DVD and CD has the same data organization, each layer is divided into lead-in area, program area, and lead out area three parts. There is a middle area for OTP discs.
The data on the DVD disc is organized by sectors. Each sector is made up by 1024 bytes of data. There would be no intervals between sectors, and they are stored on the disc as below:
1. For the single layer disc, the starting point of lead in area is the end of lead out area.
2. For the 0 layer of the double layer disc, the lead in area starts from the start of middle area and ends at the ends of lead out area.
3. For the dual-layer disc layer 1, the lead in area from the beginning of the middle zone to the export zone at the end.
For the use of OTP (backlighting Road path) mode dual-layer disc, a layer of the middle zone at the beginning of sector number from 0-layer data area according to the last place to take a sector number in fact receive, after a continuous increase in the number of sectors up to a layer of lead-out at the end.