JP4268750B2 - Optical disc, optical disc master creating apparatus, optical disc reproducing apparatus, optical disc master creating method, and optical disc reproducing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disc, an optical disc master creation device, an optical disc playback device, an optical disc master creation method, and an optical disc playback method, and in particular, an optical disc on which predetermined modulated information data is recorded, an optical disc master creation device, an optical disc playback device, and an optical disc master creation. The present invention relates to a method and an optical disc reproducing method.
[0002]
[Prior art]
In general, when a master disk such as an optical disk, for example, a CD (Compact Disk), an MD (Mini Disk), or a DVD (Digital Versatile Disk) is created, predetermined information data to be recorded is recorded in order to ensure recording and reproduction of digital information. Error correction and modulation processing.
[0003]
The modulation process will be described in the case of a CD. In the case of CD, a so-called EFM signal system is adopted as modulation processing. In EFM, 8-bit data of each symbol obtained by error correction is converted into 14-bit data. In this way, one frame signal in which each symbol is converted to 14 bits is generated as main data. Further, a subcode for realizing functions such as cuing of a song and program playback is added to the main data. The subcode is added with 14 bits of 1-symbol data consisting of 8 bits. In the EFM, a margin bit of 3 bits is prepared for combining 14-bit patterns with each other. Actually, 8-bit data is converted into 17 bits.
[0004]
The waveform of the modulation signal will be described. FIG. 6 is an example of a waveform of a modulation signal that has been subjected to EFM modulation. Here, it is assumed that the last information bit pattern is at the high level. In this case, the margin bit can set a pattern of 000 of EFM1, 010 of EFM2, and 001 of EFM3. The margin bit pattern is selected with reference to the DSV. The DSV gives +1 if the waveform is at the high level and -1 if the waveform is at the low level per channel clock, and indicates a deviation in the balance of the modulation signal. As shown in the figure, it is assumed that the end of the previous information bit is t0, the end of the margin bit is t1, the end of the next information bit is t2, and the DSV value at t0 is −3. DSV = -3 indicates that the waveform of the modulation signal is slightly shifted to the negative side. Furthermore, t1, t2, and DSV change, and the DSV of EFM1 at time t2 becomes +2. Similarly, EFM2 is −6 and EFM3 is −4. Normally, the margin bit is set so that the DSV becomes a value closest to 0 in order to minimize the balance deviation. That is, EFM1 000 is selected as the margin bit in this case. Such a procedure is sequentially repeated to generate an EFM signal.
[0005]
In the case of DVD, EFM + is adopted as the modulation process. This is to convert 1-symbol 8-bit data to 16 bits. Like EFM, DSV is calculated at the time of 8-16-bit conversion, and an EFM + bit pattern is set so that the DSV value approaches 0.
[0006]
An optical disc is manufactured based on the master disc thus created and supplied to the market. The optical disk playback device reads a signal recorded on the optical disk, performs EFM demodulation, extracts main data and subcode, and performs playback.
[0007]
On the other hand, not only a read-only optical disc in which data is recorded in advance by a disc manufacturer such as the CD described above, but also a recordable optical disc on which a user can record data at home, such as a CD-R, CD-RW, DVD-R, DVD-RAM and the like have been developed. For this reason, in recent years, an optical disk apparatus capable of recording and reproducing both a recording type and a reproduction-only optical disk with one apparatus has become widespread.
[0008]
With the widespread use of such optical disk devices, unauthorized copying of data recorded on read-only optical disks has become a major problem. Conventionally, various methods have been proposed in order to prevent such illegal copying of an optical disc. For example, there is one in which a copy prevention code is recorded on an optical disc in advance. Some data such as ECC, which is an error correction code, and subcodes described above are intentionally destroyed so that they cannot be copied.
[0009]
[Problems to be solved by the invention]
However, the conventional optical disc essentially has a problem that digital recording from a read-only optical disc to a recordable optical disc is possible, and it is difficult to prevent unauthorized copying.
[0010]
For example, when a copy prevention code is recorded in advance, a copy disk that can be accepted as a regular disk can be easily produced by using a copying machine that copies the entire recording data of the optical disk.
[0011]
Also, data that processes the contents of data such as subcodes can be analyzed after the data is read, and there is a possibility that a method for preventing unauthorized copying will be deciphered.
Furthermore, even if the information data is encrypted, there is a problem that if the encryption key can be obtained from the data, it can be easily decrypted.
[0012]
The present invention has been made in view of the above points, and an object thereof is to provide an optical disc on which predetermined additional information is recorded, an optical disc master creation device, an optical disc playback device, an optical disc master creation method, and an optical disc playback method. And The additional information indicates arbitrary information such as information for preventing unauthorized copying of the disk, information for identifying the disk, and a decryption key.
[0013]
[Means for Solving the Problems]
In the present invention, in order to solve the above-described problem, in an optical disc on which modulated predetermined information data is recorded, a DSV sampled at a predetermined period is a value corresponding to additional information added to the predetermined information data. There is provided an optical disc in which a modulated signal of the predetermined information data modulated so as to be recorded is recorded.
[0014]
When an optical disk having such a configuration modulates predetermined information data to generate a modulated signal, the modulation is performed so that the DSV sampled at a predetermined period becomes a value corresponding to the additional information. Recording according to the signal is made. That is, arbitrary additional information is expressed by DSV sampled at a predetermined cycle.
[0015]
Further, in order to solve the above-described problem, in an optical disc master creating apparatus that modulates and records predetermined information data to create an optical disc master, the optical disc from all information areas of a master in which the predetermined information data is recorded An information reproducing means for reproducing the predetermined information data recorded on the master, and a DSV sampled at a predetermined cycle is added to the predetermined information data when the predetermined information data reproduced by the information reproducing means is modulated. Modulation means for generating a bit pattern having a value corresponding to the additional information to be performed, and modulation signal output means for generating a modulation signal according to the bit pattern generated by the modulation means An optical disc master producing apparatus is provided.
[0016]
In the optical disc master producing apparatus having such a configuration, the information reproducing means reproduces the recorded predetermined information data from all the information areas of the master in which the predetermined information data recorded on the optical disc master is recorded. The modulation means performs predetermined modulation processing on the reproduced predetermined information data and converts it into a bit pattern. At this time, the bit pattern of an arbitrary section to be generated is converted so that the DSV sampled at a predetermined cycle becomes a value corresponding to the additional information added to the predetermined information data. The modulation signal output means outputs a modulation signal corresponding to the bit pattern generated by the modulation means.
[0017]
In order to solve the above problem, in an optical disc reproducing apparatus for reproducing the predetermined information data from an optical disc on which modulated predetermined information data is recorded, the optical disk is irradiated with laser light to read information, An optical pickup unit that reproduces a modulation signal recorded on an optical disk, a signal processing unit that decodes and decodes the modulation signal to decode the predetermined information data, and calculates a DSV of the modulation signal in a predetermined period DSV calculation means for analyzing the DSV and analyzing the calculated DSV to determine the presence or absence of additional information added to the predetermined information data. If there is the additional information, DSV analysis means for acquiring the additional information; There is provided an optical disc characterized by comprising:
[0018]
In the optical disk reproducing apparatus having such a configuration, the optical pickup unit irradiates the optical disk with laser light, reads the modulation signal recorded on the optical disk, and sends it to the signal processing means and the DSV calculation means. The signal processing means performs demodulation and decoding processing, and decodes predetermined information data recorded on the optical disc. The decrypted predetermined information data is reproduced by each application. The DSV calculation means calculates the DSV value of the modulation signal and sends it to the DSV analysis means. The DSV analysis means analyzes the DSV to determine whether there is additional information added to the predetermined information data, and acquires the additional information, if any.
[0019]
In addition, in order to solve the above-mentioned problem, in the optical disc master creating method for creating a master optical disc by modulating and recording predetermined information data, the predetermined information data and additional information to be added to the predetermined information data are provided. The bit pattern is generated so that when one symbol of the predetermined information data is modulated into a predetermined bit pattern, a DSV sampled at a predetermined period becomes a value corresponding to the additional information, and the generation An optical disc master having a procedure for controlling the laser light applied to the optical disc master based on a modulated signal having a bit pattern and recording the predetermined information data and the additional information on the optical disc master. A creation method is provided.
[0020]
In the optical disc master producing method of such a procedure, first, predetermined information data to be recorded on the optical disc master and additional information are input. Subsequently, one symbol of predetermined information data is converted into a predetermined bit pattern. At this time, a bit pattern is generated such that the DSV sampled at a predetermined cycle has a value corresponding to the additional information. Next, based on the modulation signal composed of the generated bit pattern, the laser light applied to the optical disc master is controlled to form pits on the optical disc, thereby creating the optical disc master.
[0021]
In order to solve the above problem, in an optical disk reproducing method for reproducing the predetermined information data from an optical disk on which modulated predetermined information data is recorded, the optical disk is irradiated with laser light and recorded on the optical disk. The modulated signal is reproduced, and the modulated signal is demodulated and decoded to decode predetermined information data recorded on the optical disc, and the DSV of the modulated signal is calculated, and the DSV is analyzed to analyze the predetermined data. There is provided a method of reproducing an optical disc characterized by having a procedure for determining whether or not there is additional information added to the information data and acquiring the additional information if it is present.
[0022]
In the reproducing method of the optical disc in such a procedure, the information recorded on the optical disc is read by irradiating the laser beam, the read modulation signal is demodulated and decoded, and predetermined information data recorded on the optical disc is read out. Decrypt. Also, the DSV of the modulation signal is calculated, the DSV is analyzed to determine the presence / absence of additional information, and if there is additional information, it is acquired.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are preferred specific examples of the present invention, and various technically preferable limitations are given, but the scope of the present invention is not limited to these embodiments. .
[0024]
First, the optical disk master producing apparatus according to the present invention will be described with an example where the optical disk is a CD. In the case of a CD, EFM modulation is performed. FIG. 1 is a configuration diagram of an optical disc master creating apparatus according to an embodiment of the present invention.
[0025]
The optical disc master producing apparatus according to the present invention takes in the information data recorded on the master optical disc 210 and the additional information 220 and generates an EFM signal according to the output signal of the EFM signal sending device 100. And a laser beam recorder 300 that controls the laser beam to cut the pits of the optical disc master 230. The EFM signal transmitting apparatus 100 includes an information reproducing unit 110 that reproduces information data recorded on the master optical disc 210, an EFM modulating unit 120 that is a modulating unit that generates an EFM bit pattern from the information data and the additional information 220, And an EFM output means 130 which is a modulation signal output means for outputting an EFM signal according to the EFM bit pattern.
[0026]
The master optical disk 210 is a master medium (information source) such as a CD-R, and records predetermined information data to be recorded on the optical disk master 230. The predetermined information data is related information such as music information and subcode when the optical disc to be created is a music CD or MD, and is a program file of application software or the like when the optical disc is a CD-ROM. These data formats are determined in advance.
[0027]
The additional information 220 is arbitrary information added to predetermined information data. For example, information for preventing unauthorized copying, information for disc identification of a manufacturer, etc., or encrypted predetermined information data is included. This is a decryption key or the like necessary for decryption. Note that the additional information 220 does not have to be information related to predetermined information data. The additional information 220 can be taken into the optical disk master production apparatus by an arbitrary method. For example, it is loaded into the apparatus in advance by loading it into a storage device of the optical disk master producing apparatus.
[0028]
The information reproducing means 110 sequentially reproduces predetermined information data recorded on the master optical disk 210 over the entire area and sends it to the EFM modulating means 120.
The EFM modulation means 120 inputs information data from the information reproduction means 110, takes in the additional information 220, performs EFM modulation, and generates an EFM bit pattern. First, the input information data is subjected to CIRC encoding processing such as scramble processing and encoding processing, and 32 symbols of data and parity are generated in one frame time. CIRC processes 8 bits as one symbol, and EFM also performs modulation processing in units of 1 symbol. In EFM, each symbol of 8 bits is converted into a pattern of 14 bits. Further, the information bit patterns of one symbol are combined with 3 margin bits. In this way, an EFM bit pattern in units of 17 bits is generated. At this time, the EFM bit pattern in a predetermined section is modulated so that the DSV sampled at a predetermined cycle becomes a value corresponding to the additional information. Hereinafter, a predetermined cycle for sampling the DSV is referred to as a sampling cycle. In general modulation processing, the EFM bit pattern is set so that the DSV value approaches zero. Therefore, the DSV of the section in which the additional information is inserted is shifted in the positive direction or the negative direction from 0, and an EFM bit pattern that sets a positive or negative value is set. In general modulation processing, the DSV does not always become 0. Therefore, a positive or negative threshold value is determined in advance and exceeds the DSV in the section in which additional information is inserted.
[0029]
The EFM output means 130 outputs the EFM bit pattern generated by the EFM modulation means 120 according to the channel clock.
The laser beam recorder 300 irradiates the optical disc master 230 with laser light in accordance with the output signal of the EFM output means 130, and creates a master by cutting pits.
[0030]
The operation of the optical disc master producing apparatus having such a configuration and the optical disc master producing method will be described. At the time of creating the optical disc master, a master optical disc 210 on which predetermined information data to be recorded on the optical disc master 230 is recorded is delivered from the information data producer. On the master optical disc 210, for example, music data and related information are recorded when a music CD is created, and a program file of application software is recorded when a CD-ROM is created. These predetermined information data may be encrypted as necessary. Further, together with the master, additional information 220 such as information for preventing illegal copying such as an arbitrary code, information for identifying an optical disk representing a manufacturer, or a decryption key for decrypting encrypted information data is provided as EFM. Provided to the signal transmission device 100.
[0031]
In the EFM signal transmitting apparatus 100, the information reproducing means 110 reads information data recorded on the master optical disk 210 and sequentially outputs it to the EFM modulating means 120. The EFM modulation means 120 inputs the reproduced information data and takes in the additional information 220. The EFM modulation means 120 performs CIRC encoding processing on input information data, and then performs EFM modulation processing with 8 bits as one symbol. In the EFM modulation process, each symbol of 8 bits is converted into a pattern consisting of 14 bits, and the information bit pattern of 1 symbol (14 bits) is combined with 3 margin bits. At this time, the EFM bit pattern in a predetermined section is modulated so that the DSV sampled at the sampling period becomes a value corresponding to the additional information. As described above, the DSV gives +1 if the waveform of the channel clock cycle is at a high level, and -1 if the waveform is at a low level. Usually, the bit pattern is set so that the DSV value approaches 0. Is done. Therefore, in the EFM bit pattern section in which the additional information is inserted, the balance of the waveform is shifted so that the DSV does not become a value near zero. For example, modulation is performed so as to form a predetermined change pattern in which a DSV value repeats a positive or negative value in a certain pattern in a certain pattern. Further, it is possible to perform modulation so that the value of DSV for each sampling period becomes a value corresponding to 1 or 0 corresponding to the value of 1 or 0 of the additional information. For example, when DSV is a negative value, information of bit 0 is determined in advance, and when DSV is a positive value, bit 1 is determined in advance, and modulation is performed accordingly. The section in which the additional information is inserted can be arbitrarily set according to the additional information to be inserted. For example, assuming that the sampling period is 1 minute, the bit pattern is set so that the DSV every minute from the start point becomes a positive value or a negative value according to the additional information. In the case of inserting 8-bit additional information, for 8 minutes from the start time, with respect to the DSV for one minute, if the additional information data is 0, the DSV is negative, and if the additional information data is 1, the DSV is a positive value. The bit pattern is selected so that In addition, a DSV change pattern can be formed in an arbitrary section, for example, a pause section of music data or a file of application software. In order to prevent malfunction when analyzing additional DSV by analyzing DSV on the optical disk playback device side, it is desirable that the DSV setting section based on the additional information appears over a certain period.
[0032]
When the EFM bit pattern is generated in this way, the EFM output means 130 outputs the EFM bit pattern according to the channel clock. The laser beam recorder 300 irradiates the optical disc master 230 with laser light in accordance with the output signal of the EFM output means 130, and creates a master by cutting pits.
[0033]
As described above, the optical disk master production apparatus according to the present invention sets the EFM bit pattern so that the DSV is based on the additional information during the EFM modulation process. Since the additional information is expressed using the DSV calculated from the modulation signal, it is not necessary to change the format of the conventional optical disc. As a result, it is possible to record additional information on the optical disc without increasing the production cost of the optical disc. Further, since the additional information is generated and recorded at the time of EFM modulation, it can be handled separately from information data obtained from demodulation and decoding. Data copying of additional information expressed in DSV is impossible, and this method is very effective as a copy prevention measure. If the information data is encrypted and recorded, and the decryption key is expressed using DSV as additional information, the decryption key cannot be obtained from demodulation and decoding, and is safe.
[0034]
Details of the EFM modulation algorithm will be described with reference to FIG. FIG. 2 is an example of an EFM bit pattern. In the EFM modulation process, 8 bits of one symbol based on information data are converted into a 14-bit pattern. Conversion to a 14-bit pattern is predetermined by a conversion table or the like. An interval in which this information bit pattern appears is defined as an information bit interval. FIG. 2 shows an information bit pattern in an information bit section when the information data is 0. Next, a 3-bit margin bit pattern is inserted between the information bit sections. Hereinafter, a section in which a margin bit pattern appears is defined as a margin bit section.
[0035]
(A) is a bit pattern when a merging bit is set so that the DSV of an arbitrary section where 0 continues as information data becomes 0. The DSV is calculated by incrementing by +1 for each channel clock when the modulation signal continues to be positive, and by -1 for each channel clock when the modulation signal continues to be negative. The value of DSV is an added value of DSV when an arbitrary sampling period (section indicated by an arrow in the figure) elapses. In the case of EFM modulation, the DSV can be changed in the positive direction or the negative direction by selecting a margin bit pattern. For example, in the case of (a), DSV approaches 0 by setting a pattern of 000 as a margin bit following the information bit (= 0). In a normal section, that is, a section in which no additional information is inserted, the bit pattern is set so that the DSV value approaches 0, as shown in (a).
[0036]
On the other hand, (b) is a bit pattern when merging bits are set so that the DSV of an arbitrary section where 0 continues as information data becomes a positive value as in (a). In the case of (b), the DSV is changed in the positive direction by setting 111 patterns as margin bits following the information bits (= 0). As described above, the margin bit pattern is selected so that the DSV value corresponding to the additional information is obtained in the section in which the additional information is inserted using the DSV.
[0037]
In this way, the DSV is changed in the plus direction or the minus direction so that the DSV value for each sampling period exceeds a predetermined threshold value. On the reproduction side, when the DSV in the sampling period exceeds the threshold value, it is determined that additional information has been detected. There may be a plurality of threshold values. For example, when the threshold value is set to +1 and −1, it can be determined that the bit is 1 when the DSV in the sampling period is larger than +1 and bit 0 when the DSV is smaller than −1. In this way, 1/0 of the additional information can be recorded as it is by the DSV.
[0038]
In addition, a section in which additional information is inserted is set in advance according to the additional information. For example, the EFM bit stream can be generated so that the DSV for each predetermined period has a value corresponding to the additional information over the entire storage area of the optical disc. In this case, a considerable amount of additional information can be recorded. Further, when the additional information is not so large, an EFM bit stream corresponding to the additional information can be generated in a section between the number of bits of the additional information × the sampling period from the start time of the storage area.
[0039]
An example of recording additional information using DSV will be described with reference to FIG. FIG. 3 is an example of a DSV pattern of an optical disc according to an embodiment of the present invention. Here, it is assumed that 8-bit additional information (11011100) is sequentially recorded as bit data. The threshold value is, for example, ± 10, the DSV value is reset for each sampling, and the data whose DSV value in the sampling interval exceeds the threshold value is treated as valid data.
[0040]
Since the recording bit for performing the initial recording of the additional information is 1, modulation is performed by changing the DSV according to the above-described procedure so that the DSV at the time when one sampling period has elapsed from the recording start time exceeds 10. Since the subsequent recording bit is also 1, the modulation is performed so that the DSV exceeds 10 when the two sampling periods have elapsed. Since the subsequent recording bit is 0, modulation is performed so that the DSV changes in the negative direction so that the DSV at the time of the elapse of 3 sampling periods becomes smaller than −10. Thereafter, modulation processing for changing the DSV in accordance with the recording bits of the additional information is performed.
[0041]
In this way, an optical disc master is recorded on which a modulated signal is recorded so that the DSV for each sampling period takes a value corresponding to the additional information added to the information data. In the optical disc according to the present invention, additional information is recorded using DSV as described above. Further, if modulation is performed so that the DSV takes a value that can distinguish 1/0, such as positive and negative, corresponding to 1 or 0 of the additional information, a modulation signal in which the additional information is recorded as it is is obtained. Can be generated. For this reason, for example, when the disc manufacturer information or the information data is encrypted, information such as a decryption key necessary for decryption can be embedded in the modulation signal.
[0042]
DSV is information generated at the time of EFM modulation, and cannot be obtained from demodulation and decoding of an optical disk reproducing apparatus. In general, in an optical disk apparatus or the like that can record and reproduce both a recording type and a reproduction-only optical disk, information recorded on the original optical disk is read, demodulated and decoded, information data is reproduced, and EFM modulation is newly performed. To record on the destination optical disk. For this reason, additional information expressed by DSV cannot be copied by an optical disk apparatus or the like that can record and reproduce both a recording type and a reproduction-only optical disk, which is effective as a copy prevention measure.
[0043]
The above description is about a CD that performs EFM modulation, but this can also be applied to an optical disk master producing apparatus that records an EFM + modulation signal performed by a DVD. In EFM + modulation, when 1 symbol (8 bits) data is converted to 16 bits, a bit pattern is set according to the state of the preceding information bit. At this time, similarly to EFM modulation, modulation processing is performed so as to select a bit pattern in which the DSV for each sampling period has a value corresponding to the additional information.
[0044]
Next, an optical disk reproducing apparatus for reproducing the above-described optical disk will be described with an example where the optical disk is a CD. FIG. 4 is a block diagram of an optical disk reproducing apparatus according to an embodiment of the present invention.
[0045]
An optical disc player 400 that is an optical disc playback apparatus according to the present invention reads an original optical disc 410 that reads recording data from a CD 240 that is an optical disc according to the present invention, and performs EFM modulation and CICR decoding on the signal read by the optical pickup 410 to obtain original information. A CD signal processing unit 420 that decodes data, a DSV circuit 430 that calculates and analyzes the DSV of the EFM signal, and a DSV analysis unit that analyzes the DSV, and a CPU 440 that controls the entire apparatus. .
[0046]
The CD 240 is an optical disk according to the present invention, in which additional information expressed using DSV together with predetermined information data is recorded as a modulation signal.
The optical pickup 410 irradiates the CD 240 with laser light, reads information recorded on the CD 240, performs waveform shaping, reproduces an EFM signal before EFM demodulation, and outputs the EFM signal to the CD signal processing unit 420.
[0047]
The CD signal processing unit 420 is a signal processing unit that performs EFM demodulation and CIRC decoding on the EFM signal and decodes information data recorded on the CD 240. In this embodiment, the EFM signal input from the optical pickup 410 and the channel clock generated by signal processing are sent to the DSV circuit 430.
[0048]
The DSV circuit 430 calculates a DSV value for each sampling period from the EFM signal and analyzes the DSV value. FIG. 5 is a configuration diagram of a DSV circuit in the optical disc reproducing apparatus according to the embodiment of the present invention. The same parts as those in FIG. The DSV circuit 430 receives the EFM signal, adds the DSV, a DSV addition unit 431, a counter 432 that generates a sampling period trigger, and a DSV additional information register 433 that stores the DSV value calculated by the DSV addition unit 431; Consists of
[0049]
The DSV adder 431 receives the EFM signal and the channel clock, and adds the level of the EFM signal with the resolution of the channel clock. When the signal level is High, +1 is added, and when the signal level is Low, -1 is added to calculate the DSV value. The calculated DSV value is sent to the DSV additional information register 433. The counter 432 counts a certain period of the channel clock, generates a DSV sampling period as a trigger, and sends it to the DSV additional information register 433. The DSV additional information register 433 stores the DSV value that is the output of the DSV addition unit 431 at the interval of the trigger input from the counter 432. The stored DSV value can be read from the CPU 440.
[0050]
In this way, the DSV circuit 430 stores the DSV value for each sampling period in the DSV additional information register 433. In addition, although the DSV circuit 430 in FIG. 5 integrates the EFM signal with a digital circuit, a change in the DSV can be extracted by integrating the envelope of the EFM signal with an analog circuit. As described above, a circuit for capturing a change in DSV can be realized by a digital circuit or an analog circuit, and has a degree of freedom.
[0051]
Returning to FIG.
The CPU 440 is DSV analysis means for analyzing the DSV value calculated by the DSV circuit 430 for each sampling period and stored in the DSV additional information register 433, and controls the entire apparatus according to the analysis result. It is analyzed whether the DSV value calculated by the DSV circuit 430 exceeds a predetermined threshold value, and the presence / absence of additional information is determined. If the DSV value exceeds the threshold value, it is determined that there is additional information. If additional information represented by the DSV change pattern and 1/0 additional information such as disc identification information or a decryption key is detected, this additional information is acquired. As a measure against unauthorized copying, when a change in DSV is changed with a specific change pattern in a predetermined section of the EFM signal, the DSV change pattern in this section is analyzed and coincides with a predetermined DSV change pattern. Determine whether or not. If they match, it is determined that the disc is a regular disc, and reproduction of information data is permitted. For example, when the CD 240 is a music CD, the decoded data is converted into an audio signal by a D / A converter (not shown) and output from a speaker (not shown). If it does not exist, it is determined that the disc has been illegally copied, and control such as interrupting reproduction of information data is performed.
[0052]
The operation of the optical disc playback apparatus having such a configuration and the optical disc playback method will be described. The optical disc player 400 reads out the recording data of the CD 240 recorded by modulating the information data and the additional information by the optical pickup 410. The read EFM signal is subjected to EFM demodulation and CIRC decoding processing in the CD signal processing unit 420, and information data is decoded. On the other hand, the DSV circuit 430 calculates the DSV for each sampling period and stores it in the DSV additional information register 433. The CPU 440 analyzes the DSV calculated by the DSV circuit 430 and determines the presence / absence of additional information. If there is additional information, the additional information expressed by DSV is reproduced. Further, as necessary, the operation of the entire apparatus is controlled in accordance with the presence / absence of additional information or the reproduced additional information.
[0053]
For example, in the regular CD 240, information relating to unauthorized copy prevention is recorded as additional information using DSV in a predetermined section of the EFM signal, for example, a section from when the recording starts until a predetermined sampling period elapses. Suppose that The CPU 440 analyzes the DSV in a section from the recording start time calculated by the DSV circuit 430 until a predetermined sampling period elapses, and checks whether there is information related to unauthorized copy prevention. If it does not exist, or if it does not match the information related to prevention of unauthorized copying determined in advance, it is determined that the CD 240 has been illegally copied, and the information data reproduction of the CD 240 is stopped.
[0054]
Further, in the reproducing apparatus, the disc identification information can be reproduced from the optical disc on which the modulation signal represented by using DSV with the disc identification information as additional information is recorded.
[0055]
Furthermore, an optical disk reproducing apparatus for reproducing an optical disk in which information data is encrypted and the decryption key is modulated and recorded together with the information data encrypted as additional information can be provided. A decryption key expressed using DSV is recorded on the optical disc. The optical disk reproducing apparatus reproduces the encrypted information data from the modulation signal of the optical disk, and also calculates the DSV for each sampling period and reproduces the decryption key. Subsequently, the encrypted information data is decrypted using the reproduced decryption key, and the information data usable by the application is reproduced.
[0056]
As described above, by mounting the DSV circuit 430 on a conventional optical disc player, additional information on the optical disc can be read and used. Further, since the additional information cannot be generated by the CD signal processing unit 420, an effective countermeasure against unauthorized copying is installed.
[0057]
The above description is about a CD that performs EFM modulation, but this can also be applied to an optical disk reproducing apparatus that reproduces an EFM + modulated signal performed by a DVD, as in the case of an optical disk master producing apparatus.
[0058]
【The invention's effect】
As described above, the optical disk of the present invention is modulated so that the DSV sampled at a predetermined period becomes a value corresponding to the additional information at the time of modulation, and recording is performed according to the generated modulation signal. Yes. As described above, in the present invention, arbitrary additional information is represented by the DSV sampled at a predetermined cycle, so that the additional information can be recorded and read out without changing the format of the optical disc. This additional information is information for preventing unauthorized copying, optical disc identification information, a decryption key, and the like. DSV is information set at the time of modulation and cannot be obtained from demodulation and decoding, and data copy is impossible. For this reason, additional information expressed by DSV cannot be copied by an optical disk apparatus or the like that can record and reproduce both a recording type and a reproduction-only optical disk, which is effective as a copy prevention measure.
[0059]
The optical disk master producing apparatus of the present invention reproduces predetermined information data recorded on the master, performs modulation processing, and converts it into a bit pattern. At this time, the DSV of the bit pattern is converted to a value corresponding to the additional information. The generated bit pattern is output as a modulation signal. As described above, since the additional information is expressed using the DSV sampled at a predetermined cycle, the additional information can be recorded without changing the format of the optical disc. This additional information can be used for arbitrary purposes such as information for preventing unauthorized copying, optical disc identification information, and encryption key. In addition, since the DSV is set and the bit pattern is set in accordance with this, the optical disc production cost does not increase.
[0060]
The optical disk reproducing apparatus of the present invention reads the modulation signal recorded on the optical disk and decodes the recorded predetermined information data. At this time, the DSV of the modulation signal is calculated and analyzed, the presence / absence of additional information is determined, and if there is additional information, it is acquired. In this way, it is possible to acquire additional information expressed in DSV along with demodulation of the read modulation signal. As a result, additional information can be recorded and read without changing the format of the optical disk. Since the additional information represented using DSV cannot be acquired from demodulation and decoding, it is an effective means for copy prevention.
[0061]
In the optical disc master production method of the present invention, predetermined information data and additional information are input, and the predetermined information data is converted into a bit pattern. At this time, the bit pattern is generated so that the DSV sampled at a predetermined cycle has a value corresponding to the additional information. Next, pits are formed on the optical disc based on the modulation signal composed of this bit pattern, and an optical disc master is created. In this way, since the bit pattern is set so as to be a DSV corresponding to the additional information and modulation is performed, the additional information can be recorded and read out without changing the format of the optical disc. Further, since only the DSV is set, the optical disc production cost does not increase.
[0062]
In the optical disk reproducing method of the present invention, information recorded on the optical disk is read, and the modulated signal is demodulated and decoded to decode predetermined information data recorded on the optical disk. Further, the DSV value of the modulation signal is calculated, and the DSV value is analyzed to obtain additional information added to the information data or information related to additional information including the presence / absence of the additional information. As described above, it is possible to acquire the additional information expressed by the DSV value of the modulation signal together with the demodulation of the read modulation signal. As a result, additional information can be recorded and read without changing the format of the optical disk. Since the additional information represented by using the DSV value cannot be obtained from demodulation and decoding, it is an effective means for preventing copy.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an optical disc master creating apparatus according to an embodiment of the present invention.
FIG. 2 is an example of an EFM bit pattern.
FIG. 3 is an example of a DSV pattern of an optical disc according to an embodiment of the present invention.
FIG. 4 is a configuration diagram of an optical disc playback apparatus according to an embodiment of the present invention.
FIG. 5 is a configuration diagram of a DSV circuit in an optical disk reproducing device according to an embodiment of the present invention.
FIG. 6 is an example of a waveform of a modulation signal subjected to EFM modulation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... EFM signal transmission device, 110 ... Information reproduction means, 120 ... EFM modulation means, 130 ... EFM output means, 210 ... Master optical disk, 220 ... Additional information, 230 ...・ Master optical disc, 300 ... Laser beam recorder

Claims (12)

In an optical disc on which predetermined information data modulated is recorded,
When 8-14 modulation (EFM modulation ) is performed on predetermined information data, a DSV (Digital Sum Variation) sampled at a predetermined sampling period is set to 1 or 0 of the additional information for a preset additional information insertion section. A modulated signal is recorded which is modulated by selecting a margin bit inserted between the information bit sections of the predetermined information data so as to be a positive value or a negative value corresponding to the value of An optical disc.   2. The optical disc according to claim 1, wherein a predetermined change pattern in which the DSV repeats a positive or negative value in a certain pattern for each sampling period is formed in the additional information insertion section.   2. The optical disc according to claim 1, wherein the additional information is information relating to prevention of unauthorized copying of information data recorded on the optical disc.   2. The optical disc according to claim 1, wherein the additional information is disc identification information that enables the optical disc to be identified.   2. The optical disc according to claim 1, wherein the predetermined information data is encrypted, and the additional information is a decryption key necessary for decrypting the encrypted predetermined information data. In an optical disc master creating apparatus that modulates and records predetermined information data to create an optical disc master,
Information reproducing means for reproducing the predetermined information data recorded on the optical disc master from all information areas of a master optical disc in which the predetermined information data is recorded;
When subjected to 8-14 modulation on the predetermined information data reproduced by said information reproducing means, the insertion section of the additional information is set in advance, 1 DSV of the additional information which is sampled in a predetermined sampling cycle or Modulation means for selecting a margin bit inserted between information bit sections of the predetermined information data so as to be a positive value or a negative value corresponding to a value of 0, and generating a bit pattern;
Modulation signal output means for outputting a modulation signal according to the bit pattern generated by the modulation means;
An optical disc master producing apparatus characterized by comprising:   The modulation means performs modulation so that the DSV for each sampling period of the bit pattern in the additional information insertion interval exceeds a predetermined threshold value. The optical disk master production apparatus described. In an optical disc reproducing apparatus for reproducing the predetermined information data from the optical disc on which the predetermined information data modulated is recorded,
An optical pickup unit that reads information by irradiating the optical disc with laser light and reproduces a modulation signal recorded on the optical disc;
Signal processing means for demodulating and decoding the modulated signal to decode the predetermined information data;
When subjected to 8-14 modulation on the predetermined information data, the insertion section of the additional information is set in advance, the positive and DSV is sampled at a predetermined sampling period corresponds to a value of 1 or 0 of the additional information DSV calculation means for calculating a DSV for each sampling period from the modulated signal modulated by selecting a margin bit inserted between information bit sections of the predetermined information data so as to be a negative value or a negative value When,
Analyzing the calculated DSV to determine the presence or absence of the additional information added to the predetermined information data, and if there is the additional information, DSV analysis means for acquiring the additional information;
An optical disc reproducing apparatus comprising:   The DSV analysis means determines that the additional information is present when a value of the DSV calculated in a predetermined insertion period of the additional information of the modulation signal exceeds a predetermined threshold value. 9. An optical disk reproducing apparatus according to claim 8, wherein The DSV analyzing means, wherein the said one or in accordance with the value of the DSV which is calculated at every sampling period generates bit information 0, characterized in that for reproducing the additional information based on the bit information Item 9. The optical disk playback device according to Item 8. In an optical disc master creating method for modulating and recording predetermined information data and creating an optical disc master,
Input the predetermined information data and additional information to be added to the predetermined information data,
When subjected to 8-14 modulation on the predetermined information data, the insertion section of the additional information is set in advance, DSV is sampled at a predetermined sampling period corresponding to the value of 1 or 0 of the additional information Selecting a margin bit inserted between information bit sections of the predetermined information data to be a positive value or a negative value to generate a bit pattern;
An optical disc comprising a procedure for controlling the laser beam applied to the optical disc master based on the modulation signal composed of the generated bit pattern and recording the predetermined information data and the additional information on the optical disc master. Master production method. In an optical disc reproducing method for reproducing the predetermined information data from an optical disc on which predetermined information data modulated is recorded,
Reproducing the modulation signal recorded on the optical disc by irradiating the optical disc with laser light,
Demodulate and decode the modulated signal to decode predetermined information data recorded on the optical disc,
When subjected to 8-14 modulation on the predetermined information data, the insertion section of the additional information is set in advance, the positive and DSV is sampled at a predetermined sampling period corresponds to a value of 1 or 0 of the additional information Or a DSV for each sampling period is calculated from the modulated signal modulated by selecting a margin bit inserted between information bit sections of the predetermined information data so as to be a negative value or a negative value,
An optical disc reproducing method comprising: analyzing the DSV to determine the presence / absence of the additional information added to the predetermined information data, and acquiring the additional information, if any.

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