JP3495004B2 - Data reproducing apparatus, data reproducing method, and program recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data reproducing device, a data reproducing method and a program recording medium applicable to, for example, an external storage device of a computer, and particularly to a retry process when data cannot be corrected. Is to have.

[0002]

2. Description of the Related Art As an example of this type of device, a CD-ROM drive or a DVD for reproducing data recorded on a disk in a contactless manner by using a pickup of a semiconductor laser.
ROM drives are known. In these discs, address information indicating the position on the disc is added to the information data, and an error correction code for correcting an error during reproduction and an error detection code for detecting an error are added. Have been recorded. To reproduce such recorded data, at least synchronization detection, demodulation, and error correction are performed.

In recent years, there has been a demand from the market for a data reproducing apparatus capable of high speed reproduction. However, the faster the playback speed, the shorter the time it takes to perform error correction.
It has become difficult to apply an error correction method having a high correction capability during continuous reproduction. Furthermore, if the recording medium is portable, the error probability during data reproduction increases due to scratches and dirt. Due to these factors, as a result of error correction, the probability of being uncorrectable due to the existence of an error is increasing. In general, when such a correction is impossible, synchronization detection, demodulation, and error correction are redone by a retry operation of rereading the corresponding data.

For example, in Japanese Patent Laid-Open No. 9-282809,
There has been proposed a recorded information reproducing apparatus which reproduces data without losing continuity while maintaining high reliability. In this example, a recording information reproducing apparatus is shown which controls error correction and data transfer to the next-stage processing in a pipeline mode during a period in which a data block to which an error correction code is added is demodulated. When it is impossible to correct, it is proposed to reduce the reproduction speed and perform a retry operation, to spend time for error correction on the data read again, and to switch to an error correction method with high error correction capability on the data read again. ing. It has also been proposed to perform error correction again on uncorrectable data without performing a retry operation.

As in this prior art example, in video reproduction in which the data rate corresponds to 1 × speed reproduction, since error-corrected data is accumulated in advance by rotating the disk corresponding to the high speed, reproduction is performed. Even if the speed is reduced to shift to the retry operation, or the error correction is performed again and then the retry operation is performed, continuous reproduction of the image can be realized.

[0006]

In order to realize continuous high-speed reproduction in the original sense, it is necessary to correct the data read again after the reproduction speed is reduced as in the conventional example. There is a problem that there is a large time difference between the final data that could be normally continuously reproduced before the disability occurred and the data that was read again and error-corrected after the retry operation.

Further, the uncorrectable demodulated data and the next demodulated data read in parallel with the error correction are read again by the retry operation, which causes a problem of increasing the power consumption of the data reproducing apparatus. is there.

Further, when the error cannot be corrected as a result of performing error correction again on the uncorrectable data without performing the retry operation, it is necessary to shift to the retry operation from that point. There is a risk of loss of continuity.

The present invention, like computer data,
Even in the data reproduction that requires higher reliability, without impairing the continuity of the error-corrected reproduction data,
The present invention realizes a data reproducing device, a data reproducing method, and a program recording medium that can be reproduced at high speed.

[0010]

The present invention has been made to achieve the above object, and a data reproducing apparatus according to claim 1 of the present invention is a demodulating means for demodulating reproduced data, and the reproducing means. Synchronization detection means for detecting a synchronization signal from data, storage means for storing demodulation data output by the demodulation means, error in the demodulation data stored in the storage means are corrected, and an error exists after the error correction. Error correction means for outputting an uncorrectable signal when the synchronization error is detected, error correction control means for controlling the error correction means according to the synchronization signal detected by the synchronization detection means, and data reproduction from a desired recording position on the recording medium. When the data cannot be corrected, a retry operation for rereading the corresponding data from the recording medium, demodulating, and error correction is started. When both the error correction control unit,
It is characterized in that the error correction means is controlled so as to perform error correction on the demodulated data already stored in the storage means. As a result, after the retry operation of data reproduction is started, the error correction for the demodulated data stored in the storage means can be continued, and high-speed and continuous data reproduction can be realized.

A data reproducing apparatus according to a second aspect of the present invention is the data reproducing apparatus according to the first aspect, wherein the error correction control means receives the uncorrectable signal for the demodulated data from the error correcting means. The error correction means is controlled to perform error correction on the next demodulation data demodulated by the demodulation means in parallel with the error correction on the demodulation data. As a result, after the retry operation of data reproduction is started, the error correction for the next demodulated data stored in the storage means can be continued, and high-speed and continuous data reproduction can be realized.

A data reproducing apparatus according to a third aspect of the present invention is the data reproducing apparatus according to the second aspect, wherein the error correction control means performs error correction on the next demodulated data by the error correcting means, and the next demodulation is performed. When an uncorrectable signal for data is received, the error correction means is controlled to perform error correction again on the next demodulated data by using an error correction method different from that during continuous reproduction of data. It is a thing. As a result, even if the next demodulated data cannot be corrected by the error correction method set at the time of continuous reproduction of data, it is possible to improve the possibility of correcting the error and realize high-speed and continuous data reproduction. be able to.

According to a fourth aspect of the present invention, in the data reproducing apparatus according to the second aspect, the next demodulation is performed before the error correction of the uncorrectable demodulated data due to the retry operation is restarted. If the error cannot be corrected by continuing error correction on the data,
The error correction control means outputs a correction interruption signal to stop the error correction means which continues error correction for the next demodulated data. As a result, the continuous error correction is stopped before returning to the continuous reproduction of data by the retry operation, so that it is possible to realize data reproduction that does not interfere with continuous reproduction control.

A data reproducing apparatus according to a fifth aspect of the present invention is the data reproducing apparatus according to the second or third aspect, wherein the error correction control means includes an error correction end signal for the next demodulated data from the error correcting means. If you receive
It is characterized in that the error correction means is controlled so as to perform error correction again on the uncorrectable demodulated data. As a result, error correction can be performed on the demodulated data and the next demodulated data after the retry operation of data reproduction is started, and faster and continuous data reproduction can be realized.

A data reproducing apparatus according to a sixth aspect of the present invention is the data reproducing apparatus according to the first aspect, wherein the error correction control means receives the uncorrectable signal for the demodulated data from the error correcting means. The error correction means is controlled to perform error correction again on the demodulated data. As a result, after the retry operation of data reproduction is started, error correction for the demodulated data can be continued, and high-speed and continuous data reproduction can be realized.

A data reproducing apparatus according to a seventh aspect of the present invention is the data reproducing apparatus according to the sixth aspect, wherein the error correction means performs error correction again on the demodulated data, and when the data is continuously reproduced. It is characterized in that error correction is performed by using an error correction method different from. As a result, even if the demodulated data cannot be corrected by the error correction method set during continuous data reproduction, it is possible to improve the possibility of error correction and realize high-speed and continuous data reproduction. You can

A data reproducing apparatus according to an eighth aspect of the present invention is the data reproducing apparatus according to the sixth aspect, wherein the demodulated data for the uncorrectable demodulated data is restarted by the retry operation until the demodulation of the demodulated data is restarted. If the error cannot be corrected by continuing the error correction, the error correction control means outputs a correction interruption signal to stop the error correction means which continues error correction on the demodulated data. It is a feature. As a result, the continuous error correction is stopped before returning to the continuous reproduction of data by the retry operation, so that it is possible to realize data reproduction that does not interfere with continuous reproduction control.

The data reproducing apparatus according to claim 9 of the present invention is the data reproducing apparatus according to claim 6 or 7, wherein the error correction control means outputs an error correction end signal for the demodulated data from the error correcting means. When received, the error correction means is controlled so as to correct the error also in the next demodulated data. With this, after the retry operation of data reproduction is started, it is possible to perform error correction on the demodulated data and the next demodulated data,
Higher speed and continuous data reproduction can be realized.

The data reproducing apparatus according to claim 10 of the present invention is the data reproducing apparatus according to any one of claims 1 to 9, in accordance with the sync signal the output from the dangerous detecting means, wherein Demodulation control means for controlling the start of demodulation of the reproduction data by the demodulation means, wherein the demodulation control means demodulates the demodulated data for which the error correction by the error correction means is completed in the retry operation of the data reproduction. The demodulation means is controlled so as not to execute. By this means, it is possible to avoid duplicate demodulation for data for which error correction has been completed, which can contribute to reduction in power consumption.

A data reproducing apparatus according to an eleventh aspect of the present invention is the data reproducing apparatus according to any one of the first to ninth aspects, wherein the error correction control means ends the error correction by the error correcting means. With respect to the demodulated data, the error correction means is controlled so as not to perform error correction processing in the retry operation of the data reproduction. By this means, it is possible to avoid duplicate error correction for data for which error correction has been completed, which can contribute to reduction in power consumption.

A data reproducing apparatus according to a twelfth aspect of the present invention is the data reproducing apparatus according to any one of the first to eleventh aspects, wherein the seek control means is configured to perform the error correction in a retry operation of data reproduction. The data next to the demodulated data after the error correction by the means is reproduced from the recording medium. This allows
It is possible to prevent the reproduction process from being performed on the data for which error correction has been completed, and it is possible to realize high-speed and continuous data reproduction.

A data reproduction method according to a thirteenth aspect of the present invention stores a demodulation step of demodulating reproduction data, a synchronization detection step of detecting a synchronization signal from the reproduction data, and a demodulation data obtained by the demodulation step. An error of the demodulated data stored in the storage means is corrected according to the storing step stored in the storing means and the synchronization signal detected by the synchronization detecting step, and when the error is present after the error correction, it is determined that the error cannot be corrected. An error correction step,
When it is determined that the demodulated data cannot be corrected in the error correction step, a retry step of starting a retry operation of rereading the data from the recording medium, demodulating and error correcting again, and the storage after the retry operation is started. And a re-error correction step for performing error correction on the demodulated data already stored in the means. As a result, after the retry operation of data reproduction is started, the error correction for the demodulated data stored in the storage means can be continued, and high-speed and continuous data reproduction can be realized.

A data reproducing method according to a fourteenth aspect of the present invention is the data reproducing method according to the thirteenth aspect, wherein in the re-error correction step, if the demodulated data is determined to be uncorrectable in the error correcting step, An error correction is performed on the next demodulation data demodulated in the demodulation step in parallel with the error correction process on the demodulation data. As a result, after the retry operation of data reproduction is started, the error correction for the next demodulated data stored in the storage means can be continued, and high-speed and continuous data reproduction can be realized.

A data reproducing method according to a fifteenth aspect of the present invention is the data reproducing method according to the fourteenth aspect, wherein in the re-error correction step, the next demodulated data is corrected as a result of error correction of the next demodulated data. If it is determined that the next demodulation data is not correct, an error correction method different from that used during continuous reproduction of data is used to perform error correction again. As a result, even if the next demodulated data cannot be corrected by the error correction method set during continuous reproduction of data reproduction, it is possible to improve the possibility of error correction and realize high-speed and continuous data reproduction. can do.

A data reproducing method according to a sixteenth aspect of the present invention is the data reproducing method according to the fourteenth aspect, wherein in the re-error correction step, error correction of the demodulated data that cannot be corrected by the retry step is performed. If the error of the next demodulation data cannot be corrected before restarting, the error correction for the next demodulation data is stopped,
It is characterized by that. As a result, the continuous error correction is stopped before returning to the continuous reproduction of data by the retry operation, so that it is possible to realize data reproduction that does not interfere with continuous reproduction control.

A data reproducing method according to a seventeenth aspect of the present invention is the data reproducing method according to the fourteenth aspect or the fifteenth aspect, wherein in the re-error correction step, when error correction for the next demodulated data is completed, It is characterized in that the error correction is also performed on the demodulated data determined to be uncorrectable in the error correction step. As a result, error correction can be performed on the demodulated data and the next demodulated data after the retry operation of data reproduction is started, and faster and continuous data reproduction can be realized.

A data reproducing method according to an eighteenth aspect of the present invention is the data reproducing method according to the thirteenth aspect, wherein in the re-error correction step, if the demodulated data is determined to be uncorrectable in the error correcting step. It is characterized in that error correction is performed again on the demodulated data. As a result, after starting the retry operation of data reproduction, it is possible to continue error correction for the demodulated data,
High-speed and continuous data reproduction can be realized.

A data reproducing method according to a nineteenth aspect of the present invention is the data reproducing method according to the eighteenth aspect, wherein in the re-error correction step, the error correction is performed when the error correction is performed again on the demodulated data. Error correction is performed using an error correction method different from that used in step error correction,
It is characterized by that. As a result, even if the demodulated data cannot be corrected by the error correction method set during continuous data reproduction, it is possible to improve the possibility of error correction and realize high-speed and continuous data reproduction. You can

A data reproducing method according to a twentieth aspect of the present invention is the data reproducing method according to the eighteenth aspect, wherein in the re-error correction step, demodulation of the demodulated data which cannot be corrected by the retry step is restarted. If the error in the demodulated data could not be corrected by the time
It is characterized in that error correction for the demodulated data is stopped. As a result, the continuous error correction is stopped before returning to the continuous reproduction of data by the retry operation, so that it is possible to realize data reproduction that does not interfere with continuous reproduction control.

A data reproducing method according to a twenty-first aspect of the present invention is the data reproducing method according to the eighteenth or nineteenth aspect, wherein in the re-error correction step, when error correction for the demodulated data is completed, for the next demodulated data demodulated in the demodulating step in parallel with the error correction process for the demodulated data that by the error correction step, performing error correction, it is characterized in. As a result, after the retry operation of data reproduction is started,
It is possible to perform error correction on the demodulated data and the next demodulated data, and to realize higher speed and continuous data reproduction.

A data reproducing method according to a twenty-second aspect of the present invention is the data reproducing method according to any one of the thirteenth to twenty-first aspects, wherein in the retry step, an error occurs in the error correction step or the re-error correction step. Do not perform demodulation processing on the corrected data,
It is characterized by that. By this means, it is possible to avoid duplicate demodulation for data for which error correction has been completed, which can contribute to reduction in power consumption.

A data reproducing method according to a twenty-third aspect of the present invention is the data reproducing method according to any one of the thirteenth to twenty-first aspects, wherein in the retry step, an error occurs in the error correction step or the re-error correction step. An error correction process is not performed on the corrected data. By this means, it is possible to avoid duplicate error correction for data for which error correction has been completed, which can contribute to reduction in power consumption.

A data reproducing method according to a twenty-fourth aspect of the present invention is the data reproducing method according to any one of the thirteenth to twenty-third aspects, wherein in the retry step, error correction is completed in the re-error correction step. The data next to the demodulated data is reproduced from the recording medium. As a result, it is possible to prevent the reproduction processing from being performed on the data for which error correction has been completed, and it is possible to realize high-speed and continuous data reproduction.

A program recording medium according to a twenty-fifth aspect of the present invention is a program recording medium for recording a program for realizing a data reproducing method by a computer, and has a reproducing step of reproducing data recorded on the recording medium. And a program having a sync detecting step of detecting a sync signal from the reproduction data,
A program having a demodulation step of demodulating the reproduction data obtained by the reproduction step, a program having a storage step of storing the demodulation data obtained by the demodulation step in a storage means, and a synchronization detected by the synchronization detection step. A program having an error correction step of correcting an error of the demodulated data stored in the storage means according to the signal and determining that the error cannot be corrected after the error correction, and the demodulated data is corrected in the error correction step. When it is determined that the data is impossible, a program having a retry step of performing re-reading of the data from the recording medium, demodulation and error correction again, and re-reading of the data from the recording medium in the retry step are performed. The demodulation already stored in the storage means while And a program having a re-error correction step of performing error correction over data and is characterized. As a result, the computer using the program recording medium can continue error correction for the demodulated data stored in the storage means after the retry operation of data reproduction is started, and thus high-speed and continuous data reproduction is realized. can do.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) An embodiment of the invention described in any one of claims 1 to 5 and claims 13 to 17 of the present invention will be described below.
1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, FIG. 10, FIG.
2 is used for the explanation. In the first embodiment, DV
A case where the present invention is applied to a D-ROM reproducing device (data reproducing device) will be described.

FIG. 1 shows a DV according to an embodiment of the present invention.
It is a block diagram which shows the structure of a D-ROM reproduction | regeneration apparatus. D
The VD-ROM reproduction device 101 uses a decoder 107 to at least perform synchronization detection, demodulation, and error correction on information optically read from the disk 100 that is a recording medium in response to an access or data transfer request from the host computer 110, for example. And outputs data or information to the host computer 110.

The disk 100 is a spindle motor 10
It is rotationally driven by 2. The pickup 103 irradiates the disk 100, which is rotationally driven, with a laser beam, photoelectrically converts the reflected light by a light receiving unit, and reads the information recorded on the disk 100. The rotation control circuit 104 controls the rotation speed of the spindle motor 102. The focus tracking control circuit 105 controls the position of the pickup 103, holds the pickup 103 on the recorded data during data reproduction, and moves the pickup 103 immediately before desired reproduction data during seek.

The signal read from the pickup 103 is amplified and binarized by the analog processing circuit 106 and supplied to the decoder 107. The decoder 107 cooperates with the memory 108 that stores data to perform at least synchronization detection, demodulation, and error correction. The CPU 109 includes a rotation control circuit 104, a focus tracking control circuit 105,
The analog processing circuit 106 and the decoder 107 are accessed to perform state management and control of each circuit.

FIG. 2 is a block diagram showing a detailed structure of the decoder 107. The reproduced data from the analog processing circuit 106 is input to the synchronization detection circuit 201 and the demodulation circuit 202. The sync detection circuit 201 extracts the sync signal from the reproduced data and outputs a sync signal that determines the start of demodulation and error correction. The demodulation circuit 202 reproduces the 16-bit data of the reproduction data recorded on the disc 100 by 8-16 modulation.
-8 demodulation is performed, and the demodulated data thus demodulated is stored in the memory 108 via the memory control circuit 207.

The error correction circuit 204 reads the demodulated data stored in the memory 108 via the memory control circuit 207, calculates the error position and error pattern of the data, and outputs the error data stored in the memory 108. Rewrite with the correct data. Further, the error correction circuit 204 cannot output all errors and outputs an error correction impossible signal indicating that errors remain and an error correction end signal indicating that predetermined error correction is completed. The interface circuit 206 transfers the error-corrected demodulated data stored in the memory 108 to the host computer 110. If the decoder 107 and the host computer 110
If another processing circuit exists between the two, the interface circuit 206 transfers the error-corrected demodulated data to the next processing circuit.

The demodulation control circuit 203 outputs a demodulation start signal in response to at least the synchronization signal input from the synchronization detection circuit 201, and controls the demodulation circuit 202. The error correction control circuit 205 outputs an error correction start signal and a correction interruption signal according to at least the synchronization signal input from the synchronization detection circuit 201 and the uncorrectable signal and the error correction end signal input from the error correction circuit 204. The error correction circuit 204 is controlled. The CPU 109 sets and controls various processes to the synchronization detection circuit 201, the demodulation control circuit 203, the error correction control circuit 205, and the interface circuit 206 via the CPU interface circuit 208, and grasps the operating state of each circuit. It can be carried out.

FIG. 11 schematically shows the error correction code added to the demodulated data stored in the memory 108. The procedure for forming the error correction code will be described below.

Header portion 12 composed of information such as ID
172 bytes, 2048 bytes of data part, and 2064 bytes obtained by 4 bytes of error detection code (EDC)
Each byte is divided into 12 sets of data, and 16 sets of these are combined to form a 172 bytes × 192 bytes data array. A 16-byte parity byte is added to 172 sets of 192-byte data to form a Reed-Solomon code (outer code) capable of correcting an error of up to 8 bytes. Next, a parity byte of 10 bytes is added to 208 sets of 172 byte data to form a Reed-Solomon code (inner code) capable of correcting an error of up to 5 bytes. Since the inner code is recorded on the disc 100 in the time-series direction, error correction by an outer code in which the error is dispersed into different code words is effective for a burst error caused by dirt or scratches on the disc. Is.

FIG. 12 shows an example of data error correction by the decoder 107. The error correction control circuit 205 outputs an error correction start signal to the error correction circuit 204 according to the synchronization signal output from the synchronization detection circuit 201. The error correction circuit 204 corrects the error of the demodulated data stored in the memory 108 according to the error correction method set by the error correction control circuit 205.

In FIG. 12, the error correction circuit 204 applies an error correction method of outer code-inner code-outer code, and outputs an error correction end signal when the error correction is completed. For example,
The outer code correction corrects an error of 8 bytes or less for 182 outer codes, and the inner code correction corrects an error of 5 bytes or less for 208 inner codes. Rotation control circuit 10
Since the interval of the synchronization signal changes depending on the data reproduction speed depending on the rotation speed of the spindle motor 102 controlled by 4, the CPU 109 can change the setting of the error correction method for the error correction control circuit 205. . When the reproduction speed is slow, there is a time margin, so it is also possible to adopt an error correction method of outer code-inner code-outer code-inner code, for example.

In the case of DVD-ROM, the synchronization signal is added in frame units. Since one inner code is composed of two frames, 416 synchronization signals are added in the data unit of the error correction code shown in FIG. As for the synchronization signals in FIG. 12 and the figures referred to hereinafter, only the synchronization signal in the data unit of the error correction code is shown.

FIG. 10 shows a conventional retry operation. The numbers 1, 2 and 3 in the figure show the order of the demodulated data allocated for each data unit to which the error correction code is added, and hereinafter, they are referred to as data 1, data 2 and data 3, respectively. I will decide.

First, the synchronization detection circuit 201 includes the decoder 1
The sync signal is detected from the reproduced data input to 07 and output to the demodulation control circuit 203 and the error correction control circuit 205. With this synchronizing signal, the demodulation control circuit 203 outputs a demodulation start signal to the demodulation circuit 202, and the demodulation of data 1 is started. The demodulation circuit 202 also continues demodulation of the data 2 by the synchronization signal detected from the continuous reproduction data. In parallel with the demodulation of the data 2, the error correction control circuit 2
Reference numeral 05 outputs an error correction start signal of data 1 to the error correction circuit 204, and the error correction circuit 204 corrects the error of data 1 by the error correction method set during continuous reproduction.

When an uncorrectable signal is output from the error correction circuit 204 as a result of the error correction of the data 1, the CPU 109
Detects that correction is impossible and stops the demodulation circuit 202 and the error correction circuit 204 through the demodulation control circuit 203 and the error correction control circuit 205. The operation of the demodulation circuit 202 and the error correction circuit 204 is stopped as shown in FIG.
This can be realized by the demodulation control circuit 203 and the error correction control circuit 205 not outputting the demodulation start signal and the error correction start signal, respectively. Alternatively, the synchronization detection circuit 201 outputs the synchronization signal of data 3 so that immediately after the demodulation circuit 202 and the error correction circuit 204 are activated,
The demodulation control circuit 203 and the error correction control circuit 205 may stop the demodulation circuit 202 and the error correction circuit 204, respectively.

Further, the CPU 109 commands the focus tracking control circuit 105 to reproduce the data 1 as the seek target data again, and the focus tracking control circuit 105 moves the pickup 103 to the inner circumference so that the data 1 of the data 1 is reproduced. Resume playback from the front. When the synchronization detection circuit 201 detects the synchronization signal of data 1, the demodulation control circuit 203 activates the demodulation circuit 202, and thereafter, demodulation and error correction are restarted in a pipeline manner. As a result, the outputable data capable of transferring the data to the host computer 110 is at least several tens of meters by the retry operation as compared with the case where the error can be corrected.
It will be delayed by sec.

According to the present invention, when the error correction circuit 204 outputs an uncorrectable signal, the focus tracking control circuit 105 starts a retry operation for reproducing data from the disk 100 again, and at the same time, the error correction control circuit 20.
5 operates the error correction circuit 204.
Here, the error correction circuit 204 outputs an uncorrectable signal at least when there is an error that cannot be corrected. The error correction circuit 204 outputs an uncorrectable signal when at least the presence of an error is detected.

FIG. 3 is a timing chart for explaining the operation of the DVD-ROM reproducing apparatus 101 according to the present invention. First, the synchronization detection circuit 201 detects a synchronization signal from the reproduction data input to the decoder 107 and outputs it to the demodulation control circuit 203 and the error correction control circuit 205. The demodulation control circuit 203 causes the demodulation circuit 20 to receive the synchronization signal.
The demodulation start signal is output to 2 and the demodulation of data 1 is started. The demodulation circuit 202 also continues demodulation of the data 2 by the synchronization signal detected from the continuous reproduction data. In parallel with the demodulation of data 2, the error correction control circuit 205
An error correction start signal of data 1 is output to the error correction circuit 204, and the error correction circuit 204 corrects the error of data 1 by the error correction method set during continuous reproduction. As a result of the error correction of the data 1 by the error correction circuit 204, if the error of the data 1 can be corrected, the demodulation of the data 3 and after and the error correction of the data 2 and after can be continued.

However, as shown in FIG. 3, when an uncorrectable signal for data 1 is output from the error correction circuit 204, the CPU 109 causes the focus tracking control circuit 105 to reproduce the data 1 as seek target data again. Order to try again. That is, the operation shifts to the retry operation. At this time, the demodulation control circuit 203 operates the demodulation circuit 20.
2 is stopped, but the error correction control circuit 205 outputs an error correction start signal to the error correction circuit 204 to execute error correction on the data 2 already demodulated.

As a result of the error correction for the data 2, if the data 2 can be corrected normally, the time at which the data 2 can be transferred from the decoder 107 to the host computer 110 becomes significantly earlier than in FIG. In the case of a data reproducing apparatus that has a constraint that data must be transferred in time series, since data 1 and data 2 can be transferred after the error correction for data 1 after the retry operation is completed, Compared with this, the data 2 can be transferred earlier by one data block.

Further, according to the present invention, as shown in FIG. 4, when the error correction circuit 204 outputs the uncorrectable signal and the error correction end signal for the data 2, the error correction control circuit 2
05 uses an error correction method different from that during continuous playback,
The error correction circuit 204 is operated to perform error correction on the data 2 again.

Compared with the interval of the sync signal at the time of continuous reproduction,
Since the time required for the retry operation is sufficiently long, it is possible to apply an error correction method that requires a long time for error correction and has a higher error correction capability. In particular,
The number of iterations of the inner code and the outer code can be increased. In addition, in correcting either the inner code or the outer code, a flag can be set for a codeword that cannot be corrected, and erasure correction used as an erasure flag at the time of error correction of the other can be applied. Further, as the error correction method at the time of continuous reproduction, in the case where the correction which is less than the maximum correction capability is performed in order to reduce the error correction probability, it is possible to switch to the maximum capability correction. As a result, even if the data 2 contains many errors and cannot be corrected by the error correction method set during continuous reproduction, the possibility of error correction can be improved.

Further, according to the present invention, if the error cannot be corrected by continuing the error correction for the data 2 before the error correction of the data 1 which cannot be corrected by the retry operation is restarted, the error correction control is performed. The circuit 205 outputs the correction interruption signal to stop the error correction circuit 204 which continues error correction for the data 2. As a result, in the retry operation, special control such as holding the activation of the error correction circuit 204 for the demodulated data 1 again becomes unnecessary, and the demodulated data 1 and the data 1 and subsequent data (data 2, data 2 3) and the error correction circuit 20
The control of 4 is the same as that during continuous reproduction. Further, it is guaranteed that demodulation and error correction after the retry operation can be started at the same time as the time shown in FIG.

Further, according to the present invention, as shown in FIG. 5, when the error correction control circuit 205 receives an error correction end signal for the data 2 from the error correction circuit 204, an error is corrected so that the data 1 is also corrected. The correction circuit 204 is operated. As a result, if the data 1 can also be corrected, the time at which the data 1 and the data 2 can be transferred to the host computer 110 becomes significantly faster than in FIG.

According to the data reproducing apparatus and the data reproducing method of the first embodiment of the present invention, when the data cannot be corrected, the retry operation for reproducing the data from the recording medium again is performed, and the demodulated data is reproduced. The error correction for the next demodulated data demodulated in parallel with the error correction is continued, so that the data reproduction can be realized at high speed and continuously.

(Embodiment 2) An embodiment of the invention described in any one of claims 6 to 9 and 18 to 21 of the present invention will be described below with reference to FIGS. , FIG. 8 will be described. FIG. 6 shows a DV according to the present invention.
6 is a timing diagram for explaining the operation of the D-ROM reproduction device 101.

The present invention is characterized in that the error correction control circuit 205 operates the error correction circuit 204 again on the demodulated data for which the uncorrectable signal is output from the error correction circuit 204.

First, the synchronization detection circuit 201 is composed of the decoder 1
The sync signal is detected from the reproduced data input to 07 and output to the demodulation control circuit 203 and the error correction control circuit 205. With this synchronizing signal, the demodulation control circuit 203 outputs a demodulation start signal to the demodulation circuit 202, and the demodulation of data 1 is started. The demodulation circuit 202 also continues demodulation of the data 2 by the synchronization signal detected from the continuous reproduction data. In parallel with the demodulation of the data 2, the error correction control circuit 2
Reference numeral 05 outputs an error correction start signal of data 1 to the error correction circuit 204, and the error correction circuit 204 corrects the error of data 1 by the error correction method set during continuous reproduction.

When the error correction circuit 204 outputs an uncorrectable signal as a result of the error correction of the data 1, the CPU 10
Reference numeral 9 instructs the focus tracking control circuit 105 to reproduce the data 1 as seek target data again. That is, the operation shifts to the retry operation. At this time, the demodulation control circuit 203 stops the demodulation circuit 202, but the error correction control circuit 205 outputs an error correction start signal to the error correction circuit 204 to execute the error correction on the data 1.

If the data 1 can be corrected normally as a result of the error correction, the time at which the data 1 can be transferred from the decoder 107 to the host computer 110 becomes significantly earlier than in FIG. According to the present invention, since error correction is performed on data 1, it is effective in the case of a data reproducing apparatus that must transfer data in time series.

Further, the error correction control circuit 205 of the present invention
Is to operate the error correction circuit 204 so as to perform error correction again on the uncorrectable data 1 by using an error correction method different from that during continuous reproduction.

Since the data 1 was determined to be uncorrectable as a result of error correction by the error correction method during continuous reproduction, it is expected that most of the data will be erroneous. Since the time required for the retry operation is longer than the interval of the synchronization signal at the time of continuous reproduction, it is possible to apply an error correction method with sufficient error correction capability by taking sufficient time. In particular,
In correcting either the inner code or the outer code, a flag can be set for a codeword that cannot be corrected, and erasure correction used as an erasure flag at the time of error correction of the other can be applied. In addition, as a method of error correction during continuous reproduction, in order to reduce the error correction probability, when the correction that is less than the maximum correction capability is performed, it is possible to switch to the maximum capability correction. Therefore, the data 1 for which the uncorrectable signal is output
Can improve the possibility of being able to correct

Further, according to the present invention, as shown in FIG. 7, when the error correction cannot be corrected by continuing the error correction for the data 1 before the demodulation of the uncorrectable data 1 is restarted after the retry operation. In this case, the error correction control circuit 205 outputs a correction interruption signal to stop the error correction circuit 204 which continues error correction for the data 1.

In the first embodiment, the error correction is performed on the data 2. Therefore, when demodulating the data 1, the demodulation circuit 202 and the error correction circuit 204 have the memory 108.
Were accessing different areas. In the second embodiment, since the error correction is performed on the data 1, it is a good idea to stop the error correction circuit 204 before restarting the demodulation on the data 1 after the retry operation. As a result, the data 1 reproduced again by the demodulation circuit 202
The memory 108 can be set to the same area in which the uncorrectable data 1 was stored, so that it is not necessary to secure an extra memory area, and the demodulation circuit 202, the error correction circuit 204, the interface circuit 206 When accessing the memory 108, the same address control as in continuous reproduction can be realized.

Further, according to the present invention, as shown in FIG. 8, after the retry operation is started, the error correction control circuit 205 sets the data 1
When the error correction end signal is received from the error correction circuit 204, the error correction circuit 204 is operated even for the data 2 already demodulated. As a result, if not only data 1 but also data 2 can be corrected,
The time at which the data 1 and the data 2 can be transferred to the host computer 110 is significantly earlier than that in FIG.

According to the data reproducing apparatus and the data reproducing method according to the second embodiment of the present invention, when the data cannot be corrected, the retry operation for reproducing the data from the recording medium again is performed and the data cannot be corrected. Since the error correction for the demodulated data which has been described above is continued, there is an effect that data reproduction can be realized at high speed and continuously.

(Embodiment 3) The embodiment of the invention described in any one of claims 10, 11, 22, and 23 of the present invention will be described below with reference to FIGS.
This will be described with reference to FIGS. 6 and 8. The present invention is characterized in that the demodulation control circuit 203 does not operate the demodulation circuit 202 for data that has already been corrected by error correction when restarting demodulation for data that has been reproduced again by the retry operation. .

As shown in FIG. 3, by the retry operation, the demodulation control circuit 203 sequentially outputs the demodulation start signal from the data 1 to the demodulation circuit 202 by the synchronization signal from the synchronization detection circuit 201, but the error correction circuit 204 does. When the error correction is performed on the data 2 and the error can be corrected, the data 2 already error-corrected is stored in the memory 108, and therefore the demodulation start signal is not output for the data 2 and the demodulation is performed. The circuit 202 can be deactivated. As a result, the power consumed by the demodulation circuit 202 can be suppressed.

Further, since the data 2 has already been corrected, the error correction control circuit 205 can prevent the error correction circuit 204 from operating without outputting the error correction start signal. As a result, it is possible to suppress the power consumed by the error correction circuit 204.

As shown in FIG. 6, the error correction circuit 2
When 04 performs error correction on the data 1 and the already error-corrected data 1 is stored in the memory 108, it is possible to prevent the demodulation circuit 202 and the error correction circuit 204 from operating in the retry operation. It is possible to suppress the power consumed by the demodulation circuit 202 and the error correction circuit 204.

Further, as shown in FIGS. 5 and 8, when the error correction circuit 204 performs error correction on the data 1 and data 2 and the error can be corrected, the data 1 and data 2 are retried. In both cases, it is possible to prevent the demodulation circuit 202 and the error correction circuit 204 from operating, and it is possible to obtain the same effect as described above.

According to the data reproducing apparatus and the data reproducing method according to the third embodiment of the present invention, demodulation and error correction of data for which error correction is completed are not performed after the start of the retry operation. Circuit 204
It has an effect that can contribute to the reduction of power consumption.

(Embodiment 4) An embodiment of the invention described in claims 12 and 24 of the present invention will be described below with reference to FIG. The present invention, the next data of the data that was able to correct the data by continuous error correction,
It is switched as data to be reproduced again from the recording medium. Conventionally, as shown in FIG. 5 and FIG. 8, since the seek target data remains the data 1, the period of the data 1 and the data 2 is in the standby state, and after the synchronization signal of the data 3 is input, The demodulation control circuit 203 is the demodulation circuit 2
02 was started. In the present invention, when the correction of the data 1 is completed, the seek target data is switched to the data 2, and when the error correction of the data 2 is also completed, the seek target data is switched to the data 3.

As shown in FIG. 9, when the error correction circuit 204 corrects the error in the data 1 after shifting to the retry operation and the error in the data 1 can be corrected, C
The PU 109 controls the focus tracking control circuit 105 according to the correction end signal of the data 1 output from the error correction circuit 204, and sets the seek target data to the data 2
Toggle its on. Further, the error correction circuit 204 sets the data 2
When the error of the data 2 can be corrected by performing error correction with respect to, the CPU 109 controls the focus tracking control circuit 105 in accordance with the correction end signal of the data 2 output from the error correction circuit 204, and determines the seek target data. Switch to data 3. As a result, the demodulation start time of the data 3 can be shortened, and faster data reproduction can be realized.

When the error correction of only the data 2 is performed as shown in FIG. 3, the seek target data cannot be switched, but when the error correction of the data 2 and the data 1 can be performed as shown in FIG. After the error correction of data 1,
Since the seek target data can be switched to the data 3 and the seek target data can be switched to the data 2 when the error correction of the data 1 can be performed as shown in FIG. 6, the same effect can be obtained.

According to the data reproducing apparatus and the data reproducing method according to the fourth embodiment of the present invention, when the data can be corrected by the continuous error correction after the data cannot be corrected, the next data is reproduced again. Since the data is switched as the data to be reproduced, high-speed and continuous data reproduction can be realized.

In the above embodiment, the case where the data 1 which is the head data is uncorrectable has been described as an example.
It is needless to say that the present invention can be applied and has the same effect even when uncorrectable data is generated in the continuous reproduction.

In the above embodiment, the present invention is applied to DV.
Although the case where the present invention is applied to the D-ROM drive has been described, the present invention can be applied to a data reproducing device using a recording medium other than the optical disc, such as a magnetic disc, a magneto-optical disc, or a magnetic tape. It has the same effect.

Further, by recording the data reproducing program for realizing the data reproducing method shown in each of the above-mentioned embodiments in a data storage medium such as a floppy (registered trademark) disk, each of the present invention can be realized. The processing shown in the embodiment can be easily executed in an independent computer system.

FIG. 13 is a diagram for explaining a case where the data reproducing process of each of the above embodiments is carried out by a computer system using a floppy disk storing the data reproducing program. FIG. 13 (a)
Fig. 13 (b) shows an external appearance, a sectional structure, and a floppy disk body as viewed from the front of the floppy disk.
Shows an example of the physical format of the floppy disk body.

In the floppy disk FD, the floppy disk body D is a floppy disk case FC.
A plurality of tracks Tr are formed concentrically from the outer circumference to the inner circumference on the surface of the floppy disk body D, and each track Tr is angularly divided into 16 sectors Se. It is divided. Therefore, in the floppy disk FD storing the above program,
The floppy disk body D has data (program) recorded in an area (sector) Se allocated thereon.

Further, FIG. 16C shows a configuration for recording the above-mentioned program on the floppy disk FD and performing data reproduction processing using the program stored in the floppy disk FD.

A floppy disk FD with the above program
In the case of recording on the disk, the data as the program is written from the computer system Cs to the floppy disk FD via the floppy disk drive FDD.
In addition, the data reproducing apparatus is set to the computer system C by the program recorded on the floppy disk FD.
Floppy disk drive F when building in
The DD reads the program from the floppy disk FD and loads it into the computer system Cs.

In the above description, a floppy disk is used as the data recording medium, but an optical disk can be used to perform data reproduction processing by software as in the case of the floppy disk. Further, the recording medium is not limited to the above-mentioned optical disk or floppy disk, but may be an IC card, a ROM cassette or the like, as long as it can record a program. Similarly, the data reproduction process by software can be performed.

[0089]

As described above, according to the data reproducing apparatus of the first aspect of the present invention, the demodulating means for demodulating the reproduced data, the synchronization detecting means for detecting the synchronizing signal from the reproduced data, and the demodulating means. Storage means for storing the demodulated data output by the means, error correction means for correcting an error in the demodulated data stored in the storage means, and outputting an uncorrectable signal when an error exists after the error correction, Inability to correct data, comprising error correction control means for controlling the error correction means in accordance with the synchronization signal detected by the synchronization detection means, and seek control means for controlling data reproduction from a desired recording position on the recording medium. sometimes, I read again from the recording medium of the relevant data, starts the retry operation to perform demodulation and error correction again together, the error correction control unit, in the storage means Since the configuration of controlling the error correcting means to perform error correction of the stored demodulated data after the retry operation start of data reproduction, it is possible to continue the error-correction on the stored demodulated data to said storage means It is possible to realize high-speed and continuous data reproduction.

According to the data reproducing method of the thirteenth aspect of the present invention, the demodulation step of demodulating the reproduction data, the synchronization detecting step of detecting a synchronization signal from the reproduction data, and the demodulation data obtained by the demodulation step In the storage means and an error of the demodulated data stored in the storage means is corrected according to the synchronization signal detected by the synchronization detection step, and when the error is present after the error correction, the error is uncorrectable. An error correction step of judging, and a demodulated data determined to be uncorrectable in the error correction step, a retry step of starting a retry operation of re-reading the data from the recording medium, demodulating and error correcting again, After the retry operation starts,
Since it has a re-error correction step of performing error correction on the demodulated data already stored in the storage means, it is possible to continue error correction for the demodulated data stored in the storage means after the retry operation of data reproduction is started. Therefore, high-speed and continuous data reproduction can be realized.

According to a twenty-fifth aspect of the present invention, there is provided a program recording medium for recording a program for realizing a data reproducing method by a computer, which is for reproducing data recorded on the recording medium. A program having a step, a program having a sync detection step of detecting a sync signal from the reproduction data, a program having a demodulation step of demodulating the reproduction data obtained at the reproduction step, and a demodulation obtained at the demodulation step According to a program having a storage step for storing data in the storage means and a synchronization signal detected by the synchronization detection step, an error of demodulated data stored in the storage means is corrected, and an error exists after the error correction. Sometimes there is an error correction step that determines that And a program having a retry step of performing a retry operation of re-reading the data from the recording medium, demodulating and error correcting again when the demodulated data is determined to be uncorrectable in the error correction step, and the retry operation. In the step, the program recording medium is used because it includes a program having a re-error correction step of performing error correction of demodulated data already stored in the storage means while re-reading data from the recording medium. Since the computer can continue error correction for the demodulated data stored in the storage means after the retry operation of data reproduction is started,
High-speed and continuous data reproduction can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a DVD-ROM reproducing device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a decoder in the DVD-ROM reproducing device of FIG.

FIG. 3 is a DVD-RO according to the first and third embodiments of the present invention.
Timing chart of data playback in M playback device

FIG. 4 is a timing chart of data reproduction in the DVD-ROM reproducing device according to the first embodiment of the present invention.

FIG. 5 is a DVD-RO according to the first and third embodiments of the present invention.
Timing chart of data playback in M playback device

FIG. 6 is a DVD-RO according to second and third embodiments of the present invention.
Timing chart of data playback in M playback device

FIG. 7 is a timing chart of data reproduction in the DVD-ROM reproducing device according to the second embodiment of the present invention.

FIG. 8 is a DVD-RO according to second and third embodiments of the present invention.
Timing chart of data playback in M playback device

FIG. 9 is a timing chart of data reproduction in the DVD-ROM reproducing device according to the third embodiment of the present invention.

FIG. 10 is a timing chart of data reproduction in a conventional DVD-ROM reproducing device.

FIG. 11 is a diagram schematically showing an error correction code added to demodulated data.

FIG. 12 is a timing chart of data reproduction showing an example of data error correction.

FIG. 13 (a) is a configuration diagram of a floppy disk,
(B) is a diagram showing an example of the physical format of the floppy disk body, (c) is an external view of the computer system and the floppy disk drive

[Explanation of symbols]

100 discs 101 DVD-ROM playback device 102 spindle motor 103 pickup 104 rotation control circuit 105 Focus tracking control circuit 106 analog processing circuit 107 decoder 108 memory 109 CPU 110 host computer 201 Sync detection circuit 202 demodulation circuit 203 Demodulation control circuit 204 error correction circuit 205 error correction control circuit 206 Interface circuit 207 Memory control circuit 208 CPU interface circuit

Front page continuation (72) Inventor Oka Zaki Makoto 8-1, Koshinmachi, Takamatsu City, Kagawa Prefecture Matsushita Electronics Co., Ltd. (56) References JP 2001-236744 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G11B 20/10 G11B 20/14 G11B 20/18

Claims (25)

(57) [Claims] 1. A demodulation means for demodulating reproduction data, a synchronization detection means for detecting a synchronization signal from the reproduction data, a storage means for storing demodulation data output by the demodulation means, and a storage means stored in the storage means. Correct the demodulated data error,
Error correction means for outputting an uncorrectable signal when an error exists after the error correction, and according to the synchronization signal detected by the synchronization detection means,
An error correction control means for controlling the error correction means and a seek control means for controlling data reproduction from a desired recording position on the recording medium are provided, and when the data cannot be corrected, the corresponding data is reread from the recording medium. together starts the retry operation to perform demodulation and error correction again, the error correction control unit, wherein said controlling the error correction means previously to perform error correction of the stored demodulated data to the storage means, it And a data reproducing device. 2. The data reproducing apparatus according to claim 1, wherein when the error correction control unit receives an uncorrectable signal for demodulated data from the error correction unit, the demodulation is performed in parallel with error correction for the demodulated data. A data reproducing apparatus, wherein the error correction means is controlled so as to perform error correction on the next demodulated data demodulated by the means. 3. The data reproducing apparatus according to claim 2, wherein the error correction control means performs error correction on the next demodulation data by the error correction means, and receives an uncorrectable signal for the next demodulation data, The data reproducing apparatus is characterized in that the error correcting means is controlled to perform error correction again on the next demodulated data by using an error correction method different from that during continuous reproduction of. 4. The data reproducing apparatus according to claim 2, wherein the error can be corrected by continuing the error correction for the next demodulated data before restarting the error correction of the uncorrectable demodulated data by the retry operation. If not, the error correction control means outputs a correction interruption signal to stop the error correction means which continues error correction for the next demodulated data. 5. The data reproducing apparatus according to claim 2 or 3, wherein the error correction control means is unable to correct when receiving an error correction end signal for the next demodulated data from the error correction means. A data reproducing apparatus, characterized in that the error correction means is controlled so as to perform error correction again on demodulated data. 6. The data reproducing apparatus according to claim 1, wherein when the error correction control means receives an uncorrectable signal for demodulated data from the error correction means, the error correction control means performs error correction on the demodulated data again. A data reproducing apparatus characterized by controlling the error correction means. 7. The data reproducing apparatus according to claim 6, wherein the error correcting means performs error correction on the demodulated data again by using an error correcting method different from that during continuous reproduction of data. A data reproducing device characterized by performing. 8. The data reproducing apparatus according to claim 6, wherein an error cannot be corrected by continuing error correction on the demodulated data until the demodulation of the uncorrectable demodulated data is restarted by the retry operation. in case of,
The data reproducing apparatus, wherein the error correction control means outputs a correction interruption signal to stop the error correction means that continues error correction on the demodulated data. 9. The data reproducing apparatus according to claim 6 or 7, wherein when the error correction control means receives an error correction end signal for demodulated data from the error correction means, it also applies to next demodulated data. A data reproducing device, characterized in that the error correcting means is controlled to perform error correction. The data reproducing apparatus according to any one of claims 10] claims 1 to 9, wherein according to the synchronization signal output from the dangerous detecting means, controls the start of the demodulation of the reproduced data by the demodulating means The demodulation control means controls the demodulation means so that demodulation data for which error correction by the error correction means is completed is not executed in the retry operation of the data reproduction. A data reproducing device characterized by the above. The data reproducing apparatus according to any one of claims 11] claims 1 to 9, wherein the error correction control unit, the retry operation of the data reproduction, the demodulated data is error correction completed by the error correction means For
A data reproducing apparatus, characterized in that the error correcting means is controlled so as not to execute an error correcting process. 12. The data reproducing apparatus according to claim 1, wherein the seek control means, in the retry operation of the data reproduction, of the demodulated data for which error correction by the error correction means is completed. A data reproducing device characterized by reproducing the following data from a recording medium. 13. A demodulation step of demodulating reproduction data, a synchronization detection step of detecting a synchronization signal from the reproduction data, a storage step of storing the demodulation data obtained by the demodulation step in a storage means, and the synchronization detection. An error correction step of correcting an error of the demodulated data stored in the storage means according to the synchronization signal detected by the step, and determining that the error cannot be corrected when the error exists after the error correction; and a demodulation in the error correction step. When it is determined that the data cannot be corrected, a retry step of starting the retry operation of re-reading the data from the recording medium, demodulating and error correcting again, and after the retry operation is started, the data is already stored in the storage means. And a re-error correction step for performing error correction on the demodulated data. Raw method. 14. The data reproducing method according to claim 13, wherein in the re-error correction step, if the demodulated data is determined to be uncorrectable in the error correction step, the error correction processing is performed in parallel with the demodulated data. For the next demodulated data demodulated in the demodulation step,
A data reproducing method characterized by executing error correction. 15. The data reproducing method according to claim 14, wherein in the re-error correction step, when it is determined that the next demodulation data is uncorrectable as a result of error correction of the next demodulation data, A data reproducing method characterized in that an error correction method different from that in continuous reproduction is used to perform error correction again on the next demodulated data. 16. The data reproducing method according to claim 14, wherein in the re-error correction step, an error of the next demodulated data is corrected before the error correction of the uncorrectable demodulated data in the retry step is restarted. If the error could not be corrected, the error correction for the next demodulated data is stopped. 17. The data reproducing method according to claim 14 or 15, wherein in the re-error correction step, when error correction for the next demodulated data is completed,
A data reproducing method, wherein error correction is also performed on demodulated data determined to be uncorrectable in the error correction step. 18. The data reproducing method according to claim 13, wherein in the re-error correction step, if the demodulated data is determined to be uncorrectable in the error correction step, error correction is performed again on the demodulated data. A data reproducing method characterized by the following. 19. The data reproducing method according to claim 18, wherein in the re-error correction step, when the error correction is performed again on the demodulated data, an error correction different from the error correction in the error correction step is performed. A data reproducing method characterized by performing error correction using the method. 20. The data reproducing method according to claim 18, wherein in the re-error correction step, an error in the demodulated data can be corrected before the demodulation of the uncorrectable demodulated data in the retry step is restarted. A data reproducing method characterized by stopping error correction on the demodulated data when there is no such error. 21. The method of claim 18 or data reproducing method according to claim 19, wherein the re-error-correction step, if the error correction for the demodulated data is completed, the error correction for by that demodulated data to the error correction step An error correction is performed on the next demodulated data demodulated in the demodulation step in parallel with the processing, wherein the data reproducing method is characterized. 22. The data reproducing method according to any one of claims 13 to 21, wherein in the retry step, data demodulated in the error correction step or the error correction step is demodulated. A data reproducing method characterized in that no processing is executed. 23. The data reproducing method according to any one of claims 13 to 21, wherein in the retry step, an error occurs in the data whose error correction is completed in the error correction step or the re-error correction step. A data reproducing method characterized by not performing correction processing. 24. The data reproducing method according to claim 13, wherein in the retry step, the data next to the demodulated data whose error correction has been completed in the re-error correction step is reproduced from a recording medium. A data reproducing method characterized by the following. 25. A program recording medium having recorded thereon a program for realizing a data reproducing method by a computer, the program having a reproducing step of reproducing data recorded on the recording medium, and a synchronization signal from the reproduced data. A program having a synchronization detection step of detecting, a program having a demodulation step of demodulating the reproduction data obtained in the reproduction step, and a program having a storage step of storing the demodulation data obtained in the demodulation step in a storage means. A program having an error correction step of correcting an error of the demodulated data stored in the storage means according to the synchronization signal detected by the synchronization detection step, and determining that the error cannot be corrected when the error is present after the error correction. , In the error correction step, demodulation data If the data is determined to be uncorrectable, the program has a retry step of performing a retry operation of re-reading the data from the recording medium, demodulating and error-correcting again, and re-writing the data from the recording medium in the retry step. A program having a re-error correction step for performing error correction on the demodulated data already stored in the storage means during reading, and a program recording medium.