Optical Disc Address Conversion Using Reed-Solomon Bit Inversion
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Solution Overview
Problem
Conventional recording and reproducing apparatuses face challenges in accurately detecting addresses on optical discs of incompatible formats, leading to potential malfunctions due to differences in error correction code formats, especially when using Reed-Solomon codes like RS (13,6,8) and RS (15,8,8), which can result in incorrect address reproduction and data loss.
Innovation Solution
A method involving bit-inversion of specific symbols in error correction-coded information to generate conversion information, ensuring a minimum distance between inverted symbols exceeds half the minimum free distance of the error correction code, preventing incorrect address detection even when reproducing incompatible optical discs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If error correction capability is improved by increasing the number of parity symbols or changing the error correction code format, then address detection accuracy is improved, but compatibility with conventional apparatuses deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-processing the error correction coded information through bit inversion of specific symbols before recording. This transformation is performed in advance so that when conventional apparatuses read the disc, they inherently encounter the transformed data structure, which prevents them from incorrectly interpreting the address information while maintaining the improved error correction capability.
Solution Approach 2:
The patent changes the parameter structure of the error correction code by selectively inverting bits in specific symbols (such as parity symbols or address symbols) while maintaining the overall code format. This parameter transformation allows the disc to store address information with enhanced error detection capability, while the transformed parameters ensure that conventional apparatuses cannot mistakenly reproduce incorrect addresses.
2Reliability
If bit inversion is applied to error correction coded information, then incorrect address detection is prevented, but device complexity increases
Solution Approach 1:
The patent applies local quality by selectively inverting bits in specific symbols rather than transforming the entire error correction code structure. For example, only certain parity symbols or specific bit positions within symbols are inverted, which provides the necessary reliability improvement while minimizing the complexity increase, as the transformation is localized rather than global.
Data Source
AI summary
According to the present invention, when an apparatus performs reproduction from an optical disc of a format not compatible to the apparatus, the apparatus is prevented from obtaining an incorrect address and thus causing a malfunction. A recording method according to the present invention performs first conversion of bit-inverting m number (1≦m<n; m an integer) of symbols at prescribed positions of a code word coded using an error correction code by a Reed-Solomon code and including symbol C(i) [i=0, 1, 2, . . . n; n is an integer] to generate conversion information; and records the conversion information on a first recording medium. The first conversion is set such that a distance between first information obtained by performing inverse conversion to the first conversion on the conversion information, and second information obtained by performing inverse conversion to second conversion, which is different from the first conversion, on the conversion information, is at least ½ of a minimum free distance of the error correction code.