JP2000187844A - Device and method for reproducing and computer readable storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain remedy effect with a small number of retries even though the surface of a recording medium is deteriorated when error of a reproduced data in a recording medium is corrected and data whose error cannot be corrected is remedied by reading again (retry) the recording medium. SOLUTION: A disk medium 101 is reproduced by an optical pickup 102 and data are detected by a data detecting section 104 and a demodulating section 105. Then, the error of the detected data are corrected by an ECC section 106. If it cannot be corrected, a CPU 111 transmits a parameter change instruction 123 to a parameter control section 110. According to the instruction, the section 110 outputs parameter change information 121 and updates the detection parameter of the section 104.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus and method suitable for reproducing a disk medium and a computer-readable storage medium used for the apparatus and method.
In particular, it relates to a reread (retry) function.

[0002]

2. Description of the Related Art In recent years, as the capacity of disk media has rapidly increased, there has been proposed an apparatus for recording and reproducing not only audio but also video signals for a long time. In particular,
A recording format based on high-efficiency encoding processing such as MPEG is adopted, and at a compressed data rate of about 5 Mbps,
There is a situation where recording and reproduction for about one hour can be realized. With respect to the disk medium itself, further densification is being promoted, and there is a clear trend toward downsizing and increasing the capacity. On the other hand, due to the ease of random access of disk media, the affinity with personal computers, and the ease of handling and reliability compared to conventional tape media, it is expected that further market needs will be met in the future. ing.

[0003] As a reproduction processing function peculiar to a disk medium, there is a re-reading (hereinafter referred to as retry) function. This is a function that attempts to read the same data again when data cannot be read correctly due to temporary adhesion of dust on the media surface, partial scratches, deterioration of the protective film, etc. It is. Generally, the data access time on a disk medium is several times faster than the recording or reproducing rate on the medium, so that the retry operation can be tried several times.

[0004]

The greatest feature of a disk medium that records and reproduces a large amount of image data at a high density is that the medium itself can be easily moved, stored, delivered, and the like (hereinafter, referred to as removable). It is excellent.
However, due to such removable handling, adhesion of dust and dirt on the medium surface, warpage under severe environments, aging such as distortion, scratches due to impact, surface changes due to disturbances, and the like are inevitable. For this reason, it is impossible to keep the surface state during recording for a long time unchanged.

[0005] The conventional retry method has the following problems. (1) When the state of the medium surface is deteriorated or changed from the time of recording, the effect of rescuing data is small even with several retries. (2) When a plurality of blocks determined to be uncorrectable occur at a plurality of places, there is a possibility that important data related to reproduction cannot be retried due to a time constraint on the retry.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and has as its object to provide a data rescue effect with a small number of retries even if the state of the medium surface changes. And

[0007]

In order to achieve the above-mentioned object, a reproducing apparatus according to the present invention comprises: reproducing means for reproducing information recorded on a recording medium; and predetermined data from a reproduced signal of the reproducing means. First detecting means for detecting
An error correction unit that performs an error correction process on the detected data and outputs error correction disable information of the data; a change unit that changes a parameter of the first detection unit based on the error correction disable information; And control means for causing the reproducing means to re-read based on the error correction disable information.

In another reproducing apparatus according to the present invention, a reproducing means for reproducing information recorded on a recording medium,
A first detection unit for detecting predetermined data from a reproduction signal of the reproduction unit, an error correction unit for performing an error correction process on the detected data, and outputting error correction disable information of the data; There are provided changing means for changing the parameters of the reproducing means based on the unacceptable information, and control means for causing the reproducing means, whose parameters have been changed based on the error correction unacceptable information, to re-read.

In the reproducing method according to the present invention,
Performing a reproduction procedure for reproducing information recorded on a recording medium, a first detection procedure for detecting predetermined data from a reproduction signal obtained in the reproduction procedure, and an error correction process for the detected data; An error correction procedure for outputting error correction disable information of the data, a change procedure for changing the parameter used in the first detection procedure based on the error correction disable information, and re-recording of the recording medium after the change of the parameter. And a re-reading procedure for performing reading.

[0010] In another reproduction method according to the present invention, a reproduction procedure for reproducing information recorded on a recording medium,
A first detection procedure of detecting predetermined data from the reproduction signal obtained in the reproduction procedure, an error correction procedure of performing an error correction process on the detected data, and outputting error correction disable information of the data; A change procedure for changing a parameter used in the reproduction procedure based on the error correction disable information and a re-read procedure for re-reading the recording medium after changing the parameter are provided.

In the storage medium according to the present invention,
A reproduction process for reproducing information recorded on a recording medium, a first detection process for detecting predetermined data from a reproduction signal obtained by the reproduction process, and an error correction of the detected data, Error correction processing for outputting the error correction disable information, a change processing for changing the parameter used in the first detection processing based on the error correction disable information, and re-reading the recording medium after changing the parameter And a program for executing a re-reading process for performing the following.

In another storage medium according to the present invention, a reproducing process for reproducing information recorded on a recording medium,
A first detection process for detecting predetermined data from the reproduction signal obtained by the reproduction process, an error correction process for performing error correction on the detected data, and outputting error correction disable information of the data; A program for executing a change process of changing a parameter used in the reproduction process based on the error correction impossible information and a re-read process of re-reading the recording medium after the change of the parameter is stored. .

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the reproducing apparatus according to the present invention. In FIG. 1, 101 is a disk medium, 102 is an optical pickup, 103 is a reproduction preamplifier, 104 is a data detection unit, 105 is a demodulation unit, 106 is an error correction unit (hereinafter, referred to as an ECC unit), 107 is a decoder, and 108 is A memory, 109 is a servo unit, 110 is a parameter control unit, and 111 is a CPU for controlling the whole.

Next, the operation will be described. As described above, the disk medium 101 receives the rotation control by the servo device 109 and controls the trace of the optical pickup 102. From the reproduction signal from the optical pickup 102, video data is extracted through a preamplifier 103, a data detection unit 104 and a demodulation unit 105, and an ECC unit 106
Sent to The ECC unit 106 and the decoder 107 control the memory 108 to perform error correction and data decompression processing, respectively.

Here, if there is any defect in the reproduction data and the ECC unit 106 determines that the error cannot be corrected, the ECC unit 106 sets the correction impossible flag 122 to the CPU 1.
Send to 11. In response, the CPU 111 issues a parameter change instruction 123 to the parameter control unit 110.
Send out. After that, the retry instruction 124 is sent to the servo unit 10.
9, and attempts to re-read the portion where the error could not be corrected.

The parameter control unit 110 includes a CPU 111
When the parameter change command 123 is received from the data detection unit 104, the parameter change information 121 is sent to the data detection unit 104.

FIG. 2 shows an example of the internal configuration of the data detection unit 104. In FIG. 2, reference numeral 201 denotes a clamp unit;
Is an A / D converter, 203 is an equalizer, 204 is a reproduction equalizer, 205 is a PLL, and 206 is a threshold level adjuster controlled by the parameter change information 121.

The output signal of the preamplifier 103 shown in FIG.
The data is digitized by the clamp unit 201 and the A / D converter 202 based on the reproduced clock extracted by the LL 205. Next, in the equalizer 203, the waveform is equalized by a digital filter or the like, and the reproduction equalizer 204 performs maximum likelihood decoding such as Viterbi decoding. Where the threshold level parameters involved in the equalization process are:
It can be variably controlled by the threshold level adjusting unit 206.

The control of the parameters is to switch detection parameters such as the level variation resistance of the reproduction data or the noise resistance, and these parameters can be switched according to the parameter change information 121.

FIG. 3 shows a retry processing flow according to this embodiment. In FIG. 3, the processing is started from the start of reproduction, and the ECC unit 106 performs error correction determination processing. If the error can be corrected, no retry is performed. If the error cannot be corrected, the detection parameter of the data detection unit 104 is switched and then a retry is performed.

As described above, even if data is read once and an error is determined to be uncorrectable, by switching the parameters of the data detection unit 104, the influence of the fluctuation of reproduced data or the influence of noise can be obtained. Since a specialized detection method can be assigned to each, data can be restored with a small number of retries.

FIG. 4 shows a second embodiment of the reproducing apparatus according to the present invention, in which an I-picture judging section 401 is added to FIG. The I picture determination unit 401 determines an I picture, which will be described later, from the reproduction data 411 from the decoder 107, and sends a determination result 412 to the CPU 111.

FIG. 5 schematically shows a stream structure of compressed data of the MPEG system. In MPEG, a video signal is a GOP (Group O
f Picture), and each GOP is encoded with a sequential header (SH). Image data in a GOP is encoded by being divided into picture layers by three different compression algorithms.

That is, the picture layer is composed of an I picture which is coded at the completion of a frame, and a P picture and a B picture by inter-frame predictive coding. Each picture data is represented by an I / P /
It is possible to determine a B picture.

Next, the operation will be described. 4, an I-picture determination unit 401 detects an I-picture based on a PCT header of reproduction data 411 compressed by the MPEG system from the decoder 107, and
The picture determination result 412 is transmitted.

If there is any defect in the reproduction data and the ECC
If it is determined by the unit 106 that the error cannot be corrected, the ECC
The unit 106 transmits the uncorrectable flag 122 to the CPU 111. In response to this, the CPU 111 checks the I picture determination result 412 and sends a parameter change command 123 to the parameter control unit 110 when the data of the I picture cannot be corrected. After that, the retry instruction 124
Is transmitted to the servo unit 109, and an attempt is made to re-read the location where the error could not be corrected.

FIG. 6 shows a retry processing flow according to the present embodiment. Starting from the start of the reproduction, the error correction determination processing is performed. If the ECC unit 106 can correct the error, no retry is performed. If error correction is not possible, PC
By executing a T determination process, it is determined whether or not the error block belongs to an I picture. Uncorrectable block is B
If it is a picture or a P picture, no retry is performed. On the other hand, when the error-correctable block is of an I-picture, the retry operation is performed by changing the detection parameter of the data detection unit 107 in the same manner as in the first embodiment.

The I picture is an important data at the time of reproduction decoding because there is no error propagation between frames due to intra-frame processing. If an I picture is missing, an error is propagated to decoding of other P pictures (forward predictive coding) and B pictures (bidirectional predictive coding), and the total deterioration is remarkable.

The present embodiment provides a retry operation in which the importance of an I-picture is weighted. When a block determined to be uncorrectable is an I-picture, the parameters of the corresponding block are switched. By retrying and mainly restoring the I picture in the limited retry operation, the restoration quality of the total image data can be improved.

FIG. 7 shows a third embodiment of the reproducing apparatus according to the present invention. In FIG. 7, the parameter control unit 110
Since then, a pickup parameter variable signal 125 is supplied to the optical pickup 125 instead of the information 123 in FIG. The configuration of the other parts is the same as in FIG.

Next, the operation will be described. ECC unit 10
6, error correction is performed by the decoder 107, and data expansion is performed by the decoder 107 using the memory 108. Here, if there is any defect in the reproduction data and the ECC unit 106 determines that the error cannot be corrected, the ECC 106 unit 106 transmits a correction impossible flag 122 to the CPU 111. In response to this, the CPU 111 sends a parameter change command 123 to the parameter control unit 110. After that, the retry command 124 is transmitted to the servo unit 109, and an attempt is made to reread the portion where the error could not be corrected.

The parameter control unit 110 includes a CPU 111
When a parameter change command 123 is received from the optical pickup 102, a parameter change signal 125 for changing the reproduction laser power is sent to the optical pickup 102. Generally, the laser power at the time of reproduction is set to a level at which the reproduction RF output level and the reproduction C / N are saturated, and the fluctuation of the reproduction characteristic with respect to the variation of the laser power is small. However, if the reproduction laser power is hardly transmitted accurately due to a change in the characteristics of the medium surface, it may be possible to rescue the RF output level to the detection limit by slightly increasing the laser power.

FIG. 8 shows a retry processing flow according to the present embodiment. Starting from the start of the reproduction, the error correction determination processing is performed. If the ECC unit 106 can correct the error, no retry is performed. If the error cannot be corrected, the laser power of the optical pickup 102 is slightly increased to retry. Of course, when increasing the reproducing power, it is apparent that the upper limit power is limited so as not to erase the recorded data.

According to the present embodiment, even if data is read once and an error is determined to be uncorrectable, the laser power parameter of the optical pickup 102 is switched to expand the retry cover range. Can be done.

FIG. 9 shows a fourth embodiment of the reproducing apparatus according to the present invention.
01, playback data 411, and a determination result.

Next, the operation will be described. 9, an I-picture determination unit 401 detects an I-picture based on a PCT header from playback data 411 compressed by the MPEG system, and sends a picture determination result 41 to the CPU 111.
Send 2.

If there is any defect in the reproduced data and the ECC unit 106 determines that the error cannot be corrected,
The correction impossible flag 122 is transmitted to the CPU 111, and the CPU 111
When the I picture data cannot be corrected for the error in the 1 picture determination result 412, the 111 sends a variable laser power signal 125 to the parameter control unit 110 so as to slightly increase the reproduction laser power of the optical pickup 102. After that, the retry command 124 is sent to the servo unit 109.
And attempts to re-read the location where the error could not be corrected.

FIG. 10 shows a retry processing flow according to this embodiment. Starting from the start of the reproduction, the error correction determination processing is performed. If the ECC unit 106 can correct the error, no retry is performed. If error correction is not possible, PC
A T determination process is executed to determine whether or not the error block belongs to an I picture. If the error-correctable block is a B picture or a P picture, no retry is performed. On the other hand, when the error-correctable block is of an I picture, the detection parameter is changed in the same manner as in the third embodiment, and a retry operation is performed.

The present embodiment provides a retry operation weighted to the importance of an I picture. If the block determined to be error-correctable is an I picture,
The reproduction laser parameters of the corresponding block are switched and retried, and the I picture is mainly restored in the limited retry operation, so that the restoration quality of the total image data can be improved.

Next, a storage medium according to another embodiment of the present invention will be described. The present invention can be realized by a hardware configuration, but can also be realized by a configuration of a computer system including a CPU and a memory. When configured in a computer system, the memory forms a storage medium according to the present invention. That is, a storage medium storing software program codes for executing the operations described in the flowcharts and the like of the above-described embodiments is used in a system or an apparatus, and the CPU of the system or apparatus is stored in the storage medium. By reading and executing the program code, the object of the present invention can be achieved.

As the storage medium, ROM, R
Semiconductor memory such as AM, optical disk, magneto-optical disk,
A magnetic medium or the like may be used, and these may be configured and used in a CD-ROM, a floppy disk, a magnetic medium, a magnetic card, a nonvolatile memory card, or the like.

Therefore, this storage medium is used in a system or apparatus other than the systems and apparatuses shown in FIGS. 1, 4, 7, and 9, and the system or computer is used to store the program code stored in the storage medium. By reading and executing the same, the same functions as those of the above embodiments can be realized, the same effects can be obtained, and the object of the present invention can be achieved.

An OS running on a computer
When performing part or all of the processing, or after the program code read from the storage medium is written to a memory provided in an extended function board or an extended function unit connected to the computer, Even when the CPU or the like provided in the above-mentioned extended function board or extended function unit performs a part or all of the processing based on the instruction of the program code, the same functions as those of the above embodiments can be realized and the same functions can be realized. Effect can be obtained,
The object of the present invention can be achieved.

[0044]

As described above, according to the present invention,
The following effects can be obtained. (1) When the state of the medium surface is deteriorated or changed from the time of recording, the data rescue effect can be improved with a small number of retries.

(2) When a plurality of blocks determined to be error-correctable occur at a plurality of locations, a retry operation is performed by weighting the I-picture among the decoded pictures, so that it is possible to contribute to the improvement of the quality of the entire reproduced picture. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a reproducing apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a data detection unit in FIG. 1;

FIG. 3 is a flowchart illustrating a retry process according to the first embodiment.

FIG. 4 is a block diagram showing a second embodiment of the reproducing apparatus according to the present invention.

FIG. 5 is a configuration diagram for explaining an I picture.

FIG. 6 is a flowchart illustrating a retry process according to the second embodiment.

FIG. 7 is a block diagram showing a third embodiment of the reproducing apparatus according to the present invention.

FIG. 8 is a flowchart illustrating a retry process according to the third embodiment.

FIG. 9 is a block diagram showing a fourth embodiment of the reproducing apparatus according to the present invention.

FIG. 10 is a flowchart illustrating a retry process according to a fourth embodiment.

[Explanation of symbols]

 Reference Signs List 101 disk medium 102 optical pickup 104 data detection unit 105 demodulation unit 106 ECC unit 107 decoder 108 memory 109 servo unit 110 parameter control unit 111 CPU 112 reproduction data 121 parameter variable signal 123 parameter change command 124 retry command 125 laser power variable signal 401 I Picture determination unit 411 Playback data 412 Determination result

Claims (11)

[Claims] 1. A reproducing means for reproducing information recorded on a recording medium, a first detecting means for detecting predetermined data from a reproduced signal of the reproducing means, and an error correcting process for the detected data. Error correction means for outputting error correction disable information of the data; change means for changing parameters of the first detection means based on the error correction disable information; and reproduction means based on the error correction disable information. And a control means for performing re-reading. 2. The method according to claim 1, wherein the parameter is an amplitude fluctuation resistance or a noise resistance of the data, and the changing means changes the parameter by changing a threshold of the first detecting means. Item 1
The playback device as described in the above. 3. A reproducing unit for reproducing information recorded on a recording medium, a first detecting unit for detecting predetermined data from a reproduced signal of the reproducing unit, and performing an error correction process on the detected data. Error correction means for outputting error-correction-impossible information of the data; changing means for changing parameters of the reproduction means based on the error-correction-impossible information; and the parameter is changed based on the error-correction-impossible information. A reproducing apparatus, comprising: a control unit for causing the reproducing unit to perform rereading. 4. The reproducing means includes an optical pickup,
4. The reproducing apparatus according to claim 3, wherein said changing means increases a laser power of said optical pickup. 5. The data is video data comprising a first screen coded by intra-screen coding and a second screen coded by inter-screen coding. 2. A method according to claim 1, further comprising a second detecting means for detecting the first screen, wherein the changing means changes the parameter based on an output of the second detecting means and the error correction disable information. Or the playback device according to 3. 6. A reproduction procedure for reproducing information recorded on a recording medium, a first detection procedure for detecting predetermined data from a reproduction signal obtained in the reproduction procedure, and an error correction of the detected data. An error correction procedure for performing processing and outputting error correction unpossible information of the data; a changing procedure for changing parameters used in the first detection procedure based on the error correction unpossible information; A re-reading procedure for re-reading the recording medium. 7. A reproduction procedure for reproducing information recorded on a recording medium, a first detection procedure for detecting predetermined data from a reproduction signal obtained by the reproduction procedure, and an error correction of the detected data. An error correction procedure for performing processing and outputting error correction unpossible information of the data; a change procedure for changing parameters used in the reproduction procedure based on the error correction unpossible information; and the recording medium after changing the parameters. And a re-reading procedure for re-reading the data. 8. The data is video data including a first screen coded by intra-screen coding and a second screen coded by inter-screen coding. 7. A method according to claim 6, further comprising: providing a second detection procedure for detecting the first screen, wherein the change procedure changes the parameter based on the output of the second detection procedure and the error correction disable information. Or the reproduction method according to 7. 9. A reproduction process for reproducing information recorded on a recording medium, a first detection process for detecting predetermined data from a reproduction signal obtained by the reproduction process, and an error correction of the detected data. Performing an error correction process of outputting the error correction disable information of the data; a change process of changing a parameter used in the first detection process based on the error correction disable information; A computer-readable storage medium storing a program for executing a re-read process for re-reading a recording medium. 10. A reproduction process for reproducing information recorded on a recording medium, a first detection process for detecting predetermined data from a reproduction signal obtained by the reproduction process, and an error correction of the detected data. Performing an error correction process of outputting error correction impossible information of the data; a change process of changing a parameter used in the reproduction process based on the error correction unusable information; A computer-readable storage medium storing a program for executing a re-read process for performing a re-read. 11. The data is video data composed of a first screen coded by intra-screen coding and a second screen coded by inter-screen coding. A second detection process for detecting one screen is provided in the program, and the change process changes the parameter based on an output of the second detection process and the error correction disable information. The computer-readable storage medium according to claim 9.