Encoding and decoding system in an optical disk storage device

Details Encoding and decoding system in an optical disk storage device Encoding and decoding system in an optical disk storage device

2000-11-15

2004-12-14

Tran, Thai (Department: 2616)

Motion video signal processing for recording or reproducing

Local trick play processing

With randomly accessible medium

C386S349000, C360S053000, C714S746000, C714S764000, C714S769000, C714S781000

Reexamination Certificate

active

06832042

ABSTRACT:

REFERENCE TO RELATED APPLICATION
The present application claims the benefit of priority under 35 U.S.C. §119 to Taiwan Application No. 089109970 entitled “Encoding and Decoding System In An Optical Disk Storage Device,” filed on May 24, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates in general to encoding and decoding systems for optical disk storage devices, and more particularly to an encoding and decoding system in an optical disk storage device of a compact disk (CD) and digital video disk (DVD) dual system.
2. Description of the Related Art
An optical disk storage device of CD and DVD dual system is capable of encoding/decoding data of either CD or DVD. If it can be more effective in the hardware design of the encoding/decoding system in an optical storage device of the CD and DVD dual system, it leads to a more compact hardware design and thus the area that the hardware requires decreases. For the purpose of a more effective hardware design, the underlying theory for encoding/decoding in all optical disk storage device is first discussed.
For providing reliable and efficient encoding/decoding of the user data, it is necessary to employ error correcting codes in disk storage systems. Although there are many different error correction codes (ECC) for this purpose, Reed-Solomon (RS) codes are the most commonly used ECC in disk storage systems.
With RS codes, input data stream is processed as a sequence of symbols and all of the symbols are elements of a finite field GF(2
w
), where w denotes the number of bits per symbol. An RS code is a (N, K) block code, where an input data block of K message symbols is encoded, resulting in an output data block of N symbols, or called a codeword of length N. Besides, the codeword of N symbols consists of a parity code of 2T=N-K symbols.
Every symbol of the input data block of K message symbols is associated with a coefficient of a polynomial I(x). Similarly, every symbol of the 2T parity symbols is associated with a coefficient of a polynomial R(x). In addition, the N symbols of a codeword are associated with the respective coefficients of a polynomial C(x). The polynomial R(x) is defined by the expression:
R
(
x
)=(
I
(
x
)·
x
m
)
MOD
(
G
(
x
)),
where G(x) is the generator polynomial of degree m and m=2T. The G(x) is expressed as follows:
G
(
x
)=Π
k=0~(2T−1)
(
x+&agr;
k
).
Then, a codeword polynomial is obtained by:
C
(
x
)=(
I
(
x
)·
x
m
)+
R
(
x
).
The above operations is performed by an RS decoder, resulting in a codeword corresponding to the codeword polynomial C(x). On the other hand, an RS decoder receives codewords transmitted through the noisy communication channel, where the received codewords are with random erroneous symbols. For the correction of the erroneous symbols occurred in the received codewords, the RS decoder performs the decoding process including the following steps: (i) compute syndromes S
i
; (ii) compute the coefficients of an error locator polynomial using the syndromes; (iii) compute the roots of the error locator polynomial; (iv) compute the error values by using the roots of the error locator polynomial and the syndromes.
Referring now to
FIG. 1
, it illustrates a conventional structure of the encoding/decoding system in CD/DVD storage devices. During the process of writing data into a disk storage medium, the input data received from a host are first stored in a data buffer
102
via the bus
101
. A cyclic redundancy check (CRC) generator and correction validator
104
then reads the data stored in the data buffer
102
and generates the CRC symbols, where the input data with the CRC symbols are stored in the data buffer
102
again. The input data with the CRC symbols are read from the data buffer
102
, which are randomized by a randomizer/derandomizer
106
. The randomized data are then stored in the data buffer
102
. For different optical storage medium, the writing operation then proceeds to different processes.
If the optical storage medium
108
is a CD, the data stored in the data buffer
102
are processed through a CD P/Q encoder/decoder
110
, a C2 encoder/decoder
112
, an interleaver/deinterleaver
114
, and a C1 encoder/decoder
116
. After that, the processed data are written into the CD. Besides, during encoding, a static random access memory (SRAM)
118
is used for storing the processing data through a bus
117
.
When the optical storage medium
108
is a DVD, the data stored in the data buffer
102
are processed by using a DVD inner/outer encoder/decoder
120
. After processing, the encoded data are written to the DVD. In addition, some DVDs include a burst cutting area (BCA) on the DVDs for optionally storing recording information after the completion of the writing process. If the optical storage medium
108
is a DVD with a BCA, a BCA ECC encoder/decoder
122
can be used to process the recording information. The encoded data appended with the encoded recording information are then written into the DVD.
In the process of writing data into a disk storage medium, the CD P/Q encoder/decoder
110
, the C2 encoder/decoder
112
, the interleaver/deinterleaver
114
, the C1 encoder/decoder
116
, the DVD inner/outer encoder/decoder
120
, and the BCA ECC encoder/decoder
112
employ generator polynomials with respective forms. Besides, different length of symbols are involved in the encoding computation with their respective polynomials.
During the reading of the data stored in a CD/DVD, the process is run in reverse. For the sake of brevity, it will not be described.
In the conventional structure of the error correction system of the CD/DVD storage device shown in
FIG. 1
, there are drawbacks as follows.
(1) When the error correction system is configured for processing data in CD data format, the DVD inner/outer encoder/decoder
120
, and the BCA ECC encoder/decoder
112
are idle. On the other hand, when the system is configured for processing data in DVD data format, the CD P/Q encoder/decoder
110
, the C2 encoder/decoder
112
, the interleaver/deinterleaver
114
, and the C1 encoder/decoder
116
are idle. Thus, no matter what the configuration for processing data in CD/DVD, a part of the circuitry are idle, resulting in the employment of the system components being low in effectiveness.
(2) When the error correction system is configured for processing data in CD data format, the interleaver/deinterleaver
114
spends additional time for access to the data buffer
102
for interleaving or deinterleaving. Thus, this increases the latency of the storage system especially in multimedia applications where large blocks of audio/video data must be read from the storage system. In this way, when the system is employed in the audio/video playback or recording applications, the quality of the playback or recording would be affected.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an encoding/decoding system for an optical storage device, which employs a shareable Reel-Solomon (RS) encoder/decoder. According to the invention, the hardware cost of an encoding/decoding system is lowered and the effectiveness of employment of the hardware components is increased. In addition, the invention involves the integration of interleaving/deinterleaving with C1 encoding/decoding or with C2 encoding/decoding, resulting in the lowering of the latency time.
According to the object of the invention, it provides an encoding/decoding system in an optical disk storage device, for performing compact disc/digital video disk (CD/DVD) encoding/decoding of data which is stored in a data buffer, the encoding/decoding system comprising: a C1 address mapper, a C2 address mapper, a CD P/Q address mapper, a DVD inner/outer address mapper, and a shareable Reel-Solomon (RS) encoder/decoder.
The C1 address mapper is for accessing to the data buffer according to access sequence stored in the C1 address mapper. The C2 address mapper is for accessing to the data buffer according to access sequen

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