The number of the chapter to play in the specified title. Possible values range from 1 to 99.
The name for each individual video file on a DVD. For example, under the title "Water Skiing", you might have the chapters "My first try," "My first wreck," and "My first jump."
The name for a group of related video files (called "Chapters") on your DVD. For example, for a DVD called "My Summer Vacation," you might have the titles "Water Skiing," "New Friends," and "Hiking." For each of those titles, you might have one or more different video files.