Multilevel modulation coding is the core technology for multilevel optical storage. The technology is employed to
increase the capacity of the read-only disc with no change on original recording symbols size. With the combination of
multilevel modulation and the run-length limited modulation, short run-length with low levels can form long run-length
with high levels while it also suitable for long run-length by short run-lengths. And the DC-suppression can be controlled
by the allowance of long run-length without sacrifice effective bits. This double-modulation scheme not only can
improve coding efficiency, but also can greatly increase the recording density. In this paper, the theory of multilevel
run-length limited modulation coding is discussed. And a high rate of 6/7, five level (1,8) code scheme is proposed. This
scheme can increase the recording density compared to that in of DVD. Therefore, it is expected that this proposed
scheme could be used for the next high-density multilevel run-length limited modulation optical storage system.
This article introduces DVD Download specification and Manufacturing On Demand (MOD) system firstly. Then it will
show a designed MOD system and analyze the function of each part in it. In this system, we need to combine two DVD's
files into one disc automatically, so in the last part, the article shows work on this problem and achievement up to now.
Disc scratches, dusts and noise corruption et al. will cause data sequence errors including random errors and burst errors.
With the recording density of multilevel (ML) optical storage system increasing, the same length of scratches on the
surface of optical disc will bring more burst errors in ML DVD than conventional optical recording systems, e.g., digital
versatile disc (DVD) and compact disc (CD). A new interleaving scheme based on Reed-Solomon code (RS) is proposed
to solve this problem. In DVD system, the burden of the Parity of Outer-code (PO) is huge, while the Parity of Innercode
(PI) has more correcting ability than needed. The new interleaving algorithm adjusts the structure of data frame and
block and improves the interleaving depth of ECC block to reduce the burden of PO. The results of numerical
simulations are presented to verify the performance of the new interleaving algorithm compared with RSPC. The new
proposed scheme can correct maximum burst error length of the proposed code is 6912 bytes. Burst error correcting
capacity of the proposed scheme is improved up to137.4% more than that of the RSPC.