JP3765493B2 - Copyright data reproduction method and digital audio signal communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the quality of an analog audio signal from being deteriorated in reproducing when copyright data are embedded into the digital data. <P>SOLUTION: The copyright data is modulated by an FM modulator 114, an oscillator 115, a spread modulator 116, a spread code 117, and a level control section 118, and the modulation data are applied via a switch 201 to an adder 121 and are embedded into digital speech data. A control section 200 detects the level fluctuation of the digital audio data and controls a copyright data supplying section 100, the spread code 117, and the switch 201 respectively by control signals a, b, and c, thereby intermittently embedding the modulated data. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a method for reproducing copyright data recorded on a recording medium after analog-digital (A / D) conversion of an analog audio signal such as a music source, and a method for communicating a digital audio signal.

Over ten years have passed since CDs (compact discs) as optical playback optical discs have been put on the market, and they have already surpassed conventional cassette tapes as audio information recording media. The physical / logical format of CDs, which are digital discs, has been established as an EFM modulation recording system for 8-bit fixed data length symbols and data formats such as subcode, audio data, CRC, and various application functions. CD players have been developed.

  The CD is also used as a data CD-ROM by identifying it with the control bit (4 bits) of the Q channel in its subcode or by identifying it in the absence of TOC (Table Of Contents). Applications of digital disks are being expanded in the field of electronic publishing by making effective use of the large capacity and high speed accessibility of digital disks. By the way, in the CD-ROM, the sound is compressed by ADPCM, the original sound quality cannot be reproduced by the compression, and recording with higher fidelity has been desired. In other words, it is expected that a disc capable of recording an audio signal equivalent to a band twice that of a normal CD even when compressed will be expected.

  However, when such a high-quality hi-fi signal is copied in the state of digital information, it is convenient for the user because it does not deteriorate, but there is a problem that it is not desirable from the viewpoint of copyright protection. As a method for solving such a problem, a method for limiting the number of times digital information is copied (US Pat. No. 5,428,598), a method in which no digital output terminal is provided in the device, an analog output, or the like. Copy by removing a part of the signal band, embedding copyright data in digital data (Japanese Patent Publication No. 7-505984), or making small changes to the original data and checking the identification signal A method for determining a user who has performed (Japanese Patent Laid-Open No. 8-45179) has been proposed.

  In the copyright data embedding method shown in the above Japanese Patent Publication No. 7-505984, when a large audio signal exists in human auditory characteristics, a low level signal (for example, noise) in the vicinity of the frequency is heard. It uses the “auditory masking characteristic” of no. In this method, as shown in FIG. 67, the power ratio CMR (Code to Music Ratio) between the copyright data signal C (= code) and the original signal M (= music) is made constant in the frequency domain. Embedded in.

  By the way, in the method of embedding copyright data in digital data, when the data is D / A converted and reproduced as an analog audio signal, the sound quality deteriorates in terms of hearing or feels uncomfortable due to a feeling of processing. There is a problem.

  Further, in actual “auditory masking characteristics”, the CMR of the level of the signal C that cannot be heard with respect to the large audio signal M differs depending on the frequency. However, in the above-described conventional example, since CMR is embedded so as to be constant in the frequency domain, if copyright data is embedded at an excessive level, the data is D / A converted and reproduced as an analog audio signal at a certain frequency. There is a problem in that the sound quality is deteriorated in the sense of hearing or a feeling of processing is caused to cause a sense of incongruity. Conversely, if copyright data is embedded at an excessive level, it cannot be embedded sufficiently.

  In recent years, the use of personal computers (hereinafter referred to as personal computers or PCs) has rapidly become multimedia, and it has become widespread that video and audio signals are processed by PCs. Recently, it has become widespread to transmit a moving image or audio signal via a communication line such as the Internet. Under such circumstances, a general user may desire to manage his / her copyright when a music source is supplied to another person via a medium or a communication line using a PC.

Therefore, the present invention is a copyright that can prevent degradation of the quality of an analog audio signal during reproduction when copyright data is embedded in digital data in order to achieve both user convenience and copyright protection. An object of the present invention is to provide a data reproduction method and a digital audio signal communication method.

In order to achieve the above object, the present invention comprises the following means 1) to 5 ).

That is,
1) Copyright data including A / D conversion of analog audio signals into digital data and copyright data relating to the digital data, the data indicating the number of copies of the digital data. Steps to modulate the spectrum by spread spectrum;
When embedding the modulated copyright data in the digital data, a peak level and an average level of the digital data are detected, and a change in the peak level with respect to the average level is detected. A step of intermittently embedding copyright data so that a power ratio of the copyright data to the digital data is constant in the frequency domain,
The original copyrighted digital data obtained by A / D-converting the analog audio signal by the copyright information embedding method possessed by the digital data in which the copyrighted data is modulated by spread spectrum and embedded A method of reproducing copyright data, comprising the step of retrieving the copyright data.
2) Copyright data including A / D conversion of analog audio signals into digital data and copyright data relating to the digital data, the data indicating the number of copies of the digital data. A step of modulating the spectrum by spread spectrum;
When the modulated copyright data is embedded in the digital data, the peak level, average level, and frequency of the digital data are detected, and the peak level varies with respect to the average level. The step of embedding the copyright data intermittently so that the power ratio of the copyright data to the digital data differs according to the frequency of the digital data and the auditory masking effect, The
The original copyrighted digital data obtained by A / D-converting the analog audio signal by the copyright information embedding method possessed by the digital data in which the copyrighted data is modulated by spread spectrum and embedded A method of reproducing copyright data, comprising the step of retrieving the copyright data.
3) Copyright data including A / D converted analog audio signals into digital data, and copyright data relating to the digital data, the data indicating the number of copies of the digital data. Steps to modulate the spectrum by spread spectrum;
When embedding the modulated copyright data in the digital data, the power ratio of the copyright data to the digital data is constant in the frequency domain, and a plurality of channels are used. A step of simultaneously embedding copyright data different in time for two or more channels of the audio signal of
The original copyrighted digital data obtained by A / D-converting the analog audio signal by the copyright information embedding method possessed by the digital data in which the copyrighted data is modulated by spread spectrum and embedded A method of reproducing copyright data, comprising the step of retrieving the copyright data.
4) A digital audio signal communication method characterized by transmitting and / or receiving a program comprising the steps of the copyright information embedding method according to any one of claims 1 to 3 through a communication line. .
5) Transmitting and / or receiving a digital audio signal embedded with copyright data via a communication line based on the copyright information embedding method according to any one of claims 1 to 3. A digital audio signal communication method characterized by the above.

  As described above, according to the present invention, the CMR at the level of the copyright data C that cannot be heard with respect to the large audio signal M is made constant in the frequency domain or different depending on the frequency, and the copyright data is changed between channels. Therefore, the quality of the analog audio signal at the time of reproduction can be prevented from being deteriorated.

  Embodiments of the present invention will be described below with reference to the drawings. 1 is a block diagram showing a copyright information embedding device (encoder) applied to the present invention, FIG. 2 is a block diagram showing in detail the signal processing circuit of FIG. 1, and FIG. 3 is a sampling of the A / D converter of FIG. FIG. 4 is an explanatory diagram showing a period and a data string, FIG. 4 is an explanatory diagram showing user data packed by the allocation circuit of FIG. 2, and FIG. 5 is a flowchart for explaining copyright data embedding processing by the control unit of FIG. 6 is an explanatory diagram showing a period of embedding copyright data by the control unit of FIG. 2, FIG. 7 is a flowchart for explaining a modification of the embedding process of FIG. 5, and FIG. 8 is data processed by the encoder of FIG. 9 is a block diagram showing in detail the signal processing circuit of FIG. 8, FIG. 10 is a block diagram showing the data decoded by the decoder of FIG. Explanatory view showing a column, Fig. 11 is a block diagram showing a modified example of the signal processing circuit of FIG. 2, FIG. 12 is a block diagram showing a modified example of the signal processing circuit of FIG.

An analog audio signal such as a music source is input to the input terminal IN shown in FIG. 1, and this input signal is sufficiently sampled by the A / D converter 31 to deny unconditional digital copying (FIG. 1). 3 is sampled at, for example, 192 kHz, converted to a high-resolution PCM signal of, for example, 24 bits, and a data string xb1, x1, xa1, x2, xb2 corresponding to the curve α as shown in FIG. , X3, xa2,
..., xbi, x2i-1, xai, x2i, ...
Is converted to

  This data string (xbi, x2i-1, xai, x2i) is encoded by the signal processing circuit 32 and the memory 33 shown in detail in FIG. 2 and then packed by the DVD encoding circuit 34. The packing data is output to the output terminal OUT1, or is modulated by the modulation circuit 35 by a modulation method corresponding to the medium and output to the output terminal OUT2. Also, copyright data is output from the output terminal OUT3 as necessary.

The configuration of the signal processing circuit 32 will be described in detail with reference to FIG. First, the output signal of the A / D converter 31 is applied to a low-pass filter (LPF) 36 after copyright data is embedded by an adder 121 as will be described later. The low-pass filter 36 is constituted by, for example, an FIR filter that passes a half band, and the band-limited curve β is changed from the data string (xbi, x2i-1, xai, x2i) corresponding to the curve α shown in FIG. Corresponding data string xc1, *, *, *, xc2, *, *, *, xc3, *, *, *, ..., xci, *, *, *, ...
Get.

Next, by thinning out the data “*” of this data string by the thinning circuit 37, the data string xc1, xc2, xc3,..., Xci,.
And the data string xb1, xa1, xb2, xa2,..., Xbi, xai, by thinning out the data xi from the data string (xbi, x2i-1, xai, x2i) by the thinning circuit 38. ...
Is generated.

Then, based on these data strings xci, xbi, xai, a difference xbi-xci = Δ1i is calculated by a difference calculation unit 39 constituted by an adder.
xai-xci = Δ2i
Is calculated. Here, the difference data Δ1i and Δ2i is, for example, 24 bits or less, and the number of bits may be fixed or variable.

  The allocation circuit 40 packs the data string xci, difference data Δ1i, Δ2i and copyright data as user data as shown in FIG. 4, and outputs the user data to record a recording medium such as a DVD (digital video disc). Or is transmitted to the transmission line. When the user data is 2034 bytes as in a DVD, the data xci and the difference data Δ1i and Δ2i are both 225, and the subheader is 9 bytes. Here, the data string xci is a data string in which the digital data A / D converted by the A / D converter 31 is band-limited and the sampling frequency is reduced to ¼.

Next, a method for embedding copyright data will be described. First, the copyright data supply unit 100 is an example of copyright data related to a signal input via the input terminal IN.
-Disc serial number (16 bytes), which is information for managing the copy status to identify copyright
・ Cutting player identifier code (4 bytes)
・ Recording date (3 bytes)
・ Number of recordings (3 bytes)
・ Number of copies (4 bytes) and ・ Number of copies allowed to manage copyright status (3 bytes)
Is supplied to the FM modulator 114 and the allocation circuit 40.

  Here, since SID (source ID) information and ISRC (International Standard Recording Code) information are common to all countries as copyright data, it is possible to easily check for pirated copies that are available worldwide. Therefore, the “cutting player identifier code” is used as the SID information indicating the manufacturer, and the ISRC information common to all countries is the “information for managing the copy state to identify the copyright”. Adopted as “Serial Number”.

  The allocation circuit 40 distributes and packs the copyright data in the subheader shown in FIG. In addition to the sub-header, these copyright data are further stored in a copyright management information area (CMI area) provided on the inner periphery of the DVD so as to correspond to a TOC area defined for a CDR disc or the like. Recorded in detail. This CMI area is recorded in a partial RAM or PCA (post-cutting area).

  In the FM modulator 114, the copyright data is modulated with a frequency of, for example, 5 kHz from the oscillator 115, and then the modulated signal is spread by the spread modulator 116 so that it cannot be heard even after D / A conversion. Using the PS code (Pseudorandom Sequence Code) 117, the frequency spectrum is widely spread to a low level, and the level control unit 118 controls the level according to the level of the data string (xbi, xa1). . In this case, for example, it cannot be normally heard by making it sufficiently lower than the CMR (Code to Music Ratio) of the psychoacoustic model such as -25 dB at 2 kHz and -19 dB at 10 kHz. This modulated data is applied to the adder 121 via the switch 201 and embedded in the output signal of the A / D converter 31.

  In this embedding process, the control unit 200 controls the copyright data supply unit 100, the spread code 117, and the switch 201 by control signals a, b, and c, respectively. The operation of the control unit 200 will be described with reference to FIG. 5. A weighting inverse characteristic filter is applied to the output signal of the A / D converter 31 for audibility correction (step S1). Next, an average level (correction value) and a peak level are detected (step S2), and then it is checked whether or not the peak level exceeds the average level (step S3).

  When the peak level> the average level, the copyright data supply unit 100 continues to generate and supply the copyright data by the control signal a, continues the modulation by the control signal b, and turns on the switch c by the control signal c. By embedding, copyright data is embedded. On the other hand, if the peak level> the average level is not satisfied, the copyright data supply unit 100 holds the copyright data increment by the control signal a, stops the modulation by the control signal b, and turns off the switch c by the control signal c. Therefore, the copyright data is not embedded.

  6A shows the original signal, and FIG. 6B is an explanatory diagram showing the embedded state of the original signal in FIG. 6A. According to the embedding process, the copyright data is embedded in a period in which the peak level of the original signal is greater than the average level, and the copyright data is not embedded in a period in which the peak level is not greater than the average level.

  FIG. 7 shows a modification of FIG. First, as in the case shown in FIG. 5, a weighting inverse characteristic filter is applied to the output signal of the A / D converter 31 for auditory sensation correction (step S11), and then the average level (correction value) and peak level are applied. Is detected (step S12). In this modification, it is checked whether or not the average level is sufficiently large, for example, whether or not the average level is higher than −19 dB with respect to the maximum level (step S13), and embedding is performed when the average level> −19 dB. (Step S15). If average level> −19 dB, as in the case shown in FIG. 5, embedding is performed when peak level> average level (step S14 → 15), whereas embedding is not performed when peak level> average level is not satisfied. (Steps S14 → S16).

Next, the decoder will be described with reference to FIG. The input signal is first demodulated by the demodulation circuit 41 in accordance with the modulation method of the modulation circuit 35 on the encoder side, then decoded by the DVD decoding circuit 42, and the decoded data (data sequence xci in which copyright data is intermittently embedded) The difference data Δ1i, Δ2i) is applied to the signal processing circuit 43 (and the memory 44) and the copyright data rewriting unit 30 shown in detail in FIG. 9 and reproduced from the copyright data or CMI area unpacked from the subcode. The copyright data is applied to the decryption unit 50. In the signal processing circuit 43, as shown in FIG. 9, first, the adder 46 makes Δ1i + xci = xbi.
Δ2i + xci = xai
Is calculated, and the data strings xbi and xai are restored. Here, the data strings xbi and xai are the original 24 bits.

  Next, the interpolation processing circuit 47 interpolates the data string xi between them using a plurality of data of the data strings xai and xbi as shown in FIG. Note that the interpolation processing circuit 47 can obtain the interpolation data string xi by using, for example, an upsampling method and filling each of them with zero data and passing through a low-pass filter. The interpolation data string xi may also be obtained by curve approximation or prediction approximation. In this case, the degree of approximation can be increased by adding approximate auxiliary data for transmission.

Data interpolated in this way is
xb1, x1, xa1, x2, xb2, x3, xa2,
..., xbi, x2i-1, xai, x2i, ...
And are applied to the D / A converter 45, the LPF (low-pass filter) 56 and the digital output terminal 90 shown in FIG.

  In the D / A converter 45, a data string (xbi, x2i-1, xai, x2i) which is A / D converted at the encoder side with a quantization bit number of 24 bits and copyright data is embedded and recorded on the recording medium. Is converted to an analog signal at a sampling frequency of 192 kHz and output through the analog output terminal 55. In the LPF 56, the input data is limited to, for example, a quarter band (48 kHz), is output as digital data via the output terminal 53, and is further a data string (xbi, x2i-1) in which copyright data is embedded. , Xai, x2i) are output as they are through the digital output terminal 90.

FIG. 11 and FIG. 12 respectively show signal processing circuits of an encoder and a decoder that realize a modification of the first embodiment. In the encoder shown in FIG. 11, the thinning circuit 38 shown in FIG. 2 is omitted, and the data xi is not thinned out. Then, the difference calculation unit 39 calculates the difference xbi−xci = Δ1i
xai-xci = Δ2i
xi -xci = Δ3i
The data string (xci, Δ1i, Δ2i, Δ3i) and copyright data are packed by the allocation circuit 40 and transmitted. Also in this case, the copyright data is intermittently embedded in the data string (xci, Δ1i, Δ2i, Δ3i).

In the decoder shown in FIG. 12, since the data sequence xi is not thinned out on the encoder side as described above, the interpolation processing unit 47 is omitted. In the adder 46, xci + Δ1i = xbi
xci + Δ2i = xai
xci + Δ3i = xi
To restore the original high-quality data string (xbi, x2i-1, xai, x2i). Since the other configurations are the same as those in FIGS. 2 and 9 for both the encoder and the decoder, description thereof will be omitted.

  Next, a second embodiment will be described with reference to FIGS. 13 is a flowchart for explaining copyright data embedding processing by the control unit 200 according to the second embodiment, FIG. 14 is an explanatory diagram showing an embedding period by the processing in FIG. 13, and FIG. 15 is an embedding processing in FIG. It is a flowchart for demonstrating a modification.

  In FIG. 13, first, the control unit 200 detects the peak level from the output signal of the A / D converter 31 with a predetermined rising time constant (for example, 1 millisecond) and a falling time constant (for example, 150 milliseconds) (step) S21). Next, the average level is detected (step S22), and then it is checked whether the peak level is less than the average level (step S23). If the peak level <the average level and this is the first time, embedding is performed with one piece of information of the copyright data being continuously generated (steps S23 → S24 → S25). On the other hand, if peak level <average level is not satisfied (step S23) or if peak level <average level is not the first time (step S24), copyright data is not embedded (step S26).

  Therefore, according to the above embedding process, copyright data is embedded in a period when the peak level <average level is the first time, and copyright data is embedded in a period where the peak level <average level or the peak level <the average level is not first. Since it is not performed, the embedding becomes intermittent. FIG. 14A shows an original signal, and FIG. 14B is an explanatory diagram showing an embedded state with respect to the original signal of FIG. Here, in a music source whose level fluctuates as shown in FIG. 14 (A), even if the source is modified by embedding it at the time when the level becomes small as shown in FIG. Since it is known that it is difficult to detect the above, it is possible to prevent the quality of the analog output signal from deteriorating.

  The process shown in FIG. 15 corresponds to a modification of the first embodiment shown in FIG. That is, first, similarly to the case shown in FIG. 13, the peak level and the average level (step S32) of the output signal of the A / D converter 31 are detected (step S31). In this modified example, in the following step S33, it is checked whether or not the average level is sufficiently large, for example, whether or not the average level is larger than −19 dB with respect to the maximum level. Is embedded (step S36).

  If the average level is not higher than −19 dB in step S33, the embedding is performed when the peak level <average level and this is the first time as in the case shown in FIG. 13 (steps S34 → S35 → S36). On the other hand, when peak level <average level is not satisfied (step S34) or when peak level <average level is not the first time (step S35), copyright data is not embedded (step S37).

  Next, a third embodiment will be described with reference to FIGS. 16 is a flowchart for explaining copyright data embedding processing by the control unit 200 of the third embodiment, FIG. 17 is an explanatory diagram showing an embedding period by the processing of FIG. 16, and FIG. 18 is an embedding processing of FIG. It is a flowchart for demonstrating a modification. Here, the second embodiment is configured to perform embedding when the level decreases, but the third embodiment is configured to perform embedding when the level increases.

  That is, in FIG. 16, first, the control unit 200 detects the peak level from the output signal of the A / D converter 31 with a predetermined rising time constant (for example, 1 millisecond) and a falling time constant (for example, 150 milliseconds). (Step S41). Next, the average level is detected (step S42), and then it is checked whether or not the peak level exceeds the average level (step S43). If peak level> average level and this is the first time, embedding is performed while continuing to generate one piece of copyright data (steps S43 → S44 → S45), while peak level> If it is not the average level (step S43) or if the peak level> average level is not the first time (step S44), the copyright data is not embedded (step S46).

  Therefore, according to the above embedding process, copyright data is embedded in a period when the peak level> average level is the first time, and copyright data is embedded in a period where the peak level> the average level is not or the peak level> the average level is not the first time. Since it is not performed, the embedding becomes intermittent. FIG. 17A shows an original signal, and FIG. 17B is an explanatory diagram showing an embedded state with respect to the original signal of FIG. As shown in FIG. 17 (A), the music source whose level fluctuates is perceived in terms of audibility even if the source is modified by embedding it at the time when the level increases (arrow shown) as shown in FIG. 17 (B). Since it is known that it is difficult, it is possible to prevent the quality of the analog output signal from deteriorating.

  The process shown in FIG. 18 corresponds to the modification of the first embodiment shown in FIG. 7 and the modification of the second embodiment shown in FIG. That is, first, as in the case shown in FIG. 15, the peak level and the average level (step S52) of the output signal of the A / D converter 31 are detected. In this modification, in the following step S53, it is checked whether or not the average level is sufficiently large, for example, whether or not the average level is larger than −19 dB with respect to the maximum level. Is embedded (step S56).

  If the average level is not higher than −19 dB in step S53, the embedding is performed when the peak level is higher than the average level and it is the first time as in the case shown in FIG. 15 (steps S54 → S55 → S56). On the other hand, when peak level> average level is not satisfied (step S54) or when peak level> average level is not the first time (step S55), copyright data is not embedded (step S57).

Next, a fourth embodiment will be described with reference to FIGS. In FIG. 19, steps S41 to S44 are the same as the processes shown in FIG. 16 (third embodiment). If the peak level is not higher than the average level in step S43 and if it is not “first time” in step S44, the embedding flag F is set in step S800 (F = 1), then embedding is not performed in step S46, and then step Return to S41.
If “first time” in step S44, it is determined in step S500 whether the embedding flag F is set. If F = 1, the process proceeds to step S47. In step S47, a timer is started to determine whether the timer has elapsed, for example, 1 millisecond (m) seconds. If NO, the process proceeds to step S45 to perform embedding, and the process returns to step S41.

  Then, when 1 millisecond has elapsed in step S47, the process proceeds to step S49 to determine whether or not the timer has elapsed, for example, 1.5 seconds. If NO, the process proceeds to step S600 and the embedding flag F is reset. (F = 0), the process proceeds to step S46 to stop the embedding, and the process returns to step S41. If F = 0 in step S500, the process proceeds to step S49. If 1.5 seconds have elapsed, the process proceeds to step S700 to set the embedding flag F (F = 1), and then passes through step S46. The process returns to step S41.

  According to such a configuration, as shown in FIG. 20, since the copyright data is embedded in bursts with a period of 1 millisecond and 1.5 seconds or more, it is not embedded continuously for a long time. Thus, it is possible to prevent the quality of the analog output signal during reproduction from deteriorating. Further, steps S51 to S57 in the modification shown in FIG. 21 are the same as the processes shown in FIG. 18 (modification of the third embodiment), and similarly, steps S58, S60, S500, S600, S700, and S800 are performed. By this process, the copyright data is embedded in bursts in a burst of 1 millisecond and 1.5 seconds.

  Next, a fifth embodiment will be described with reference to FIGS. Here, in the fourth embodiment, since the copyright data is embedded at a cycle of 1.5 seconds or more, depending on the music source, it may be embedded at a fixed cycle of 1.5 seconds. There is a possibility. Therefore, in the fifth embodiment, the copyright data embedding period Tx is randomly changed.

  That is, when embedding is performed in step S45, first, for example, it is continued for 1 millisecond as in the fourth embodiment. When 1 millisecond elapses in step S47, the process proceeds to step S49a, for example, an arbitrary random embedding period Tx from 10 milliseconds to 1.5 seconds is set, and then in step S49b, the embedding period Tx has not elapsed. In this case, the process proceeds to step S600 to reset the embedding flag F (F = 0), and then proceeds to step S46 to stop the embedding and return to step S41.

  If F = 0 in step S500, the process proceeds to step S49b. If the random embedding period Tx has elapsed, the process proceeds to step S700 to set the embedding flag F (F = 1), and then passes through step S46. Then, the process returns to step S41.

  Further, in the modification shown in FIG. 23, similarly, when the average level> −19 dB, the copyright data is embedded in a burst form for 1 millisecond and at a random embedding period Tx. According to this modified example, as shown in FIG. 24, the copyright data is burst in a random cycle Tx (= T1 ≠ T2 ≠ T3...) Particularly in a period where the average level is sufficiently large, for example, a period where the average level> −19 dB. Since it is embedded in, it can prevent becoming an annoyance.

  In the decoders of these first to fifth embodiments (FIG. 8), the bit stream transmitted and input via the medium is left as it is, the copyright data rewriting unit 30, the switch 51, and the bit stream output. The terminal 49 can be output via the terminal 52, and the terminal 49 for inputting the personal identification number, the personal identification number input via the terminal 49 and the copyright data from the DVD decryption circuit 42 are turned on. In addition, a decryption unit 50 for controlling the copyright data rewriting unit 30 is provided. The decryption unit 50 has an authentication function for determining the authenticity of the password.

  When the code number is input, the decryption unit 50 receives an authentication check, and when it is authenticated as authentic, it allows a copy permission condition in the copyright data from the DVD decryption circuit 42, for example, “recording is possible”. The number is checked, and when it is not “0”, the copyright data rewriting unit 30 is controlled so as to decrement the recordable number in the bitstream by one, and the output is permitted by turning on the switch 51. On the other hand, if it is “0”, the copying of the unlimited bit stream is prohibited by prohibiting the output without turning on the switch 51. As copy permission conditions, in addition to “recordable number”, “copyable period” is transmitted via the medium, and a clock function is provided in the decryption unit 50 to set the time when the PIN is entered as “copyable” If it is outside the “period”, copying may be prohibited.

  Further, the timing of embedding copyright data is not limited to when the level of the audio signal changes, but may be embedded at a fixed period (or in this case and when the level fluctuates) only when the peak level exceeds −19 dB. 6 embodiment). In this case, if the embedding time is about 0.49 seconds, the embedding stop time is about 0.49 seconds and one period is about 0.98 seconds in FIG. The change of the reproduction signal due to the embedding becomes rhythmical, and it becomes difficult to detect it by the masking effect due to the period close to the human heartbeat. In addition, since the amount of embedded data can be increased because interruption is performed at a constant period, the embedding efficiency can be improved.

Here, in the “auditory masking effect”, the maximum level of the masked signal C (code) when there is a masked signal M (music) as shown in FIG. Can be expressed as The masking sensitivity X (= CMR) shown in FIG. 25 differs depending on the nature of the signal M on the masking side,
・ When the signal is tone-like (close to a sine wave): approx. 25 dB
・ When the signal is noise-like… Approx. 5 dB
It is believed that. Further, in an actual audio signal, the lower frequency range is more like a tone, and in the higher frequency range, it is considered that the harmonics of the musical instruments overlap each other and become noise-like. Therefore, the value of the masking sensitivity X (= CMR) is shown in FIGS. 27, it can be determined to some extent according to the frequency.

  Therefore, the level control unit 118 sets the level of the modulation signal C of the copyright data based on the frequency of the data string (xbi, xai), for example, the pattern C0 indicated by the solid line in FIGS. Only the CMR of the auditory psychological model is set to a level that cannot be normally heard by setting it to a level sufficiently lower than that. This modulated data is applied to the adder 121 and embedded in the output signal of the A / D converter 31.

  In this embedding process, as shown in FIG. 28, the control unit 200 determines a predetermined rising time constant (for example, 1 millisecond) and falling time constant (for example, 150 milliseconds) from the output signal of the A / D converter 31. The peak level is detected (step S1a), and then the average level (correction value) is detected (step S2a). Then, it is checked whether or not the peak level is lower than the average level (step S3a), and when the peak level <average level, the level of the modulation signal C of the copyright data is increased as in the pattern C1 indicated by the broken line in FIG. Step S4a). On the other hand, when the peak level <the average level, the CMR is changed to the fixed pattern C0 as shown by the solid line in FIGS. 26 and 27, that is, the level of the modulation signal C of the copyright data is changed only according to the frequency of the original signal M ( Step S5a).

  Therefore, according to the above-described embedding process, the level of the modulation signal C is increased in the case where the peak level <the average level, that is, in the section where the original signal M is small as shown in FIG. 29. Sound quality does not deteriorate.

  In this modification shown in FIG. 30, first, the peak level is similarly detected (step S11a), and then the average level is detected (step S12a). In the subsequent step S13a, it is checked whether or not the average level is sufficiently large, for example, whether or not the average level is greater than −19 dB with respect to the maximum level. If average level> −19 dB, the copyright is determined only according to the frequency. The copyright data is embedded at the level of the fixed pattern C0 in which the level of the data modulation signal is changed (step S16a).

  If the average level is not greater than −19 dB in step S13a, as in the case shown in FIG. 28, when the peak level <the average level, the modulation signal C of the copyright data as shown by the broken line in FIG. Is embedded (step S15a). On the other hand, when the peak level <the average level is not satisfied, the CMR is embedded with a fixed pattern C0 as indicated by a solid line in FIGS. 26 and 27 (step S16a).

  Next, a method in which an intermittent embedding method and an embedding method using the “auditory masking effect” are combined will be described. First, when FIG. 28 is combined with FIG. 5, in step S1 shown in FIG. 5, first, a flat filter or auditory correction filter processing is executed, and then an average level (correction value) and a peak level are detected. (Step S2). When embedding is performed when the peak level> the average level in steps S3 and S4, the CMR of the modulation output is set to the fixed pattern C0 as in step S5a shown in FIG. The fixed pattern is preferably a pattern C0 having a different CMR depending on the frequency as shown in FIG. 27, but may be a fixed pattern C regardless of the frequency as shown in FIG.

  FIG. 31 shows a method in which FIG. 28 is combined with the method shown in FIG. 7, and steps S17 and S18 are added. First, a flat filter or auditory correction filter processing is executed (step S11), and then an average level (correction value) and a peak level are detected (step S12). In this modification, it is checked whether or not the average level is sufficiently large, for example, whether or not the average level is larger than −19 dB with respect to the maximum level (step S13). If the average level> −19 dB, step S17 is performed. In step S15, the CMR is set to the fixed pattern C0 (or C) to perform embedding (step S15). If the average level is not more than −19 dB, the embedding is performed by setting the CMR to the variable pattern C1 (> C0, C) shown in FIG. 27 when the peak level> the average level, as in the case shown in FIG. Steps S14 → S18 → S15). When the peak level> the average level is not satisfied, the embedding is not performed (steps S14 → S16).

Here, the variable pattern C1 shown in FIG. 32 shows a modification of FIG. The CMR of the variable pattern C1 is embedded (not “0”) even at 2 kHz or less, but becomes smaller as the frequency becomes lower, becomes constant at 2 kHz to 7 kHz, and is larger than the fixed pattern C0 at 7 kHz to 10 kHz.
Further, when FIG. 28 is combined with the method shown in FIG. 13, the fixed patterns C0 and C are set and embedded in step S25 of FIG.

  FIG. 33 shows a method in which FIG. 28 is combined with the method shown in FIG. Only the processing different from the method shown in FIG. 15 will be described. If the average level> −19 dB in step S33, the CMR is set to the fixed pattern C0 (or C) in step S38 and embedding is performed (step S36). If the peak level is less than the average level in steps S34 and S35 and this is the first time, the CMR is set to the variable pattern C1 (> C0, C) in step S39 to perform embedding (step S36).

  Further, when FIG. 28 is combined with the method shown in FIG. 16, the fixed patterns C0 and C are set and embedded in step S45 of FIG.

  34, 35, and 36 show a method in which FIG. 28 is combined with the methods shown in FIGS. 18, 21, and 23, respectively. Only the processing different from the method shown in FIGS. 18, 21, and 23 will be described. If the average level is greater than −19 dB in step S53, the CMR is set to the fixed pattern C0 (or C) in step S61 and embedding is performed. (Step S56). If the peak level> the average level in steps S54 and S55 and this is the first time, the CMR is set to the variable pattern C1 (> C0, C) in step S62 and embedding is performed (step S56).

  Further, when FIG. 28 is combined with the method shown in FIGS. 19 and 22, the fixed patterns C0 and C are set and embedded in step S45 of FIGS.

  FIG. 37 shows, as a modification of FIG. 21, a method in which the CMR is set to only the fixed patterns C0 and C and embedded intermittently. First, similarly, the peak level is detected (step S51), and then the average level is detected (step S52). In the subsequent step S53, it is checked whether or not the average level is sufficiently large, for example, whether or not the average level is greater than −19 dB with respect to the maximum level. If average level> −19 dB, flag determination and time passage determination are performed. After the steps S500 and S58, the copyright data is embedded with the CMR of the fixed pattern C0 (step S56). On the other hand, if the average level is not more than −19 dB, the flag F is set to 1 (step S800). No embedding is performed (step S57).

  If the embedding time is about 0.49 seconds (step S58), the embedding stop time is about 0.49 seconds (step S60), and one cycle is about 0.98 seconds, Therefore, the change of the reproduction signal due to the embedding becomes rhythmical, and it is difficult to detect it due to the masking effect due to the period close to the human heartbeat. In addition, since the amount of embedded data can be increased because interruption is performed at a constant period, the embedding efficiency can be improved.

  Then, if the embedding time is about 0.49 seconds (step S58), the embedding stop time is about 0.49 seconds (step S58, step S60), and one cycle is about 0.98 seconds, the average of human heartbeats Therefore, the change in the reproduction signal due to the embedding becomes rhythmical, and it is difficult to detect in the sense of hearing due to the masking effect due to the period close to human heartbeat. In addition, since the amount of embedded data can be increased because interruption is performed at a constant period, the embedding efficiency can be improved.

  Next, a seventh embodiment will be described with reference to FIGS. 38 and 39. FIG. In the first to sixth embodiments, the case of embedding in only one channel has been described. However, since audio signals are actually reproduced in two stereo channels or multi-channel, they are embedded in all channels. And a method of embedding only in a specific channel (for example, the front L channel of 6 channels). However, if the embedding is continuously performed on all channels or only on a specific channel, the sound quality may be deteriorated in the sense of hearing or a feeling of processing may be caused, which may cause a sense of discomfort.

  Therefore, in the seventh embodiment, one or more channels of a plurality of channels are selectively embedded in time. Thereby, since the audibility between channels becomes unbalanced, it can be made difficult to detect in audibility. FIG. 38 shows a process for changing the channel flag for embedding (step S-W1). This change process is performed by interruption. Various methods are conceivable as the interrupt timing. For example, the interrupt timing may be set for every fixed period, random period, each music segment, or each movement segment.

  For simplification of explanation, FIG. 39 shows, as an example, processing in the case of alternately embedding in each channel of stereo 2ch (Lch and Rch) temporally and in combination with the processing shown in FIG. First, Lch and Rch peak levels (step S51 ′) and average levels (step S52 ′) are detected. Then, an embedded channel (Lch or Rch) is selected based on the embedded channel flag set in step S-W1 shown in FIG. 38 (steps S52b, S52c, S52d). In the following step S53, it is checked whether or not the average level of the selected channel is sufficiently large, for example, whether or not the average level is larger than −19 dB with respect to the maximum level, and if the average level> −19 dB, the process goes through steps S500 and S47. In step S56 ′, the copyright data of the selected channel is embedded.

  Further, if the average level of the selected channel is not -19 dB in step S53, as in the case shown in FIG. 15, the selected channel is embedded when the peak level is greater than the average level and this is the first time (step S53). S54 → S55 → S500 → S47 → S56 ′) On the other hand, when peak level> average level is not satisfied (step S54) or when peak level> average level is not the first time (step S55), copyright data is embedded in the selected channel. No (step S57 '). Further, when embedding the selected channel, it is embedded in a burst shape for 1 millisecond and at a random embedding period Tx as in the case shown in FIG.

  Here, in the processing shown in FIG. 39, whether to embed is determined according to the level, and the CMR fixed patterns C0 and C and the variable pattern C1 are embedded in one channel of 2ch. Regardless of the level variation, only the CMR fixed patterns C0 and C are embedded in one channel of stereo 2ch or one or more channels of multi-channel (for example, the rear two channels of 6 channels). May be.

    Next, an eighth embodiment will be described with reference to FIG. By the way, in the first to seventh embodiments, a method of simultaneously embedding the same copyright data in a plurality of channels is conceivable. However, since the listener listens to all channels at the same time, in this method, the reproduction sound is reproduced. For reasons such as a sense of orientation, it may be easy to detect in the sense of hearing. Therefore, this can be prevented by embedding “copyright data that differs in time” in each channel. Note that “copyright data different in time” may be completely different data, or may be the same or data with a time difference.

  FIG. 40 shows a configuration applied to stereo 2ch for the sake of simplicity. The copyright data supply unit 100 supplies “L-channel copyright data L and R-channel copyright data R that are temporally different” to the FM modulators 114L and 114R, respectively. The copyright data L and R are modulated by the two systems of FM modulators 114L and 114R and spread modulators 116L and 116R by the oscillator 115 and the spread code 117, respectively, and then the levels are controlled based on the control of the control unit 200. It is controlled by the level controllers 118L and 118R and applied to the embedding adders 121L and 121R via the switch 201. As in the first to seventh embodiments, the control unit 200 controls the switch 201 based on the Lch and Rch levels, level fluctuations, etc. Embed channel copyright data R ".

  Here, in the process shown in FIG. 40, when “copying copyright data different in time” is embedded in two or more channels, the fixed patterns C0 and C and the variable pattern C1 may be embedded. It may be embedded only with the CMR fixed patterns C0 and C regardless of the change or according to the level or the level change.

  Next, a ninth embodiment will be described with reference to FIGS. 41 and 42. By the way, in the first to eighth embodiments, since the copyright data changing in a burst shape includes a component exceeding the band of the original audio data, both data are stored when the copyright data is embedded in the original audio data. If the adder 121 simply adds, it causes distortion, and this distortion is easily detected during reproduction. Further, if the amount of copyright data embedded is reduced in order to make it difficult to detect it during listening, the amount of embedded data is limited. Therefore, the ninth embodiment is configured to solve this problem.

  FIG. 41 shows a copyright data embedding circuit used in place of the adder 121. This circuit is configured by a digital filter, the upsampling unit 4 performs interpolation (interpolation) and LPF processing, and the downsampling unit 5 performs thinning (decimation). 42 shows the main signals of the circuit in FIG. 41. First, as shown in FIGS. 42A and 42B, the sampling frequency fs of the original audio signal a and the copyright information b is the same, and the copyright information The number of bits of b is smaller than that of the original signal a. When the adder 3 adds the original signal a and the copyright information b, a signal c including distortion is obtained as shown in FIG.

  The subsequent upsampling unit (up ↑ 2 in the figure) 4 performs a zero sampling between the sampling positions of the input signal c in order to upsample the signal c input from the adder 3 at twice the sampling frequency fs × 2. Alternatively, the hold value at the sampling position before the input signal c is inserted as an interpolation signal, and this is then subjected to LPF processing to create a data string d having a double sampling frequency fs × 2 as shown in FIG. To do. This data string d is a signal having the same value except that it is delayed from the time difference τ 1 with respect to the input signal c by the processing time by the upsampling unit 4.

  The subsequent down-sampling unit (down ↓ 2 in the figure) 5 thins out the interpolation signal and outputs a data string e only at the sampling position of the signal c, whereby the signal d is converted into the original sampling frequency as shown in FIG. Downsample to fs. The data string e is a signal having the same value except that it is delayed from the time difference τ2 with respect to the input signal d, and is therefore a signal having the same value except that it is delayed from the time difference τ1 + τ2 with respect to the signal c. According to such processing, both the phase and the amplitude are displaced when embedding the copyright data b in the original audio data a. Therefore, even if the embedding amount of the copyright data b is increased, it is detected on hearing. Can be made difficult.

  FIG. 43 shows a modification of the up / down sampling section of FIG. 41, and the embedding circuit 6 is configured to perform up sampling and down sampling simultaneously. That is, the embedding circuit 6 inserts an interpolation signal between the sampling positions of the original signal a added by the adder 3 and the added signal c of the copyright information b as shown in FIGS. Thus, the upsampling process and the downsampling process for converting the sampling frequency to twice the sampling frequency fs × 2 are performed only at the original sampling frequency fs. According to such a circuit, it is possible to realize the same embedding process with a small amount of calculation compared to the circuit shown in FIG.

  FIG. 44 shows another modification of the up / down sampling section of FIG. The up-sampling units 4-1 and 4-2 respectively up-sample the original audio signal a and the copyright information b at a sampling frequency fs × 2 that is twice that of the sampling positions of the signals a and b. Alternatively, a hold value at a sampling position before the input signals a and b is inserted as an interpolation signal, and then this signal is subjected to LPF processing to create a data string a ′ and b ′ having a double sampling frequency fs × 2. . The adder 3 adds the original audio signal a ′ having twice the sampling frequency fs × 2 and the copyright information b ′, and the subsequent down-sampling unit 5 converts the signal c ′ added by the adder 3 into the original sampling. The signal e down-sampled to the frequency fs is output. According to such processing, distortion due to the copyright information b is removed before addition, so that distortion remaining in the output signal e can be reduced by the circuit shown in FIG.

  45 and 46 show still another up / down sampling unit and its processing, respectively. In this example, the adder 3 is omitted, and the up-sampling unit 4 up-samples the original signal a and the copyright information b at a sampling frequency fs × 2 that is twice that as shown in FIGS. Then, the copyright information b is inserted as an interpolation signal between the sampling positions of the original signal a, and a data string c having a double sampling frequency fs × 2 is created as shown in FIG. Next, the up-sampling unit 4 performs a low-pass filter (LPF) process on the data string c, and outputs a signal d obtained by extracting a low-frequency component as shown in FIG.

  The subsequent downsampling unit 5 downsamples the data string d to the original sampling frequency fs and outputs a data string e only at the sampling position of the original signal a as shown in FIG. According to such processing, both the phase and the amplitude are displaced when embedding the copyright data b in the original audio data a. Therefore, even if the embedding amount of the copyright data b is increased, it is detected on hearing. Can be made difficult. FIG. 47 shows a modification of the circuit of FIG. 45, and the embedded circuit 6 is configured to perform up-sampling and down-sampling at the same sampling frequency fs at the same time as in the case of FIG. .

  48 and 49 show still another up / down sampling unit and its processing, respectively. The copyright information b is delayed by the one-sample delay circuit (Z-1) 7, and copyright data strings b1, b2,... As shown in FIG. Then, the copyright data strings b1, b2,... And the original audio data strings a1, a2,.

In order to upsample the data sequence a1 + b1, a2 + b2... And the copyright data sequence b1, b2... Added by the adder 3 at a sampling frequency fs × 2 that is twice the data sequence a1 + b1, a2 + b2. .. Are inserted as interpolated signals, and as shown in FIG. 49C, the data sequence b1, a1 + b1, b2, a2 + b2,...
Create Next, the upsampling unit 4 extracts a low-frequency component as shown in FIG. 49D by performing a low-pass filter (LPF) process on the data string c.

  The subsequent downsampling unit 5 downsamples this data string at the original sampling frequency fs and outputs data strings a′1, a′2,... Only at the sampling position of the original signal a as shown in FIG. . Similarly, in such processing, both the phase and amplitude are displaced when embedding the copyright data b in the original audio data a. Therefore, even if the embedding amount of the copyright data b is increased, it is audible during reproduction. It can be made difficult to detect. FIG. 50 shows a modification of the circuit of FIG. 48, and the embedded circuit 6 is configured to perform upsampling and downsampling at the same time by performing the upsampling and downsampling at the original sampling frequency fs as in the case of FIGS. Has been.

  51 and 52 show still another up / down sampling unit and its processing, respectively. In this circuit, in order to generate an interpolation signal, the original audio data strings a1, a2,... Shown in FIG. 52 (A) and the copyright data strings b1, b2,. Next, the addition signals a1 + b1, a2 + b2,... Are delayed by the one-sample delay circuit (Z-1) 7.

The up-sampling unit 4 performs up-sampling of the original audio data sequences a1, a2,... And the data sequences a1 + b1, a2 + b2,. .. Are inserted as interpolation signals between the sampling positions of the original audio data strings a1, a2,..., And as shown in FIG. 52 (C), the data string a1, double sampling frequency fs × 2 is inserted. a1 + b1, a2, a2 + b2 ...
Create Next, the up-sampling unit 4 performs low-pass filter (LPF) processing on this data string to output data strings d1, d2,... From which low-frequency components are extracted as shown in FIG.

  The subsequent down-sampling unit 5 down-samples the data strings d1, d2,... At the original sampling frequency fs, and generates data strings d1, d3, d5... Only at the sampling position of the original signal a as shown in FIG. Output. FIG. 53 shows a modification of the circuit of FIG. 51, and the embedded circuit 6 performs upsampling and downsampling at the same time by performing the upsampling and downsampling at the original sampling frequency fs, as in the case of FIGS. 43, 47, and 50. It is configured as follows.

  54 and 55 show still another up / down sampling unit and its processing, respectively. In this circuit, first, the up-sampling unit 4-1 up-samples the copyright data strings b1, b2,... And the interpolation signal “0” at a sampling frequency fs × 4 that is four times that of the copyright data strings b1, b2. Interpolation signal “0” is inserted between the sampling positions of... And then LPF-processed to obtain a data sequence c1, c2, c3 of four times the sampling frequency fs × 4 as shown in FIG. , C4, c5... Here, b1 and c1, b2 and c5, that is, bn and c4 (n−1) +1 are the same sampling position.

  Next, the adder 3-1 adds the original audio data strings a1, a2-an and the data strings c1, c5-c4 (n-1) +1 generated by the upsampling unit 4-1, at the sampling frequency fs. The adder 3-2 adds the interpolation signal “0” and the data strings c1 and c5 to c4 (n−1) +1 at a sampling frequency fs × 4 that is four times.

The subsequent upsampling unit 4-2 adds the signals added by the adders 3-1, 3-2 by the adder 3-1, in order to upsample the signals at a sampling frequency fs × 4 that is four times higher. The signal added by the adder 3-1 between the sampling positions of the signal is inserted as an interpolated signal, and this is then subjected to LPF processing, whereby FIG.
As shown in FIG. 4, a data string of four times the sampling frequency fs × 4 a1 + c1, c2, c3, c4, a2 + c5, c6.
, An + c4 (n-1) +1
Create Further, the upsampling unit 4-2 performs low-pass filter (LPF) processing on this data string to output data strings e1, e2,... From which low-frequency components are extracted as shown in FIG.

  The subsequent downsampling unit 5 downsamples the data strings e1, 42... To the original sampling frequency fs, and as shown in FIG. 55 (F), the data string f1 (= e1), f2 only at the sampling position of the original signal a. (= E5) is output. 56 shows a modification of the circuit of FIG. 54, and the embedded circuit 6 performs upsampling and downsampling at the original sampling frequency fs in the same manner as shown in FIGS. 43, 47, 50, and 53. , Configured to do at the same time.

  Next, a medium on which data subjected to the embedding process is recorded will be described. First, the user data sequence (see FIG. 4) created by the allocation circuit 40 shown in FIGS. 2, 11, and 40 is encoded by the DVD encoding circuit 34 shown in FIG. EFM modulation is performed by the modulation circuit 35.

  Next, this data is supplied to a DVD cutting machine (player) (not shown) to manufacture a master disc of the DVD audio disc. Next, a metal thin film is formed on the master by sputtering and plating, and further thickened and peeled from the master to produce a stamper. Next, the base material on which the disc is based is formed by injection molding with this stamper and bonded to produce a DVD audio disc.

As shown in FIG. 57, the audio (A) pack {and video (V) pack} in the DVD audio disk is composed of 4 bytes of pack start information and 6 bytes for 2034 bytes of user data (A data and V data). SCR (System Clock Reference) information, 3-byte Mux rate information, and 1-byte stuffing total 14-byte pack header (1 pack = total 2048 bytes) . In this case, the time of the A pack in the same album can be managed by setting the SCR information, which is a time stamp, as “1” in the first pack in the ACB unit and continuing in the same album.

  Next, a tenth embodiment will be described with reference to FIGS. Recently, the use of multimedia by a PC has progressed rapidly, and it has become widespread to process video and audio signals using a PC. Recently, it has become widespread to transmit a moving image or audio signal via a communication line such as the Internet. Under such circumstances, a general user may desire to manage his / her copyright when a music source is supplied to another person via a medium or a communication line using a PC.

  58 is a block diagram showing a digital audio signal processing system according to the tenth embodiment of the present invention, FIG. 59 is a flowchart for explaining a digital audio signal processing program of the personal computer of FIG. 58, and FIG. 60 is a flowchart of FIG. FIG. 61 is a flowchart for explaining the copyright data embedding program in detail, and FIG. 61 is a flowchart for explaining the copyright data reproduction program.

  58 is connected to a digital audio signal processing program as shown in FIG. 59 (the copyright data embedding program shown in detail in FIG. 60 and the copyright data reproduction shown in detail in FIG. 61) from the disk drive device 104 or the network terminal 105. (Including programs) and music sources such as surround music.

  The personal computer 106 includes a CPU 106a having a special-purpose instruction set added mainly for efficiently processing digital signals such as images and sounds, such as Intel's PP55C extended instruction set (MMX), and data A RAM 106b used as a buffer at the time of processing, a data converter 106c for converting data supplied from the disk drive device 104 or the network terminal 105, and a plurality of processed audio data via a D / A converter and an amplifier An audio interface (I / F) 106d for supplying to speakers (103L and 103R in the figure, and further surround speakers 103C and 103S), a display processor 106e for controlling display of a display unit (not shown), and an illustration (not shown) Mouse and keys An operation signal generating section 106f for generating an operation signal based on the operation input signal from the over-de.

  In such a configuration, as shown in FIG. 59, the CPU 106a receives a program load command (command) via a keyboard (not shown) in a state where a disk on which a digital audio signal processing program is recorded is set in the disk drive device 104. When input is made (step S61), the program data is read from the disk and loaded into the internal RAM (step S62). When loading is completed, the program load flag is set (step S63), and the process is terminated. At this time, since the CPU 106a is MMX compatible, high-speed signal processing is possible.

  Further, when a play command is input via a keyboard (not shown) while a disc on which a music source such as surround music is recorded is set in the disc drive device 104, the CPU 106a accesses the first track of the disc and A subcode indicating the type of disc is read, and it is checked whether or not the subcode is “music source” (step S64). If YES, a copyright data embedding program shown in detail in FIG. 60 is executed (step S65). Then, the processed audio data is passed to the audio I / F 106d (step S66). Next, returning to step S65, the copyright data embedding program is repeated. If it is not “music source” in step S64, “unable to play” is displayed on a display unit (not shown) (step S67), and the process ends.

  The CPU 106a executes a copyright data embedding program as shown in FIG. In FIG. 60, first, a process of inputting A / D conversion data of a music source is executed (step S100), and a process of inputting copyright data via a keyboard is executed (step S101). Is executed to spread the spectrum (step S102). In this spread spectrum process, the FM modulator 114 and the spread modulator 115 shown in FIGS. 2, 11, and 40 execute the process with software instead of hardware.

  In the subsequent step S103, the copyright data modulated by the embedding process as described above is embedded in the digital audio data (step S103), and then format conversion for recording the digital audio data on the recording medium is performed (step S104). ).

Next, with reference to FIG. 61, a process for reproducing the copyright data thus modulated and embedded will be described. First, digital audio data in which copyright data is embedded is captured (step S200), and then a modulation signal is extracted based on the digital audio data and original digital audio data in which no copyright data is embedded (step S201). Next, the modulated signal is subjected to spread spectrum demodulation using the same spreading code 117 (see FIGS. 2, 11, and 40) as that at the time of modulation, and then the same frequency as that at the time of modulation (shown in FIGS. 2, 11, and 40). The original copyright data is extracted by FM demodulation using the oscillator 115 (step S202). Next, the copyright data is decrypted by collating with the database (step S203).
Next, a case where the above program and a digital audio signal processed by this program are transmitted via a communication line will be described. 62 is a block diagram showing details of the network terminal 105 in the personal computer 106 shown in FIG. 58, FIGS. 63 and 64 are flowcharts showing processing of the data conversion unit of FIG. 62, and FIG. 65 is an explanatory diagram showing a communication network. 66 is an explanatory diagram showing packet processing on the network of FIG. The terminal 105 is provided on both the data transmission side and the data reception side personal computer 106, and includes a reception buffer T1 and a transmission buffer T2 connected to the internal bus of the personal computer 106, a data conversion unit T4, and an adapter T3 which is a communication interface. And a communication terminal T6 and a controller T5.

  As shown in FIG. 63, the data conversion unit T4 on the data transmission side divides the transmission data stored in the transmission buffer T2 into packets of predetermined length (step S141), and then sets the destination address at the beginning of the packet. A header including the same is added (step S142), and this is then output on the network NW via the adapter T3 and the communication terminal T6 (step S143). As shown in FIG. 64, the data conversion unit T4 on the data receiving side removes the header from the packet received from the network NW via the communication terminal T6 and the adapter T3 (step S151), and then restores the received data (step S152). Then, this is transferred to the program RAM 106b shown in FIG. 58 via the reception buffer T1 (step S153).

  The communication terminal T6 on the data transmission side and the data reception side is connected via a network NW as shown in FIG. 65, for example. In this network NW, for example, data is transmitted in units of packets 1) 2) 3)... Using a CATV line or a TCP / IP (Transmission Control Protocol / Internet Protocol) protocol called the Internet. In this case, the packets 1) 2) 3)... Output from the data transmission side are packets 1) 2) 3)... As shown in FIGS. Each packet separated by the router R and then separated by the router R is sent to the personal computer 106 on the data receiving side in order through the packet switch Pn (n = 1 to k).

  Therefore, the personal computer 106 on the data receiving side can embed copyright data in the music source in the disc set in the disc drive device 104 based on the program on the program RAM 106b. When a copyright data embedding program or a music source in which copyright data is embedded based on this program is transferred by such a communication method, a program usage fee is charged to the transmitting side or the receiving side. To do.

  The present invention is not limited to a case where the data transmission side transmits unilaterally to the reception side. For example, a user on the data reception side transmits a program transmission request or an audio signal transmission request based on a home page on the data transmission side. The present invention can also be applied when the data transmission side transmits a program or an audio signal based on this request. In the case of such an Internet, a TCP / IP protocol group is used as the adapter T3 that functions as an interface.

  Here, the copyright data is embedded by special printing or molding on a medium for storing the music source in which the copyright data is embedded, for example, the surface or inside of the base material of the DVD-audio disc. The copy protection function can be realized by forming the visible image shown. Note that a method for forming such a visible image is described in, for example, Japanese Patent Application Laid-Open Nos. 7-99889, 8-2158, and 9-128812, and detailed description thereof is omitted. However, the visible image formed by such a method is not easily duplicated or tampered with.

It is a block diagram which shows the embedding apparatus (encoder) of the copyright information applied to this invention. It is a block diagram which shows the signal processing circuit of FIG. 1 in detail. It is explanatory drawing which shows the sampling period and data sequence of the A / D converter of FIG. It is explanatory drawing which shows the user data packed by the allocation circuit of FIG. 3 is a flowchart for explaining copyright data embedding processing by a control unit in FIG. 2; It is explanatory drawing which shows the embedding period of the copyright data by the control part of FIG. It is a flowchart for demonstrating the modification of the embedding process of FIG. FIG. 2 is a block diagram illustrating a decoder that decodes data processed by the encoder of FIG. 1. It is a block diagram which shows the signal processing circuit of FIG. 8 in detail. It is explanatory drawing which shows the data sequence decoded by the decoder of FIG. FIG. 3 is a block diagram illustrating a modification of the signal processing circuit in FIG. 2. FIG. 10 is a block diagram illustrating a modification of the signal processing circuit of FIG. 9. It is a flowchart for demonstrating the embedding process of the copyright data by the control part of 2nd Embodiment. It is explanatory drawing which shows the embedding period by the process of FIG. It is a flowchart for demonstrating the modification of the embedding process of FIG. It is a flowchart for demonstrating the embedding process of the copyright data by the control part of 3rd Embodiment. It is explanatory drawing which shows the embedding period by the process of FIG. It is a flowchart for demonstrating the modification of the embedding process of FIG. It is a flowchart for demonstrating the embedding process of the copyright data by the control part of 4th Embodiment. It is explanatory drawing which shows the embedding period by the process of FIG. FIG. 20 is a flowchart for explaining a modification of the embedding process of FIG. 19; FIG. It is a flowchart for demonstrating the embedding process of the copyright data by the control part of 5th Embodiment. It is a flowchart for demonstrating the modification of the embedding process of FIG. It is explanatory drawing which shows the embedding period by the process of FIG. It is explanatory drawing which shows an auditory masking characteristic. It is explanatory drawing which shows CMR of the original signal and copyright signal on a frequency axis. It is explanatory drawing which shows CMR of the original signal and copyright signal on a frequency axis. 3 is a flowchart for explaining copyright data embedding processing by a control unit in FIG. 2; It is explanatory drawing which shows the level change of the copyright data by the control part of FIG. 10 is a flowchart for explaining a modification of the embedding process in FIG. 8. It is a flowchart for demonstrating the copyright data embedding process which combined FIG. 7 and FIG. It is explanatory drawing which shows the other CMR of the original signal and copyright signal on a frequency axis. It is a flowchart for demonstrating the copyright data embedding process which combined FIG. 15 and FIG. FIG. 29 is a flowchart for explaining copyright data embedding processing in which FIGS. 18 and 28 are combined. FIG. It is a flowchart for demonstrating the copyright data embedding process combining FIG. 21 and FIG. FIG. 29 is a flowchart for explaining copyright data embedding processing in which FIGS. 23 and 28 are combined. FIG. It is a flow chart for explaining other copyright data embedding processes. It is a flowchart for demonstrating the embedding process of 7th Embodiment. It is a flowchart for demonstrating the embedding process of 7th Embodiment. It is a block diagram which shows the signal processing circuit of 8th Embodiment. It is a block diagram which shows the copyright data embedding circuit of 9th Embodiment. 42 is an explanatory diagram showing a process of embedding the circuit of FIG. 41. FIG. FIG. 42 is a block diagram showing a modification of the copyright data embedding circuit of FIG. 41. FIG. 42 is a block diagram showing another modification of the copyright data embedding circuit of FIG. 41. FIG. 10 is a block diagram showing still another copyright data embedding circuit. FIG. 46 is an explanatory diagram showing a process of embedding the circuit of FIG. 45. FIG. 46 is a block diagram showing a modification of the copyright data embedding circuit of FIG. 45. FIG. 10 is a block diagram showing still another copyright data embedding circuit. FIG. 49 is an explanatory diagram of a process of embedding the circuit of FIG. 48. FIG. 49 is a block diagram showing a modification of the copyright data embedding circuit of FIG. 48. FIG. 10 is a block diagram showing still another copyright data embedding circuit. FIG. 52 is an explanatory diagram showing a process of embedding the circuit of FIG. 51. FIG. 52 is a block diagram showing a modification of the copyright data embedding circuit of FIG. 51. FIG. 10 is a block diagram showing still another copyright data embedding circuit. FIG. 55 is an explanatory diagram showing a process of embedding the circuit of FIG. 54. FIG. 55 is a block diagram showing a modification of the copyright data embedding circuit of FIG. 54. It is explanatory drawing which shows the audio pack of a DVD-audio disk. It is a block diagram which shows the digital audio signal processing system which concerns on the 10th Embodiment of this invention. FIG. 59 is a flowchart for explaining a digital audio signal processing program of the personal computer of FIG. 58. FIG. 60 is a flowchart for explaining in detail the copyright data embedding program of FIG. 59; It is a flowchart for demonstrating a copyright data reproduction | regeneration program. It is a block diagram which shows in detail the network terminal in the personal computer shown in FIG. 63 is a flowchart showing processing of a data conversion unit in FIG. 62. 63 is a flowchart showing processing of a data conversion unit in FIG. 62. It is explanatory drawing which shows a communication network. FIG. 66 is an explanatory diagram showing packet processing on the network of FIG. 65. It is explanatory drawing which shows the conventional CMR characteristic.

Explanation of symbols

3 Adder (addition means)
3-1 Adder (first adding means)
3-2 Adder (second adding means)
4 Upsampling unit (upsampling means)
4-1 Upsampling unit (first upsampling means)
4-2 Upsampling unit (second upsampling means)
5 Downsampling unit (downsampling means)
6 Embedded circuit (upsampling means and downsampling means)
7 1-sample delay circuit (delay means)
30 Copyright Data Rewriting Unit 31 A / D Converter (A / D Converter)
32, 43 Signal processing circuit 33, 44 Memory 34 DVD encoding circuit 35 Modulation circuit 36, 56 Low pass filter 37, 38 Decimation circuit 39, 46, 121 Adder 40 Allocation circuit 41 Demodulation circuit 42 DVD decoding circuit 45 D / A converter 47 Interpolation processing circuit 49 Terminal 50 Cryptographic decryption section 51, 201 Switch 52, 53, 90 Digital output terminal 55 Analog signal output terminal 100 Copyright data supply section 114 FM modulator (oscillator 115, spread modulator 116, spread code 117, (The modulation means is configured together with the level control unit 118)
DESCRIPTION OF SYMBOLS 115 Oscillator 116 Spreading modulator 117 Spreading code 118 Level control part 200 Control part (A copyright data embedding means is comprised with the adder 121 and the switch 201)

Claims (5)

An analog audio signal is A / D converted into digital data, and copyright data including copyright data relating to the digital data and data indicating the number of copies of the digital data is spectrumd. Steps modulated by diffusion;
When embedding the modulated copyright data in the digital data, a peak level and an average level of the digital data are detected, and a change in the peak level with respect to the average level is detected. A step of intermittently embedding copyright data so that a power ratio of the copyright data to the digital data is constant in the frequency domain,
The original copyrighted digital data obtained by A / D-converting the analog audio signal by the copyright information embedding method possessed by the digital data in which the copyrighted data is modulated by spread spectrum and embedded A method of reproducing copyright data, comprising the step of retrieving the copyright data . An analog audio signal is A / D converted into digital data, and copyright data including copyright data relating to the digital data and data indicating the number of copies of the digital data is spectrumd. A modulating step that modulates by spreading;
If the embed relative data, said digital de - - the data the digital de - copyright De said modulated by detecting the peak level and the average level and the frequency of the data, variations with respect to the mean level of the peak level The step of embedding the copyright data intermittently so that the power ratio of the copyright data to the digital data differs according to the frequency of the digital data and the auditory masking effect, The
The original copyrighted digital data obtained by A / D-converting the analog audio signal by the copyright information embedding method possessed by the digital data in which the copyrighted data is modulated by spread spectrum and embedded A method of reproducing copyright data, comprising the step of retrieving the copyright data . An analog audio signal is A / D converted into digital data, and copyright data including copyright data relating to the digital data and data indicating the number of copies of the digital data is spectrumd. Steps modulated by diffusion;
When embedding the modulated copyright data in the digital data, the power ratio of the copyright data to the digital data is constant in the frequency domain, and a plurality of channels are used. A step of simultaneously embedding copyright data different in time for two or more channels of the audio signal of
The original copyrighted digital data obtained by A / D-converting the analog audio signal by the copyright information embedding method possessed by the digital data in which the copyrighted data is modulated by spread spectrum and embedded A method of reproducing copyright data, comprising the step of retrieving the copyright data . Deio signal communication method - Dejitaruo, characterized in that transmitting and / or receiving via a communication line program consisting of the steps of the copyright information embedding method according to any one of claims 1 to 3. Copyright information embedding method Copyright de on the basis of of any one of claims 1 to 3 - to Shin及 beauty / or send and receive via a communication line Deio signal - data Dejitaruo embedded is A digital audio signal communication method characterized by the above.

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