real 25fps or speedup?

[DvdKhl]

I have a Pal DVD Movie
when the Movie runs on 25fps it's 42:09 long
on 24fps it's 43:54 long
it has 63227 frames
now how can I be 100% sure which fps is used?

when it isn't a speedup what about the deinterlaceing?

[jggimi]

PAL is 25fps. However, the conversion from 24fps 35mm film to PAL video can happen in several different ways. See the PAL section in www.doom9.org/ivtc-tut.htm