JP3658279B2 - Digital watermark creation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic watermark create how that includes a copyright identification information to be given to music data.
[0002]
[Prior art]
In recent years, various multimedia devices using digital data have become widespread, and music data is also digitally copied from a CD (compact disc) to an MD (mini disc) or distributed via the Internet using a personal computer. The MP3 (MPEG Audio Layer 3) music data is downloaded to a dedicated portable player, and an environment where the user can easily copy in an easy-to-use form is prepared.
[0003]
In this way, music is digitized and recorded, increasing convenience, and the usage forms are diversifying. Even on the music creation side, only a part of the recorded music can be played and copied. The use is increasing, and it is also possible to rearrange the copied parts and reconstruct them so that they appear as if they were original creations.
[0004]
However, since music data is of course a musical work, it is inherently obliged to pay a copyright fee to the copyright holder each time music data is copied or broadcasted. In the present situation where copying is easy, it is very difficult to prevent the infringement of copyright and neighboring rights and to identify the infringer.
[0005]
Therefore, in order to protect the copyright holder's rights and to collect the copyright fee of the music data used, digital watermark technology is used to identify the distribution route and history of each music data. The technique of embedding using is being sought.
[0006]
[Problems to be solved by the invention]
However, particularly in music data, it is difficult to embed copyright information without deteriorating the sound quality of the original music data and to make it difficult to detect the embedded copyright information. There is a problem that copyright information becomes noise to the original music data.
[0007]
In order to avoid this, it is conceivable to embed copyright information as a signal outside the human audible frequency range, for example, about 30 kHz, so that the information is not heard as noise.
[0008]
However, the standard of many digital music data has been determined corresponding to the human audible frequency range, and even music data handled by CD, MD, and MP3 can be completely reproduced by the sampling theorem when considered from the sampling frequency. The upper limit of the frequency to be obtained is about 20 to 22 [kHz].
[0009]
Therefore, even if the copyright information is embedded in the music data using a frequency band that completely exceeds the audible frequency range and is not reliably detected by humans, the copyright information is eventually erased from the music data by digital copying. This is not practical.
[0010]
In addition, the music data is not limited to users who listen to the music by prohibiting illegal copying etc. in the dark, but allows the user to copy and broadcast freely to some extent, It is in accordance with the interests of the copyright holder that the copyright fee as a consideration is collected without fail while expanding the scope of listening to the music.
[0011]
For this purpose, a digital watermark technique for music data that can easily specify a distribution route and history is eagerly desired.
[0012]
The present invention has been made in view of the above circumstances, and its purpose is to minimize the deterioration of the sound quality of the original music data without causing noise while being a signal within the audible frequency range. while there editing music data, compression, copy, not erased conversion, etc., the route of delivery, to provide an electronic watermark creator how for music data such as history can easily identify.
[0013]
According to the first aspect of the present invention, an electronic watermark is created for original music data, which is not included in the music data and includes work identification information composed of a consonant corresponding to the tonality. And a recording step of synthesizing and recording the digital watermark created in the creation step with the music data.
[0014]
If this method is used, the sound quality of the original music data will be almost deteriorated because it is a signal within the audible frequency range but does not cause noise due to its high affinity for music data and does not give the listener a sense of incongruity. In addition, the distribution route and history can be easily specified without being erased even if the music data is edited, compressed, copied, or converted.
[0015]
The invention according to claim 2 is the invention according to claim 1, wherein the consonant includes at least one of a harmony sound, a pedal point, a tension tone, and an approach tone.
[0016]
In such a method, in addition to the operation of the first aspect of the invention, the affinity of the digital watermark sound with respect to the original music data is extremely high, so that even a very deaf listener can hardly detect it. No watermark sound can be created.
[0017]
According to a third aspect of the present invention, in the first aspect of the present invention, only the scale near the upper limit within the audible frequency range is used as the consonant.
[0018]
According to such a method, in addition to the operation of the invention described in claim 1, the watermark sound is limited to a specific frequency band within the audible frequency range, and the watermark sound is analyzed and extracted. In addition, it is possible to set a large amount of digital watermark sound copyright information to be synthesized with music data by using a scale near the upper limit within the audible frequency range, and to specify the distribution route and history. Detailed information can be given.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
[0022]
FIG. 1 shows processing steps of a program for synthesizing and distributing a digital watermark for music data of an MP3 file prepared in advance, which is given as application software for a personal computer, for example.
[0023]
At the beginning, as copyright information to be given to the target music data, JASRAC (JAPANESE Society for Rights of Authors, Composers and publishers) code and data related to copyright rights at that time, The date and time information and the information indicating the contents to be distributed are input (step A01).
[0024]
Here, the JASRAC code is given by registering the music in advance in the JASRAC, and the author, composer, copyright holder, and registration date of the music can be specified by the JASRAC code.
[0025]
Further, as the copyright adjacent right information, the performer who created the music data, the record producer, etc. are input.
[0026]
When the copyright information or the like is input in this way, the tonality and harmony structure of the music data are automatically analyzed (step A02). Based on the analysis result, the affinity of the music data is theoretically determined. An identification code sound with a high consonance is selected (step A03).
[0027]
FIG. 2 exemplifies the principle of a concerto with high affinity with music data. Here, the chord is (C) → “Am7” → “FΔ7” → “ "G7" indicates music data for four measures developed.
[0028]
For such music data, the sound 11 of “C (do)” that is a tonic pedal point and the sound 12 of “G (so)” that is a dominant pedal point may be added as identification chord sounds. it can.
(Here, “pedal point (holding sound)” refers to a full-harmonic common sound that continues one or more sounds even when other sounds move due to chord expansion) .)
In the fourth measure, in addition to the half note of the same pitch as the previous measure, the sound of the tonic pedal point “C (do)” and the dominant pedal point “G (so)” is used. The diminished approach 13 using half notes can be used as the identification code sound.
[0029]
In this case, an 8-bit identification code sound can be represented by the diminished approach 13 composed of eight 16th notes.
(Here, “Diminished Approach” is one of “Dominant Approach Group”, which is one of the methods of “Harmonyization” for constructing a rational harmony in melody. The one used is an “extended diminished approach” if it is described musically correctly, but for the sake of simplicity, it will be simply referred to as “diminished approach” in the following description.) In FIG. In order to facilitate the explanation, it has been described that the identification chord sound that is very slowly developed corresponding to the original music data is selected. However, in actuality, for example, the 128th note is used in the diminished approach 13, As a sequence of sounds that cannot be completely recognized by human hearing, the above copyright information etc. is converted into binary numbers and dimmed. If a new approach is constructed and assigned, the above-mentioned copyright information can be converted into music data using a consonant sound with a data capacity of 128 bits, and the data capacity can be further increased. Easily possible.
[0030]
In this way, an identification code sound that is developed at a sufficiently high speed corresponding to the data amount of copyright information or the like is converted into a frequency band located in the vicinity of the upper limit in the human audible frequency range, for example, 16 [ It is assumed that the sound is composed of kHz] to 20 [kHz] and the sound pressure level with respect to the original music data is sufficiently suppressed.
[0031]
In this case, particularly by limiting the identification code sound to a specific frequency band within the audible frequency range, it becomes easier to analyze and extract the identification code sound later, and particularly near the upper limit within the audible frequency range. By using a scale and making its sound pressure level sufficiently low compared to the original music data, it can hardly be recognized by human hearing and will be disturbed as noise for the original music data. The amount of copyright information data that can be synthesized can be set large because the frequency is high.
[0032]
Therefore, it can be constructed by giving detailed information for specifying the distribution route and history as the copyright information as described above.
[0033]
Then, after the identification code sound thus created is recombined as a digital watermark sound over the entire area of the original music data (step A04), the music data obtained by embedding the digital watermark sound throughout the entire area is synthesized. Is distributed via some recording medium such as MD, CD-R, memory card, or communication medium such as the Internet (step A05), and the processing of FIG.
[0034]
In the above description, the copyright information has been described as a digital watermark composed of tonic pedal points that are consonants, dominant pedal points, and identification chord sounds based on a diminished approach, but this is not restrictive. It only needs to be able to analyze the harmonic composition of the data and cooperate with the harmonics, and in addition to the above, it has a theoretical meaning in terms of music such as other harmonics, pedal points (holding sounds), tension tones, and approach tones. It is also possible to use a certain pitch, and in any case, by using a consonant that has a high affinity for the original music data, the listener is almost aware of the identification data sound while being heard along with the original music. Copyright information etc. can be given without obstructing the musical impression.
[0035]
In addition, the copyright information by the identification code sound synthesized with the music data is not part of the music data, but is synthesized over the entire bar as described above. Even if copying, division, and reconstruction are performed, it is possible to reliably specify the distribution source of the music data.
[0036]
Next, if you have a recording medium on which music data that should have been delivered by synthesizing the above digital watermark sound is available, or obtained from a site that you do not remember delivering via a network such as the Internet In this case, a processing step for determining whether or not the music data has been distributed via a regular route will be described.
[0037]
FIG. 3 shows the processing steps of a program for analyzing a digital watermark sound synthesized with given music data, which is given as application software for a personal computer, for example.
[0038]
Note that this personal computer has a database in which copyright information and the like corresponding to all music data distributed in the past are stored in advance.
[0039]
At the beginning of the processing, by analyzing the waveform of the given music data, if the identification chord sound corresponding to the tonality is synthesized, it is extracted (step B01). It is determined whether or not the identification code sound has been synthesized (step B02).
[0040]
If it is determined that the identification code sound could not be extracted and was not synthesized, the music data was created without the permission of the copyright holder, so the music data was immediately illegal. The use is displayed as a message (step B03), and the process is terminated.
[0041]
If it is determined in step B02 that the identification code sound can be extracted and synthesized, the database is searched based on the content of the identification code sound (step B04), and the corresponding copyright information, etc. It is determined whether or not there is (step B05).
[0042]
Here, when the copyright information corresponding to the database is not stored, or when a plurality of identification code sounds are synthesized with the music data and a plurality of copyright information is searched (without permission from the copyright holder). If the music data of the medley has been created in step S3), a message indicating that the music data is illegally used is displayed (step B03), and the process is terminated.
[0043]
If the copyright information corresponding to the database is stored in step B05, it is determined that the music data has not been created illegally, and distribution based on the copyright information is performed. After displaying the history, distribution route, and the like (step B06), the process is completed.
[0044]
By displaying the distribution history, distribution route, etc. based on the copyright information in this way, the music data was obtained through an appropriate route by considering the background of the acquisition of the music data. It can be easily verified whether there is any copyright fee already paid.
[0045]
In the above embodiment, the processing of FIG. 1 has been described as a program for MP3 file music data prepared in advance as application software for a personal computer. However, the original music data is, for example, If there is data that originally represents a musical scale, such as MIDI data, it is possible to generate and give an identification code sound that is very musically compatible as a digital watermark sound to be synthesized more easily. It becomes possible.
[0046]
Further, the above embodiment describes the digital watermark that is not erased even if the music data is digitally copied, but it is combined with the original digital data that is erased by copying. If the distribution is made later, it is possible to easily determine whether the music data is the primary copy or the secondary copy when the processing as shown in FIG. 3 is executed later.
[0047]
In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.
[0048]
Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, at least one of the problems described in the column of the problem to be solved by the invention can be solved, and described in the column of the effect of the invention. In a case where at least one of the obtained effects can be obtained, a configuration in which this configuration requirement is deleted can be extracted as an invention.
[0049]
【The invention's effect】
According to the first aspect of the present invention, the sound quality of the original music data is hardly deteriorated because it is a signal within the audible frequency range but does not cause noise due to its high affinity with music data and does not give the listener a sense of incongruity. The distribution route and history can be easily specified without being deleted, and without being erased even after editing, compression, copying, and conversion of music data.
[0050]
According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, the affinity of the digital watermark sound with respect to the original music data is extremely high, so that even a very good listener can be almost detected. A digital watermark sound can be created.
[0051]
According to the invention described in claim 3, in addition to the effect of the invention described in claim 1, the watermark sound is limited to a specific frequency band within the audible frequency range, so that the watermark sound is analyzed and extracted. In particular, by using a scale near the upper limit within the audible frequency range, the data amount of the digital watermark sound copyright information synthesized with the music data can be set large, and the distribution route and history Detailed information for specifying can be given.
[Brief description of the drawings]
FIG. 1 is a flowchart showing processing steps of a program for synthesizing and distributing a digital watermark sound according to an embodiment of the present invention.
FIG. 2 is a view for explaining the principle of digital watermark sound generation according to the embodiment;
FIG. 3 is a flowchart showing processing steps for determining appropriate / inappropriate for music data according to the embodiment;
[Explanation of symbols]
11 ... Tonic pedal point 12 ... Dominant pedal point 13 ... Diminished approach

Claims (3)

A creation step of creating a digital watermark including copyright identification information that is not included in the music data and is composed of a consonant corresponding to the tonality of the original music data;
A digital watermark creating method comprising: a recording step of synthesizing and recording the digital watermark created in this creation step with the music data.   2. The digital watermark creating method according to claim 1, wherein the consonant includes at least one of a harmony sound, a pedal point, a tension tone, and an approach tone.   2. The digital watermark creating method according to claim 1, wherein only the scale near the upper limit in the audible frequency range is used as the consonant.

Images