KR19990033795A - How to play data on disc - Google Patents

Abstract

The present invention relates to a data reproducing method of a disc, and more particularly, to a data reproducing method capable of compensating for track slippage of an optical pickup apparatus during a disc reproducing operation.

The data processing method includes the steps of determining the continuity of the sector address of the data input from the disk and whether the error correction of the address data is normal, and if the error correction of the continuity or the sector address is not normal, reading from the corresponding sector address. Determining whether or not in the error correction process of the entered data, and the step of compensating the data according to each of the miscorrection.

Description

How to play data on disc.

The present invention relates to a data reproducing method of a disc, and more particularly, to a data reproducing method capable of compensating for track slippage of an optical pickup apparatus during a disc reproducing operation.

A digital video disc (hereinafter referred to as a 'DVD') is a recording medium developed for recording about 2 hours of digital images on an optical disc having a diameter of 12 cm. That is, it is a recording medium having a very large capacity of 6 to 8 times the capacity of a compact disc (hereinafter referred to as 'CD'), which is currently in the spotlight as a large capacity recording medium.

Although the DVD can be a medium for recording information, a large capacity can be achieved, and data compression technology or a light source with a short wavelength can be used. However, information forming a pit for storing information on the DVD is fundamental. This is because the pitch of the track is dense so that it is not about half that of the CD. Usually, the track pitch of a DVD is 0.725 탆, whereas the track pitch of a CD is 1.6 탆. That is, in DVD, information is recorded in finer pit than in CD, and the recorded information is reproduced.

When the optical pickup device reads data from a disc having a very narrow track interval, the optical pickup device may not track the track correctly and slide to an adjacent track due to defects or defects on the disk. The phenomenon occurs. If track slippage occurs and data cannot be reproduced sequentially, an error occurs during the decoding of the data, which results in a problem that normal display cannot be achieved.

Accordingly, an object of the present invention is to provide a disc data reproducing method that can detect and compensate track slip as soon as possible by using sector addresses and block addresses included in a disc format during a disc reproducing operation.

1 is a block diagram showing a general disc player;

2 is a flowchart illustrating operations of a data reproducing method of a disc according to the present invention.

* Explanation of symbols for main parts of the drawings

1: disc 3: optical pickup device

5 demodulation circuit 7 servo unit

9 microprocessor unit 11 error correction circuit

13: video decoding circuit 15: graphics circuit

17: audio decoding circuit 19, 21: digital to analog converter

23: NTSC / PAL encoder 25: motor

29: high frequency signal processing unit 31: ID ECC

In accordance with another aspect of the present invention, there is provided a data reproducing method of a disc, including determining whether the continuity of sector addresses of data input from the disc and error correction of address data are normal, and the error correction of the continuity or sector address. If the error is not normal, the method includes determining whether or not an error is corrected in the error correction process of data read from the sector address, and compensating the data according to whether the error is corrected.

The data reproducing method of the disc of the present invention detects track slip as soon as possible using the sector address and the block address of the disc format.

In particular, by detecting the presence of the beginning of the block at the time of the track slip occurs, it is possible to compensate for errors in the previous block.

Hereinafter, a method of reproducing data of a disc according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing a general disc player.

Examine the configuration.

Information on a disk (hereafter referred to as 'DVD') 1, a rotation drive motor 25 of the DVD 1, and a data recording surface of the DVD 1 having a track pitch of 0.725 µm. Accurately tracks tracks, reads the recorded data, converts them into electrical signals, outputs them, and inputs electrical signals output from the optical pickup devices 3 to perform basic signal processing for reproduction. And a high frequency signal processor 29.

The high frequency signal processor 29 inputs an electrical signal output from the optical pickup device 3 to calculate a tracking and focusing error signal of the optical pickup device 3. The calculated tracking error signal is input to the servo unit 7, and the tracking servo included in the servo unit 7 controls to maintain the position in the recording surface of the laser beam on the information pit row, that is, on the track, based on this signal. do. In addition, a focusing error signal is also input to the servo unit 7, and the focusing servo included in the servo unit 7 controls to maintain the focus position of the laser beam on the information recording surface of the disc based on this signal. And a microprocessor unit 9 which is in charge of the system.

The reproduction high frequency signal output from the high frequency signal processor 29 is demodulated by the demodulation circuit 5 as 16 bits of digital data and output. The reproduced data output from the demodulation circuit 5 will hereinafter be described as sectors to help understand the contents of the specification. The sector data output from the demodulation circuit 5 is input to the ID ECC 31 to error correct the ID information of the sector data. The error corrected sector data is then input to the error correction circuit 11.

In addition, the sector data obtained by error correction of the ID by the ID ECC 31 is also input to the microprocessor unit 9. The microprocessor unit temporarily stores only the sector address from the input sector data, compares the continuity with the next input sector address, the input sector address is discontinuous, and the process of the sector address is performed by some processes to be described later. When judged abnormal, the track slip of the optical pickup device 3 is determined.

The microprocessor unit 9 also calculates a block address from the sector address and stores it. When it is determined that the track slip of the optical pickup device 3 is compared with the sector address and the block address currently input, the control signal for the back track jump of the optical pickup device 3 is supplied to the servo unit ( 7)

On the other hand, while the track slip signal is detected as described above, the sector data input to the error correction circuit 11 is temporarily stored in the VBR buffer 27 after error correction of user data is performed in units of 16 sectors. . The VBR buffer 27 stores data in FIFO (First-In First-Out) order and outputs the stored data. In other words, it is a memory based on the principle of outputting the first stored data for the first time.

In the above process, the data stored in the VBR buffer 27 is applied to each decoding circuit under the control of the microprocessor unit 9, and the configuration of the decoding circuit is as follows. The video decoding circuit 13 inputs, decodes and outputs only video data from the sector data output from the VBR buffer 27, and inputs only subtitle data from a reproduced digital signal under the control of the microprocessor unit 9 and performs signal processing. And an audio decoding circuit 17 for inputting, decoding and outputting only an audio signal from a reproduction digital signal under the control of the microprocessor unit 9.

The video signal output from the video decoding circuit 13 is converted into an analog signal by the video digital / analog converter 19, and then converted into a broadcast signal according to the NTSC / PAL standard by the NTSC / PAL encoder 23 and output. do. The audio signal output from the audio decoding circuit 21 is also converted into an analog signal by the audio digital / analog converter 21 and then output.

Next, a detailed description will be given of a process of compensating for a signal when a track slip is detected during a disc reproducing process according to the above configuration.

2 is a flow chart illustrating a data processing method of a disc for detecting and compensating for track slips according to the present invention.

When the power is supplied, the microprocessor unit 9 applies a signal to load circuits such as the servo unit 7 and the high frequency signal processing unit 29 to control the initial state for the disc reproducing operation. By this operation, the servo unit 7 drives the motor 25 to rotate the optical disc 1, and the optical pickup device 3 reads the recorded data from the rotated optical disc 1.

At this time, the data read out by the optical pickup device 3 are data recorded on the pit located on the information track of the optical disc 1, and therefore, the optical pickup device 3 accurately tracks the track for continuous reproduction of the data. You have to read the data. In this way, the data read from the optical pickup device 3 is input to the high frequency signal processing unit 29. The data input to the high frequency signal processor 29 is output after predetermined signal processing such as amplification and hygiene adjustment, and is then converted and output as a digital signal.

The digital reproduction signal output from the high frequency signal processing unit 29 is input to the demodulation circuit 5, and after demodulating data to 16 bits in the demodulation circuit 5, it is output. Data output from the demodulation circuit 5, that is, sector data, is input to the ID ECC 31, and error correction of the sector address is performed by the ID ECC 31.

On the other hand, the disk has a block which is a minimum data unit that can be accessed by adding IDs in predetermined sector units. Accordingly, the ID information of each sector is firstly corrected to confirm that normal sector data is input, and then signal processing is performed until reproduction is performed, such as error correction of data in units of blocks.

Therefore, the ID ECC 31 performs error correction on the address information of the input sector data to monitor whether or not the data recorded on the disc 1 has been normally played back.

After error correction of the sector address in the ID ECC 31, data is input to the error correction circuit 11, and the error correction circuit 11 bundles the input sector data into 16 units to decode the sector data. do. The sector data in which the decoding process is completed in the error correction circuit 11 is temporarily stored in the VBR buffer 27 and then output to each decoding circuit under the control of the microprocessor unit 9.

The data output to each of the decoding circuits is decoded to the original signal, adjusted to be displayed on the screen, and then output to produce a display in a state desired by the viewers.

While the disc 1 is being played back as described above, the ID ECC 31 has sector data in which error correction of the sector address is performed first, and the microprocessor unit 9 performs the normal playback process of the sector data currently input. It is monitored whether or not the data is caused by data or by abnormal reproduction process due to the track slip of the optical pickup apparatus 3.

This is because the tracks and track intervals of the disc are very narrow, such as 0.725 占 퐉, so that when there is a defect or scratch or the like on the disc, the optical pickup device 3 slides the track being reproduced and records the adjacent track. This is because the read data is generated.

In this way, if the optical pickup device 3 does not know whether the data is discontinuously reproduced by the track slipping and the signal processing is continuously performed according to the data reproduction, the error correction circuit 11 and each decoding circuit, etc. An error occurs during signal processing, because an error occurs during screen playback.

First, the sector data corrected by the ID ECC 31 is input to the microprocessor unit 9. Then, the microprocessor unit 9 recognizes the sector address from the input sector data, and this recognized sector address SN is compared with the non-existing sector address SP which has been stored in the sector address register (not shown). Compare and see if 1 is greater. It is determined that the compared values of the sector addresses are continuous, and at the same time, it is determined that the number of error occurrences IDP due to the track slip until the previous time is "0" (step 100).

When all of the conditions of step 100 are satisfied, the microprocessor unit 9 determines that the optical pickup device 3 currently tracks tracks and reads data, and stores the sector address in the sector address register. Replaces the newly input sector address SN, and simultaneously stores the block address BN calculated from the input sector address SN. The number of error occurrences IDP for the track slip signal compensation is set to 0 (step 102).

Here, the sector and block structure of the DVD data format will be briefly described. Although mentioned above, the sector structure is largely divided into sector information, identification information and user data. The sector address has six digits as a hex (HEX) value. More specifically, in a digital video disc, identification information (ID) is added in a predetermined sector unit to have a minimum data unit that can be accessed. This is called a block. That is, a block is composed of 16 sectors to form a block.

The address of the head of the block is represented by XXXXX0, and the five digits before the sector address in one block always have the same value. Therefore, dividing the sector address by 16 yields the block address.

However, when the sector address after the input error correction does not satisfy the condition of the step 100, that is, when the input sector address SN is not equal to 1 compared with the existing sector address SP, the microprocessor The unit 9 determines whether an error has occurred in the ID ECC process (step 104). That is, it is determined whether an error has occurred in the decoding of the sector address.

If it is determined in step 104 that the error is in the decoding process, that is, if it is determined that the error in the simple decoding process or a very partial error due to a small scratch or the like without large damage to the sector data, It is determined whether the currently input sector data is the head of the block (step 106). As mentioned above, since 16 sector data are gathered to form a block, the case where the sector address is divided by 16 and 0 is the head of the block.

If it is determined that the block is the head in step 106, it is determined whether or not there has been an error caused by track slip before (IDP = 0) (step 108).

If it is determined in step 108 that no error has occurred due to the track slip, the error has occurred in the ID decoding process of the current sector address SN. Judging by the input.

Therefore, since an error has occurred in the decoding process of the currently input sector address, the input sector address is discarded and a value obtained by adding 1 to the existing sector address SP stored in the sector address register is stored as the sector address. Since the input sector address is the head of the block, the block address stored in the block address register stores the stored block address BP as it is, in view of the fact that the block does not compensate for errors in the previous block. Step 110).

When it is determined in step 108 that an error has occurred due to the track slipping (IDP is not 0), an error occurred during the decoding of the sector address, an error occurred secondly, and the input sector address Since it is estimated to be the head of the block, the microprocessor unit 9 instructs the servo unit 7 to back track jump of the optical pickup device 3. At this time, the optical pickup device 3 performs a back track jump to the initial position of the block address stored in the block address register.

The microprocessor unit 9 then initializes the values of the respective functions for detecting the occurrence of an error due to the track slip. That is, the error occurrence number IDP is set to "0", and the sector address SP and the block address BP stored in the sector address register and the block address register store the block address value at the position where the back track jump is performed. Save (step 112).

Next, when it is determined that the sector address is not satisfied and the sector address is discontinuous, and in step 104, it is determined that there is an error in the decoding process of the sector address, and in step 106, it is determined that it is not the head of the block. It is detected how many errors occur due to the track slip up to (step 114).

In step 114, if no error has occurred before, an error in the ID ECC 31 circuit has occurred, it is assumed that the initial sector address is abnormal, and that the currently input sector data is not the head of the block.

Therefore, the sector address SP stored in the sector address register stores a value obtained by adding 1 to the previously stored sector address, and the block address register continues to hold the block address in the stored state. This is because the sector in which the current error has occurred is determined to be included in the same block as the previous sector. The error occurrence number IDP maintains the existing error occurrence number (step 116).

In step 114, if there has been an error (IDP) caused by track slipping once (IDP = 1), an error has occurred in the decoding process of the sector data instead of the first input sector address. It is determined that the error is caused by the second track slip. This is assumed to be an error in the decoding process of data due to scratches or the like existing on the disk.

Therefore, at this time, the sector address stored in the sector address register stores a value obtained by adding 1 to the stored sector address SP, the block address maintains the stored block address as it is, and the number of error occurrences increases by 1. (Step 120).

However, when the next determination is made from the sector data read from the next optical pickup apparatus 3 and inputted after error correction, it is determined that the track is slipped and the back track jump of the optical pickup apparatus is performed. In this case, in step 114, an error occurrence by track slip (IDP) has already occurred twice (IDP = 2), and the currently input sector address is not the head of the block but only in the decoding process of sector data. An error has occurred, but an error has occurred due to the third track slip.

Therefore, at this time, the microprocessor unit 9 outputs the back track jump command of the optical pickup device 3 to the servo unit 7, and the servo unit 7 picks up the optical pickup to the position of the block address stored in the block address register. Move the device 3.

In order to perform error detection due to track slipping from the initial state, the sector address SP and the block address BP stored in the sector address register and the block address register are controlled to take and store the value of the stored block address. In step 118, the error occurrence number IDP due to the track slip is initialized to " 0 ".

Next, when the input sector address does not satisfy the continuous condition of the address in step 100 and the decoding of the sector address is performed without error in step 104, the input sector address is divided by 16 to start the block. It is determined whether the address is an in-sector address (step 122).

When the value obtained by dividing the sector address input by 16 in step 122 is "0", it is determined to be the head of the block, there is no error in the decoding process of the sector address, and the input sector address is abnormal due to discontinuity. Therefore, this is determined as an error due to track slip. Therefore, the microprocessor unit 9 outputs a back track jump signal for controlling to the initial position of the block address where the optical pickup device 3 has been stored. The sector address register and the block address register take and store the stored block address. The error occurrence frequency IDP due to the track slip is initialized to " 0 " (step 124).

When the value obtained by dividing the sector address inputted in step 122 by 16 is not "0", it is determined whether there has been an error occurrence number IDP due to track slip before (step 126).

When the inputted sector address is determined to be an abnormal state for the first time and not in the continuous state by the determination of step 126, there is no error in the decoding process of the sector address, and it is determined that the inputted sector is not the head of the block. The unit 9 replaces and stores the input sector address, the block address maintains the stored block address, and the number of error occurrences due to track slip increases by one (step 130).

Finally, even if the sector address input by the determination of step 126 is not the head of the block, it appears as the second discontinuous state, and since there is no error in the decoding process of the sector address, it is determined that the error is caused by the track slip. A back track jump of the pickup device 3 is performed (step 128). The sector address and the block address store the block address where the optical pickup device 3 performs the back track movement, and the number of error occurrences IDP due to the track slip is initialized to " 0 ".

That is, when there is an error in the sector address decoding process of the ID ECC 31, the microprocessor unit 9 determines that the second sector is determined to be second abnormal even if the input sector data is the head of the block (step 112). If the sector data is not the head of the block but is determined to be abnormal for the third time (step 118), the back track jump of the optical pickup apparatus 3 is performed.

When there is no error in the sector address decoding process of the ID ECC 31, when the input sector data is the head of the block, the first sector data (step 124) that is determined to be abnormal, and the input sector data block In the case where it is determined that the second time is abnormal (step 128), the back track jump of the optical pickup apparatus 3 is performed.

As described above, the back track jump position of the optical pickup device 3 becomes the position of the block address stored in the block address register included in the microprocessor unit 9, and from the initial position of the block address, the optical pickup device ( 3) reads data back. The error occurrence frequency lDP due to track slipping is initialized to " 0 ", the stored value of the sector address register is replaced with the block address, and the stored value of the block address register is maintained as it is.

In this way, the optical pickup apparatus 3 moves the track to the position of the block address including the position at which the track slip is generated, and the operation of reading data from there begins again, and the data read from the optical pickup apparatus 3 again. The signal processing according to signal reproduction is sequentially performed through circuits such as the high frequency signal processor 29 and the demodulation circuit 5.

As described above, the disc data reproducing method according to the present invention detects as soon as possible by using the sector and block address of the disc format to compensate that the optical pickup device does not properly follow the play track and has slipped to an adjacent track. It can work. In particular, the present invention has the advantage of compensating for the presence of the head of the block at the time of the track slip occurs.

Claims (4)

Determining whether the continuity of the sector address of the data input from the disk and the error correction of the address data are normal; and if the error correction of the continuity or the sector address is not normal, an error correction process of the data read from the sector address. Determining whether or not miscorrection is performed by the processor and compensating data according to the miscorrection. The method of claim 1, wherein the data compensating step comprises determining whether a currently inputted sector is the head of a block, and compensating data according to the result. The data compensation step of claim 2, wherein the data compensating step determines a head of a block, reads a previous block again if it is a head, and determines an error correction result of a sector address if it is not a head. And rereading the previous block. 3. The data compensating step of claim 2, wherein the data compensating step determines the head of the block, and if it is the head, determines the error correction result of the sector address, and if it is normal, plays the previous sector address + 1 if it is normal. And reproducing the previous sector address + 1 or reloading the previous block according to the accumulated number of times of error correction result determination if the data is not at the head of the block.