How do I know if a clip is a pure clip or hybrid one?

[Valeron]

I can't find any knowlege about this issues.
According to the reference manual of decomb and tutorial,I checked a great amount of my NTSC DVD source(both anime and music video clips),a 3:2 pull down can be seen through the whole clip mostly of them,not only in the fast motion scenario.
But I can't see any duplicate frame in one pattern(without telecide).
Or telecide simply generate it?

I haven't view the clip frame by frame after apply telecide.
Because the decimate job sometimes is not so perfect.So if anyone can help?

Thanks.

[Mug Funky]

assuming you've got a telecined clip with a regular pattern, you can do:

separatefields()

then step though the video frame by frame. if you get 3 dups, then 2 dups, then 3 dups, then 2 dupes... 3,2,3,2,3,2 etc ad infinitum, then it's a pure telecine (hence the name 3:2 pulldown...)

if you're seeing pans or motion graphics moving each frame (no dupes), or moving every 2, then you've got either pure interlaced or 30p progressive.

my rule of thumb is if it was shown in a cinema, it'll be pure 3:2 pulldown. if it was straight-to-teev, it'll be a horrible mix

[Valeron]

Thank you very much for your so particular reply.

I've followed your guide to judge what the clips are.But several questions about your guide:
Don't we have to set the field order first in this process?
What will separatefields() do by default?
And if the 3 or 2 dups will not look like completely the same but have slightly horizontal moves?