6.2. Part Of Title (Chapter)
A title can be divided into parts and navigation links can be added to each part. The DVD specifications refer to these parts as parts-of-titles, or PTTs.
These parts are also known as chapters. This makes the random access to a particular video segment on the DVD fast and easy. Some DVD players support the repeat playback of a chapter via the remote control. A chapter or PTT is defined by a PGC and a program number within the PGC. Each VTS contains a PTT table which lists the PGC number and the program number associated with each chapter of each title defined in the VTS.

6.3. Graphical display of Part Of Title (Chapter)

Each VTS has its own Part-Of-Title table to keep track of chapters in each title in the VTS (indicated by arrows drawn in magenta).The above picture illustrates a VTS that has two titles. The first title has three chapters and the second title has two chapters. The first two chapters of title 1 is in the first PGC, and the third chapter of title 1 is in the second PGC. The second title has two chapters in one PGC.