The pregroove is the spiral-shaped groove on the blank. This groove serves as a writing and reading aid for the laser. The pregroove contains a scaling in time units and starts at 96:15:00. The first area is reserved for the lead-out, which starts at 97:27:55, the following data area at 00:00:00. The lead-out starts at 74:05:10 and the groove ends at 76:05:10.