KR20000055185A - Method for correcting error in reproduced data - Google Patents

Abstract

PURPOSE: A method for correcting the error of read data is provided to carry out duplicated error correction process for read data outputted from an optical disk by means of a smaller capacity of storage unit. CONSTITUTION: According to a read request after the insertion of an optical disk(10), an error correction unit pack of symbol 182 read from a pickup unit(11) is filtered in an R/F unit(20), converted into a digital bit stream in a bit restorer(50) and demodulated into a symbol data of 8 bit in an ESM demodulator(60). A PI decoder(81) in an RS decoder(80) carries out error correction for the demodulated and outputted error correction unit pack, but stores a result data pack of symbol 172 in sequence from the first row in a buffer(85) of the RS decoder(80), excepting a parity data from the error correction result data pack. If the result data of symbol 172 are stored and completed 208 times, the PO decoder(84) carries out error correction for the stored data.

Description

Method for correcting error in reproduced data

The present invention relates to an error correction method of reproduction data, and more particularly, to double error correction of pre-error correction and post-error correction of reproduction data read and reproduced from an optical disc, without conflict in a single storage means. The present invention relates to an error correction method of reproduction data for changing the format of storing and reading error corrections before and after the storage and reading are performed to correct the errors.

In general, recording data on an optical disc (DVD) is encoded in a predetermined format. In encoding the recording data, a Reed Solomon (referred to as a double encoding scheme using an outer parity code (PO) and an inter parity code (PI) encoder) is used. Reed-Solomon) code is used.

In the recording data encoding method using the Reed Solomon (RS) code, the PO encoder PO in the RS encoder first generates parity of 16 symbols in units of 192 symbols (or codewords) from the input recording data. The coded unit pack data of the coded 208 symbols is sequentially stored in a column in a buffer in the RS encoder.

According to the repetition of the above process, when 208 symbols of unit data of 208 symbols are sequentially stored in the buffer in the RS encoder, the PI encoder PI encodes the unit data sequentially encoded and stored in the column from the PO encoder PO. A parity of 10 symbols is selected for the selected data in units of 172 symbols of the first row, and subsequently encoded.

In this way, the RS encoder double-codes the input recording data to generate and output one error correction unit block (1 ECC block (172 bytes x 192 bytes (12row x 16 Data Sectors)) having a format as shown in FIG. Each symbol data of 8 bits in the generated error correction unit block is converted (ESM) into 16 bits of data scheduled to be corresponding thereto and recorded on the optical disk.

Fig. 2 shows a general configuration of an optical disc reproducing apparatus in which double-encoded data is recorded in the above-described manner, and a pickup section 11 for injecting a light source into the inserted optical disc 10 to read out a recording signal. ); An R / F unit 20 for filtering the signal detected by the pickup unit 11; A drive unit 30 for driving motors 12a and 12b for moving or rotating the pickup unit 11 and the inserted optical disc 10, respectively; The drive of the drive unit 30 is controlled from the output signal of the R / F unit 20 and the rotational speed of the optical disk 10, and the synchronization of the output signal of the R / F unit 20 is detected. Servo unit 40; A bit decompressor 50 for detecting a synchronization signal from the output analog signal of the R / F unit 20 and restoring a bit stream from the RF signal; An ESM demodulator (60) for demodulating a 16-bit signal into an 8-bit signal in the bit stream; An RS decoder (80) for performing error detection and correction on the demodulated data in an error correction block unit; And a control unit 70 for controlling the movement of data to the buffers B1 and B2 in the RS decoder 80.

In the optical disc reproducing apparatus configured as described above, first, when the optical disc 10 is inserted and then a reproduction request is made, the control unit 70 controls the pickup unit 11 to retrieve a track from the data area of the optical disc. Accordingly, an error correction unit pack (comprising 172 symbols of playback data and 10 symbols of parity data) is sequentially read out, and the signal read out by the pickup unit 11 is R. After filtering by the / F unit 20, the data strobe unit 50 recovers the digital bitstream and outputs the converted ESM-converted digital data.

The ESM demodulator 60 demodulates the input 16-bit digital conversion data into 8-bit symbol data corresponding thereto. The data demodulation of the ESM demodulator 60 is a predetermined ESM conversion table. It is based on.

The ESM demodulated digital data is applied to the PI decoder 81 in the RS decoder 80, and the PI decoder 81 is an error correction unit pack unit in the input data. Based on the parity data of the above, by performing the line error correction, the reproduced data having the error is restored and output to the original normal data, and the result data pack which is line error corrected and output from the PI decoder 81 is outputted as the error. The parity data in the correction unit pack is sequentially stored in the first buffer 82 in the RS decoder 80. The first buffer 82 has a size of (172 + 10) × (192 + 16) symbols, and the second buffer 83 has the same size. For the convenience of explanation of the reading and storing process of the buffer, the access in order according to the structure of the buffer is expressed as 'row' access, and the access by skipping the address by 182 as the 'row' access. Shall be.

According to the repetition of the line error correction process, when 182 symbols of data size are stored 208 times in the first buffer 82, that is, the data stored in the first buffer 82 forms the configuration of FIG. 2. In this case, the contents of the stored data in the first buffer 82 are prevented from being updated by a unit pack in which error correction data of the ESM demodulation data is corrected, and error correction is performed on the error corrected result data, which will be described later. For this purpose, the controller 70 reads out all the error correction unit block data of FIG. 2 which are sequentially stored, and copies and stores them in the second buffer 83 in the RS decoder 80.

When the same data as the first buffer 82 is copied to the second buffer 83, the PO decoder 84 in the RS decoder 80 corrects an error of 208 symbols from the first column of the second buffer 83. By selecting a unit pack and performing error correction on the selected error correction unit pack based on parity data of 16 symbols in the selected error correction unit pack, the reproduced data having an error is restored to the original normal data. .

By the way, in the conventional error correction method of the reproduction data made as described above, in order to perform error correction on the input data twice as described above, it has a size of (172 + 10) × (192 + 16) symbols. Since there are two buffers, that is, the total capacity of the buffers should be 2 × ((172 + 10) × (192 + 16)) symbols, there is a problem that the cost of the playback apparatus increases.

Accordingly, the present invention was created to solve the above problems, and the error correction of the reproduction data is performed such that a double error correction process for the reproduction data read and reproduced from the optical disc is performed by using a smaller capacity storage means. The purpose is to provide a method.

FIG. 1 shows the form of data of one ECC block double-coded by RS (Reed-Solomon) coding method.

2 shows a general configuration of an optical disc reproducing apparatus,

3 is a block diagram of an optical disk reproducing apparatus in which an error correction method of reproduction data according to the present invention is implemented;

FIG. 4 is a diagram showing a storage and reading method that is alternately made in a single buffer in the RS decoder of the playback apparatus of FIG.

※ Explanation of code for main part of drawing

10 optical disc 11: pickup portion

20: R / F section 30: drive section

40: servo unit 50: bit recoverer

60: ESM demodulator 70: control unit

80: RS decoder 81: PI (Inter Parity) decoder

84: PO (Outer Parity) decoder 82,83,85: buffer

The error correction method of the reproduction data according to the present invention for achieving the above object, the error correction unit pack of the input of the reproduction data to perform the error correction (pre-correction), while the error correction result data pack arbitrary A first step of sequentially storing the rows in the storage means of the; After performing the first step for a predetermined number of error correction unit packs, a first error correction is performed on the error correction unit pack of the inputted reproduction data, and as a result, the data packs are sequentially loaded in the storage means. A second step of storing; After completion of storing the line error corrected result data pack until the last column of the storage means, sequentially storing the error corrected result data pack in rows in the remaining area of the storage means not stored by the second step. Third step; And a fourth step of repeating the first step until the reproduction stop request of the playback data.

In the error correction method of the reproduction data according to the present invention as described above, the first error correction unit pack of the error correction unit pack of the reproduction data read and reproduced from the first inserted optical disk, and the line error correction result data pack Are stored sequentially from the first row of any storage means. According to the repetition of the above process for a predetermined number of error correction unit packs, the storage of the error-corrected result data pack is completed until the last row of the storage means. The resultant data packs are sequentially stored from the columns of the free area of the storage means which are secured according to the reading of the error correction data after performing the columns.

According to the repetition of the above process for a predetermined number of error correction unit packs, the storage of the error corrected result data pack is completed up to the last column of the storage means, and then read from the optical disc and reproduced. The resultant data pack is sequentially stored from the first row of the remaining area of the storage means, and when this process is completed, the spare area of the storage means secured by reading the data of the error correction is performed after skipping rows and columns. The error correction result data pack is stored sequentially from the row of.

Best Mode for Carrying Out the Invention Preferred embodiments of the error correction method of reproduction data according to the present invention will be described in detail with reference to the accompanying drawings.

Fig. 3 shows the configuration of an optical disc reproducing apparatus in which an error correction method of reproduction data according to the present invention is implemented, wherein buffer 85 in RS decoder 80 is (n + 1) × ((m + 1). The configuration is the same as that of FIG. 2 except that it is constituted by one buffer having a + (q + 1)) symbol (n = 171, m = 191, q = 15).

Referring to the error correction method according to the invention made in the configuration of Figure 3 in detail as follows.

First, in response to a regeneration request after insertion of the optical disc 10, the error correction unit pack 182 symbols read and reproduced from the pickup unit 11 are filtered by the R / F unit 20 as described above. After being formatted and converted into a digital bit stream in the bit decompressor 50, 16 bits of digital data are demodulated and output into 8 bits of symbol data in the ESM demodulator 60.

The PI decoder 81 in the RS decoder 80 performs error correction in the same manner as in the conventional method described above with respect to the error correction unit pack of the 182 symbols to be demodulated and output, except that in the error correction result data pack. Except for the parity data, as shown in Fig. 4A, the result data of the 172 symbols is sequentially stored in the buffer 85 in the RS decoder 80 from the first row.

As such, if the resultant data pack of 172 symbols, which is as large as the storage capacity of the buffer 85, has been stored 208 times, the PO decoder 84 will post-error the same as in the conventional method described above for the stored data. Correction will be performed.

However, even after performing the error correction after the PO decoder 84, the PI decoder 81 continues to read the result data of the 172 symbols that are read-reproduced from the optical disk 10 and corrected in advance to the buffer 85. In order to prevent the contents of the previous error correction unit block from being updated, the result data of the above-mentioned error correction unit 172 symbol is stored in a row as in the previous error correction unit block. In the error correction process of the PO decoder 84 performed immediately before, instead of sequentially storing, 208 symbol data corresponding to the column are read from the first column of the buffer 85, and the buffer 85 corresponding to the column is read. ), The PI decoder 81 stores the line error-corrected 172 symbol data starting from the first column of the buffer 85 at this time.

By repeating this process, when the pre-correction of the line error correction data is completed from the first column to the last (172th) column of the buffer 85, that is, when 172 symbol data have been stored 172 times (at this time, All data (= 208 symbol data x 172 times) have been read for error correction, and the PI decoder 81 has the first row on the remaining area of the buffer 85 for the 172 symbol data output after error correction. The buffer 85 has a size of 172 × 208 symbols, and when the 172 symbol data packs that are sequentially stored in the columns of the buffer 85 are stored 172 times, the buffer 85 has 172 symbols. The second and subsequent rows have a residual area of size (208-172) x 172, and from this area, the PI decoder 81 sequentially stores the result data corrected for the line error again in rows.

By repeating this process, when the 172 symbol data packs are stored 36 x (208-172) times in the remaining area of the buffer 85, the PO decoder 84 stores the stored data of the buffer 85. After reading sequentially, error correction is performed. When the PO decoder 84 reads data from the buffer 85, the buffer 85 performs the buffer 85 as shown in FIG. The 172 symbol data and the symbol data in the row area after the 172th row are sequentially read as 36 symbol data in columns, and the 172 symbol data and the 36 symbol data are configured as one error correction unit pack. Then, the error correction unit pack of 208 symbols configured as described above is performed in the same manner as described above.

When the error correction process of the PO decoder 82 is performed 172 times, since error correction for the error correction unit block on the buffer 85 is completed, the PI decoder 81 is executed at the same time. As a result of the 173 th error correction, the data for the later error correction process is not updated even when the data pack is stored in the row of the data pack. After storing and reading the data as shown in FIG. The same storage and reading is done alternately with each other.

In the error correction method of the reproduction data according to the present invention as described above, the double error correction for the reproduction data read and reproduced from the optical disc is performed by using a single storage means having a smaller capacity, and according to the double error correction Since there is no need to provide a separate storage means, it is a very useful invention that the cost of the device accordingly is reduced.

Claims (8)

In the decoding method of reproduction data, A first step of sequentially storing the error corrected result data packs in a row in any storage means while performing error correction on the error correction unit pack of the inputted reproduction data; After performing the first step for a predetermined number of error correction unit packs, a first error correction is performed on the error correction unit pack of the inputted reproduction data, and as a result, the data packs are sequentially loaded in the storage means. A second step of storing; After completion of storing the line error corrected result data pack until the last column of the storage means, sequentially storing the error corrected result data pack in rows in the remaining area of the storage means not stored by the second step. Third step; And And a fourth step of repeating from the first step until the reproduction stop request of the playback data. The method of claim 1, In the first step, immediately after the completion of the sequential storage of the line error correction result data pack into the row of the storage means, the stored error correction result data pack is read from the first column of the storage means to perform subsequent error correction. Error correction method of the reproduction data characterized in that it further comprises the step of performing. The method of claim 2, The post-error correction of the data pack read out from the first column of the storage means in the post-error correction performing step is performed before performing the previous error correction on the error correction unit pack in the second step. Error correction method of playback data. The method of claim 1, In the third step, immediately after completion of sequential storage of the line error correction result data pack into the row of the storage means, the error correction result data packs stored in the second and third steps are respectively stored from the first row and column of the storage means. And reading out the error correcting unit pack, and performing error correction afterwards. The method of claim 4, wherein The error correction unit of the error correction unit pack configured to read out from the first row and the column of the storage means in the subsequent error correction performing step is the error correction unit in the first step according to the repetition from the first step. An error correction method for playback data, characterized in that it is performed prior to performing an earlier error correction on a pack. The method of claim 1, The first step is to perform a line error correction for the error correction unit pack consisting of the playback data of the N symbol size and the parity data of the K symbol size, and sequentially storing the data pack of the error correction result of the N symbol size in the storage means. Error correction method of the playback data, characterized in that. The method of claim 6, And the capacity of the storage means has a symbol size of Nx (the number of unit packs in a single error correction block). In the decoding method of reproduction data, Pre-error correction and post-error correction for the error correction unit pack of the inputted reproduction data are shared by a single storage means, but after the result data is stored after storing the result data in the storage means according to the pre-error correction. The error correction method of the reproduction data, wherein the reading and storing positions of the storage means by correction and pre-error correction are spaced apart by at least one error correction unit pack.