Tempo definition/ set tempo from definition

I am using the “set definition from tempo” function to establish a tempo for pre-recorded material. I am not sure of the correct choice to use of the available selections. It seems to want to apply the definition to either the “project” or “globally”. The question is: does this somehow imbed some information into the audio file? I think that if I knew some examples of how and when to use either of these options it would help when I am attempting to use them.
It is equally confusing on using the opposite “set tempo from definition”. Real world examples would clear this up. It is also important to know if these definitions are “permanent” Can they be removed and re-done? Google search reveals only a few entries on these subjects. Thanks for any help.

If I remember this correctly (not in the studio right now), “set definition from tempo” is to create hitpoint data in the audio event based on the current tempo track or project tempo. Let’s say you have an audio event that already is in time with the tempo track, but does not have intelligent data in it to time-stretch correctly if you should change the tempo. The applied hitpoints will then make the audio time-stretch correctly if the track is set to musical mode, and you change the tempo afterwards.

The word “tempo” in these terminologies, refers to “tempo data”, like the tempo track.
(Please correct me if I’m wrong.)

It appears to me that what you want to do is the opposite, since you want to analyze recorded material and create tempo data (a tempo track) based on that.

I tend to prefer to use the time warp tool to do this manually. It’s a great tool, quite fast once you get used to it, and it seems more fail-safe than the “analyze tempo” mode.