Abstract: A recording parameter setting device including a trial recording parameter setting section and a reproduced signal quality judging section. The reproduced signal quality judging section judges whether or not a reproduced signal obtained by reproduction of the trial recording carried out in accordance with the trial recording parameter satisfies a predetermined reproduced signal quality. If no, the recording parameters of the predetermined recording mark length or longer are further classified into detailed groups and trial recording is carried out again. If the reproduced signal satisfies the predetermined reproduced signal quality, the reproduced signal quality judging section sets the trial recording parameters as a recording parameter. This makes it possible to form a recording mark capable of surely providing a good reproduced signal quality while the number of recording parameters to be used is reduced.

Abstract: A recording parameter setting device includes a trial recording parameter setting section (23) and a reproduced signal quality judging section (26). The trial recording parameter setting section (23) inquires, in accordance with the recording information, a storage section (3) containing recording parameters used for controlling heat of recording marks, and sets a trial recording parameter, wherein (a) the recording parameters are used for controlling heat of at least rear edges, (b) the recording parameters are classified in accordance with recording mark lengths, and (c) recording parameters of a predetermined recording mark length or longer are classified into a same group. The reproduced signal quality judging section (26) judges whether or not a reproduced signal obtained by reproduction of the trial recording carried out in accordance with the trial recording parameter satisfies a predetermined reproduced signal quality.

Abstract: A Viterbi decoding circuit performs Viterbi decoding on the basis of a reproduced signal obtained by reading an optical disc. A decoded bit sequence is fed to a first specific pattern detection circuit and a first reverse pattern detection circuit. A path metric difference ?M is fed to a reproduced signal evaluation circuit. The reproduced signal evaluation circuit extracts path metric differences for a specific pattern and a reverse pattern detected by the first specific pattern detection circuit and the first reverse pattern detection circuit and evaluates the reproduced signal on the basis of results. The evaluation uses not only the bit sequence for which the ideal SAM value is a minimum. The invention achieves accurate evaluation for reproduction.