Re: 25 fps to 24 fps by Dave LaRonde on Apr 23, 2008 at 8:57:06 pm
The most painless way to do it is to highlight the footage, then go File>Interpret>Main. This opens the Interpretation window for the footage. Now conform the footage to 24fps!
Or should the frame rate really be 24fps, hmmmmmmm?
Unless you're doing AE work that will immediately go to film -- you're making 2K files in AE for a film company, for instance -- you DO NOT WANT to use 24fps, no way, no how.
I'm willing to bet that since this is going to HD, you actually need your PAL footage and your comp in the NTSC film frame rate, which is 23.976 fps. Not 24, not 23.98, but 23.976.
So conform your PAL footage to 23.976, and put it in a 23.976 comp. Now, because you're slowing down that PAL footage a tiny bit, you may want to raise the audio pitch a little bit... but that's a different application.
And we still don't know whether or not this PAL footage is interlaced, either.............
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Re: 25 fps to 24 fps by Steve Roberts on Apr 23, 2008 at 9:24:30 pm
To see if it is interlaced, interpret with fields "off". If you then see interlacing, it was interlaced.
To confirm the proper field order (NOT "DOMINANCE", APPLE!) re-Interpret lower fields first. Alt-double-click on the clip in the Project window. Step through the video in the window that just appeared, using the PageDn key. If the video jerks back and forth (ugh!), it should have been interpreted Upper field first.
Re: 25 fps to 24 fps by Dave LaRonde on Apr 23, 2008 at 9:54:58 pm
Steve tells you how to check for interlacing. If you see it, your fun is just beginning.
Why? Well, for most of its life, TV used interlaced scan exclusively -- an Interlaced Scan camera would scan one field, then the next field, creating a complete frame. In the case of PAL, those two fields were separated in time by 1/50 second. A LOT of motion can happen in that time, and film cameras don't work in fields. They work in frames.
If you're going to render a 23.976 AE file -- a film frame rate, where interlacing is taboo -- you're going to have to do something about those fields or there'll be trouble ahead. You can:
• Render out of AE with NO fields. You lose the interlacing, but unfortunately, you also lose half the vertical resolution, because you're only rendering one field. Not a good idea when going to HD.
• Use a third-party plugin like Twixtor, ReelVision or Magic Bullet to create new, complete frames out of interlaced footage. They're tricky to use, but you save all the vertical resolution in the picture.
But what if you've checked that footage ten ways from Sunday, and you see absolutely NO difference, despite changing the field order interpretation eight times or so -- it's like the interlacing doesn't exist!
Well, theres's ANOTHER, very attractive possibility: this footage may have been shot on a Progressive Scan TV camera. It works by scanning the entire frame at the same instant, and then it splits it into two fields. The two fields are NOT separated in time -- no goofy motion problems caused by interlacing! You can use this footage with no problem -- it'll work just like film. And you would use it with NO field interpretation at all.
This TV stuff is fun, huh?
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
