3:2 and 2:2 pulldown?

[Thunder18]

I know these terms have to do with the fact that film is produced at 24 fps and TV is produced at 30 fps and you usually see 3:2 pulldown detection as something that is reviewed when a reviewer tests a dvd player. My question is, how do you recognize poor pulldown detection?

 

[j_garcia]

This is from Secrets:

Motion picture photography is based on 24 frames per second. Time to call to mind all that math you learned in school and realize that 24 doesn't go into 60 very easily. To boil it down a little, our challenge is to make 4 frames from the film fit as evenly as possible across 10 video fields. We can't just double up the fields on every fourth film frame or we'd get a real 'stuttered' look. Instead, a telecine process is used known as 3-2 pulldown to create 10 video fields from 4 film frames. This form of telecine alternates between creating 3 fields from a film frame and 2 fields from a film frame. Hence the name 3-2.

If this is not done correctly, the image quality suffers greatly, potentially in a number of ways. There are a LOT of factors too. Probably more than you ever wanted to know can be found here.

 

[Thunder18]

Awesome resource J_Garcia. Thank you very much!

 

[Jedi2016]

Good post, J_Garcia. I was going to say pretty much the same thing.. about stair-stepping, visible fields (i.e. "combing"), double-exposure, etc. That article covers pretty much all of it.

Luckily, I know what to look for. I'm still just a poor boy with a SDTV, but when I upgrade, I'll be able to tell instantly if my player and/or TV is doing it's job.