Book type refers to the field of data consisting of four bits on the lead-in of a DVD, which is decoded by a DVD-ROM drive or DVD player. The book type then tells the DVD device what format (DVD-R, DVD+R, or DVD-ROM) is contained on the disc. The data included in the Book type can be changed on DVD+R discs, but currently no proven method exists to change the book type of a DVD-R disc. The ability to change book type is important as older devices can be fooled into playing DVD+R discs that have had their book type changed to that of DVD-ROM.
The book type field values are as follows:
- DVD-ROM – 0000
- DVD-RAM – 0001
- DVD-R (single- and dual-layer) – 0010
- DVD-RW – 0011
- DVD+RW – 1001
- DVD+R – 1010
- DVD+RW dual layer – 1101
- DVD+R dual layer – 1110