Deinterlacing

Brian_Rice

Brian_Rice

Carbonite Member
I still see lots of talk about deinterlacing video. Are people deinterlacing their consumer 24/25p footage because it's not "authentic" progressive, or are people only deinterlacing when their footage is in fact 50/60i etc?

I swear I saw on a different site people talking about deinterlacing progressive footage. Is there any instance when that would make sense?

Thanks
 
Never deinterlace inherently-progressive video. People who tell you do to so are confused.

There's removal of pulldown, which isn't the same thing.

Deinterlacing is taking inherently-interlaced video and deinterlacing it, making an approximation of progressive video from video which was never progressive.

Removing pulldown is taking footage which was shot as progressive, but recorded in an interlaced stream, and restoring the original progressive frames.
 
Hmmm... So if I have AVCHD footage shot at 24p, should I be "removing pulldown"? And if so, how?

Thanks!
 
If it's already 23.976, you don't have to do anything with it. Just cut on a 23.976 timeline.

If it's embedded in a 60i stream, then you'll have to use software which can do it (and depending on your OS). There are not many good options for pulldown removal in AVCHD, though. The nature of the codec makes it difficult.
 
To give you some history, interlacing is an artifact of 1950's technology. NTSC and PAL television were the best that could be achieved at the time, so it became a standard that's followed us into the 21st century. NTSC video is 60fps which easily synchronizes with 120hz power delivery, but it's delivered as two overlapping 30 frame fields; even lines drawn for 1/30th of a second, then odd lines drawn for 1/30th. This gives video its distinctive look because moving objects can be in one spot in one field and in a different spot the next. When 24fps film is displayed on NTSC video, frames are repeated to fill out the 30 frames. This is called pulldown, and again, because of movement, things are spread between different interlaced fields on certain pulldown frames. This pulldown is what's added to cameras that capture at 24 frames to reproduce the 'film look' for display on NTSC monitors . However, now that most monitors are progressive, and most editing programs can handle 24 natively, these interlaced pulldown frames are a nuisance and need to be removed in order to create true 24 frame progressive footage.


See Mr. Mayhew, I was paying attention in your fundamentals of broadcast television class!
 
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