Recording medium, recording apparatus, recording method, reproducing apparatus, and reproduction method

A reproducing apparatus comprising:

• a reproducing section that performs reproduction from a recording medium having recorded thereon a multilevel code of at least three ML values produced by coding user data into a (d,k)-RLL code of the ML values, and a particular pattern of the ML values that includes a run of repeated codes which is greater than a maximum run k of the multilevel code;
• a detecting section that detects the particular pattern from a string of the multilevel code reproduced from the recording medium;
• and
• a decoding section that decodes the multilevel code according to the particular pattern, wherein
• the detecting section
• detects the particular pattern according to dissimilarity representing a degree of dissimilarity between the string of the multilevel code reproduced from the recording medium and the particular pattern, and
• computes, as the dissimilarity, a value corresponding to a magnitude of a difference between NRZ (Non Return to Zero) codes of the string of the multilevel code reproduced from the recording medium and the particular pattern, the NRZ codes expressing the multilevel code by the ML values which include 0 as a central value.

A reproduction method comprising:

• performing reproduction from a recording medium having recorded thereon a multilevel code of at least three ML values produced by coding user data into a (d,k)-RLL code of the ML values, and a particular pattern of the ML values that includes a run of repeated codes which is greater than a maximum run k of the multilevel code;
• detecting the particular pattern from a string of the multilevel code reproduced from the recording medium;
• and
• decoding the multilevel code according to the particular pattern, wherein
• the detecting
• detects the particular pattern according to dissimilarity representing a degree of dissimilarity between the string of the multilevel code reproduced from the recording medium and the particular pattern, and
• computes, as the dissimilarity, a value corresponding to a magnitude of a difference between NRZ (Non Return to Zero) codes of the string of the multilevel code reproduced from the recording medium and the particular pattern, the NRZ codes expressing the multilevel code by the ML values which include 0 as a central value.