JP2005241796A - Embedding method of electronic watermark, and reproducing device of acoustic signal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an embedding method of an electronic watermarks for music materials that consist of multi-tracks, while will not give any deterioration whatsoever in the combined music quality and making it difficult to eliminate the electronic watermarks embedded in each music material. <P>SOLUTION: When a plurality of acoustic signals A and B is combined and reproduced as an acoustic signal C, an acoustic signal D in which a voice message is recorded and acoustic signals -D, in which positive and negative codes of the signal D are reversed, are combined beforehand and made into acoustic signals A' and B'. When the acoustic signals A' and B' are combined and reproduced, the acoustic signals D and -D are canceled and reproduced as the acoustic signal C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a digital watermark embedding technique suitable for production, distribution, and distribution of package music for viewing in consumer / business applications using CD / DVD.

  In CD and DVD audio, high-quality original sound is stored in an uncompressed manner, and in recent years anyone can easily and inexpensively create a copy of the same quality as the original disc using a personal computer. The importance is increasing. In particular, since the music material data becomes a material for creating various music by synthesis, the usage range of the music material is greatly expanded and the copyright management becomes serious.

  As a method of copyright management, there is a method of inserting a digital watermark into music data (see, for example, Patent Documents 1 to 3), but some modification is made to the original music data, Quality degradation was inevitable. In addition, if the level of the watermark information is reduced in order to suppress deterioration, the watermark information is erased by signal processing such as compression.

JP-A-11-145840 JP-A-11-219172 Japanese Patent No. 3321767

  The invention described in Patent Document 1 is a simple method of assigning the lower bits of the 24 bits to the digital watermark. However, if the dynamic range is reduced by 2 bits and signal processing such as smoothing is applied, the digital watermark can be simplified. Can be removed. Further, the invention described in Patent Document 2 is to insert a digital watermark where there is a lot of noise at the beginning of music and make the deterioration inconspicuous due to the masking effect. Easy to remove watermark. Further, the invention described in Patent Document 3 is to insert a digital watermark at a place where the rate of change of the signal is large and to make the deterioration inconspicuous due to the masking effect. It is easy to find the part and remove the watermark.

  In view of the above points, the present invention eliminates the digital watermark embedded in each music material without degrading the synthesized music quality for the music material composed of multi-tracks. It is an object of the present invention to provide an electronic watermark embedding method that is difficult to perform.

  In order to solve the above problems, in the present invention, as a method of embedding an identification acoustic signal as a digital watermark for a plurality of material acoustic signals that are combined to generate a reproduced acoustic signal, identification that serves as a digital watermark is performed. An identification signal creating stage for creating an acoustic signal; a composite position setting stage for selecting two or more material acoustic signals from the plurality of material acoustic signals and setting a composite position having the same length as the identification acoustic signal; and the identification An identification signal synthesis step of synthesizing at least one or more acoustic signals by addition and at least one or more by subtraction is provided at the synthesis position of the two or more selected material acoustic signals.

  According to the present invention, since the same identification sound signal is synthesized by addition or subtraction at the same time of a plurality of material sound signals, the digital watermark is deleted from each material sound signal in which the digital watermark is embedded. On the other hand, there is an effect that the music quality is not deteriorated at all when a plurality of material acoustic signals are synthesized and reproduced.

(1. Basic principle of embedding)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the basic principle of the digital watermark embedding method according to the present invention will be described. FIG. 1 is a diagram showing a general composition of two digital acoustic signals. 1A to 1C, the horizontal axis represents the time axis and the vertical axis represents the amplitude. When the digital acoustic signal (source waveform data) A shown in FIG. 1 (a) and the digital acoustic signal (source waveform data) B shown in FIG. 1 (b) are synthesized, the amplitudes at each time are simply added together. become. As a result, a digital acoustic signal (synthetic waveform data) C as shown in FIG. 1C is obtained. In FIGS. 1A to 1C, a horizontal line indicated by a bold line indicates an amplitude value of 0, and a positive value and a lower value are indicated above the bold line.

  FIG. 2 is a diagram illustrating how a digital watermark is embedded in the digital audio signal A. FIG. 2A shows the waveform of the digital acoustic signal A, which is exactly the same as FIG. FIG. 2B shows a waveform of a digital acoustic signal (watermark waveform data) D to be embedded as a digital watermark. FIG. 2C is a diagram showing a waveform of a digital acoustic signal A ′ obtained by synthesizing the digital acoustic signal A shown in FIG. 2A and the digital acoustic signal D shown in FIG. As described above, the synthesis of the digital audio signal A and the digital audio signal D is performed by adding the amplitudes at each time.

  FIG. 3 is a diagram illustrating a state in which a digital watermark is embedded in the digital audio signal B. FIG. 3A shows the waveform of the digital acoustic signal B, which is exactly the same as FIG. FIG. 3B is a diagram showing a waveform of a digital acoustic signal -D to be embedded as a digital watermark. As can be seen by comparing FIG. 3B and FIG. 2B, the digital acoustic signal -D is obtained by inverting the sign of the amplitude value of each time of the digital signal D. However, if the sign is inverted, it will sound exactly the same when reproduced as an acoustic signal. FIG. 3C shows a waveform of a digital acoustic signal B ′ obtained by synthesizing the digital acoustic signal B shown in FIG. 3A and the digital acoustic signal −D shown in FIG. As described above, the synthesis of the digital acoustic signal B and the digital acoustic signal -D is performed by adding the amplitudes at the respective times.

  FIG. 4 is a diagram showing how the digital acoustic signal A ′ and the digital acoustic signal B ′ are synthesized. FIG. 4A shows the waveform of the digital acoustic signal A ′, which is exactly the same as FIG. FIG. 4B shows the waveform of the digital acoustic signal B ′, which is exactly the same as FIG. FIG. 4C is a diagram showing a waveform of a digital acoustic signal C obtained by synthesizing the digital acoustic signal A ′ shown in FIG. 4A and the digital acoustic signal B ′ shown in FIG. As described above, the synthesis of the digital acoustic signal A ′ and the digital acoustic signal B ′ is performed by adding the amplitudes at each time. The resulting digital acoustic signal C is exactly the same as the digital acoustic signal C obtained when the digital acoustic signal A and the digital acoustic signal B are synthesized. This is because the digital acoustic signal D embedded in the digital acoustic signal A ′ and the digital acoustic signal −D embedded in the digital acoustic signal B ′ cancel each other out at each time.

  If a material sound signal is recorded as the digital sound signal A and the digital sound signal B as described above, and a human voice is recorded as the digital sound signal D and the digital sound signal -D, the digital sound signal A ′ When the digital audio signal B ′ is reproduced, the sound is superimposed on the music material, but when the digital audio signal C, which is the synthesized reproduction audio signal, is reproduced, only the synthesized music is heard. It will be.

(2. Preparation of material acoustic signal)
Next, a specific method of the digital watermark embedding method according to the present invention will be described. In the present embodiment, a case will be described in which a material acoustic signal to be used for a playback apparatus that synthesizes and reproduces material acoustic signals set in five tracks is used. If the user can select, for example, five pieces of music for each track in the playback apparatus, a total of 25 material acoustic signals are required. Therefore, first, 25 analog material sound signals are obtained by digitizing analog material sound signals obtained by recording or the like. Digitization of the analog material acoustic signal is performed using a conventional general PCM technique. Specifically, an analog sound signal is sampled at a predetermined sampling frequency, and an amplitude is converted into digital data using a predetermined number of quantization bits. The acoustic signal digitized in this way becomes a set of time series of samples having a value corresponding to the number of quantization bits. For example, when the sampling frequency is 44.1 kHz and the number of quantization bits is 16 bits, an analog sound signal for 1 second is converted into a digital sound signal composed of 44100 samples having values of -32768 to 32767. Become.

  In order to synthesize a plurality of material sound signals and reproduce them as one reproduced sound signal, it is necessary to process the material sound signals to be combined so that the reproduction times are the same. This is based on one material sound signal, and each sample of other material sound signals (quantized with a predetermined number of bits at each time) is synchronized temporally and musically with the material sound signal used as a reference. The process of adjusting is performed. In the present embodiment, each material sound signal is created by dividing it into parts such as melody, chord, rhythm, etc. so that the user who reproduces can freely change the music composition. Each material acoustic signal is obtained by converting an analog acoustic signal into digital data by a method such as PCM as described above.

  Here, the material acoustic signal set as five tracks will be described. FIG. 5 schematically shows the signal waveform of the material acoustic signal of each track. In the example of FIG. 5, the case where each material acoustic signal is a stereo acoustic signal composed of two left and right (LR) channels is shown. In FIG. 5, for simplification of description, a portion where the amplitude value of the signal has a level higher than a certain level, that is, a non-silence portion, shows a waveform with the same amplitude, and a silence portion is shown with no waveform. . When combining and playing music from multiple tracks and making it possible to select multiple songs for each track, to ensure that the combined music is decent regardless of the combination In addition, each material acoustic signal needs to be created according to a predetermined rule. Therefore, each track is configured such that, regardless of which piece of music is selected, the temporal positions of the silent section and the silent section are basically the same. That is, for example, the five material acoustic signals prepared for the track 1 have a silent part (sounded part) and a silent part at the same position, in order to avoid a lack of musical change. The lengths of the non-silence portion and the silence portion are also changed somewhat within a range that does not hinder the music rules.

  When the material acoustic signal having the waveform as shown in FIG. 5 is synthesized and reproduced, the sound from the track 1 and the track 5 is first heard, and then the sound from the track 5 disappears and the sound from the track 3 is heard. Next, the sound from track 1 and track 3 disappears and the sound from track 2 and track 4 is heard. Next, the sound from tracks 2 and 4 disappears and the sound from tracks 1 and 3 Then, the sound from the track 3 disappears, the sound from the track 5 is heard, and finally the sounds from the track 1 and the track 5 disappear.

(3. Embedding digital watermark)
When the material acoustic signal having the waveform having the characteristic as shown in FIG. 5 is prepared, the identification acoustic signal is embedded in each material acoustic signal as a digital watermark. Creation of the identification acoustic signal and embedding of the created identification acoustic signal in the material acoustic signal are performed by a dedicated device. However, such a dedicated device is realized by installing dedicated software on a general-purpose computer. First, in such a dedicated device, an identification acoustic signal is created. In the present embodiment, as described above, a digital identification acoustic signal that produces a human voice as a message is used as a digital watermark. Since the dedicated device has a voice synthesis function for converting text data into a digital sound signal, the creator inputs a message to be recorded as a digital watermark in the form of text data. For example, text may be directly input from a keyboard or the like connected to a computer used as a dedicated device. The input text data is converted into a digital identification sound signal by a known speech synthesis technique. For example, create a message that identifies the author, such as “This music material is copyrighted by XX. Copying without permission from XX infringes copyright.” It is desirable to keep it. Of course, as a message, a voice spoken by a person may be recorded as it is and digitized to generate an identification acoustic signal. In the present specification, the terms identification acoustic signal, digital watermark, and voice message are used. However, the “voice message” means the content itself to be transmitted as voice, and is real voice, Regardless of whether the sound is artificially synthesized, both are included. “Identification sound signal” means a digital sound signal obtained by recording a voice message or the like and digitizing it, and “digital watermark” is the same as “watermark printing” used for preventing counterfeiting of vouchers. By embedding electronically so that another identification sound signal can be heard overlapping with the material sound signal at the same time, it gives the effect of suppressing duplication of the original material sound signal. When used without permission, it means that a voice message is played back on the music, so that the listener can be warned that the music has been produced using the work of a third party without permission. To do.

  Subsequently, a material acoustic signal is read by the dedicated device, and processing for embedding a digital watermark in the material acoustic signal is performed. That is, the identification acoustic signal is synthesized. Specifically, the dedicated device displays the read material acoustic signal as waveform information on the screen, and allows the creator to specify the position to be embedded on the screen. The creator specifies the position to be embedded on the screen. In this case, the identification acoustic signal (message) may be embedded in an arbitrary place (or embedded in the entire region of the material acoustic signal), or the present invention. However, it is desirable to bury the silent part as much as possible. This is because, when embedded in the silent portion, when lossless compression described later is applied, the amount of information increases by the amount of the embedded data, resulting in a demerit that compression efficiency decreases. In addition, the silence part has a weak need for copyright protection, and if the identification sound signal is embedded only in the silence part, it can be cut off and the non-silence part can be used, thus preventing illegal duplication. This is because cannot be obtained. Since it is almost impossible to separate the music from the message if it is placed in the non-silent part, even if the duplication is illegal, the duplicator cannot use the music itself, and it is possible to suppress illegal duplication. Moreover, it is necessary to embed data in which the positive and negative signs of all the samples constituting the signal waveform are inverted at the same time so that the identification acoustic signal is removed when synthesized with a plurality of tracks. For example, in the example of FIG. 6, the identification acoustic signal Da is embedded in the head portion of the track 1, and the identification acoustic signal −Da obtained by inverting all the sample values of the identification acoustic signal Da and the sign is embedded in the head portion of the track 5. . As a result, when the track 1 and the track 5 are synthesized and reproduced, the synthesized value of all the samples embedded as the digital watermark becomes 0, so that the message cannot be heard. Similarly, the identification acoustic signals Db, De and Df embedded in the track 1 are canceled by the identification acoustic signals -Db and -De of the track 3 and the identification acoustic signal -Df of the track 5 at the same time, respectively. Further, the identification acoustic signals Dc and Dd embedded in the track 2 are offset by the identification acoustic signals -Dc and -Dd of the track 4 at the same time, respectively. Note that the identification acoustic signal Da and the identification acoustic signal -Da are obtained by inverting the amplitude value at each time and can be heard as exactly the same message when reproduced independently. The same applies to the identification acoustic signal Db to the identification acoustic signal Df. The identification acoustic signal Da to the identification acoustic signal Df may all be the same message, or may be six different messages.

  In the example of FIG. 6, the message is canceled by combining two material acoustic signals, but the message may be canceled by combining three or more material acoustic signals. For example, in order to cancel the message by synthesizing three material acoustic signals, when the identification acoustic signal Da is put in the track 1, the signs of the identification acoustic signal Da are inverted at the same time in the track 2 and the track 3. In addition, the identification acoustic signal -Da / 2 having an amplitude halved may be embedded.

  As described above, for the five material acoustic signals that can be selected in the same track, the identification acoustic signal is embedded in the same position. That is, in principle, an embedding process corresponding to that shown in FIGS. 2 and 3 is performed.

(4. Lossless compression)
The material acoustic signal in which the digital watermark is embedded as described above is recorded on a recording medium such as a CD or a DVD. At this time, it is desirable to perform data compression in order to reduce the amount of data. Various known methods can be used as the data compression method. However, in order to ensure that the digital watermark is correctly deleted when multiple material acoustic signals are combined, data loss is lost before and after compression. It is necessary to adopt a lossless compression method without any problem.

(5. Playback device)
Next, a playback device that plays back the material acoustic signal will be described. This playback device extracts a plurality of material acoustic signals and reproduces them as music by synthesizing and reproducing them. In the present embodiment, as described above, a case where five material acoustic signals are synthesized and reproduced as one piece of music will be described as an example.

  The apparatus for reproducing an acoustic signal according to the present invention is realized by installing dedicated software on a general-purpose computer. When playing music with such a playback device, the user causes the playback device to read the recording medium on which the material acoustic signal created as described above is recorded. Then, the playback apparatus displays a material acoustic signal designation screen as shown in FIG.

  At this time, a screen for specifying the material acoustic signal to be displayed is shown in FIG. In FIG. 7, the material acoustic signal can be specified in a matrix, and five tracks can be selected. As an option, a check column is provided on the left side of the track name, and a material acoustic signal selection area and a level (volume) designation column are provided on the right side of the track name. In the standard usage mode, all the five tracks are checked, but the user can uncheck and synthesize and play with less than four tracks. However, in this case, the digital watermark remains without being canceled. In the example of FIG. 7, the level designation is the standard value “100” for all five tracks, but this does not mean that the five encoded data are synthesized at the same volume ratio, and the volume adjusted by the producer in advance. It will be synthesized at a ratio. The volume ratio of the signal waveform when the five tracks are combined is set in advance by adjusting the amplitude of the signal waveform data on the producer side. If the level designation is set to “100”, the producer Will be synthesized at the intended volume ratio. The level specification can be changed so that the user has a ratio different from the creator's intention, but in this case also, the digital watermark remains without being canceled. The set level for each track is given to the sound signal reproducing unit in addition to the composition ratio of the material sound signal set in advance by the producer.

(6. Reproduction of acoustic signal)
The material acoustic signal extracted as described above is reproduced by the acoustic signal reproducing unit of the reproducing apparatus. The acoustic signal reproduction unit is a part having a function of synthesizing the material acoustic signal extracted in the reproduction apparatus to obtain a reproduction acoustic signal, converting the analog signal into an analog signal, and reproducing it as sound, and using various known ones An example is described here.

  FIG. 8 is a functional block diagram showing details of the acoustic signal reproducing unit in the present embodiment. The acoustic signal reproducing unit shown in FIG. 8 reads lossless compressed encoded data as a material acoustic signal, decodes and synthesizes it, and reproduces it. In FIG. 8, 1 is a compressed block reading means, 2 is a block decoding means, 3 is a synthesis ratio setting means, 4 is a waveform synthesis processing means, 5 is a synthesis block storage means, 6 is a sound device driver, 7 is a sound device, 8 Is a timer.

  The compressed block reading unit 1 has a function of reading data in compressed block units from a compressed encoded data file. The block decoding means 2 has a function of decoding the read compressed block and restoring it to an uncompressed block that is in a state before compression encoding. The composition ratio setting unit 3 has a function of setting a ratio at which a plurality of uncompressed blocks are to be combined. The waveform synthesis processing unit 4 has a function of synthesizing a plurality of uncompressed blocks decoded by the block decoding unit 2, so-called digital waveform data, at a synthesis ratio set by the synthesis ratio setting unit 3. The synthesized block accumulating means 5 has a plurality of buffer memories for accumulating synthesized synthesized blocks, and the synthesized blocks accumulated in these buffer memories are converted into FIFO (first-in first-out) method, that is, first. It has a function of processing incoming information in a way that goes out first. That is, the synthesis block accumulating unit 5 has a function of accumulating the synthesis blocks input from the waveform synthesis processing unit 4 in the input order and passing them to the sound device driver 6 in that order. The sound device driver 6 has a function of driving the sound device 7 to reproduce the synthesized block sound, and the sound device 7 has a function of D / A converting the synthesized block that is digital data and reproducing it as sound. Have. That is, the sound device driver 6 and the sound device 7 function as synthetic block reproduction means. The timer 8 is a timer used for timing the reproduction of the acoustic signal by the sound device and the reproduction of the acoustic signal of the external device, and is shared with a timer that performs time management in the computer.

  Next, the processing operation of the acoustic signal reproduction unit shown in FIG. 8 will be described. First, the compressed block reading means 1 reads each encoded data block by block. Next, the encoded data read by the block decoding means 2 is decoded in units of blocks. Specifically, by performing a decoding process corresponding to the encoding method, the sample of the original digital audio signal is restored in units of blocks, and an uncompressed block is obtained.

  In the acoustic signal reproducing unit according to the present embodiment, the decoding process is performed a plurality of times for each read encoded data. As a result, a plurality of uncompressed blocks are obtained almost simultaneously.

  Subsequently, the plurality of uncompressed blocks obtained are synthesized by the waveform synthesis processing means 4 to generate a synthesized block. Specifically, it is performed by adding each sample constituting each uncompressed block multiplied by the synthesis ratio. This composition ratio is set by the composition ratio setting means 3. Specifically, the level ratio of each track set on the designation screen shown in FIG. 7 is set as the synthesis ratio. As described above, in order to completely erase the digital watermark, the ratio of each track needs to be set to be the same. When all the tracks are set at the same ratio, the digital watermark is deleted by synthesis. This is based on the principle described with reference to FIG. As a result of this synthesis, a synthesis block is obtained. Therefore, the voice message or the like included in the uncompressed block is deleted in this synthesized block.

  The synthesized block obtained by synthesizing by the waveform synthesis processing unit 4 is accumulated in the synthesized block accumulating unit 5. In this embodiment, since it is possible to store up to 4 blocks in the synthetic block storage means, the processing by the sound device driver 6 is not started until 4 blocks are stored. As shown in FIG. 9, when four synthesized blocks are accumulated in the synthesized block accumulating unit 5, the sound device driver 6 acoustically reproduces the first block among the synthesized blocks accumulated in the synthesized block accumulating unit 5. Specifically, the sound device 7 performs D / A conversion on the synthesized block data and outputs it to the speaker. The synthesized block that has been acoustically reproduced is deleted from the synthesized block storage means 5.

  When the synthesized block is deleted and there is room in the synthesized block storage unit 5, the synthesized block synthesized by the waveform synthesis processing unit 4 is input to the synthesized block storage unit 5. As a result, the combined block storage means 5 is stored up to the maximum capacity again. The synthesized block synthesized by the waveform synthesis processing means 4 is actually put into the synthesized block storage means 5 when the CPU functions as a synthesized block throwing means. This synthesis block input means not only simply inputs the synthesis block into the synthesis block storage means 5, but also when the synthesis block storage means 5 has no free space, the compressed block reading means 1, the block decoding means 2, and the waveform synthesis processing. A signal for interrupting processing is sent to the means 4 to control the input of the synthesis block to the synthesis block storage means 5.

  On the other hand, the sound device driver 6 sequentially reproduces the sound of the first block among the synthesized blocks stored in the synthesized block storage means 5. At this time, the sound device driver 6 sends a signal permitting execution of each process to the synthesis block input unit, the compressed block reading unit 1 and the block decoding unit 2 every time the sound reproduction of one synthesis block is finished. .

  Here, the outline of the processing in the acoustic signal reproducing unit is organized and shown in the flowchart of FIG. First, the synthesis block input means searches for a vacant buffer memory in the synthesis block storage means 5 (step S1). When there is no free buffer memory, a signal for interrupting the processing is sent to the compressed block reading means 1, the block decoding means 2, and the waveform synthesis processing means 4, and waiting for reception of a reproduction end signal from the sound device driver 6. (Step S2). If there is a reproduction end signal from the sound device driver 6, it is deleted from the buffer memory storing the synthesized block for which reproduction has been completed (step S3). Since the reproduction end signal from the sound device driver 6 is simultaneously transmitted to the synthesis block input unit, the compressed block reading unit 1, the block decoding unit 2, and the waveform synthesis processing unit 4, the compressed block reading unit 1 and the block decoding unit 2 are also transmitted. Then, the waveform synthesis processing means 4 restarts the process, and decoding of the uncompressed block and synthesis of the uncompressed block are performed (step S4). Subsequently, the composite block is stored in an empty buffer memory (step S5). On the other hand, the sound device 7 always searches the buffer memory in the synthesized block storage means 5 (step S6), and if a synthesized block exists, the synthesized block is reproduced (step S7). Waiting for the reproduction of one synthesis block (step S8), when the reproduction is completed, a reproduction end signal is transmitted to the synthesis block input means, the compressed block reading means 1, the block decoding means 2, and the waveform synthesis processing means 4 (step S9). .

  As described above, each means controls each other and operates, so that an acoustic signal can be reproduced seamlessly. It is also possible to perform using the timer 8 in synchronization with an external performance device. Specifically, the timing of the sound reproduction by the sound device 7 and the sound reproduction of the external performance device is matched by supplying the clock signal of the timer 8 as a synchronization signal from the performance device external to the present device. . As a method of matching the timing in hardware, a method of supplying the synchronization signal instead of generating a clock signal of the timer 8 that drives D / A conversion of the sound device 7 by an autonomous oscillator can be mentioned. Further, as a method of matching the timing in terms of software, the recommended playback start time of the uncompressed block played by the sound device driver 6 is compared with the real time time code obtained from the clock signal of the timer 8, If the recommended playback start time for an uncompressed block is delayed compared to the real time, the data of the uncompressed block is reduced by the delayed time, and the recommended playback start time for the uncompressed block advances compared to the real time. In such a case, there is a method of controlling the reproduction start time so that the reproduction start time of the non-compressed block matches the real time code. In this method, if the delay or advance time is significantly large, the seamlessness of the performance is hindered.However, since the time to adjust for each uncompressed block is generally smaller than the block length, the playback quality is almost improved. There is no hindrance.

  By synthesizing and playing the material sound signal with the digital watermark embedded as described above, no message is recorded in the reproduced sound signal and only music can be heard. When it is attempted to divert only by copying only the embedded message, it is difficult to remove the embedded message, so that the reproduction of the material acoustic signal can be suppressed.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and has substantially the same configuration as the technical idea described in the claims of the present invention, and has the same operational effects or equivalents thereof. Is included in the technical scope of the present invention.

It is a figure which shows the mode of the general synthesis | combination of two digital sound signals. It is a figure which shows a mode that a digital watermark is embedded in the digital acoustic signal A. FIG. It is a figure which shows a mode that a digital watermark is embedded in the digital acoustic signal B. FIG. It is a figure which shows a mode that the digital acoustic signals which embedded the electronic watermark are synthesize | combined. It is the figure which showed the signal waveform of the material acoustic signal typically. It is a figure which shows the embedding position of the identification acoustic signal Da to a raw material acoustic signal. It is a figure which shows the designation | designated screen of the material acoustic signal in an acoustic signal reproducing | regenerating apparatus. It is a functional block diagram which shows the detail of an acoustic signal reproducing part. It is a figure which shows the acoustic signal reproduction | regeneration part of the state by which the synthetic | combination block was accumulate | stored. It is a flowchart which shows in an acoustic signal reproduction | regeneration part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Compression block reading means 2 ... Block decoding means 3 ... Composition ratio setting means 4 ... Waveform composition processing means 5 ... Synthesis block storage means 6 ... Sound device driver 7 ... Sound device 8 ... Timer

Claims (9)

A method of embedding an identification acoustic signal as a digital watermark for a plurality of material acoustic signals that are combined to generate a reproduced acoustic signal,
An identification signal creation stage for creating an identification acoustic signal that serves as a digital watermark;
A composite position setting step of selecting two or more material acoustic signals from the plurality of material acoustic signals and setting a composite position having the same length as the identification acoustic signal;
An identification signal synthesizing step for synthesizing the identification acoustic signal at the synthesis position of the selected two or more material acoustic signals by adding at least one or more and subtracting at least one or more;
An electronic watermark embedding method for an audio signal, comprising: In claim 1,
The synthetic position setting step detects a silent part region for the two or more selected material acoustic signals, and selects and sets a position that is not a silent part in all selected material acoustic signals. A method for embedding a digital watermark into an acoustic signal. In claim 1,
The method for embedding a digital watermark in an acoustic signal, wherein the identification acoustic signal created in the identification signal creating step is a recording of contents expressed by voice. In claim 1,
The method of embedding a digital watermark in an acoustic signal, wherein the identifying signal creating step creates the identifying acoustic signal by text-to-speech synthesis based on text data capable of identifying a copyright source. In claim 1,
When each material acoustic signal is a stereo signal composed of a plurality of channels,
The identification signal creation step creates an identification acoustic signal composed of a plurality of channels,
The method of embedding a digital watermark in an acoustic signal, wherein the identification signal synthesis step performs synthesis on a synthesis position composed of a plurality of channels. In claim 1,
The synthesis position setting step and the identification signal synthesis step are repeatedly executed to synthesize a plurality of identification sound signals into a plurality of synthesis positions and to synthesize the same identification sound signal into a plurality of different synthesis positions. A method for embedding a digital watermark in a signal. In claim 1,
A method for embedding a digital watermark in an acoustic signal, comprising a compression coding step for performing lossless compression on each material acoustic signal synthesized with the identification acoustic signal after the identification signal synthesis step.   A recording medium storing a plurality of material acoustic signals obtained by synthesizing the identification acoustic signal by an electronic watermark embedding method for the acoustic signal based on any one of claims 1 to 7. A plurality of material sound signals obtained by combining identification sound signals created as digital watermarks are read, and a plurality of the material sound signals are combined to create a reproduction sound signal in a state where the identification sound signals are erased. A sound signal reproducing apparatus.

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