An optical data carrier includes at least one session in which one or more tracks are stored, wherein each session includes a plurality of data frames, and wherein each data frame includes controlling data and content data coded in a first format. In place of at least part of at least one bit sequence which would be included within said content data and which would correspond to constant data with respect to a second format into which said content data would be converted during a reading process, if said one or more tracks had been transferred onto said optical data carrier in accordance with a predetermined CD standard, the at least part of the at least one bit sequence is represented by a bit sequence which does not correspond to constant data with respect to said second format.