KR100224643B1 - Device and method for descrambling digital video disc system - Google Patents

Abstract

Disclosed are an apparatus and method for descrambling a digital video disc system. The apparatus comprising setting data detecting means for detecting setting data for setting a descrambling initial value among identification data of a data sector comprises: a counter for inputting and counting setting data and outputting a counted value; First selection means for selectively outputting one of the setting data input from the storage means storing the descrambling initial value into the setting data detection means and the counted value input from the counter as an initial value address in response to the first selection signal. The block synchronization signal is generated in units of data blocks, and the first selection signal is generated depending on whether the error is corrected, and descrambles are performed by reading an initial value of descrambling from the storage means. Set the initial descrambling value according to the miscorrection of As, this has the effect of de-scrambling the data with reliability.

Description

Descrambling device and method of digital video disc system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to digital video disk (DVD) systems, and more particularly, to a descrambling apparatus and method for a digital video disk system.

Hereinafter, a conventional descrambling method will be described with reference to the accompanying drawings.

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.

In general, the decoding unit stores data input from the disk in memory through EFM (Eight to Fourteen Modulation) plus demodulation, and after the error correction unit block is input, proceeds with error correction and finishes error correction. After data descrambling and error detection code processing, the data is transmitted to the corresponding part according to the DVD system. Here, the descrambled data is output to an MPEG 2 decoder when the DVD system is a DVD player, and output to a host interface when the DVD system is a DVD ROM.

As shown in FIG. 2, the error correction parities P0 and PI are added in units of one block horizontally and 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.

On the other hand, descrambling is performed on the main data 16 (2048 bytes) except for the ID data 10, the reservation data 12, and the EDC parity in one sector. The data of which error correction is completed is subjected to descrambling and EDC check, and the descrambling process determines the first descrambling mode among the ID data 10 of the sector.

Therefore, if an error exists in the ID data 10, the possibility that the data of all sectors is error processed is narrowed. Therefore, by adding a separate ECC parity for the ID data 10, error correction is made once again in addition to the ECC for the main data 16.

However, in the conventional error correction method, since error correction for the ID data 10 always has a possibility of miscorrection, when the descrambling is performed only by correcting the ID data 10 by error correction, the data of all sectors is lost. There is a possibility that it can not be used.

An object of the present invention is to provide a descrambling apparatus for a digital video disc system capable of stably generating a descrambling initial value regardless of the presence or absence of an error in data.

Another object of the present invention is to provide a descrambling method performed in a descrambling apparatus of the digital video disc system.

1 shows a DVD data sector.

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

3 is a conceptual diagram of an example of a conventional scrambler.

4 is a conceptual diagram of another example of a conventional scrambler.

5 is a circuit diagram of a preferred embodiment of the descrambling apparatus according to the present invention.

Fig. 6 is a diagram for explaining 4-byte ID data.

In order to achieve the above object, the descrambling apparatus of the digital video disc system according to the present invention includes setting data detecting means for detecting setting data for setting a descrambling initial value among identification data of the data sector. A counter for inputting and counting and outputting a counted value, storage means for storing the descrambling initial value at an initial value address, the setting data inputted from the setting data detecting means and the counted inputted from the counter A first selection means for selectively outputting one of a value as the initial value address in response to a first selection signal, a block synchronization signal is generated in units of data blocks, and the first selection signal is generated depending on whether or not an error is corrected. The descrambling seconds from the storage means It is preferable to perform descrambling by reading a preset value.

In order to achieve the above another object, in a digital video disc system including setting data detecting means for detecting setting data for setting a descrambling initial value in identification data of a data sector, storing for storing the descrambling initial value at an initial address. The descrambling method according to the present invention carried out after an error correction step of determining the presence or absence of an error in a descrambling apparatus including means comprises: counting the configuration data in data block units if the error exists; Performing descrambling using the descrambling initial value read using a counted value as the initial address, and if the error does not exist, descrambled initial value read using the configuration data as the initial address. To perform descrambling It is preferably made of a step.

Hereinafter, with reference to the accompanying drawings the configuration and operation of the descrambling method and apparatus for performing the same according to the present invention will be described as follows.

Before describing the descrambling apparatus and method according to the present invention, scrambling will be described as follows.

3 is a conceptual diagram of an example of a conventional scrambler, and is composed of 15 buffers BO to B14 and two exclusive logical sums 30 and 32.

The scrambling processing unit performed in the scrambler shown in FIG. 3 is performed in units of one sector, and scrambling processing is performed only on the main data 16 except for the ID data 10, the reservation data 12, and the EDC parity among one sector. . To this end, an arbitrary initial value is set in the scramble register, that is, the buffers shown in FIG. 3, and a combination of the shifting process and the scrambling data is performed based on the initial value.

For example, by default, an arbitrary initial value is set in 32 register stages, and the initial value stored in this register is serially shifted in the direction of the arrow as shown in FIG. 3 one byte per time, and the shifted initial value is exclusive-OR. After the exclusive OR with the main data input through the input terminal IN in the 30 and 32, the result of the exclusive OR is output as the scrambled data through the output terminal OUT.

4 is a conceptual diagram of another example of a conventional scrambler, and is composed of fifteen buffers B0 to B15 and eight exclusive ORs 40, 42, 44, 46, 48, 50, 52, and 54.

Since the scrambler shown in FIG. 4 performs the shifting operation in parallel unlike the scrambler shown in FIG. 3, scrambling can be performed much faster. To this end, each exclusive OR sums the corresponding input terminal and the output of the buffer simultaneously and outputs the result through the corresponding output terminal as scrambled data. For example, the first exclusive OR 42 performs an exclusive OR on the output of the seventh buffer B7 and the data input through the input terminal IN7 and outputs b7 + IN7 through the output terminal OUT1 (where b7 is the value of the seventh buffer). Output, and IN7 represents the data input through input terminal IN7.)

5 is a circuit diagram of a preferred embodiment of the descrambling apparatus according to the present invention, including a counter 70, first and second multiplexers (MUX: MUlplepleXers) 72 and 76, a ROM 74, a D It consists of a scrambling register 78 and an exclusive OR 80.

FIG. 6 is a diagram for describing the 4-byte ID data 10. The three bytes 104, 106, and 108 of the least significant bit (LSB) representing the sector number 100 and the remaining bytes ( 102).

The counter 70 and the first MUX 72 shown in FIG. 5 are the 4-bit setting data 110 shown in FIG. 6 detected to set the descrambling initial value of the identification data of the data sector through the input terminal IN1. Enter. That is, the setting data detection unit (not shown) inputs the 4-byte ID data 10 shown in FIG. 6 to detect the most significant 4 bits 110 of the 1 byte 108 of the least significant bit side, and this is the first MUX. Output to 72 and the counter 70.

The counter 70 increases the input 4-bit setting data 110 by 1 in response to a block sync signal (BS: Block Sync) generated in units of blocks and outputs the counted value to the first MUX 72. . This is to change the initial value in blocks. Here, the counting operation and the setting data detection operation are performed at the same time.

Meanwhile, the first MUX 72 selectively selects one of the setting data input through the input terminal IN1 and the counted value output from the counter 70 as an initial address of the ROM 74 in response to the first selection signal S1. Output Here, error correction is performed before the descrambling method is performed, where an existence of an error is determined.

If there is an error, the first selection signal causes the output of the counter 70 to be selected and output. If there is no error, the first selection signal causes the setting data input through the input terminal IN1 to be selected and output. Here, it is also possible to count one by one block synchronization unit on the basis of ID data 10 of the first block and use it as an initial address for an initial value at the time of descrambling. This is because it is the same as the ID data obtained from the data actually input.

In the initial address (or ID data) of the ROM 74 output from the first MUX 72, for example, an initial value is stored as shown in Table 1 below, and the stored initial value is read out and output to the second MUX 76. .

Initial address Initial value (Hex) Initial address Initial value (Hex) 0 One 8 10 One 5500 9 5000 2 2 A 20 3 2A00 B 2001 4 4 C 40 5 5400 D 4002 6 8 E 80 7 2800 F 5

Meanwhile, the second MUX 76 inputs an initial value read from the ROM 74 and an output of the descrambling register 78, and selectively descrambles one of the input data in response to the second selection signal S2. Output to register 78. That is, the second selection signal is generated such that the second MUX 76 selects the output of the ROM 74 in the initial state for descrambling, and selects and outputs the output of the descrambling register 78 in the shifting state.

The exclusive OR 80 performs an exclusive OR on the data input through the input terminal IN2 and the data output from the descrambling register 78, and outputs the result through the output terminal OUT as descrambled data.

That is, in the descrambling method according to the present invention, if an error exists first, setting data is counted in data block units, and descrambling is performed using the initial value read using the counted value as an initial address. However, if no error exists, descrambling is performed using the initial value read out using the configuration data as the initial address.

The descrambling apparatus and method according to the present invention described above can be used both in a digital video disc player or a digital video disc ROM.

As described above, the descrambling apparatus and method of the digital video disc system according to the present invention have an effect of reliably descrambling data by setting an initial value of descrambling corresponding to whether or not misidentification of identification data occurs.

Claims (5)

A descrambling apparatus of a digital video disc system, comprising setting data detecting means for detecting setting data for setting an initial value of descrambling among identification data of a data sector. A counter for inputting and counting the setting data and outputting a counted value; Storage means for storing the descrambling initial value at an initial value address; And First selecting means for selectively outputting, as the initial value address, one of the setting data input from the setting data detecting means and the counted value input from the counter in response to a first selection signal, The block synchronization signal is generated in units of data blocks, and the first selection signal is generated depending on whether an error is corrected, and the digital video disc system reads out the descrambling initial value from the storage means and performs descrambling. Descrambling device. The descrambling apparatus of claim 1, wherein the descrambling apparatus outputs the descrambled data to an MPEG 2 decoder. The descrambling apparatus of claim 1, wherein the descrambling apparatus outputs the descrambled data to a host interface. The method of claim 1, wherein the descrambling device Second selection means for inputting descrambling data and the initial value of the descrambling read out from the storage means and selectively outputting the descrambling data in response to a second selection signal; A descrambling register for inputting and latching an output of the second selection means and outputting the latched data as the descrambling data; And And an exclusive logical sum of the descrambling data and the data input from the system, and outputting an exclusive logical sum signal as descrambled data. And the second selection signal is generated according to whether the descrambling device is in an initial state or a shifting state. A descrambling apparatus comprising storage means for storing a descrambling initial value at an initial address in a digital video disk system including setting data detecting means for detecting setting data for setting an initial value of descrambling among identification data of a data sector. In the descrambling method performed after the error correction step of determining the presence of an error in Counting the configuration data in data block units if the error exists; Performing descrambling using the descrambling initial value read using the counted value as the initial address; And And if the error does not exist, performing descrambling using the initial value of the descrambling read out from the configuration data as the initial address.