JP3295052B2 - Master music data creation apparatus and method for creating music data with copy protection effect - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a music CD.
(Compact Disk).

[0002]

2. Description of the Related Art With the spread of digital music equipment, an environment in which ordinary users can easily enjoy digitally recorded music has been established. For example, it is common practice to enjoy a music CD at home, copy the music CD to an MD (Mini Disk) and enjoy it when going out.

[0003] However, copying from a CD to an MD or distribution via the Internet or the like is performed by digital signals, so that sound quality is less deteriorated. This is a problem from the standpoint of music copyright protection.

[0004] For this purpose, conventionally, SCMS (Serial Cop) is used.
y Management System). The SCMS can copy data from a CD to a medium such as an MD that digitally records data, but cannot copy data from a digital recording medium on which copy data is recorded to another digital recording medium. In other words, copying to the first generation is possible, but copying to the second and subsequent generations is not possible.

[0005]

To put it the other way around, SCMS
Thus, any number of first-generation digital copies from a CD to a digital recording medium are possible, and there is virtually no limit to creating first-generation copies. For that purpose, there is a need for further enhanced music copyright protection means.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for copying music data recorded on a CD to a medium for compressing and recording data such as an MD, or distributing the data in a compressed or distributed manner. It is an object of the present invention to provide an apparatus and a method for creating master music data capable of generating music data that causes the above.

[0007]

SUMMARY OF THE INVENTION According to the present invention, when music data recorded on a CD has noise, when the music data is reproduced after compression recording, the noise portion of the music data recorded on the CD is filtered at the time of compression. In addition, it uses the property that it is emphasized by sampling and becomes distorted, and cannot be realized as music.

In order to utilize the above-mentioned properties, the master music data created by the master music data creation apparatus and the creation method thereof according to the present invention intentionally converts an actuator signal, which is a substitute for noise, into original music data. It is made by overlapping. At that time, pay attention not to hear the actuator signal superimposed on the original music data from the playback sound of the master music data, and if it is compressed and recorded on the media or if it is compressed and distributed, The waveform of the actuator signal and the timing of the superposition are determined so that the distortion generated in the reproduction sound and the distribution sound of the medium becomes as large as possible.

[0009] The master music data creation device for that purpose is:
A master music data creation device including an acquisition unit and a recording unit, adapted to fetch original music data stored in a primary master and record master music data based on the original music data in a secondary master. In, between the capturing unit and the recording unit, to the original music data captured from the capturing unit,
A mixer is provided that superimposes an actuator signal that causes distortion in reproduction sound or distribution sound of the medium when the master music data recorded in the secondary master is compressed and recorded or compressed and distributed to the medium. Thereby, the master music data based on the original music data on which the actuator signal is superimposed is recorded on the secondary master by the recording unit. The secondary master itself may be a CD, but is generally a medium for recording master music when mass-producing a CD.

The master music data creation device further includes an actuator device for generating an actuator signal, thereby simplifying control without requiring an external input. In addition, the timing for superimposing the actuator signal is changed by providing a timing adjuster for delaying or advancing the timing of superimposing the actuator signal by one or two cycles of the CD sampling cycle every 0.01 to 2 seconds. Thus, when the copy music data recorded on the CD is compressed and recorded and reproduced, distortion can be emphasized, and the effect of copy prevention can be improved.

Further, by providing a compressor for compressing or deleting the signal level of the actuator signal, it is preferable that noise caused by the actuator signal at the time of reproducing the CD is eliminated so that the noise cannot be heard by human hearing. By providing 512 cycles of the original music data with the sampling clock of the CD and incorporating a timing specifier for superimposing 256 cycles of the actuator signal from the point of the maximum volume in the first 256 cycles of the original music data, When the copy music data recorded on the CD is compressed and recorded and reproduced, the distortion can be further emphasized.

[0012] As described above, a method of creating master music data which causes distortion in a reproduced sound or a delivered sound when the master music data is compressed and recorded and reproduced or when the master music data is compressed and distributed is a primary method. A master music data creation method in which master music data generated based on original music data recorded on a master is recorded on a secondary master, wherein the master music data is recorded on the original music data on the secondary master When the master music data obtained is compressed and recorded on a medium or distributed for distribution, the generated master music data is generated by superimposing an actuator signal that causes distortion in the reproduction sound or distribution sound of the medium.

The superimposition of the actuator signal is carried out every 0.01 second to 2 seconds by changing the timing by delaying or advancing the sampling period of the CD by one or two periods or changing the timing so that the copied music data is recorded on the CD. Can be emphasized when compressed and recorded and reproduced or when compressed and distributed. Such an actuator signal is
By not including a frequency component in the audible sound region, noise due to an actuator signal during CD reproduction can be eliminated. In particular, by setting the actuator signal to half the sampling frequency of the CD,
It is completely read during playback, yet sounds inaudible to human hearing. Also, 512 cycles of the original music data are fetched by the sampling clock of the CD, and 2 cycles from the point of the maximum volume in the first 256 cycles of the original music data.
When actuator signals for 56 cycles are superimposed, distortion can be further emphasized when copy music data recorded on a CD is compressed and recorded and reproduced.

According to the results of research conducted by the present inventor, the following two types of actuator signals used in the present invention, in particular, show remarkable sound distortion in the reproduced sound after compression recording and the distributed sound after compressed distribution. Can occur. The actuator signal is a signal obtained by intermittently generating a group of sine waves having a frequency half the CD sampling frequency,
Alternatively, it is a signal obtained by performing balanced modulation of a signal having a frequency half of the CD sampling frequency by an impulse signal.

[0015] 1/2 of the sampling frequency of the former CD
A signal obtained by intermittently generating a group of sine waves having the following frequency may be generated such that a sine wave corresponding to 64 sampling cycles of the CD is generated at a time every 512 sampling cycles of the CD. Further, the 512 periods may be generated by shifting them by about 16 periods. At this time, the next sine wave is generated by being shifted by the same amount in the reverse direction. In addition, when a signal is generated every 512 cycles, the amplitude of the sine wave increases stepwise, and the amplitude of the sine wave attenuates at the end, so that audible noise due to sidebands can be reduced. CD
By adding a sine wave whose level is lower than the sine wave, preferably lower by 20 dB, to a signal obtained by intermittently generating a group of sine waves having a half of the sampling frequency of The distortion of the reproduced sound of the copy music data of the compressed and recorded CD can be emphasized. There are two types of sine waves to be added, one at 22 KHz and the other at 15 KH
When z is set, the effect of the distortion of the reproduced sound can be further emphasized.

In the latter signal, the signal obtained by balance-modulating a signal having a frequency half of the CD sampling frequency by the impulse signal has a pulse width of 4 to 15 CD sampling periods.

With the master music data creating apparatus and method as described above, the master music data generated based on the original music data recorded on the primary master is copied to a CD as a music recording CD created. When the recorded master music data is compressed and recorded on the medium or compressed and distributed, an actuator signal that generates noise in the reproduction sound or distribution sound of the medium is converted into the original music data.
A music recording CD can be made by copying the master music data generated by the superimposition.

[0018]

Embodiments of the present invention will be described below.

FIG. 1 is a block diagram of a first embodiment of the present invention. A fetch unit 30 for fetching original music data recorded on a primary master 10 and an actuator signal to be superimposed on the original music data are generated. Actuator signal generator 60
A timing adjuster 70 that adjusts the timing of superimposing the actuator signal on the original music data; a mixer 50 that superimposes the actuator signal on the original music data; and a secondary master that superimposes the original music data on which the actuator signal is superimposed by the mixer 50. And a recording section 40 for recording the information in the recording section 20. The secondary master 20 is a medium in which music data serving as a master when mass-producing CDs is recorded.

The actuator signal generated by the actuator signal generator 60 is converted into a C signal by the timing adjuster 70.
The D music data is superimposed on the original music data fetched from the primary master 10 at the timing when the distortion of the reproduced sound after the compression recording of the D music data is maximized. The timing is adjusted by, for example, changing the interval between pulses in a pulse signal, as shown in FIG. In FIG. 2, the interval between the fifth pulse signal and the sixth pulse signal is longer by two CD sampling periods than the intervals between the other pulse signals. Such an interval change is performed for one or two CD sampling periods, and the interval may be lengthened or shortened.

As described above, the timing is adjusted by the timing adjuster 70 when the actuator signal is superimposed on the original music data, so that the reproduced sound after compression recording has a larger distortion as compared with the case where the timing is not adjusted. Occurs.

FIG. 3 is a block diagram of a second embodiment of the present invention. A fetch unit 30 for fetching original music data recorded on the primary master 10 and an actuator signal to be superimposed on the original music data are generated. Actuator signal generator 60
A compressor 60 for compressing the actuator signal; a timing identifier 70 for identifying the timing of superimposing the compressed actuator signal on the original music data; and a mixer 50 for superimposing the compressed and timing-identified actuator signal on the original music data. And a recording unit 40 for recording in the secondary master 20 the original music data on which the actuator signal has been superimposed by the mixer 50.

The compressor 60 reduces or eliminates frequency components in the audible sound region from the actuator signal as shown in FIG. 4 to reduce noise due to the actuator signal during CD reproduction. As a result, when the actuator signal is output from the secondary master 20, the noise becomes indistinguishable to human hearing, and when compressed and recorded on an MD or the like and reproduced, the actuator signal may be distorted. The frequency components in the audible sound region can be deleted by a method using a filter or a method of analyzing the frequency components of the audible sound, synthesizing a pseudo audible sound from a sine wave of each component, and subtracting it from the actuator signal.

Although the actuator signal can be hidden from human hearing only by compressing the actuator signal by the compressor 60 as described above, the timing specifying unit 70
By using, the noise due to the actuator signal at the time of reproducing the CD becomes more inaudible to human hearing, and the effect of the distortion of the reproduced sound increases.

The timing is specified by a method as shown in FIG.

In FIG. 5, the sampling period of the CD is 25.
The actuator signals for six cycles are superimposed from the point of maximum volume in the first 256 cycles of the original music data for 512 cycles. Subsequently, the same operation is repeated for the following 512 cycles of original music data. As a result, noise due to the actuator signal cannot be identified by the masking effect of the original music data.

The following signals are particularly effective as the actuator signal, which is one of the important elements used in the present invention.

As a first example, a group of sine waves as shown in FIG. 6B is used. This sine wave group has a frequency of 2
There are 64 cycles of a 2 KHz sine wave, which corresponds to 128 cycles of a CD sampling clock. The 16 rising and falling 16 cycles of the sine wave group avoid abrupt changes in order to reduce audible noise due to sidebands, and their magnitudes are gradually changed. When such a group of sine waves is generated intermittently as shown in FIG. 6A and superimposed on the original music data, the effect of the distortion of the reproduced sound after compression recording is increased. The interval at which sine waves are generated may be basically 512 cycles of a CD sampling clock,
It may be generated by shifting 16 cycles at random. At this time, the next sine wave group is generated with the same amount of shift in the reverse direction. Further, the actuator signal may be generated by a method of generating the first and second sine wave groups and compressing the signal levels of the third and fourth sine wave groups to zero in the division diagram a.

Further, by adding a sine wave having a level lower than that of the sine wave group by about 20 dB to such a signal, the effect of distortion of the reproduced sound is increased. Any number of sine waves may be added. However, according to experiments performed by the present inventors, it has been confirmed that adding two types of sine waves increases the effect of the distortion of the reproduced sound. It is good to set it to 22 KHz and the other to 15 KHz. Here, since the 15 KHz sine wave is in the audible range, by adding the original music data at a large timing, it is possible to prevent the 15 KHz sine wave from being distinguished by the masking effect.

As a second example, the impulse signal shown in FIG.
May be balanced modulated to generate an actuator signal shown in FIG. 7B.

In FIG. 7A, the impulse signal is represented by a sine-square wave, but it may be a square wave or a sine wave.
Then, the pulse width is set to 4 to 15 of the CD sampling period.
With the period, the distortion of the reproduced sound is greatly emphasized at the time of reproduction after MD copying, and at the time of CD reproduction, the noise is of a level that is not bothersome to human hearing.

The modulated impulse signal in FIG. 7B corresponds to a balanced modulation output of a high-frequency signal by the impulse signal. Here, the high-frequency signal is set to a frequency half of the sampling frequency of the CD. When the impulse signal is continuously generated, the modulated impulse signal becomes a modulated impulse train signal as shown in FIG.

Although the modulated impulse train signal is generated periodically here, it may be generated aperiodically.
The polarity can also be changed. In the case of FIG. 7C, the polarity is reversed between the first half of the three-modulation impulse signal and the second half of the three-modulation impulse signal.

In this embodiment, the copy protection device for compressed digital recording from a music CD to an MD has been described. However, in the case of a medium in which the copy side performs digital compression to record audio data, the copy protection device is used. Thus, the copy protection function of the music CD created effectively works.

[0035]

The master music data created by the master music data creation apparatus and the creation method according to the present invention are transferred to the M
When recorded and recorded on a digital recording medium such as D or played back on the Internet, or when used for digital broadcasting, it is reproduced as a distorted sound completely different from the original sound of the master music data by the actuator signal. Therefore, it is no longer feasible for copy products and distribution, resulting in copyright protection.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is an exemplary diagram of timing adjustment.

FIG. 3 is a block diagram of a second embodiment of the present invention.

FIG. 4 is an exemplary view showing compression of an actuator signal.

FIG. 5 is an exemplary diagram of timing adjustment.

FIG. 6 is a waveform diagram of an actuator signal.

FIG. 7 is a waveform diagram of an actuator signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Primary master 20 Secondary master 30 Capture part 40 Recording part 50 Mixer 60 Actuator signal generator 70 Timing adjuster 80 Compressor 90 Timing identification device

Claims (26)

(57) [Claims] 1. An apparatus according to claim 1, further comprising an acquisition unit and a recording unit, adapted to fetch original music data stored in a primary master and record master music data based on the original music data in a secondary master. In the master music data creation device, between the capture unit and the recording unit, the master music data recorded on the secondary master is compressed into the original music data captured from the capture unit and recorded or compressed on the medium. A mixer that superimposes an actuator signal that causes distortion in the reproduction sound or the distribution sound of the media when the music data is distributed, thereby recording master music data based on the original music data on which the actuator signal is superimposed. A master music data creation device characterized in that the master music data is recorded on a secondary master. 2. The master music data creation device according to claim 1, further comprising an actuator device for generating an actuator signal. 3. The master music data creation device according to claim 1, further comprising a timing adjuster for changing a timing at which the actuator signal is superimposed. 4. The master music data creating apparatus according to claim 3, wherein the timing of superimposing the actuator signal is changed every 0.01 to 2 seconds. 5. The master music data creating apparatus according to claim 3, wherein the change of the timing of superimposing the actuator signal is delayed or advanced by one or two cycles in the CD sampling cycle. 6. A compressor according to claim 1, further comprising a compressor for compressing or removing a signal level of the actuator signal.
The master music data creation device according to the paragraph. 7. A timing specifier for fetching 512 cycles of original music data with a sampling clock of a CD and superimposing an actuator signal for 256 cycles from the point of the maximum volume in the first 256 cycles of the original music data. The master music data creation device according to claim 1. 8. The actuator signal may be a signal obtained by intermittently generating a group of sine waves having a frequency half of the sampling frequency of a CD, or an actuator signal of a half of the sampling frequency of a CD by an impulse signal. The master music data creation device according to any one of claims 1 to 7, wherein a signal obtained by balance-modulating a signal having a frequency is used. 9. A signal obtained by intermittently generating a group of sine waves having a frequency half of the sampling frequency of a CD generates a sine wave for 64 sampling cycles of the CD at a time. Item 9. The master music data creation device according to Item 8. 10. A signal obtained by intermittently generating a group of sine waves having a frequency half of the sampling frequency of a CD is generated every 512 sampling cycles of the CD. 10. The master music data creation device according to item 9. 11. A signal obtained by intermittently generating a group of sine waves having a frequency half of the sampling frequency of a CD, the amplitude of the sine wave increases stepwise when the signal is generated, and the sine wave 11. The method according to claim 8, wherein the amplitude of the signal attenuates.
The master music data creation device according to the paragraph. 12. A signal obtained by intermittently generating a group of sine waves having a frequency half of the sampling frequency of a CD, and further adding a sine wave at a level lower than the sine wave to obtain an actuator signal. The master music data creation device according to claim 8, wherein the master music data creation device generates the master music data. 13. A signal obtained by balance-modulating a signal having a half of the sampling frequency of a CD by an impulse signal has a pulse width of 4 to 15 CD sampling periods. 8. The master music data creation device according to item 8. 14. A method for creating master music data, wherein master music data generated based on original music data recorded on a primary master is recorded on a secondary master, wherein the master music data is the original music data. Is generated by superimposing an actuator signal that causes distortion in reproduction sound or distribution sound of the medium when the master music data recorded in the secondary master is compressed and recorded or compressed and distributed to the medium. Master music data creation method. 15. The superposition of the actuator signal is 0.0
The timing is changed every one to two seconds.
The master music data creation method described. 16. The master music data creating method according to claim 15, wherein the timing of superimposing the actuator signal is changed by delaying or earliering by one or two cycles in the CD sampling cycle. 17. The master music data creating method according to claim 14, wherein the actuator signal does not include a frequency component in an audible sound region. 18. The actuator signal according to claim 14, wherein the frequency of the actuator signal is half the sampling frequency of the CD.
The method for creating master music data according to any one of the above. 19. The sampling clock of a CD is 512
The master music data according to any one of claims 14 to 18, wherein the original music data for a cycle is taken in, and an actuator signal for 256 cycles is superimposed from the point of the maximum volume in the first 256 cycles of the original music data. How to make. 20. The actuator signal is a signal obtained by intermittently generating a group of sine waves having a frequency of 1/2 of the sampling frequency of a CD, or an actuator signal of 1/2 of the sampling frequency of a CD by an impulse signal. 15. A signal obtained by performing balanced modulation on a signal having a frequency.
21. The master music data creation method according to any one of 20. 21. A signal obtained by intermittently generating a group of sine waves having a frequency half the sampling frequency of a CD generates a sine wave corresponding to 64 sampling cycles of the CD at a time. Item 21. The method for creating master music data according to Item 20. 22. A signal obtained by intermittently generating a group of sine waves having a frequency half the sampling frequency of a CD is generated every 512 sampling cycles of the CD. 21. A method for creating master music data according to item 21. 23. A signal obtained by intermittently generating a group of sine waves having a frequency half of the sampling frequency of a CD, the amplitude of the sine wave increases stepwise when the signal is generated, and the sine wave The master music data creating method according to any one of claims 20 to 22, wherein the amplitude of the master music data is attenuated. 24. A signal obtained by intermittently generating a group of sine waves having a frequency half the sampling frequency of a CD, and further adding a sine wave having a lower level than the sine wave to obtain an actuator signal. The master music data creating method according to any one of claims 20 to 23, wherein the master music data is created. 25. A signal obtained by balance-modulating a signal having a frequency half of a CD sampling frequency by an impulse signal, wherein the pulse width of the impulse signal is 4 to 15 CD sampling periods. 20. A method for creating master music data according to item 20. 26. A music recording CD created by copying master music data generated based on original music data recorded on a primary master, wherein the master music data recorded on the CD is compressed. A music recording CD obtained by copying master music data generated by superimposing an actuator signal, which generates noise on the reproduction sound or distribution sound of the medium when recorded or compressed and distributed on the medium, on the original music data. .