JP2001343974A - Method of generating digital watermark and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a digital watermark for music data which does not become noise even though the watermark signals are located within an audible frequency range, which is not erased by conducting editing, compressing, copying and converting the music data while degradation in tone quality of original music data is minimized and which enables the route and the history of distribution to be easily specified. SOLUTION: Digital watermark sound is generated to include copyright identification information made up with a tonic pedal point 11 and a dominant pedal point 12 as a consonance corresponding to the key characteristic of the original music data, for example. Then, the generated digital watermark sound and the music data are synthesized and recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital watermark creation method including copyright identification information to be given to music data, and a recording medium in which the created digital watermark sound is combined with original music data and recorded.

[0002]

2. Description of the Related Art In recent years, various multimedia devices based on digital data have become widespread and widely used. Music data can be digitally copied from a CD (compact disc) to an MD (mini disc) or by using a personal computer. There is an environment where copying can be easily performed in a format that is easy for the user to use, such as downloading music data of MP3 (MPEG audio layer 3) distributed via the Internet to a dedicated portable player.

[0003] In this way, music is digitized and recorded, and the convenience is enhanced, so that the usage form is diversified. On the music creation side, only a part of the recorded music is reproduced and reproduced. Increasingly, they are being copied and used, and it is also possible to rearrange the copied parts and reconstruct them as if they were original creations.

However, since music data is of course a music work, it is originally obliged to pay a copyright fee to the copyright owner every time the music data is copied or broadcasted. Under the current situation where digital data can be easily copied, it is extremely difficult to prevent infringement of copyrights and neighboring rights and to reliably identify infringers.

Therefore, in order to protect the rights of the copyright holder and to reliably collect the copyright fee of the music data used, copyright information for specifying the distribution route and history of each music data is provided. A technique for embedding using a digital watermark technique is being sought.

[0006]

However, in particular, in the case of music data, the existing digital watermarking technology embeds the copyright information without deteriorating the sound quality of the original music data, and detects the embedded copyright information. It is difficult to make it difficult, and there is a problem that the copyright information inevitably becomes noise for the original music data.

[0007] To avoid this, it is conceivable to embed the copyright information as a signal outside the audible frequency range of humans, for example, as a signal of about 30 [kHz], so that the information is not heard as noise.

However, the standard of many digital music data is determined according to the human audible frequency range. Even if music data handled by CD, MD, and MP3 is considered from the sampling frequency, it is completely determined by the sampling theorem. The upper limit of the frequency that can be reproduced in
[KHz].

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 perceived by humans, the copyright information is eventually converted from the music data by digital copying. Is likely to be erased, which is not practical.

Also, due to the nature of the music data, it is not necessary to prohibit illegal copying or the like and to limit the users who listen to the music, but to allow the users to freely copy and broadcast the music data to some extent. In any case, it would be better for the copyright owner to collect the copyright fee in exchange for a wider audience for the music.

For this reason, there is a strong need for a digital watermarking technique for music data that can easily specify a distribution route and history.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object the purpose of minimizing the deterioration of the sound quality of original music data even though the signal is within the audible frequency range. The digital watermark creation method and the created digital watermark sound for music data, which are not erased by editing, compression, copying, conversion, etc. of the music data, and can easily specify the distribution route and history, The present invention provides a recording medium in which music data is synthesized and recorded.

[0013]

According to the first aspect of the present invention,
A step of creating a digital watermark sound including copyright identification information of a consonant corresponding to the tonality of music data, and synthesizing and recording the digital watermark sound created in the creation step with the music data. Recording step.

According to this method, although the signal is within the audible frequency range, it has a high affinity for the music data, so that it does not cause noise and does not give a listener a sense of incongruity. The distribution route and history can be easily specified without deterioration and without being erased even after editing, compressing, copying, and converting the music data.

According to a second aspect of the present invention, in the first aspect of the present invention, the consonant tone includes at least one of a harmony, a pedal point, a tension tone, and an approach tone.

According to such a method, in addition to the effect of the first aspect of the present invention, since the affinity of the digital watermark sound with the original music data is extremely high, even a listener with a very good ear can hardly sense it. It is possible to create a digital watermark sound that does not occur.

According to a third aspect of the present invention, in the first aspect of the present invention, the consonant uses only a scale near an upper limit in an audible frequency range.

According to this method, in addition to the effect of the first aspect of the present invention, the digital watermark sound is analyzed by limiting the digital watermark sound to a specific frequency band within the audible frequency range. By making it easier to extract and especially by using scales near the upper limit in the audible frequency range,
The data amount of the copyright information of the digital watermark sound to be synthesized with the music data can be set large, and detailed information for specifying the distribution route and history can be added.

According to a fourth aspect of the present invention, there is provided a recording medium on which music data is recorded, wherein a digital watermark sound including consonant copyright identification information corresponding to the tonality of the music data is generated. And recorded.

With such a recorded content, although the signal is within the audible frequency range, it has a high affinity for music data, so that it does not cause noise, and does not give a listener a sense of incongruity. The distribution route and the history can be easily specified without deteriorating the music data and without being deleted even after the operation of editing, compressing, copying and converting the music data.

[0021]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the processing steps of a program for synthesizing and distributing a digital watermark to music data of an MP3 file prepared in advance, which is provided as application software for a personal computer, for example.

At the beginning, the copyright information to be given to the target music data is JASRAC (JAPAN).
ee Society for Rights ofs
Authors, Composers and pu
(bashers: Japan Music Copyright Association) A code and data related to adjacent rights are input together with date and time information at that time and information indicating the content to be distributed (step A0).
1).

Here, the JASRAC code is set in advance by JA
It is given by registering the song in SRAC, and the writer of the song,
Composer, copyright holder, and registration date can be specified.

As the copyright neighboring information, the performer who created the music data, the record creator, and the like are input.

When the copyright information or the like is input in this way, the tonality and the harmony structure of the music data are automatically analyzed (step A02). An identification chord sound having a high affinity consonant is selected (step A03).

FIG. 2 illustrates the principle of a consonant having high affinity with music data. In this example, the chord (of the sound) is changed from "C" to "Am7" to "F.DELTA. "→
The music data for four measures developed as “G7” is shown.

To such music data, a sound 11 of "C (do)" as a tonic pedal point and a sound 12 of "G (so)" as a dominant pedal point are given as identification code sounds. can do. (Here, the “pedal point (holding sound)” indicates a common chordal sound that maintains one or more sounds even when other sounds move due to (chord) chord development. .) In addition, in the fourth measure, in addition to the half-note having the same pitch as the previous measures, the tonic pedal point “C (do)” and the dominant pedal point “G (so)”
The diminished approach 13 based on the sixteenth note using the above sound can be used as the identification code sound.

In this case, an 8-bit identification code tone can be represented by the diminished approach 13 composed of eight sixteenth notes. (Here, the “diminish approach” is one of the “dominant approach groups,” which is one of the “harmonization” methods for constructing harmony that is reasonable in melodies. What is used is an "extended diminished approach" if described precisely musically, but for ease of explanation, it is simply referred to as "diminished approach" in the following text.) In order to facilitate the explanation, it has been described that the identification code tone which is very slow to develop corresponding to the original music data is selected. However, in practice, the diminished approach 13 uses, for example, a 128th note,
If the copyright information and the like are converted into binary numbers and a diminished approach is constructed and assigned and set as a sequence of sounds that cannot be recognized in terms of human hearing at all, the 128-bit data Since the above-mentioned copyright information and the like can be converted into music data by consonance with the capacity, the data capacity can be easily increased.

In this way, the identification code sound which develops at a sufficiently high speed corresponding to the data amount of the copyright information or the like is converted into a frequency band located near the upper limit of the human audible frequency range, based on the harmonic composition thereof. For example, 16 [kHz] to 20
It is assumed that the sound is [kHz] and the sound pressure level of the original music data is sufficiently suppressed.

In this case, in particular, by limiting the identification code sound to a specific frequency band within the audio frequency range, it becomes easier to analyze and extract the identification code sound later, and particularly, the identification code sound within the audio frequency range. Using the scale near the upper limit,
In addition, by making the sound pressure level sufficiently lower than that of the original music data, it is possible to reliably prevent the human music from being hardly recognizable and disturbing the original music data as noise. However, the data amount of the copyright information that can be synthesized because of the high frequency can be set large.

Therefore, it is possible to construct by adding detailed information for specifying the distribution route and history as the copyright information and the like as described above.

Then, after the identification code sound created in this way is newly synthesized as a digital watermark sound over the entire area of the original music data (step A04), the digital watermark sound obtained by the synthesis is embedded in the entire area. Music data such as MD, CD-R, memory card,
Alternatively, distribution is performed via a communication medium such as the Internet (step A05), and the processing in FIG.

In the above description, the copyright information and the like as a digital watermark have been described as being constituted by a tonic pedal point, a dominant pedal point, and an identification code sound by a diminished approach, which are consonants. It is sufficient that the harmonic composition of the original music data is analyzed and the harmonics are harmonized with the harmonics. Further, music theory such as a harmony, a pedal point (holding tone), a tension tone, and an approach tone other than the above. In some cases, a consonant with a high affinity to the original music data may be used, so that the listener can hear the identification data sound together with the original music even though Copyright information etc. can be added without disturbing the musical impression so as not to be conscious

The copyright information and the like based on the identification code sound synthesized with the music data are not part of the music data but are synthesized over the entire bar as described above. No matter how the copy, division, and reconstruction are performed, the distribution source of the music data can be reliably specified.

Next, if a recording medium on which music data that should have been delivered by synthesizing the digital watermark sound as described above is obtained, or a site that has not been delivered via a network such as the Internet, A description will be given of a processing step for judging whether or not the music data has been distributed via a regular route when the music data has been obtained.

FIG. 3 shows processing steps of a program for analyzing a digital watermark sound synthesized with given music data, which is provided as application software for a personal computer, for example.

It is assumed 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.

At the beginning of the processing, by analyzing the waveform of the given music data, if the identification code 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 based on the determination (step B02).

Here, if it is determined that the identification code sound could not be extracted and that the music data was not synthesized, the music data was created without permission of the copyright owner, and the music data was immediately created. A message that the data is illegally used is displayed by a message (step B03), and the process is completed.

If the identification code sound can be extracted in step B02, and it is determined that the identification code sound has been synthesized, the above database is searched according to the content of the identification code sound (step B04), and the corresponding copyrighted work is searched. It is determined whether there is right information or the like (step B05).

Here, when the copyright information corresponding to the database is not stored, or when a plurality of identification code sounds are synthesized with music data and a plurality of copyright information is searched (copyright information). (For example, when medley music data is created without permission of the user), a message indicating that the music data is illegally used is displayed as a message (step B03), and the process is completed.

If the copyright information or the like corresponding to the database is stored in step B05, it is determined that the music data is not illegally created, and the copyright information or the like is determined. After displaying the distribution history, distribution route, and the like based on this (step B06), the process is completed.

By displaying the distribution history and distribution route based on the copyright information in this way, the music data can be obtained through an appropriate route by considering the history of the acquisition of the music data. You can easily verify that you are paying or that the royalties have already been paid.

In the above embodiment, especially for the processing of FIG. 1, a previously prepared MP provided as application software for a personal computer is used.
The description has been made assuming that the program is a program for music data of three files. However, if the original music data has data indicating the original scale, for example, MIDI data, a digital watermark to be synthesized more easily is provided. As a sound, it is possible to generate and provide an identification code sound having a very high musical affinity.

Although the above embodiment has been described with reference to a digital watermark which is not erased by digitally copying music data, the original music data can be combined with a digital watermark which is erased by copying. If the music data is distributed after being synthesized, it is possible to easily determine whether the music data is a primary copy or a secondary copy when the processing shown in FIG. 3 is performed on the music data later. .

In addition, the present invention is not limited to the above-described embodiment, and can be variously modified and implemented without departing from the gist thereof.

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 embodiments, at least one of the problems described in the column of the problem to be solved by the invention can be solved and the effects described in the column of the effect of the invention can be solved. In a case where at least one of the effects described above is obtained, a configuration in which this component is deleted can be extracted as an invention.

[0049]

According to the first aspect of the present invention, although the signal is within the audible frequency range, it has a high affinity for music data, so that it does not cause noise and does not give a listener a sense of incongruity. The distribution route and history can be easily specified without deteriorating the sound quality of the data and without being deleted even after the operation of editing, compressing, copying, and converting the music data.

According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, since the affinity of the digital watermark sound with the original music data is extremely high, even a listener with a very good ear can hardly hear it. It is possible to create an undetectable digital watermark sound.

According to the third aspect of the invention, in addition to the effect of the first aspect, the digital watermark sound is analyzed by limiting the digital watermark sound to a specific frequency band within the audible frequency range. And easier to extract,
In particular, by using a scale near the upper limit of the audible frequency range, the data amount of the copyright information of the digital watermark sound to be synthesized with the music data can be set large, and detailed information for specifying the distribution route and history can be obtained. Can be granted.

According to the fourth aspect of the present invention, although the signal is within the audible frequency range, it has a high affinity for music data, so that it does not cause noise and does not give a listener a sense of incongruity. The distribution route and history can be easily specified without deteriorating the sound quality and without being deleted even after the editing, compression, copy, and conversion operations of the music data.

[Brief description of the drawings]

FIG. 1 is a flowchart showing processing steps of a program for synthesizing and distributing digital watermark sound according to an embodiment of the present invention.

FIG. 2 is an exemplary view for explaining the principle of generation of a digital watermark sound according to the embodiment;

FIG. 3 shows an appropriate /
9 is a flowchart showing a processing step for determining inappropriateness.

[Explanation of symbols]

 11: Tonic pedal point 12: Dominant pedal point 13: Diminished approach

Continued on front page F-term (reference) 5D044 AB05 BC02 BC10 CC04 CC08 DE50 DE52 DE57 EF05 FG18 GK12 HL08 5D378 FF01 GG11 KK01 PP01 QQ03 QQ08 QQ22 QQ25 5J104 AA14 AA15

Claims (4)

[Claims] 1. A step of creating a digital watermark sound including music identification information composed of a consonant corresponding to the tonality of music data, and the digital watermark sound created in the creation step is combined with the music data. A digital watermark creation method, comprising a recording step of combining and recording. 2. The consonant sound includes a harmony, a pedal point,
2. The digital watermark creation method according to claim 1, further comprising at least one of a tension tone and an approach tone. 3. The digital watermark creation method according to claim 1, wherein the consonant tone uses only a scale near an upper limit in an audible frequency range. 4. A recording medium on which music data is recorded, wherein an electronic watermark sound including copyright identification information of a consonance corresponding to the tonality is synthesized with the music data and recorded. A recording medium characterized in that: