2.3. Programs
Following are excerpts from the Unofficial DVD specifications Guide 2.2 ebook.

A sequence of one or more cells (within a PGC, explanations of PGC are covered in later section) with consecutive cell numbers can be defined as a program. By default, the playback of cells without cell commands in a program are seamless. Programs are primarily used as units of playback for random or shuffle play, or references to groups of cells to be accessed via commands or chapter search (see next topic). Many well-authored commercial movie DVDs assign only one cell per program. Programs which support multi-angle video always have multiple cells.


The following illustration shows some typical arrangements of programs and cells. The typical relationship of programs and cells is visually explained on pages 10-12 of the Unofficial DVD specifications Guide 2.2 ...