[Ghitulescu]

To my knowledge there is no clear definition of what a VID is, with respect to its uses.
However, based on the movies I have analysed, I can tell that different VIDs are used when there are parts of movies (scenes) that come from different parts and "joined" in (logos, credits, sometimes the "defective" cells).
But most times the only different VID is associated with the last, empty cell - used to jump at the end of the movie.

The requirements of layer break does not explicitly request a VID change, only a new CID (which may have a new VID, or not).