Method and device for embedding digital watermark in video, equipment and medium

Abstract

The invention discloses a method, a device, equipment and a medium for embedding a digital watermark in a video, and relates to the field of image processing, and the key points of the technical scheme are as follows: obtaining multiple frames of images of the video, converting a part of the image at any position in each frame of image into a YUV format, and extracting a brightness channel of the YUV format; dividing a brightness channel at any position of each frame of image into a plurality of N * N first image blocks, and performing discrete cosine transform on each first image block to obtain an N * N frequency domain coefficient matrix; coding a randomly generated digital watermark to obtain a binary coding sequence; wherein the digital watermark refers to a character string with identification information; and selecting a frequency domain coefficient pair from the frequency domain coefficient matrix, and embedding a binary coding sequence of a one-bit digital watermark in each image block based on the frequency domain coefficient pair, so that each frame of image of the video is embedded with the digital watermark. According to the invention, the problem of insufficient processing efficiency and robustness of a video watermarking algorithm provided by a related technology is solved.

Description

Technical Field

[0001] The present invention relates to the field of image processing, and more specifically, to a method, device, equipment and medium for embedding a digital watermark in a video. Background Art

[0002] With the rapid development of video coding technology and network communication technology, the types of digital video services are increasing, which has also led to a growing demand for video watermarking technology, especially in protecting digital video copyrights.

[0003] Video watermarking technology is often vulnerable to geometric attacks. Due to the huge amount of video data and the need for compression and encoding, the video watermarking algorithms provided by current related technologies are difficult to achieve efficient real-time processing and strong robustness against geometric attacks. Summary of the invention

[0004] The purpose of the present invention is to provide a method, device, equipment and medium for embedding a digital watermark in a video, so as to solve the problem of insufficient processing efficiency and robustness of the video watermark algorithm provided by the related art.

[0005] A first aspect of the present invention provides a method for embedding a digital watermark in a video, the method comprising: Get multiple frames of video, convert part of the image at any position in each frame into YUV format, and extract the brightness channel in YUV format; Divide the brightness channel at any position of each frame image into a plurality of first image blocks of N×N size, perform discrete cosine transform on each first image block, and obtain an N×N frequency domain coefficient matrix; wherein N represents the size information of the first image block; Encoding a randomly generated digital watermark to obtain a binary code sequence; wherein the digital watermark refers to a character string with identification information; A frequency domain coefficient pair is selected from the frequency domain coefficient matrix, and a binary coding sequence of a digital watermark is embedded in each image block based on the frequency domain coefficient pair, so that each frame of the video is embedded with a digital watermark.

[0006] In one implementation, obtaining multiple frames of video images includes: Slice the video to obtain multiple video clips of equal length; Extract multiple frames from video clips.

[0007] In one implementation, the method further includes: Assign tasks to each video clip and obtain the task queue of the video clip; According to the task queue, a memory block is allocated for each task of the video segment based on the task status of each video segment; Find a free memory block in the memory block. If a free memory block is found, the task is assigned to the free memory block to perform the embedding of the digital watermark. If no available memory block is found, the task enters the waiting queue.

[0008] In one implementation, a randomly generated digital watermark is encoded to obtain a binary code sequence, specifically: Get a string with identification information; Use the CityHash algorithm to perform a hash operation on the string with identification information, generate a 64-bit CityHash value, and convert the CityHash value into a binary code sequence.

[0009] In one implementation, selecting a frequency domain coefficient pair from the frequency domain coefficient matrix includes: selecting a frequency domain coefficient pair from a low frequency band or a mid frequency band in the frequency domain coefficient matrix.

[0010] In one implementation, the method further includes: Select an arbitrary position corresponding to the watermark embedded in each frame of image, and divide the partial image at the arbitrary position into a second image block of size N×N; The image format of each second image block is converted from BGR format to YUV format, the brightness channel of the YUV format is extracted, the brightness channel is subjected to inverse discrete cosine transform, and the multi-bit digital watermark embedded in each frame of the image is extracted.

[0011] In one implementation, the embedding strength of a digital watermark embedded in a video can be adjusted.

[0012] A second aspect of the present invention provides a device for embedding a digital watermark in a video, the device comprising: An image acquisition module is used to acquire multiple frames of video images, convert a portion of the image at any position in each frame into a YUV format, and extract a brightness channel in the YUV format; A transformation module, used to divide the brightness channel at any position of each frame image into a plurality of first image blocks of N×N size, perform discrete cosine transformation on each first image block, and obtain an N×N frequency domain coefficient matrix; wherein N represents the size information of the first image block; The encoding module is used to encode a randomly generated digital watermark to obtain a binary code sequence; wherein the digital watermark refers to a character string with identification information; The embedding module is used to select frequency domain coefficient pairs from the frequency domain coefficient matrix, and embed a binary coding sequence of a digital watermark in each image block based on the frequency domain coefficient pairs, so that each frame of the video is embedded with a digital watermark.

[0013] According to a third aspect of the present invention, an electronic device is provided, comprising a processor, a memory, and a computer program stored in the memory and executable by the processor, wherein when the computer program is executed by the processor, the steps of a method for embedding a digital watermark in a video as provided in the first aspect of the present invention are implemented.

[0014] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the steps of a method for embedding a digital watermark in a video as provided in the first aspect of the present invention are implemented.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for embedding a digital watermark in a video, which divides a video with a long time length into multiple video clips with short time lengths, and decodes, frames and embeds watermarks on these clips through multi-threading to ensure the real-time and robustness of the processing. The CityHash algorithm is used to convert the input string into a 64-bit binary watermark sequence, and the watermark is embedded in the frequency domain to prevent information embedding loss. Then, the image is converted from BGR format to YUV format, and the watermark information is embedded in the frequency domain of the brightness channel of the image using discrete cosine transform. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings: Figure 1 A schematic diagram of a flow chart of a method for embedding a digital watermark in a video provided by an embodiment of the present invention; Figure 2 A principle block diagram of a device for embedding a digital watermark in a video provided by an embodiment of the present invention; Figure 3 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0018] It should be noted that the terms "include" or "may include" used in various embodiments of the present application indicate the presence of the function, operation or element applied for, and do not limit the addition of one or more functions, operations or elements. In addition, as used in various embodiments of the present application, the terms "include", "have" and their cognates are only intended to indicate specific features, numbers, steps, operations, elements, components or a combination of the foregoing items, and should not be understood as first excluding the presence of one or more other features, numbers, steps, operations, elements, components or a combination of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or a combination of the foregoing items.

[0019] It should be understood that terms such as "first" and "second" are only used for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0020] Video watermarking technology is often vulnerable to geometric attacks. Due to the huge amount of video data and the need for compression and encoding, the video watermarking algorithms provided by current related technologies are difficult to achieve efficient real-time processing and strong robustness against geometric attacks.

[0021] In view of the problems existing in the related art, the present invention proposes a watermark embedding scheme based on DCT transform, the purpose of which is to enhance the ability to resist geometric attacks. In addition, combined with the idea of ​​decoding to accelerate encoding decisions of FFmpeg, only the relevant frames in the video source stream are decoded, and after embedding watermarks in these frames, the encoding output is re-performed according to the decoding information. As for irrelevant frames, they are spliced ​​in sequence with the modified bit stream after caching to generate a video stream containing the watermark, thereby realizing the embedding of the watermark in the original domain. This method can not only maintain good visual quality, but also effectively reduce redundant calculations and improve computational efficiency. In addition, in order to meet the real-time requirements of watermark embedding during client playback, the present invention also proposes a multi-threaded parallel processing strategy, which significantly improves the efficiency and real-time performance of watermark embedding.

[0022] The method provided in this embodiment will be described in detail below in conjunction with specific implementation methods. Figure 1 , Figure 1 A flow chart of a method for embedding a digital watermark in a video provided by an embodiment of the present invention is shown as follows: Figure 1 As shown, the method includes: S101, obtaining multiple frames of video images, converting a portion of the image at any position in each frame of the image into a YUV format, and extracting a brightness channel in the YUV format.

[0023] In this embodiment, the video is sliced ​​to obtain a plurality of video segments of equal time length, and a plurality of image frames are extracted from the video segments.

[0024] Specifically, FFmpeg is used to decode the video frame data from the specified time period, the video is segmented into 30s long video segments using ffmpeg, and then the images of the video segments are extracted to obtain multiple frames of the video. YUV is a color encoding method that separates the brightness channel (Y) from the chrominance channel (color U and saturation V) to achieve efficient encoding and transmission of images or videos.

[0025] S102, dividing the brightness channel at any position of each frame image into a plurality of first image blocks of N×N size, performing discrete cosine transform on each first image block, and obtaining an N×N frequency domain coefficient matrix; wherein N represents the size information of the first image block.

[0026] In this embodiment, an arbitrary position of the image is taken, and the image size of the arbitrary position is 240*240, the image at the arbitrary position is converted into YUV format, the brightness channel of the YUV format is extracted, and the image is divided into image blocks of size N×N, and the image blocks do not overlap. For each image block, a 2D discrete cosine transform (DCT) is applied to transform the brightness channel, and finally after each image block is transformed, an N×N DCT coefficient matrix M, that is, a frequency domain coefficient matrix, can be obtained.

[0027] For example, a 240×240 QR code image can be divided into 64 image blocks of 30×30 in size.

[0028] S103, encoding a randomly generated digital watermark to obtain a binary code sequence; wherein the digital watermark refers to a character string with identification information.

[0029] In this embodiment, a UID can be input as needed, for example, the UID is a string with identification meaning, such as "trj" or "shudunma", etc., and then a 64-bit CityHash hash value is generated using the CityHash algorithm, and the hash value is converted into a binary sequence.

[0030] S104, selecting frequency domain coefficient pairs from the frequency domain coefficient matrix, and embedding a binary coding sequence of a digital watermark in each image block based on the frequency domain coefficient pairs, so that each frame of the video is embedded with a digital watermark.

[0031] In this embodiment, since the low- and medium-frequency regions of the image have less impact on the visual content and have better stability in common image processing operations (such as compression and scaling), the frequency domain coefficient pairs c1 and c2 are selected in the low-frequency band or medium-frequency band region in the DCT domain for watermark embedding. For example, in each 30×30 image block, the frequency domain coefficient pairs with positions c1= M(15, 19) and c2= M(19, 15) are selected. Then, one watermark bit is embedded for each N×N image block, and the embedding process can be formulated as: , where and are the coefficients of the resulting embedding. w ∈{0, 1} is the watermark to be embedded, Δ is the embedding strength parameter (in this embodiment, it can take any value in the range of 10-50), the purpose is to amplify the difference between the frequency domain coefficient pair c1 and c2. At the same time, the embedding strength parameter controls the strength of the watermark modification, so it is actually a key parameter for controlling robustness. Secondly, the embedding strength of the digital watermark embedded in the video can be adjusted. In this embodiment, the embedding strength is set to 40.

[0032] In some embodiments, the method further includes: assigning tasks to each video clip to obtain a task queue for the video clip; according to the task queue and based on the task status of each video clip, allocating a memory block to the task of each video clip; searching for free memory blocks in the memory blocks, and if a free memory block is found, assigning the task to the free memory block to perform digital watermark embedding, and if no available memory block is found, the task enters a waiting queue.

[0033] In this embodiment, for each video, the start time and duration of each video segment are determined, and the size of the area where the digital watermark needs to be embedded is determined. The task status includes unprocessed, processing, successful processing, and failed processing.

[0034] During the video processing process, first, a memory block pool is initialized. Each memory block in the memory block pool represents an available memory. The memory block will be released and reallocated after the video processing task is completed to avoid insufficient memory.

[0035] After starting task processing, perform the following steps: First, start the task: get the task from the task queue and allocate a memory block. After the allocation is successful, the task enters multi-threaded processing. Second, schedule waiting tasks: when all tasks are allocated, try to schedule the tasks in the waiting queue. Finally, wait for the task to complete: after waiting for all threads to complete execution, retry all failed tasks to ensure that all tasks are processed.

[0036] In order to improve the processing efficiency of video watermark embedding, ThreadPoolExecutor is used to manage the maximum number of concurrent workers, and multi-core CPU resources are used to execute tasks in parallel. The synchronous control of task waiting and scheduling is achieved through condition and lock mechanisms.

[0037] Secondly, it is necessary to create tasks based on the relevant time information of the video clips and add them to the task queue. During the execution of the tasks, they will be processed in the order of creation to ensure the order consistency of the watermark embedding results.

[0038] In some embodiments, the method further includes: selecting an arbitrary position corresponding to the watermark embedded in each frame of the image, dividing the partial image at the arbitrary position into a second image block of N×N size; converting the image format of each second image block from the BGR format to the YUV format, extracting the brightness channel in the YUV format, performing an inverse discrete cosine transform on the brightness channel, and extracting the multi-bit digital watermark embedded in each frame of the image.

[0039] In this embodiment, after embedding, each image block is subjected to an inverse DCT transform, and the image is combined and restored to the size before the image is divided into blocks. The restored image is then subjected to the following operations: 1. For pixels that have not changed after embedding, no operation is performed 2. For pixel values ​​that overflow {0, 255}, perform the following operations: in, Represents the pixel value at position i, j of the image after embedding the watermark, It is the pixel value after the watermark embedding operation.

[0040] 3. For pixel values ​​between [0.255], downgrade or upgrade as follows: ,in, It is the pixel value of the entire image after the watermark embedding operation is performed, and I(i, j) is the pixel value of the image without watermark.

[0041] Please refer to 2, Figure 2 A block diagram of a device for embedding a digital watermark in a video provided by an embodiment of the present invention, such as Figure 2 As shown, the device comprises: The image acquisition module 210 is used to acquire multiple frames of video images, convert a portion of the image at any position in each frame into a YUV format, and extract a brightness channel in the YUV format; The transformation module 220 is used to divide the brightness channel at any position of each frame image into a plurality of first image blocks of N×N size, and perform discrete cosine transformation on each first image block to obtain an N×N frequency domain coefficient matrix; wherein N represents the size information of the first image block; The encoding module 230 is used to encode a randomly generated digital watermark to obtain a binary code sequence; wherein the digital watermark refers to a character string with identification information; The embedding module 240 is used to select frequency domain coefficient pairs from the frequency domain coefficient matrix, and embed a binary coding sequence of a digital watermark in each image block based on the frequency domain coefficient pairs, so that each frame of the video is embedded with a digital watermark.

[0042] In a device for embedding a digital watermark in a video provided by an embodiment of the present invention, a video with a long duration is divided into multiple video segments with a short duration, and these segments are decoded, frame processed and watermarked by multithreading to ensure the real-time and robustness of the processing. The CityHash algorithm is used to convert the input string into a 64-bit binary watermark sequence, and the watermark is embedded in the frequency domain to prevent information embedding loss. Then, the image is converted from BGR format to YUV format, and the watermark information is embedded in the frequency domain of the brightness channel of the image using discrete cosine transform.

[0043] Please refer to Figure 3 , Figure 3 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device 300 includes a processor 310, a memory 320, a communication interface 330, and at least one communication bus for connecting the processor 310, the memory 320, and the communication interface 330. The memory 320 includes, but is not limited to, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (PROM), or a portable CD-ROM, and the memory 320 is used for related instructions and data.

[0044] The communication interface 330 is used to receive and send data. The processor 310 can be one or more CPUs. When the processor 310 is a CPU, the CPU can be a single-core CPU or a multi-core CPU. The processor 310 in the electronic device 300 is used to read one or more programs 321 stored in the memory 320, and perform the following operations: obtain multiple frames of video images, convert a portion of the image at any position in each frame of the image into a YUV format, and extract the brightness channel in the YUV format; divide the brightness channel at any position of each frame of the image into a plurality of first image blocks of N×N size, perform a discrete cosine transform on each first image block, and obtain an N×N frequency domain coefficient matrix; wherein N represents the size information of the first image block; encode a randomly generated digital watermark to obtain a binary coding sequence; wherein the digital watermark refers to a character string with identification information; select a frequency domain coefficient pair from the frequency domain coefficient matrix, and embed a binary coding sequence of a digital watermark in each image block based on the frequency domain coefficient pair, so that each frame of the video is embedded with a digital watermark.

[0045] It should be noted that the specific implementation of each operation can be Figure 1 The corresponding description of the method embodiment shown, the electronic device 300 can be used to execute a method of embedding a digital watermark in a video in the above method embodiment of the present application, which will not be described in detail here.

[0046] In the embodiments of the present disclosure, a computer-readable storage medium is also provided, and the computer-readable storage medium is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both built-in storage media in a computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory (non-volatile memory), such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of a method for embedding a digital watermark in a video in the above embodiment. Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0047] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for embedding a digital watermark in a video, characterized in that: Methods include: Get multiple frames of video, convert part of the image at any position in each frame into YUV format, and extract the brightness channel in YUV format; Divide the brightness channel at any position of each frame image into a plurality of first image blocks of N×N size, perform discrete cosine transform on each first image block, and obtain an N×N frequency domain coefficient matrix; wherein N represents the size information of the first image block; Encoding a randomly generated digital watermark to obtain a binary code sequence; wherein the digital watermark refers to a character string with identification information; A frequency domain coefficient pair is selected from the frequency domain coefficient matrix, and a binary coding sequence of a digital watermark is embedded in each image block based on the frequency domain coefficient pair, so that each frame of the video is embedded with a digital watermark.

2. A method for embedding a digital watermark in a video according to claim 1, characterized in that: Get multiple frames of video, including: Slice the video to obtain multiple video clips of equal length; Extract multiple frames from video clips.

3. A method for embedding a digital watermark in a video according to claim 2, characterized in that: The method further comprises: Assign tasks to each video clip and obtain the task queue of the video clip; According to the task queue, a memory block is allocated for each task of the video segment based on the task status of each video segment; Find a free memory block in the memory block. If a free memory block is found, the task is assigned to the free memory block to perform the embedding of the digital watermark. If no available memory block is found, the task enters the waiting queue.

4. A method for embedding a digital watermark in a video according to claim 1, characterized in that: Encode a randomly generated digital watermark to obtain a binary code sequence, specifically: Get a string with identification information; Use the CityHash algorithm to perform a hash operation on the string with identification information, generate a 64-bit CityHash value, and convert the CityHash value into a binary code sequence.

5. A method for embedding a digital watermark in a video according to claim 1, characterized in that: Selecting a frequency domain coefficient pair from the frequency domain coefficient matrix includes: selecting a frequency domain coefficient pair from a low frequency band or a mid frequency band in the frequency domain coefficient matrix.

6. A method for embedding a digital watermark in a video according to claim 1, characterized in that: The method further comprises: Select an arbitrary position corresponding to the watermark embedded in each frame of image, and divide the partial image at the arbitrary position into a second image block of size N×N; The image format of each second image block is converted from BGR format to YUV format, the brightness channel of the YUV format is extracted, the brightness channel is subjected to inverse discrete cosine transform, and the multi-bit digital watermark embedded in each frame of the image is extracted.

7. A method for embedding a digital watermark in a video according to claim 6, characterized in that: The embedding strength of the digital watermark embedded in the video can be adjusted.

8. A device for embedding a digital watermark in a video, characterized in that: The device includes: An image acquisition module is used to acquire multiple frames of video images, convert a portion of the image at any position in each frame into a YUV format, and extract a brightness channel in the YUV format; A transformation module, used to divide the brightness channel at any position of each frame image into a plurality of first image blocks of N×N size, perform discrete cosine transformation on each first image block, and obtain an N×N frequency domain coefficient matrix; wherein N represents the size information of the first image block; The encoding module is used to encode a randomly generated digital watermark to obtain a binary code sequence; wherein the digital watermark refers to a character string with identification information; The embedding module is used to select frequency domain coefficient pairs from the frequency domain coefficient matrix, and embed a binary coding sequence of a digital watermark in each image block based on the frequency domain coefficient pairs, so that each frame of the video is embedded with a digital watermark.

9. An electronic device, characterized in that: The electronic device includes a processor, a memory, and a computer program stored in the memory and executable by the processor, wherein when the computer program is executed by the processor, the steps of a method for embedding a digital watermark in a video as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, wherein when the computer program is executed by a processor, the steps of a method for embedding a digital watermark in a video as claimed in any one of claims 1 to 7 are implemented.

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