JP2003303475A - Recording device, recording medium, and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To superpose additional information in a state of the conventional format. <P>SOLUTION: A margin bit is separated by a margin bit separating circuit 34 from an EFM signal containing the margin bit read from a CD 10. Since the additional information is built in the margin bit, the additional information is obtained in an additional information decoder 36. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for recording additional information on a recording medium in addition to ordinary data.

[0002]

2. Description of the Related Art Conventionally, CDR, CDRW, DVDR
There is known a disk recording device for writing data on an optically readable disk such as. These disc recording devices can record all kinds of conventionally recordable data such as programs, data, and music data, and are used for a wide range of purposes.

In such a writable disc, write data is EFM-modulated and written. That is, 1 byte (8 bits) of data is subjected to EFM modulation to make it 14 bits redundant, and then written to the disc. Also, in this case, the 14-bit EFM
A margin bit of 3 bits is inserted between the data and the next EFM data. Then, by this margin bit, redundancy is further added and the DC component of the write data is removed.

Further, the write data has a subcode, and various attribute data of the record data and a part of the error correction code are written therein.

In this way, the standard has been determined for recording on a recording medium such as a CDR, and a recording device and a reproducing device are manufactured in accordance with the standard.

[0006]

However, in CDR and the like, there is a demand to further improve the error correction capability and add a copy guard function. If data for these functions is added and stored in the disk, error correction can be performed and a copy guard function can be achieved according to the added data.

However, when such additional data is added, there is a problem that the disc cannot meet the standard and cannot be reproduced by a normal reproducing apparatus.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a recording device, a recording medium, and a reproducing device capable of recording additional information while maintaining the standard for a disc.

[0009]

The present invention provides data EF
EFM modulation means for M-modulating and margin-bit adding means for adding a margin bit which is a channel bit for connection to the EFM-modulated signal obtained by this EFM modulation are provided, and the EFM modulation is performed with the margin bit added. A recording device for recording a write signal on a recording medium, characterized in that the margin bit adding means encodes the margin bit based on the additional information.

Further, the present invention is a recording medium on which a write signal modulated by EFM is recorded, wherein the EFM data and the EFM data are recorded.
Margin bits, which are connection channel bits, are added to the FM data, and the margin bits are coded based on the additional information, so that it is possible to take out the information from the margin bits. Characterize.

Further, according to the present invention, the EFM signal is extracted from the read signal read from the recording medium, and the EFM signal is extracted.
A reproduction device that demodulates and outputs the EFM signal and the EF.
Margin bit separating means for extracting a margin bit which is a connection channel bit added between M data and additional information reproducing means for decoding information from the margin bit are provided, and the additional information is obtained from the margin bit. It is characterized by

The margin bit is composed of 3 bits, of which 4 patterns are used.
Since the amount of information is 2 bits, it is preferable to use these 2 bits for additional information.

The additional information is divided into two sets of 4 patterns each having a margin bit of 2 bits, and each set has 0, 1 respectively.
Is preferably given.

The signal written in the recording medium is divided into frames, and 34 frames are included in one frame.
Includes × 3 merge bits, of which 32 × 2
It is preferable to express 32-bit additional information using bits.

It is also preferable that the coding of the additional information with respect to the margin bits is stopped regularly or randomly and the uncoded margin bits are used for the signal for suppressing the DC component.

Further, it is preferable that the additional information is an error detection or error correction code.

The additional information is preferably an encryption key.

As described above, according to the present invention, the additional information is superimposed on the margin bit, which has not conventionally included any information. Since the margin bit has a sufficient margin, it is possible to prevent the pit size adjustment and the DC component suppression, which are the original functions, from being affected even if the information is superimposed on the margin bit. The recording format itself is in accordance with the conventional standard. Therefore, the additional information can be used for various purposes.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

[Incorporation of Additional Information in Margin Bit] First, in the recording medium (CD) according to the present embodiment, additional information is embedded in the margin bit.

That is, in EFM modulation, 8-bit data is converted into 14-bit data.
A 3-bit margin bit is inserted between the 4-bit EFM signal and the 14-bit EFM signal. In this embodiment, the additional information is written in the 3-bit margin bit (channel bit) inserted between the 14-bit EFM signals at the time of this EFM modulation.

In the original EFM modulation, (i) the signal pattern is 3T to 11T when the adjacent EFM signal patterns of 14 bits are 3 bits of the connection margin bits.
It is advantageous for suppressing the DC component of (ii) DSV (Digital Sum Value) from among the patterns that fit in (the sequence of “0” and “1” is continuous from 3 to 11). A pattern is selected and added.

Therefore, in selecting a connection bit consisting of 3 bits (4 patterns), redundancy occurs from the EFM signal patterns of 14 bits before and after.

Further, the function for suppressing the direct current component of the DSV has not been specified as a solution for selection, and if the maximum of the direct current component is suppressed in a fixed cycle, the reproduction performance will not be adversely affected. Therefore,
In this embodiment, this margin bit is changed based on the additional information, and the additional information is included therein. That is, the margin bits are encoded with the additional information.

Specifically, (i) the four patterns of margin bits are divided into two sets, and the meanings of 0 and 1 are given respectively.

(Ii) The connection bit in one frame is 34
It is a set (34 × 3 bits), and 32 bits (4 bytes) are extracted from this as additional information.

It should be noted that this is an amount of information which is four times as large as user bits (8 bits = 1 byte) such as a subcode, and by this method, a considerable amount of additional information can be included in the margin bits.

Furthermore, the embedding of additional information in the margin bits can be stopped periodically or randomly in order to make the most of the original DSV function. As a result, it is possible to prevent deterioration of the signal (increase in DC component) due to the additional information. For example, if 50% (that is, about once every two times) margin bits are used for the DSV function (suppression of DC component), the DC component can be sufficiently suppressed.

"Contents of additional information" Additional information (M-dat
The information "a" may be information of any content, but may be the following content, for example.

(1) Use as error detection or correction code Additional information of 4 bytes in one frame is used together with error detection or error correction. That is, for example, the CRC for the data in units of the subcode synchronization signal.
(Error detection code) or error correction code Md
Make it ata. This ensures the reliability of the data.

Here, the user's bit in the subcode is composed of a 2-byte sync signal and 96-byte data. Of these, 16 bytes are used as a CRC for error detection. Further, when an error correction code having the same degree of redundancy as CIRC is added and 50% is used for the purpose of DSV (direct current component suppression) and 50% is M-Data, the amount of information that can be used as additional information is It will be about 40MB on CD.

(2) Use as content guard M-Data can be used for the content guard function. For example, M-data is used as an encryption key. Then, the data is encrypted with the encryption key. As a result, if this encryption key cannot be reproduced, the encrypted data cannot be read, and reproduction becomes impossible. This allows the content to be guarded.

Specifically, the following method can be considered.

(A) Content guard (A-1) Put file system in M-data The file system in the CD has a "volume descriptor" (VD) in the area next to the lead-in area of each session.
= Volume Descriptor).

Therefore, incorrect data is described in this VD, and data concerning the file system is described in the margin bit additional information (M-data). As a result, the conventional device, which cannot read the additional information of the margin bit, cannot access the file and cannot read the content. Note that in this case, it does not have to work for all file systems.

For example, a PIT disk is first M-dat.
Insert a. As a result, reproduction is possible only with a drive having the M-data reading function.

That is, if a PIT disk in which the correct VD is inserted in M-Data is made, only the corresponding drive can be reproduced.

(A-2) The content which uses M-Data as an encryption key cannot be reproduced unless it is decrypted using the encryption key. Therefore, the encryption key can be obtained only by a new system capable of decrypting M-data, and reproduction cannot be performed.

(A-3) Placing the subcode in M-data The subcode is abolished and the data described in the subcode is put in M-data. By this, M-dat
If the drive cannot read a, the CD cannot be played.

(B) Copy guard reproduction is possible, but the copied disc cannot be reproduced. Specifically, the following is done.

(B-1) In the consumer drive, only the playback function of M-Data is prepared, and M-data is used.
The recording function of a is not provided. This allows consumer drives to play but not playable discs.

(B-2) The recording function of M-Data is for special mastering. This enables the stamp to be used in CDR as well.

[Structure of Reproducing Device] FIG. 1 is a diagram showing the structure of a reproducing device for reproducing a CD in which the encryption key is embedded in the margin bits.

The CD 10 having the encryption key recorded on the margin bit is read by the pickup.
In the usual case, a high-frequency read signal (EFM signal) is obtained by converting the reflected light of the light emitted from the laser diode onto the CD into an electric signal by the photodiode. The read EFM signal is the EFMRF circuit 1
2 and is amplified here. EFMRF circuit 12
Is supplied to the PLL circuit 14, and a clock PCK synchronized with the EFM signal read here is obtained. The clock PCK obtained here is appropriately used in the subsequent circuits.

The amplified EFM signal is supplied to the synchronization detection circuit 1
6, the synchronization detection for each data of the EFM signal is performed. That is, the EFM signal is EFM data obtained by making the 8-bit original data redundant to 14 bits, but the actually recorded data is further 3 bits in the 14 bits.
The margin bit of the bit is added. Therefore, the sync detection circuit 16 detects a break in the EFM data. The clock PCK generated in the PLL circuit 14 is used for the synchronization detection in the synchronization detection circuit 16.

The EFM data whose delimiter has been detected by the synchronization detection circuit 16 is supplied to the EFM demodulation circuit 18.
Here, the EFM inverse conversion is performed, and the original data of the EFM modulation is demodulated. The clock PCK is used as the data clock in this EFM demodulation.

This EFM demodulated data is CIRC.
It is supplied to the circuit 20 where the error correction processing is performed.
That is, CIRC, which is an error correction code, is added to the original data of EFM modulation, and error correction processing is performed using this. The CIRC circuit 20 is
Error correction processing is performed using M22.

If the CD is a CDROM, the error-corrected data output from the CIRC circuit 20 is stored in the ROM.
It is supplied to the decoder 24, where it is decoded. Then, the decoded data is supplied to the host computer 28 via the interface 26. In the normal case, a buffer RAM is provided between the interface 26 and the ROM decoder 24 to coordinate communication with the outside and internal processing. If the CD is a music CD, ROM decoding is not necessary and
The output of the RC circuit 20 is directly supplied to the interface 26 via the buffer RAM.

Further, the output of the synchronization detection circuit 16 is supplied to the SUBC separation circuit 30, where the subcode is separated, and the subcode is decoded by the SUBC decoder 32 and taken out. The time information of the subcodes is used for controlling the rotation of the CD and the like, and the information of the contents is supplied to the host computer 28 via the interface 26.

Further, the output of the synchronization detection circuit 16 is supplied to the margin bit separation circuit 34, and the 14-bit EF is supplied.
Three margin bits between M data are taken out. Then, this margin bit is supplied to the additional information decoder and decoded. That is, the additional information is superimposed on the margin bits as described above, and the additional information (M-data) is extracted by the additional information decoder. The additional information is appropriately used according to the content of the additional information as described above.

The system is also provided with a CPU 38, which controls the entire operation.

As described above, according to the reproducing apparatus of the present embodiment, the margin bit is separated from the signal read from the CD 10 and the additional information in the margin bit is taken out. Therefore, the obtained additional information can be used for the above-mentioned error correction, copy guard, and the like.

[Structure of Recording Device] FIG. 2 shows the structure of a recording device in which additional information is included in margin bits and data is stored in a CD. Host computer 2
The data from 8 is fed to the ROM encoder 40 via the interface 26, preferably via the RAM, where it is encoded for the CDROM. This R
The output of the OM encoder 40 is, in the CIRC circuit,
The error correction code CIRC is added to the SUBC adding circuit 4
4 is supplied. The SUB is added to the SUB adding circuit 44.
The subcode from the C encoder 46 is supplied,
This subcode is added to the data and the EFM modulation circuit 48
Is supplied to. In the EFM modulation circuit 48, the SUB
The 8-bit data supplied from the C addition circuit 44 is converted into 14-bit data.

Here, a margin bit is supplied from the margin bit adding circuit 50 to the EFM modulation circuit 48. The margin bit adding circuit 50 generates a merge bit based on the additional information data supplied from the additional information encoder 52. As for the margin bits, about 50% of all the margin bits generated as described above are created based on the additional information, and the rest are used for suppressing the DC component. Regarding such a point, a rule is determined in advance so that decoding can be performed at the time of reproduction. It is also preferable to provide a header portion for the additional information, and to record therein what additional information and what format is recorded. According to this, by predetermining only the format of the header part, the format of the additional information of the other parts can be set arbitrarily. Further, the format of the additional information may be described in the subcode or the information of the lead-in area, and this may be read to decode the additional information. The margin bit adding circuit 50 selects the margin bit for suppressing the DC component based on the information about the EFM data before and after the margin bit. A known encoding method can be used for encoding in the additional information encoding circuit 52.

In this way, the margin bits from the margin bit adding circuit 50 are supplied to the EFM modulation circuit 48, so that the output of the EFM modulation circuit 48 inserts a 3-bit margin bit between 14-bit EFM data. It has been made.

The output of the EFM modulation circuit 48 is converted into a pulse signal in the strategy circuit 54, and this pulse signal is supplied to the LD driver 56. The LD (laser diode) driver 56 is a strategy circuit 54.
Based on the pulse signal supplied from the LD, the LD is driven to write the data on the CD (for example, CDR).

In this way, the information including the additional information in the margin bit can be written in the CD 10.

The CD 10 may be a medium other than CDR and CDRW as long as it includes margin bits.

[0059]

As described above, according to the present invention,
Conventionally, additional information is superimposed on the margin bit, which does not include any information. Since the margin bit has a sufficient margin, it is possible to prevent the pit size adjustment and the DC component suppression, which are the original functions, from being affected even if the information is superimposed on the margin bit. The recording format itself is in accordance with the conventional standard. Therefore, the additional information can be used for various purposes.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a playback device.

FIG. 2 is a block diagram showing a configuration of a recording device.

[Explanation of Codes] 10 CD, 30 SUBC separation circuit, 32 SUBC
Decoder, 34 margin bit separation circuit, 36 additional information decoder, 38 CPU.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 5/922 H04N 5/92 H

Claims (9)

[Claims] 1. An EFM modulation means for EFM-modulating data, and a margin bit adding means for adding a margin bit, which is a channel bit for connection, to an EFM-modulated signal obtained by this EFM modulation. A recording device for recording an EFM-modulated write signal to which is added to a recording medium, wherein the margin bit adding means is based on the additional information,
A recording device that encodes margin bits. 2. A recording medium on which an EFM-modulated write signal is recorded, wherein a margin bit which is a connection channel bit is added between the EFM data and the margin bit is added. A recording medium that is coded based on information and is capable of extracting information from margin bits. 3. A reproducing apparatus which extracts an EFM signal from a read signal read from a recording medium, demodulates the EFM signal and outputs the EFM signal, the connection channel bit being added between the EFM signal and the EFM data. A reproducing apparatus having margin bit separating means for extracting a certain margin bit and additional information reproducing means for decoding information from the margin bit, and obtaining additional information from the margin bit. 4. The apparatus or medium according to claim 1, wherein the margin bits are formed of 3 bits and 4 patterns.
A recording device, a recording medium, or a reproducing device that uses four patterns of the additional information for two bits. 5. The apparatus or medium according to claim 4, wherein the additional information divides four patterns of margin bits into two sets, and gives 0 and 1 meanings to each set. 6. The apparatus or medium according to claim 5, wherein the signal to be written in the recording medium is divided into frames, and one frame includes 34 × 3 merge bits. A recording device, a recording medium, or a reproducing device that expresses 32-bit additional information by using 32 bits. 7. The apparatus or medium according to any one of claims 1 to 6, wherein coding of additional information with respect to a margin bit is stopped regularly or randomly, and the non-coding margin bit is DC component suppressed. Recording device used for signals for
Recording medium or playback device. 8. The device or medium according to claim 1, wherein the additional information is an error detection or error correction code, a recording device, a recording medium, or a reproducing device. 9. The device or medium according to claim 1, wherein the additional information is a cryptographic key, a recording device, a recording medium, or a reproducing device.