Following are excerpts from the Unofficial
DVD specifications Guide 2.2
A sequence of one or more cells (within a
, 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
(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 ...