Subcode

On digital media, there is a region of the tape where audio data is not recorded. Rather, this area has subcode written to it. Subcode can consist of a variety of different types of non-audio information; track number, indexing, and timing information such as track length and elapsed time, is found there. Digital tape has a higher capacity for subcode information, and such proprietary information as text (song titles), timecode, or even picture can be found written to subcode.