Patent ID: 7539092
Filing Date: 2009-05-26
Classification: G11B

Abstract:
1. An optical disk playback apparatus which reads out sub-code information recorded in advance from a lead-in area of a CD standard optical disk, and decodes into and playbacks TEXT information according to a CD-TEXT standard from R-W channel data of the sub-code information, the playback apparatus comprising: a decoder that decodes into the TEXT information from the R-W channel of the sub-code information read out from the lead-in area and determines whether the TEXT information is present based on a result of decoding the R-W channel data into the TEXT information, in parallel with being decoded into TOC information from Q channel data of the sub-code information read out, wherein the TEXT information is formed from a plurality of packs that each comprises header information, a TEXT content, and an error detection code, and wherein the decoder, each time part of the R-W channel data for one of the packs is read out, performs error detection based on the error detection code included in the one pack, in parallel with reading out the Q channel data from the lead-in area, and the decoder determines that the TEXT information is present if the number of times when normal is above a predetermined reference value in results of the error detection for a predetermined number of packs, and that the TEXT information is nonexistent if the number of times when normal is not above the predetermined reference value.