KR19980065723A - Method and apparatus for processing data in digital video disc system - Google Patents

Abstract

Disclosed are a data processing method and apparatus of a digital video disc system. The method performed in a digital video disc system having a buffer memory includes the steps of reading data from the disc and demodulating the EFM, writing the demodulated data to the buffer memory, reading the written data, and calculating syndromes. Detecting identification data, calculating the location and error size of the error using a syndrome, searching the chain, performing error correction, calculating, descrambles the syndrome, and error detection code And a step of writing data into the buffer memory, and since ECC, EDC, and descrambling are performed by one DRAM access, the number of cases of accessing the DRAM is reduced and one access is performed. As a result, as much data can be read as possible, thereby improving the data processing speed.

Description

Method and apparatus for processing data in digital video disc system

The present invention relates to a digital video disk (DVD) system, and more particularly, to a data processing method and apparatus of a DVD system.

FIG. 1 shows a DVD data sector, which is composed of identification (ID) data 10, reserved (RSV: reserved) data 12, error detection code 14, and main data 16. As shown in FIG.

FIG. 2 is a diagram showing a DVD Error Correction Code (ECC) block, which is composed of an information field 20 and parity bits P0 and PI.

In the DVD system, data processing proceeds on the basis of sectors and blocks, as shown in Figs. 1 and 2, respectively.

As shown in FIG. 2, 16 data in sector units shown in FIG. 1 form one information data area 20, and external and internal parities P0 and PI are transverse to increase the reliability of such information data. Are added in units of one block vertically, and an Error Detection Code (EDC) is added in units of one sector. Here, ECC is a code used for error location, error value and error correction, EDC is a code used to detect the presence or absence of an error.

In the conventional data processing method of the DVD system, the modulated data read from the disk is stored in the memory through EFM (Eight to Fourteen Modulation) plus demodulation, and error correction of identification data is performed for synchronous protection. . After the EFM demodulation, the ECC process on the main data 16 determines whether there is an error in the entire data and corrects the error. Finally, the data that has been corrected has been checked for error through descrambling and error detection code processing. After the inspection, it is transmitted to the corresponding part, such as an audio / video (A / V) decoder or ATAPI, depending on the DVD system. In order to control the buffer memory, the above-described series of data processing must be performed at the same time, and priority control is performed to process them according to the priority.

In the above-described series of data processing procedures, access to the required buffer memory includes writing EFM demodulated data, reading ECC data, writing ECC data, reading for descrambling EDC, writing descrambling EDC data, and A / V decoder. Alternatively, there are various forms such as reading for data transfer to the ATAPI decoder and refreshing the DRAM. Therefore, the more types of these accesses, the lower the efficiency of using the buffer memory.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a data processing method of a DVD system which performs error correction, descrambling, and error detection by one DRAM access during data processing on a DVD.

Another object of the present invention is to provide a data processing apparatus of a DVD system which performs the data processing method of the DVD system.

1 shows a DVD data sector.

2 is a diagram illustrating a DVD error correction code block.

3 is a flowchart for explaining a data processing method of the DVD system according to the present invention.

4 is a block diagram of a data processing apparatus according to the present invention in which the method shown in FIG. 3 is performed.

FIG. 5 is a block diagram of the descrambling unit shown in FIG. 4.

In order to achieve the above object, a data processing method of a DVD system according to the present invention carried out in a digital video disk (DVD) system having a buffer memory comprises the steps of: reading data from a disk and performing EFM demodulation; Writing to a buffer memory, reading the written data to calculate a syndrome, detecting identification data, calculating a position and error size of the error using the syndrome, searching for a chain, and , Performing error correction, calculating the syndrome, descrambles, checking an error detection code, and writing the data to the buffer memory.

In order to achieve the above object, a data processing apparatus of a DVD system according to the present invention, which is performed in a DVD system, includes an EFM demodulation means for EFM demodulating data read from a disc, and a buffer for storing data output from the EFM demodulation means. A memory, memory control means for controlling data writing / reading of the buffer memory, syndrome calculation means for calculating syndromes of data stored in the buffer memory and error corrected data, and a syndrome output from the syndrome calculation means. Error position and error value calculation means for calculating an error position and an error value using the same, chain search means for chain searching using the error position and error value, and errors in the chain searched data to correct the error correction. Error correction means for outputting as data, said error corrected data and identification Descrambling means for inputting and descrambling the input, error detecting means for inputting the descrambling means and the error-corrected data to detect an error, and an error corresponding to the presence or absence of an error in response to the output of the error detecting means. Error flag generating means for generating a presence or absence plaque, a buffer for temporarily storing before outputting the error detection means and the error presence flag, and identification data stored in the buffer memory are temporarily stored and outputted to the descrambling means. It is preferable that it is comprised of the register for identification data.

Hereinafter, a data processing method of a digital video disc system according to the present invention will be described with reference to the accompanying drawings.

FIG. 3 is a flowchart for explaining a data processing method of a DVD system according to the present invention, comprising calculating error positions and error sizes of data demodulated from a disk (steps 40 to 46) and deciding error corrected data. Scrambling and writing to the memory (steps 48 to 54).

FIG. 4 is a block diagram of a data processing apparatus according to the present invention in which the method shown in FIG. 3 is performed. The EFM demodulator 60 and the data output from the EFM demodulator 60 perform EFM demodulation of data read from a disk. Buffer memory 62 for storing data, memory controller 64 for controlling data write / read of buffer memory 62, data transfer unit 66, syndromes of data stored in buffer memory 62 and error corrected data; The error calculation unit 70 calculates the error position and the error value by using the syndrome output unit 70 and the syndrome calculation unit 70 calculates the error position and error value using the error position and error value. A main error correction unit 68 comprising a chain search unit 74 for performing a chain search, an error correction unit 76 for correcting errors in the chain searched data, and outputting the data as error corrected data; Enter identification data Before transmitting the output of the descrambling unit 78, the descrambling unit 78, and the error-corrected data to detect the presence or absence of the error detection unit 80, the error detection unit 80, and the error presence flag Temporarily stores identification data stored in the buffer 82 for temporarily storing, the error flag generator 84 for generating an error presence flag in response to the presence of an error, and the buffer memory 62 in response to the output of the error detector 80. And an identification data register 86 which is output to the descrambling section 78.

FIG. 5 is a block diagram of the descrambling unit 78 illustrated in FIG. 4, wherein the first multiplexer (MUX) 100, the counter 102, the ROM 104, the second multiplexer 106, and the disc are shown in FIG. 4. It consists of a scrambling register 108 and a synthesizer 110.

First, data is read from the disk and subjected to EFM demodulation (step 40). After the forty-second step, the EFM demodulated data is written to the buffer memory 62 (step 42). After the forty-second step, the data is read for the syndrome calculation for error correction, and at this time, the original data of the descrambling register 108 shown in FIG. 5 of the descrambling register is fetched by patching the unique data of the sector for descrambling. Set. That is, after step 42, the syndrome calculating unit 70 calculates the syndrome and the identification data is detected (step 44). After step 44, the error position and error value calculation unit 72 shown in Fig. 4 calculates the error position and error value (step 46). After the forty sixth step, the chain search portion 74 searches for the chain (step 48). After step 48, the error correction unit 76 corrects an error (step 50). Here, since the error correction is performed in units of blocks, the initial value set by the unique data of the first sector of the block is the same in the next scrambling of data of 16 sectors.

The descrambling register 108 has the initial value set and waits until the error correction for the main data is completed. In error correction, when the error of the data is corrected using the internal parity, the error of the data is corrected using the external parity, and when the error is corrected again using the internal parity, the data at the last internal parity correction When data is input to the syndrome calculation unit 70 for confirmation, it is also input to the descrambling unit 78 and the error detection unit 80, so that the syndrome calculation, the descrambling, and the error detection code are simultaneously checked ( Step 52). However, when the error correction code is read, the parity of the main data and the internal and external parity codes are also read. Therefore, only the data corresponding to the main data needs to be read by the descrambler 78 and the error detector 80. This can be controlled by the counter 102 at the time of checking the descrambler and the error detection code. In the case of the error detection unit 80, the entire 2064 bytes are read from the head byte of the sector, and in the case of the descrambling unit 78. Reads only main data (2048 bytes). After step 52, data is written into memory (step 54).

As a result, in the data processing method and apparatus according to the present invention, after the final error correction, the data is used as it is as input data for descrambling and error detection code check. That is, as shown in FIG. 4, for error correction, the read data is subjected to error correction by determining the position and size of the error, and to determine whether the corrected data is corrected or not. It is fed back to calculate.

Further, the corrected data at this time is simultaneously inputted to the descrambling section 78, and is stored in 2048 bytes based on the initial value of the descrambling register 108 set by the unique data which has already completed the error correction processing in the EFM block. Start descrambling for

At the same time as the descrambling process, the error detection code process is performed at the same time. The DVD generates an error detection code parity as shown in Equation 1 below.

[Equation 1]

G (X) = X ³² + X ³¹ + X ⁴ + 1

The error detector 80 may be implemented as a division circuit for dividing X ³² by G (X) as a general error detection algorithm.

The buffer memory 64 stores data in units of blocks, and in the case of data for DVD, when 4MDRAM is used as the memory size, about 13 blocks of data can be stored. When reading data for error correction, in case of DRAM, reading in the column direction (error correction using internal parity) and in the row direction (error correction using external parity) coexist. When DRAM is used as 62, the precondition is that the last correction must be terminated by internal parity at the time of repeated correction of error correction.

This is because, when correcting the external parity, data is read in the row direction, and thus data for one sector is not read sequentially, and thus descrambling and error detection code processing are impossible. In the case of DVD, the final iterative correction is generally an internal parity correction.

The first MUX 100 shown in FIG. 5 selectively outputs the output of the unique data and the counter input through the input terminal IN1 to the ROM 104 in response to a unique error correction code flag. The initial value of the descrambling unit 78 is set as the unique data, and the process of descrambling is sequentially implemented through the shifting of the register 108. The error detector 80 is a device for checking an error detection code of a general type formed by G (X).

In the data processing method and apparatus according to the present invention described above, the data read out by the ECC is performed by performing descrambling and EDC before writing the corrected data through a series of ECC processes, and then writing the data after all data processing processes are completed. Eliminates descrambling, memory access by EDC.

As described above, the data processing method and apparatus of the digital video disc system according to the present invention integrates the priority of ECC, descrambling and EDC into one during the data processing in the DVD system. Since ECC, EDC, and descrambling are performed, the number of accesses to the DRAM is reduced, and as much data can be read as possible by one access, thereby improving the data processing speed.

Claims (2)

A data processing method of a DVD system performed in a digital video disk (DVD) system having a buffer memory, comprising: reading data from a disk and performing EFM demodulation; Writing the demodulated data to the buffer memory; Reading the written data to calculate a syndrome and detecting identification data; Calculating a location and an error magnitude of an error using the syndrome; Searching the chain; Performing error correction; Calculating, descrambling, and checking an error detection code; And writing the data into the buffer memory. A data processing apparatus of a DVD system performed in a digital video disk (DVD) system, comprising: EFM demodulation means for EFM demodulating data read from a disk; A buffer memory for storing data output from the EFM demodulation means; Memory control means for controlling data write / read of the buffer memory; Syndrome calculation means for calculating syndromes of data stored in the buffer memory and error corrected data, respectively; Error position and error value calculating means for calculating an error position and an error value using a syndrome outputted from the syndrome calculating means; Chain search means for chain search using the error position and error value; Error correction means for correcting an error of the chain searched data and outputting the error corrected data; Descrambling means for inputting and descrambling the error corrected data and identification data; Error detecting means for detecting the presence or absence of an error by inputting the descrambling means and the error corrected data; Error flag generating means for generating an error-free plaque corresponding to the presence or absence of an error in response to the output of the error detecting means; A buffer for temporarily storing the output of the error detecting means and before transmitting the error presence flag; And a register for identification data which temporarily stores identification data stored in the buffer memory and outputs the identification data to the descrambling means.