A watermark embedding method, characterized in that it includes:

Determine the number of polynomial functions to be constructed according to the preset number of divisions of the watermark information, and select multiple values as coefficients of each item in the polynomial function to construct the polynomial function; when the independent variable takes zero The function value of is the decimal representation value of the watermark information;

Selecting multiple real values as elements to form a real number set; the number of elements in the real number set is equal to the preset number of divisions;

Substitute each element in the real number set into the polynomial function, calculate and save the function value corresponding to each element;

Each element in the set of real numbers is embedded in the target file; each element and the function value corresponding to each element are used to extract the watermark information.
The watermark embedding method according to claim 1, wherein the target file is a MIDI file, and embedding each element in the real number set into the target file includes:

Convert each element in the real number set to a corresponding binary value;

The binary values corresponding to the elements in the real number set are sequentially embedded into the note instructions in the MIDI file according to the chronological order of the note instructions in the MIDI file.
The watermark embedding method according to claim 2, wherein the note instruction includes a velocity parameter and/or a time identification parameter; and the elements in the real number set are sequentially corresponding to the chronological order of the note instruction in the MIDI file The note instructions embedded in the binary value of the MIDI file include:

Determine the bit value corresponding to the velocity parameter and/or time identification parameter in each note instruction according to the chronological order of the note instructions in the MIDI file; wherein the bit number value is one of the binary values corresponding to each element in the real number set Digit value

Replace the last digit of the velocity parameter and/or time identification parameter in each note command with the corresponding digit value.
A watermark extraction method, which includes:

Extracting at least a preset number of elements embedded in the target file from the target file;

Obtaining a function value corresponding to the at least a preset number of elements saved during the watermark information embedding process;

Determining a polynomial function in the process of embedding watermark information according to the at least a preset number of elements and a function value corresponding to the at least a preset number of elements;

The watermark information embedded in the target file is determined according to the function value of the polynomial function when the argument is zero.
The watermark extraction method according to claim 4, wherein the target file is a MIDI file, and the note instructions of the MIDI file include velocity parameters and/or time identification parameters; the extracted from the target file is embedded into The at least preset number of elements in the target file includes:

Extract the last digit of the velocity parameter of each note command in the MIDI file to form the first sequence; and/or extract the last digit of the duration parameter of each note command in the MIDI file to form the second sequence;

Divide the first sequence and/or the second sequence according to the data length information in the process of embedding the watermark information to obtain each element embedded in the target file;

Select a preset number of elements from each element embedded in the target file.
The watermark extraction method according to claim 4 or 5, characterized in that the determination according to the at least a preset number of elements and a function value corresponding to the at least a preset number of elements during the watermark information embedding process The polynomial functions of include:

The polynomial function in the process of embedding the watermark information is determined according to the at least a preset number of elements, a function value corresponding to the at least a preset number of elements, and a Lagrange difference formula.
A watermark embedding device is characterized by comprising:

A first construction module, used to determine the number of polynomial functions to be constructed according to the preset number of divided watermark information, and select multiple values as coefficients of each item in the polynomial function to construct the polynomial function; the polynomial The function value of the function when the argument is zero is the decimal representation of the watermark information;

The second building module is used to select multiple real values as elements to form a real number set; the number of elements in the real number set is equal to the preset number of divisions;

A storage module, used to substitute each element in the real number set into the polynomial function, and calculate and save the function value corresponding to each element;

The embedding module is used to embed each element in the real number set into the target file; each element and the function value corresponding to each element are used to extract the watermark information.
The watermark embedding device according to claim 7, wherein the target file is a MIDI file, and the embedding module is specifically used for:

Convert each element in the real number set to a corresponding binary value;

The binary values corresponding to the elements in the real number set are sequentially embedded into the note instructions in the MIDI file according to the chronological order of the note instructions in the MIDI file.
The watermark embedding device according to claim 8, wherein the note instruction includes a velocity parameter and/or a time identification parameter; the embedding module is specifically used to:

Determine the bit value corresponding to the velocity parameter and/or time identification parameter in each note instruction according to the chronological order of the note instructions in the MIDI file; wherein the bit number value is one of the binary values corresponding to each element in the real number set Digit value

Replace the last digit of the velocity parameter and/or time identification parameter in each note command with the corresponding digit value.
A watermark extraction device is characterized by comprising:

An extraction module, configured to extract at least a preset number of elements embedded in the target file from the target file;

An obtaining module, configured to obtain a function value corresponding to the at least a preset number of elements saved during the watermark information embedding process;

A first processing module, configured to determine a polynomial function in the process of embedding watermark information according to the at least a preset number of elements and a function value corresponding to the at least a preset number of elements;

The second processing module is configured to determine the watermark information embedded in the target file according to the function value of the polynomial function when the argument is zero.
The watermark extraction device according to claim 10, wherein the target file is a MIDI file, and the note instructions of the MIDI file include velocity parameters and/or time identification parameters;

The extraction module 71 is specifically used to:

Extract the last digit of the velocity parameter of each note command in the MIDI file to form the first sequence; and/or extract the last digit of the duration parameter of each note command in the MIDI file to form the second sequence;

Divide the first sequence and/or the second sequence according to the data length information in the process of embedding the watermark information to obtain each element embedded in the target file;

Select a preset number of elements from each element embedded in the target file.
The watermark extraction device according to claim 10 or 11, wherein the first processing module is specifically used to:

The polynomial function in the process of embedding the watermark information is determined according to the at least a preset number of elements, a function value corresponding to the at least a preset number of elements, and a Lagrange difference formula.
A terminal device, characterized in that the terminal device includes a memory and a processor, and the memory stores computer-readable instructions executable on the processor, and the processor executes the computer-readable instructions The following steps are implemented:

Determine the number of polynomial functions to be constructed according to the preset number of divisions of the watermark information, and select multiple values as coefficients of each item in the polynomial function to construct the polynomial function; when the independent variable takes zero The function value of is the decimal representation value of the watermark information;

Selecting multiple real values as elements to form a set of real numbers; the number of elements in the set of real numbers is equal to the preset number of divisions;

Substitute each element in the real number set into the polynomial function, calculate and save the function value corresponding to each element;

Each element in the set of real numbers is embedded in the target file; each element and the function value corresponding to each element are used to extract the watermark information.
The terminal device according to claim 13, wherein the target file is a MIDI file, and embedding each element in the set of real numbers into the target file includes:

Convert each element in the real number set to a corresponding binary value;

The binary values corresponding to the elements in the real number set are sequentially embedded into the note instructions in the MIDI file according to the chronological order of the note instructions in the MIDI file.
The terminal device according to claim 14, wherein the note instruction includes a velocity parameter and/or a time identification parameter; and the elements corresponding to each element in the real number set are sequentially assigned in accordance with the time order of the note instruction in the MIDI file The note instructions embedded with binary values in the MIDI file include:

Determine the bit value corresponding to the velocity parameter and/or time identification parameter in each note instruction according to the chronological order of the note instructions in the MIDI file; wherein the bit number value is one of the binary values corresponding to each element in the real number set Digit value

Replace the last digit of the velocity parameter and/or time identification parameter in each note command with the corresponding digit value.
A terminal device, characterized in that the terminal device includes a memory and a processor, and the memory stores computer-readable instructions executable on the processor, and the processor executes the computer-readable instructions The following steps are implemented:

Extracting at least a preset number of elements embedded in the target file from the target file;

Obtaining a function value corresponding to the at least a preset number of elements saved during the watermark information embedding process;

Determining a polynomial function in the process of embedding watermark information according to the at least a preset number of elements and a function value corresponding to the at least a preset number of elements;

The watermark information embedded in the target file is determined according to the function value of the polynomial function when the argument is zero.
The terminal device according to claim 16, wherein the target file is a MIDI file, and the note instructions of the MIDI file include a velocity parameter and/or a time identification parameter; the extracted from the target file is embedded into the The at least preset number of elements in the target file includes:

Extract the last digit of the velocity parameter of each note command in the MIDI file to form the first sequence; and/or extract the last digit of the duration parameter of each note command in the MIDI file to form the second sequence;

Divide the first sequence and/or the second sequence according to the data length information in the process of embedding the watermark information to obtain each element embedded in the target file;

Select a preset number of elements from each element embedded in the target file.
The terminal device according to claim 16 or 17, wherein the determining of the watermark information embedding process based on the at least a preset number of elements and a function value corresponding to the at least a preset number of elements Polynomial functions include:

The polynomial function in the process of embedding the watermark information is determined according to the at least a preset number of elements, a function value corresponding to the at least a preset number of elements, and a Lagrange difference formula.
A computer-readable storage medium storing computer-readable instructions, characterized in that, when the computer-readable instructions are executed by a processor, the method according to any one of claims 1 to 3 is implemented A step of.
A computer-readable storage medium storing computer-readable instructions, wherein the computer-readable instructions are executed by a processor to implement the method according to any one of claims 4 to 6. A step of.