When to do inverse 3:2 pulldown

[sivagita]

All the guides from the web says that NTSC has 3:2 pulldown done to convert a film of 24 fps to 30fps.

I am capturing the content from my cam corder Hi8 (not digital) using S-Video input. Should I need to do reverse pulldown?

If I capture from a VHS tape (not a movie) from composite video input should I have to do reverse pulldown?

How to detect if the source NTSC has 3:2 already done?

Thanks
Siva

[Doom9]

the process of reversing 3:2 pulldown is called IVTC - InVerse TeleCine. Whatever is analogue and NTSC will always be 29.90fps.. but if it's not from a movie source it has never been telecined in the first place and can't be properly encoded at 23.976fps

[sumptor]

Simple way to determine if your video is telecined. Load your captured video using Vdub and advance the video one frame at a time using the arrow key. If you see a pattern of 3 progressives frames followed by 2 interlaced frames, then you must use the IVTC filter in Vdub to get rid of the interlace effects.

Telecined videos is usually performed on commercial films. Home videos don't have this. To get rid of interlacing on home videos, I usually use SmartDeinterlace and use settings suggested by the author.