JP2009289301A - Medium processing device, and method for discriminating medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for discriminating an information storage medium having a different modulation system. <P>SOLUTION: The method for discriminating a medium reads a signal from the information storage medium, detects frame synchronization from the read signal which is read, detects a data ID from the read signal on the basis of the frame synchronization and a first demodulation system, discriminates the adequacy of the first demodulation system on the basis of the detected situation of the data ID, detects a data ID from the read signal on the basis of the frame synchronization and a second demodulation system when discriminating the first discrimination system to be inadequate, and discriminates the adequacy of the second demodulation system on the basis of the detected situation of the data ID. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a medium discriminating technique for discriminating information storage media such as optical discs of different types.

  Various products compliant with the DVD standard (first generation DVD standard) formulated for standard image quality are already in widespread use. On the other hand, with improvements in image compression technology over the past few years, both users and content suppliers have expressed their desire to achieve higher image quality. In addition to content such as menu screens and privileged videos, content providers want a more attractive content provision environment for users by expanding the content, such as more colorful menus and improved interactivity. In order to realize the provision of more attractive content, the HD DVD standard (second generation DVD standard) was formulated.

  As a result, various types of optical discs such as CDs, DVDs, and HD DVDs are prevalent in the market. Examples of the CD include a CD-R (Recordable), a CD-ROM (Read Only Memory), and a CD-RW (ReWritable). Examples of the DVD include a DVD-ROM (Digital Versatile Disk Read Only Memory), a DVD-RAM, a DVD-RW, and a DVD + RW.

  When reproducing / recording an optical disc, the optical disc is first inserted into the optical disc apparatus. In order to reproduce / record the inserted optical disk, it is necessary to determine the type of the optical disk. This is because the method of reproducing / recording data differs depending on the type of optical disc. For this reason, various methods for discriminating the type of the optical disk inserted into the optical disk apparatus have been proposed. As an example of a method for determining the type of the optical disc, there is a method for comparing the tracking error signal amplitude of the push-pull method with a predetermined threshold value and determining the type of the optical disc according to the comparison result.

  By the way, the reflectance when the optical disk is irradiated with laser light varies depending on the type of the optical disk. Even in the same type of optical disk, the reflectance may not always be the same depending on the individual optical disks. When the reflectivity is different, the amplitude of a signal (for example, tracking error signal) obtained from the optical disc is also different.

  As described above, in recent years, optical discs such as HD DVDs have been developed. Therefore, in order to discriminate the type of the optical disc, it is necessary to discriminate an optical disc called HD DVD in addition to the optical disc such as CD and DVD.

Therefore, a technique for discriminating between CD, DVD and HD DVD has been proposed by paying attention to the characteristics of HD DVD (see Patent Document 1). Specifically, the reflectivity of the optical disk, the amplitude value of the DPD signal obtained from the optical disk, the amplitude value of the push-pull signal obtained from the data area of the optical disk, and the amplitude value of the push-pull signal obtained from the lead-in area of the optical disk, respectively. This is a technique for measuring and discriminating the type of optical disk from these measurement results.
JP2008-4229

  However, it is predicted that the optical disc cannot be properly discriminated even with the optical disc type discrimination technique described above.

  In the above HD DVD standard, 8/12 modulation (ETM: Eight to Twelve Modulation) is adopted. On the other hand, a CB HD (C-HD DVD) standard that is almost the same as the HD DVD standard is being formulated except for the modulation method. In this CB HD standard, 4/6 modulation (FSM: Four to Six Modulation) is adopted. That is, it is extremely difficult to discriminate between an HD DVD standard disc and a CB HD standard disc by the above-described optical disc type discrimination technology.

  An object of the present invention is to provide a technique for discriminating information storage media having different modulation schemes.

  A medium processing apparatus according to an embodiment of the present invention detects a frame synchronization from a reading unit that reads a signal from an information storage medium, and a reading signal read by the reading unit, and uses the frame synchronization and the first demodulation method. And detecting the data ID from the read signal, determining whether the first demodulation method is appropriate based on the detection status of the data ID, and determining whether the first demodulation method is inappropriate. And a detection means for detecting a data ID from the read signal based on the second demodulation method and determining whether or not the second demodulation method is appropriate based on a detection state of the data ID; and a demodulation based on the determination result by the determination means Reproduction means for determining a method and reproducing a signal recorded in the information storage medium by the determined demodulation method.

  According to an embodiment of the present invention, there is provided a medium discrimination method that reads a signal from an information storage medium, detects frame synchronization from the read signal, and reads data from the read signal based on the frame synchronization and the first demodulation method. ID is detected, it is determined whether or not the first demodulation method is appropriate based on the detection status of the data ID, and the frame synchronization and the second demodulation method are determined by determining that the first demodulation method is inappropriate. And detecting the data ID from the read signal, and determining whether or not the second demodulation method is appropriate based on the detection status of the data ID.

  According to the present invention, it is possible to provide a technique for discriminating information storage media having different modulation methods.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of an optical disc apparatus (medium processing apparatus) according to an embodiment of the present invention. The optical disc apparatus condenses recording-controlled laser light emitted from a pickup head (PUH) 11 on an information recording layer of the optical disc, and records information on the optical disc. Further, the optical disc apparatus collects the laser beam controlled for reproduction emitted from the pickup head (PUH) 11 on the information recording layer of the optical disc, and reproduces the information recorded on the optical disc. Specifically, the laser beam focused on the optical disc is reflected from the optical disc, passes through the optical system of the PUH 11 again, and is detected as an electrical signal by the photodetector.

  The detected electrical signal is amplified by the preamplifier 12 and output to the signal processing circuit 13. The signal processing circuit 13 includes a servo circuit, an address signal processing circuit, and an RF signal processing circuit.

  In the servo circuit, servo signals such as focus, tracking, and tilt are generated, and the signals are output to the focus, tracking, and tilt actuators of the PUH 11, respectively.

  The RF signal processing circuit reproduces information such as recorded user information by mainly processing the sum signal among the detected signals. Also, under the control of the control unit 14, a demodulation method (ETM demodulation method) corresponding to ETM is set for the RF signal processing circuit, or a demodulation method (FSM demodulation method) corresponding to FSM is set. be able to. The RF signal processing circuit detects frame synchronization by detecting a synchronization signal included in the detected signal or by detecting a specific pattern (13T-3T) included in the synchronization signal. Further, the RF signal processing circuit detects the data ID based on the frame synchronization.

  The address signal processing circuit processes the detected signal to read physical address information indicating a recording position on the optical disc and output it to the control unit 14. Based on this address information, the control unit 14 reads information such as user information at a desired position, or records information such as user information at a desired position. At this time, the user information is modulated into data suitable for optical disc recording by a recording signal processing circuit constituting the waveform generation circuit 16. Further, the waveform generation circuit 16 generates a signal for controlling the laser emission waveform based on the input code, and the LD drive circuit 15 drives an LD (laser driver) based on the laser emission waveform control signal, Thereby, information is recorded on the optical disc.

  Further, the control unit 14 discriminates the type of the disc based on the result of the signal processing by the signal processing circuit 13, and controls the reproduction based on the discrimination result. The disc type discrimination and playback control will be described in detail later.

  Next, physical sector data recorded on the optical disc will be described with reference to FIGS. The physical sector data described here is physical sector data corresponding to the HD DVD standard and the CB HD standard. The difference between them is only the modulation method. In the HD DVD standard, 8/12 modulation (Eight to Twelve Modulation) is adopted as the data modulation method, and in the CB HD standard, 4/6 modulation (FSM: Four to Six Modulation) is adopted as the data modulation method. Yes. FIG. 2 is a diagram illustrating an example of the configuration of a data frame. FIG. 3 is a diagram illustrating an example of the configuration of an ECC block. FIG. 4 is a diagram illustrating an example of the arrangement of scrambled frames. FIG. 5 is a diagram illustrating an example of an ECC block after row interleaving. FIG. 6A is a diagram illustrating an example of a configuration of even-numbered physical sector data. FIG. 6B is a diagram illustrating an example of a configuration of odd-numbered physical sector data. FIG. 7 is a diagram illustrating an example of the synchronization code.

  Recording data such as video and audio is converted into physical sector data shown in FIGS. 6A and 6B and recorded on the optical disc. Here, generation of physical sector data will be described. First, a plurality of data frames shown in FIG. 2 are generated based on recording data in units of 2048 bytes. One data frame includes 2048-byte recording data (main data), data ID, IED (data ID error detection code), RSV, and EDC (error detection code). The data ID includes information for identifying the data frame, and the IED is a code for detecting an error in the data ID. One data frame is composed of (172 bytes + 172 bytes) × 6 rows.

  Subsequently, one ECC block shown in FIG. 3 is generated based on the 32 data frames. One ECC block includes 32 data frames, PI (inner parity), and PO (outer parity). PI, which is a type of error correction code, is parity for detecting an error by correcting the detected error by looking at the data frame in the column direction (horizontal direction). PO, which is a kind of error correction code, is parity for detecting an error by correcting the detected error by looking at the data frame in the row direction (vertical direction). One ECC block is composed of (172 bytes of main data + 10 bytes of PI + 172 bytes of main data + 10 bytes of PI) × (192 rows of main data + 16 rows of PO).

  Subsequently, the data frame in the ECC block is scrambled to generate the scrambled frame shown in FIG. Further, row interleaving is applied to the scrambled frame, and the ECC block after row interleaving shown in FIG. 5 is generated. Further, 16 even-numbered physical sector data shown in FIG. 6A and 16 odd-numbered physical sector data shown in FIG. 6B are generated from the ECC block after row interleaving.

  As shown in FIGS. 6A and 6B, each physical sector data includes a synchronization code (SY0, SY1, SY2, SY3). The synchronization code is as shown in FIG. 7 and includes a 13T-3T pattern (0000000000001001).

  Next, optical disc type determination by the above optical disc apparatus will be described.

  As described above, the difference between the HD DVD standard and the CB HD standard is only the modulation method, and other physical parameters are exactly the same. For this reason, it is very difficult to discriminate whether the optical disk conforms to the HD DVD standard or the optical disk conforms to the CB HD standard based on the disk shape, reflectivity (signal waveform), and the like.

  A disc type is recorded in a BCA (burst cutting area) of a disc of the HD DVD standard or CB HD standard family. Normally, if the disc type can be read, it can be discriminated whether the disc is an optical disc conforming to the HD DVD standard or an optical disc conforming to the CB HD standard.

  However, some low-cost optical disk drives with reduced costs cannot determine the absolute position of the pickup when the optical disk is inserted. Such an inexpensive optical disc drive cannot read data recorded in the BCA when the optical disc is inserted. Therefore, such an inexpensive optical disc drive does not read the data recorded in the BCA when the optical disc is inserted, but reproduces the RF signal corresponding to the data recorded in the data area, reads the physical address, and calculates the radial position, Only then can the pickup be moved to the BCA.

  However, proper demodulation is required to read the physical address. In other words, an optical disc that supports the HD DVD standard requires demodulation corresponding to 8/12 modulation (ETM demodulation method), and an optical disc that supports the CB HD standard requires demodulation corresponding to 4/6 modulation (FSM demodulation method). It becomes.

  In order to determine whether an inexpensive optical disc drive as described above is an optical disc conforming to the HD DVD standard or an optical disc conforming to the CB HD standard, for example, both the ETM demodulator circuit and the FSM demodulator circuit are simultaneously used during optical disc playback. A method of moving, or a method of switching to the other demodulation circuit when it cannot be read by one of the demodulation circuits is conceivable.

  In the case of a system in which both the ETM demodulator circuit and the FSM demodulator circuit are moved simultaneously, the optical disc drive needs to have both the ETM demodulator circuit and the FSM demodulator circuit, which increases the circuit scale and power consumption of the optical disc drive. In the method of switching the demodulation circuit, it is difficult to distinguish whether the RF signal quality is low and data cannot be read, or whether the data cannot be read because the modulation method is different, and it takes time to discriminate.

  Therefore, in the first and second optical disc type determination processes described in the present embodiment, the synchronization code included in the recording data to which ETM is applied and the synchronization code included in the recording data to which FSM is applied are both: The type of the optical disk is determined using the fact that the 13T-3T pattern is included.

  For example, when the RF signal processing circuit included in the signal processing circuit of the optical disc apparatus is set to the ETM demodulation method and an optical disc (ETM disc) on which data modulated by ETM is recorded is reproduced, naturally, the synchronization code is correct. Is detected, and the 13T-3T pattern included in the synchronization code is also detected, so that frame synchronization can be detected. However, even when the RF signal processing circuit included in the signal processing circuit of the optical disc apparatus is set to the ETM demodulation method and an optical disc (FSM disc) on which data modulated by FSM is recorded is reproduced, an RF signal with a certain degree of quality is obtained. If so, the 13T-3T pattern included in the synchronization code is detected, and frame synchronization can be detected. This means that the servo and the read channel are operating normally. Therefore, when a number of errors are detected by IED and EDC included in the demodulated data even when frame synchronization is detected (when errors exceeding the reference value are detected), an appropriate demodulation method is set. Can be expected not. Similarly, when a large number of errors are detected by the PI included in the demodulated data, it can be expected that an appropriate demodulation method is not set.

  FIG. 8 is a flowchart showing a first optical disc type determination process based on the error detection result of the data ID by the IED. The outline of the first optical disc type determination process will be described. When one of the ETM demodulation method and the FSM demodulation method (for example, ETM demodulation method) is set, the RF signal is reproduced, and frame synchronization is detected. The data ID reading rate is detected by IED, and it is determined whether or not the set demodulation method is appropriate based on the detected data ID reading rate. If the data ID is correctly read to some extent (if the data ID reading rate is higher than the reference value), it is determined that the set demodulation method is appropriate. In this case, the recording data (main data) recorded on the information storage medium is reproduced based on the demodulation method determined to be appropriate. On the contrary, if the data ID is not read correctly to some extent (the reading rate of the data ID is equal to or less than the reference value), it is determined that the set demodulation method is inappropriate.

  When it is determined that the set demodulation method is inappropriate, the other demodulation method (for example, FSM demodulation method) of the ETM demodulation method and the FSM demodulation method is set, the RF signal is reproduced, and the frame synchronization is detected. Then, the data ID reading rate is detected by the IED, and it is determined whether or not the set demodulation method is appropriate based on the detected data ID reading rate. If the data ID is correctly read to some extent (if the data ID reading rate is higher than the reference value), it is determined that the set demodulation method is appropriate. In this case, the recording data (main data) recorded on the information storage medium is reproduced based on the demodulation method determined to be appropriate. On the other hand, if the data ID is not read correctly to some extent (the reading rate of the data ID is less than the reference value), it is determined that the set demodulation method is inappropriate.

  Next, the first optical disc type determination process will be described with reference to the flowchart shown in FIG.

  First, the control unit 14 of the optical disc apparatus discriminates which type of optical disc of the CD, DVD, HD DVD system (HD DVD / CB HD) corresponds to the set optical disc based on disc physical discrimination (ST101). -ST106). Specifically, the reflectivity of the disc is detected from the signal processed by the signal processing circuit 13, and the type of the optical disc is discriminated.

  As a result, if it is found that the optical disc is an HD DVD type optical disc (ST105, YES), for example, first, the control unit 14 sets an ETM demodulation method for the RF signal processing circuit of the signal processing circuit 13 ( ST107). Subsequently, when the RF signal is reproduced by the RF signal processing circuit and frame synchronization is detected (ST108, YES), the control unit 14 detects the reading rate of the data ID by the IED, and reads the detected data ID. Based on the rate, it is determined whether or not the set demodulation method is appropriate. If the data ID has been read correctly to some extent (ST110, YES), it is determined that the set demodulation method is appropriate. That is, in this case, it is determined that the ETM demodulation method is an appropriate demodulation method, the optical disk to be processed is determined to be an HD DVD (ETM disk) (ST111), and the RF signal processing circuit is based on the ETM demodulation method. The recorded data (main data) recorded in is reproduced. If frame synchronization is not detected (NO in ST108), the process proceeds to error processing or retry processing (ST109).

  Conversely, if the data ID is not read correctly to some extent (ST110, NO), it is determined that the set demodulation method is inappropriate. In this case, the control unit 14 sets the FSM demodulation method for the RF signal processing circuit of the signal processing circuit 13 (ST112). Subsequently, the RF signal is reproduced by the RF signal processing circuit, and the control unit 14 detects the reading rate of the data ID by the IED, and whether or not the set demodulation method is appropriate based on the detected reading rate of the data ID. Determine. If the data ID is read correctly to some extent (ST113, YES), it is determined that the set demodulation method is appropriate. That is, in this case, it is determined that the FSM demodulation method is an appropriate demodulation method, the optical disk to be processed is determined to be a CB DVD (FSM disk) (ST114), and the RF signal processing circuit is based on the FSM demodulation method. The recorded data (main data) recorded on the optical disc is reproduced. If the data ID cannot be read to some extent (ST113, NO), the process proceeds to error processing or retry processing (ST115).

  In the above description, the case where the ETM demodulation method is set first and then the FSM demodulation method is set has been described, but the present invention is not limited to this. For example, the FSM demodulation method may be set first, and then the ETM demodulation method may be set.

  FIG. 9 is a flowchart showing a second optical disc type determination process based on the error detection result of main data by PI. The outline of the second optical disc type determination process will be described. When one of the ETM demodulation method and the FSM demodulation method (for example, ETM demodulation method) is set, the RF signal is reproduced, and frame synchronization is detected. , PI detects an error included in the main data, and determines whether the set demodulation method is appropriate based on the error detection status. Specifically, a PI syndrome (Syndrome) check is performed for determination. When the demodulation result is correctly decoded, the frequency of PI syndrome being “0” is high. On the other hand, when the correct decoding cannot be performed, all PI syndromes do not become “0”. If the main data has been read correctly to some extent (if the error detection status from the main data is lower than the reference value), it is determined that the set demodulation method is appropriate. In this case, the main data recorded on the information storage medium is reproduced based on the demodulation method determined to be appropriate. On the other hand, if the main data is not read correctly to some extent (the error detection status from the main data is equal to or greater than the reference value), it is determined that the set demodulation method is inappropriate.

  When it is determined that the set demodulation method is inappropriate, the other demodulation method (for example, the FSM demodulation method) of the ETM demodulation method and the FSM demodulation method is set, the RF signal is reproduced, and the main signal is regenerated by PI. An error included in the data is detected, and it is determined whether the set demodulation method is appropriate based on the error detection status. If the main data has been read correctly to some extent (if the error detection status from the main data is lower than the reference value), it is determined that the set demodulation method is appropriate. In this case, the main data recorded on the information storage medium is reproduced based on the demodulation method determined to be appropriate. On the other hand, if the main data is not read correctly to some extent (the error detection status from the main data is equal to or greater than the reference value), it is determined that the set demodulation method is inappropriate.

  As shown in FIG. 3, PI (10 bytes) is half of the main data as shown in FIG. 3 because the PI of the parity codes PI and PO for detecting the main data error is used. This is because the error can be checked when the line (172 bytes) is read. On the other hand, the PO (line 16) cannot check for an error unless most of the main data is read. Therefore, using the PI can shorten the disc discrimination time. The present invention is not limited to this, and both PI and PO may be used, or only PO may be used.

  The flowchart shown in FIG. 9 is a flowchart for explaining the second optical disc type determination process, but the processes other than ST210 and ST213 in the flowchart shown in FIG. 9 are the same as the flowchart shown in FIG. Since description of ST210 and ST213 of the flowchart shown in FIG. 9 is as above, description along the flowchart of FIG. 9 is omitted.

  As described above, the optical disc apparatus according to an embodiment of the present invention can quickly and reliably discriminate between HD DVD (ETM disc) and CB DVD (FMS disc) without having both the ETM demodulation circuit and the FSM demodulation circuit. And can be processed. In other words, by applying the above-described first or second optical disc type determination process to the above-described low-priced optical disc drive, HD DVD (ETM disc) and CB DVD (FMS disc) can be used quickly and reliably even in the low-priced optical disc drive. ) Can be determined and processed.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention in the implementation stage. In addition, the embodiments may be appropriately combined as much as possible, and in that case, the combined effect can be obtained. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be obtained as an invention.

1 is a block diagram showing a schematic configuration of an optical disc apparatus (medium processing apparatus) according to an embodiment of the present invention. It is a figure which shows an example of a structure of a data frame. It is a figure which shows an example of a structure of an ECC block. It is a figure which shows an example of arrangement | positioning of the scrambled flame | frame. It is a figure which shows an example of the ECC block after row interleaving. It is a figure which shows an example of a structure of the even-numbered physical sector data. It is a figure which shows an example of a structure of the odd-numbered physical sector data. It is a figure which shows an example of a synchronous code. It is a flowchart which shows the 1st optical disk type determination process based on the error detection result of data ID by IED. It is a flowchart which shows the 2nd optical disk type determination process based on the error detection result of the main data by PI.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... PUH, 12 ... Preamplifier, 13 ... Signal processing circuit, 14 ... Control part, 15 ... LD drive circuit, 16 ... Waveform generation circuit, 17 ... Memory

Claims (7)

Reading means for reading a signal from the information storage medium;
Frame synchronization is detected from the read signal read by the reading means, data ID is detected from the read signal based on the frame synchronization and the first demodulation method, and the first demodulation method is determined based on the detection status of the data ID The data ID is detected from the read signal based on the frame synchronization and the second demodulation method based on the determination that the first demodulation method is inappropriate, and depending on the detection status of the data ID Discrimination means for discriminating whether or not the second demodulation method is appropriate;
Reproduction means for determining a demodulation method based on a determination result by the determination means, and reproducing a signal recorded on the information storage medium by the determined demodulation method;
A medium processing apparatus comprising: The discrimination means includes
A data ID and an error detection code for the data ID are detected from the read signal based on the frame synchronization and the first demodulation method, and a data ID read rate is detected by the error detection code. If it is higher than the reference value, it is determined that the first demodulation method is an appropriate demodulation method. If the data ID read rate is equal to or lower than the reference value, the first demodulation method is determined to be inappropriate. It is determined that it is a method,
Based on the frame synchronization and the second demodulation method, a data ID and an error detection code for the data ID are detected from the read signal, a data ID read rate is detected by the error detection code, and the data ID read rate is If it is higher than the reference value, it is determined that the second demodulation method is an appropriate demodulation method. If the data ID read rate is equal to or lower than the reference value, the second demodulation method is determined to be inappropriate. To determine that it is a method,
The medium processing apparatus according to claim 1. The first demodulation method is a demodulation method corresponding to the 8/12 modulation method,
The second demodulation method is a demodulation method corresponding to the 4/6 modulation method,
The data modulated by the 8/12 modulation method and the data modulated by the 4/6 modulation method include a common pattern,
The determination unit detects the common pattern from a read signal read by the reading unit, and detects frame synchronization based on a detection result of the common pattern;
The medium processing apparatus according to claim 1. Reading means for reading a signal from the information storage medium;
Frame synchronization is detected from the read signal read by the reading means, and recording data and an error correction code for the recording data are detected from the read signal based on the frame synchronization and the first demodulation method. Based on the error correction processing result of the recorded data, it is determined whether or not the first demodulation method is appropriate, and based on the frame synchronization and the second demodulation method by determining that the first demodulation method is inappropriate. Discriminating means for detecting recording data and an error correction code for the recording data from the read signal, and discriminating whether or not the second demodulation method is appropriate based on an error correction processing result of the recording data by the error correction code;
Reproduction means for determining a demodulation method based on a determination result by the determination means, and reproducing a signal recorded on the information storage medium by the determined demodulation method;
A medium processing apparatus comprising: The discrimination means includes
When the record data and the error correction code for the record data are detected from the read signal based on the frame synchronization and the first demodulation method, and the record data can be decoded by the error correction code, the first data It is determined that the demodulation method is an appropriate decoding method, and when the recording data cannot be decoded by this error correction code, the first demodulation method is determined to be an inappropriate decoding method,
When the recording data and the error correction code for the recording data are detected from the read signal based on the frame synchronization and the second demodulation method, and the recording data can be decoded by the error correction code, the second data It is determined that the demodulation method is an appropriate decoding method, and when the recording data cannot be decoded by the error correction code, the second demodulation method is determined to be an inappropriate decoding method.
The medium processing apparatus according to claim 4. Reads signals from information storage media,
Frame synchronization is detected from the read read signal, data ID is detected from the read signal based on the frame synchronization and the first demodulation method, and whether the first demodulation method is appropriate based on the detection status of the data ID And determining whether the first demodulation method is inappropriate, detecting the data ID from the read signal based on the frame synchronization and the second demodulation method, and detecting the second ID according to the detection status of the data ID. To determine whether the demodulation method is appropriate,
A medium discrimination method characterized by the above. Reads signals from information storage media,
Frame synchronization is detected from the read read signal, recording data and an error correction code for recording data are detected from the read signal based on the frame synchronization and the first demodulation method, and the recording data based on the error correction code Based on the error correction processing result, it is determined whether or not the first demodulation method is appropriate, and the read signal is determined based on the frame synchronization and the second demodulation method by determining that the first demodulation method is inappropriate. Detecting the recording data and the error correction code for the recording data, and determining whether the second demodulation method is appropriate based on the error correction processing result of the recording data by the error correction code.
A medium discrimination method characterized by the above.

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