JPS63261578A - Defective track avoiding system - Google Patents

Abstract

PURPOSE:To perform a recording or reproducing job with exclusion of the defective tracks by providing a track number converting means which converts the track numbers into those of nondefective tracks of a video disk. CONSTITUTION:A defective track detecting device 1 first reproduces an unrecorded video disk 4 via a video disk reproducing part 11 and checks the possibility for occurrence of drop-outs, the reading propriety of track addresses, the tracking and focus servo follow-up performance, etc. A defective track deciding part 12 decides whether each physical track has a defect or not. A data processing part 13 totals the deciding results of the part 12 and produces a conversion table where the 1:1 correspondence is secured between the nondefective physical track numbers and logical track numbers respectively. When a user designates a track number for the recording or reproducing purpose, a track converting part 22 converts the designated track number into a logical track number and then searches the corresponding physical track number with retrieval of the conversion table.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a defective track avoidance method that enables recording or reproduction of a writable video disc while avoiding defective tracks on the disc. .

[Conventional technology]

Reproduced images from video discs and the like are affected by imperfections 41 in the recording tracks. For example, if a track is defective due to a scratch on the disc, the level of the playback RF signal will be insufficient, causing dropouts, and +
1! j The image deteriorates significantly.

Therefore, in order to compensate for such dropouts,
Conventionally, for example, JP-A-60-86985, JP-A-60-94592, JP-A-60-195
Methods such as those disclosed in Publication No. 774 have been adopted.

[Problem that the invention seeks to solve]

In the above conventional technology, plural) 1 (H is -horizontal movement period)
If a significant dropout occurs, such as when the dropout occurs, it may not be possible to compensate, and there is a problem in that image deterioration cannot be prevented. Also.

Furthermore, there are other track defects such as track distortion and address defects, which cause recording defects and search defects, but of course the conventional technology described above could not deal with such defects. .

As mentioned above, in the past, it was not possible to tell whether the track was good or not until the image was actually recorded, and if a defect occurred,
It was necessary to re-record it on a separate track.

Furthermore, in the past, there was a problem in that it was difficult to record the same 1M picture on the same track of a plurality of video discs.

Therefore, an object of the present invention is to provide a defective track avoidance method that can hide the existence of defective tracks in a video disc from the user and perform recording or playback while avoiding the defective tracks. Means for Solving the Problems] In order to achieve the above object, the present invention provides a defective track detection device that scans a video disc to detect defective tracks, creates defective track information, and records it on the video disc; Defect truck information 1! A video disc device is used which reads the i file and converts the track number specified by the user into the track number of a defect-free trunk based on the read data, thereby recording and reproducing the video.

The defective track detection device includes a video disc playback means for playing back a video disc and outputting various signals indicating abnormalities in the playback track, a defective track determination means for determining a defective track from the signal output, and a defective track determination means for determining a defective track from the signal output. It consists of a data processing means for creating defective track information regarding a video disc, and a modulating means for modulating this defective track information and recording it on the video disc. The video disc device also includes a demodulating means for reproducing a video disc and demodulating defective track information recorded on the video disc, and a demodulating means for reproducing defective track information recorded on the video disc, and converting a designated track number to a defect-free track based on the demodulated defective track information. and a video disc recording/reproducing means for recording or reproducing information on the video disc based on the converted track number.

[Effect]

The video disc playback means scans each track of the video disc and detects the occurrence of dropouts.

Outputs a signal indicating tracking error, etc.

The defective track determining means determines whether the valley track is defective or not based on the level, duration, etc. of these signals. The determination results for each valley track are aggregated and processed by the data processing means, and recorded on the video disc by the modulation means as defective track information. The 4I modulation means of the video disc device demodulates this and outputs it to the track conversion means. The track conversion means includes:
The track number designated by the user is assigned to the track number of a defect-free track based on this defective track information. Then, the video disc recording/reproducing means performs recording or reproduction according to the printed track number. By doing this, the user is forced to always access tracks without defects, and information is recorded and reproduced while avoiding defective tracks. Therefore, the user can treat the disc as a video disc with no defective tracks.

〔Example〕

FIG. 1 is a block diagram showing one embodiment of the present invention.

This embodiment is roughly divided into two devices, namely, a defective track detection device ft1 and a video disc device f2.

Furthermore, in the defective track detection device 1 shown in FIG.
11 is a video disc playback section; 12 is a defective track determination section that determines defective tracks from the playback output of the video disc playback section 11; and 15 is a defective track report 3 for storing and processing the determination results output from the defective track determination section 12. 14 is a modulation section that modulates the defective track information 5 outputted from the data processing section 13 and records it on the video disc 4. Furthermore, as signals input to the defective track determination section 12 from the video disc playback section 11, 111 is a dropout signal indicating the occurrence of a dropout, 112 is a tracking error signal indicating the occurrence of a tracking error, and 113 is a focus error signal. A focus error signal 114 indicating the occurrence is an address fail number 100 indicating that the track address cannot be read. On the other hand, in the video disc device 2, 21 is a demodulation unit that reproduces and demodulates the defective track information 3 recorded on the video disc 4, and 22 is a track number designated by the user based on the demodulated defective track information 3. a trough for converting the logical track number into an actual track number on the video disc 4, i.e. a physical track number;
This is the conversion section.

The operation of this embodiment configured as described above in 5 will be explained next.

In the present invention, the logical track number specified by the user is distinguished from the actual physical track number, and only physical tracks without defects are associated with the logical track. .

For this reason, the defective track detection device 1 determines whether the video disc 4? : Scan and detect defective tracks.

That is, in the defective track detection device 1, first, the video disc playback section 11 plays back the unrecorded video disc 4, and
Investigate the possibility of dropout occurrence, readability of the track address, followability of tracking servo and focus servo, etc. This result is the dropout signal 11
1. ) racking error signal 112. Focus error signal 113 # is output as address fail signal 114. The defective track determination unit 12 receives these signals, determines whether each physical track has a defect according to the level or duration of the signal, and outputs the determination result. Next, the data processing unit 13 aggregates the results,
A conversion table is created in which defect-free physical track numbers are associated one-to-one with logical track numbers.

An example of this conversion table is shown in FIG. In this example, 1
The logical track numbers from 20,000 to 20,000 are assigned physical track numbers that are free of defects in descending order. Of course, it is sufficient that the one-to-one correspondence between the logical track and the physical track is maintained even if the tracks are in reverse order or not aligned.

Next, the conversion table created in this way is converted into the area 1 of the video disc 4 by the modulator 14.
For example, defective track information ms is written on the innermost circumference of the disk. The above is the preprocessing for avoiding defective tracks.

Next, the operation of the video disc device 2 for recording and reproducing the video disc 4 on which the defective track information 3 has been recorded as described above will be explained.

First, when the video disc 4 is inserted into the device 2,
The demodulator 21 reads defective track information 3 recorded on the video disc 4 and demodulates it.

As a result of this demodulation, the aforementioned conversion table is outputted to the track conversion section 22 and held as defective track information 3. Thereafter, when the user specifies a track number for recording or playback, the track conversion unit 22 uses the track number as a logical track number and searches the conversion table to obtain a physical track number.

To explain this situation using the example of Fig. 2, if the user specifies @5'' as the recording track, 'a<Ic as shown in the figure is actually the 7th track on the video disc 4. The data will be accessed and recorded there.In the same manner, all designated logical tracks are converted to defect-free physical tracks, making it possible to avoid defective tracks.

Note that the modulation section 14. As for the modulation method used in the demodulation section 21, any method may be used as long as it can record the digital data constituting the conversion table. Specifically, either add an error correction code and record it directly, or
Alternatively, a method such as PCM modulation is possible.

Further, in this embodiment, a conversion table as illustrated in FIG. 2 is recorded as the defective track information 3, but other methods are also possible. For example, it is conceivable to simply record only the defective physical track number as the defective track information 3. In this case, video disc 7 device if2
Although it is necessary to create a conversion table based on the defective track information 5, the amount of information to be recorded can be compressed. For example, the translation table for racks (20,000) must be at least 2 bytes x 2 x 20,000 -
80,000 bytes are required, but if only the defective track number is 1000) 2 bytes per rack x 10
00-2000 bytes is sufficient. Therefore, there is an advantage that the recording area for the defective track information 3 on the video disc 4 can be reduced and at the same time the time for reading this information can be shortened.

Further, in this embodiment, the defective track detection device 1.

Although the video disc device f2 has been described as being implemented by separate devices, it goes without saying that both devices may be integrated into one device.

〔Effect of the invention〕

According to the present invention, the existence of defective tracks in a video disc can be hidden from the user, and recording or reproduction can be performed while avoiding the defective tracks. Therefore, recording defects do not occur, and it is possible to save the trouble of re-recording images, which was conventionally required when a recording defect occurs.Furthermore, according to the present invention, it is possible to It will also be possible to easily record images of

[Brief explanation of drawings]

5g1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is an explanatory diagram for explaining a conversion table as defective track information in FIG. 1. Explanation of symbols 1... Defect track detection horizontal position, 11... Video disc playback unit, 12-... Defective track determination unit, 13...
- Data processing unit, 14...Modulation unit, 2...Video disk device, 21...Demodulation unit, 22...Track conversion unit, 3...Defective track information, 4...Video disc.

Claims (1)

[Scope of Claims] 1. A video disc reproducing means for reproducing and outputting each track of a video disc, and a defective track determining means for determining a defective track of the video disc from a detection signal from the video disc reproducing means; a defective track detection device comprising: a data processing means for creating defective track information of the video disc from the determination result by the defective track determining means; and a demodulation means for reproducing and demodulating the defective track information from the video disc. a track number converting means for converting a track number externally designated for recording or playback into a track number of a defect-free track of the video disc based on the demodulated defective track information; a video disc recording and reproducing means for recording or reproducing information on the video disc based on the number; A defective track avoidance method is characterized in that it can be performed while avoiding. 2. A defective track avoidance method according to claim 1, characterized in that the defective track detection device and the video disc device are integrated into one device.