24p w/ XL2, Edit w/ FCP, Transfer to 35mm
 

OK if I shoot with an XL2 in 24p, does it actually record it as interlaced? I have been reading and reading trying to understand what exactly happens when you feed the footage into the computer. I understand how the 2,3:3,2 pulldown process works but don't understand exactly why it is needed if you shoot in 24p and edit in 24p as is possible with FCP and a few other editing programs. Can someone please help me understand this?

I am getting a G5 in next month and getting the FCP production suite with it. As far as I can tell, I can do almost everything I need with that equipment. Right up till it is time to transfer to print. But again I need to understand in more simplified terms. What exactly happens to the video as it goes into FCP after being shot on 24p?

I have "A Guide to Digital Filmmaking by Marcus van Bavel and it is pretty good at explaining most of it. However, the way it is written, I can't always tell exactly which camera he is talking about from one sentence to the next. By the way some of the sentences are constructed, I am not sure
if 24p goes into the computer as interlaced or if he is only refering to NTSC and PAL but talking about it in the same sentence as he talks about 24p. I am well versed in analog but have been out of the buisiness for over 7 years and am going crazy trying to understand some of the newer tech stuff. Please help!

Thanks

Heres a brief summary of how it works :)

- Camera captures progressive frames (30p or 24p).
- These frames are then written to a 60interlaced signal to comply with the DV format
- In post the pulldown can be removed, restoring the original 24 frames (24pA is the best option for this)
- You can also shoot in 24p Normal and edit on an interlaced timeline.

Aaron,

I think your reply has pointed me in the right direction. I have been reading and studying and this is how I picture it to happen as of yet.

1. I shoot it using my XL2. Set the switch on 24p with the 2:3:3:2 pulldown. This converts it into 60 interlaced frames patterned aa bbb ccc dd for the transfer into the computer via firewire.

2. FCP converts it back to 24p by removing 12 of the interlaced fields per second. Those are the BC frames in the sequence. aa bb ( Removes bc ) and continues with cc dd and repeats for the length of the clip.

Now at this point the video is truely compressed and those deleted fields are gone for good yes or no? Now you should be working in 48i or 24p?

3. The edited footage is deinterlaced as it is being rendered and thus is now in 24p. How am I doing so far?

Thanks

Cleveland, so far so good. When you export 24p footage, it will be 24p in the final file if that's what you tell it to do. You can also export to tape (60i) or to a 60i file and your software will re-insert whichever pulldown scheme you choose.

The one part of all this that isn't clear: what's happening internally with the NLE? It isn't that important since it doesn't affect what goes in or what comes out (capture and export), but is a point of interest for understanding workflow and how some filters/effects will behave. In some circumstances, a NLE may directly read the source file (which would be 60i 2:3:3:2) and ignores the extra fields "on the fly" as it does its work, and in others it might read a temp file that could also be 60i or perhaps 24p...which method used in a given situation is anyone's guess so far.

Although I'm sure there are some differences in the way different NLEs handle footage internally, they probably arrive at similar solutions. I'm sorting through 24p / 24pA workflow using PPro and will share what I learn, such as what kind of video temp files are created by the software; most of the info should still apply to other NLEs.

Thanks Pete. You have helped clear up a lot of what happens inside the PC. I still do not have any editing capabilities for 24p yet. I'll be getting a PowerMac G5 with the FCP Production Suite probably next month. I am kinda waiting till I finish this class on the 10th.

http://dvfilm.com/school/index.htm

Because it may point me in another direction as far as editing is concerned. But I think I'll most likely go with the Mac & FCP.

All of my research seems to end with the mac being the best technology but it still costs more than I would like it to. Lately when you see a computer in a movie, it's usually an Apple and it's probably the one they are using to edit the film on.

"Lately when you see a computer in a movie, it's usually an Apple and it's probably the one they are using to edit the film on."

Actually, it's probably the one that paid a fee to the production for "product placement." Not that they won't be using a Mac to edit on.

Wayne Orr (who is writing this while wearing his Cleveland Browns tee shirt, for which he did not get paid.)

Pete,

As I understand it 24p with the 2:3 pulldown will have more problems if your going to edit in 24fps. Mainly because of the sampling to 60i aa bbb cc ddd. Compressed it would look like this. aa bb (remove bc) cd dd witch would cause every 3rd frame to have distortion because you will have 2 interlaced fields from 2 different frames.

24p advanced is simply 2:3:3:2 pulldown. I could be slightly off about the compression of the 2:3 pulldown but from what I have read, you should never use it if your going to finish in 24p.

Yes...or at least that's the standard advice based on whatever info we've been able to snare here about the way 24p works. Here's a couple of threads that take it about as far as any of us has info:

http://www.dvinfo.net/conf/showthrea...threadid=36253

http://www.dvinfo.net/conf/showthrea...threadid=40508

The second thread has a couple of links that I found helpful in trying to understand this...although I'm not 100% there yet, either!

Great links! Thanks. I think I understand it enough at this point to move on to dealing with some of the new problems that will arise once I actually get my hands on the editing stuff.

Like for instance. Having shot in 24p, 2:3:3:2 pulldown, 16:9 Aspect Ratio, edited in 24p and then moved the file into a DVD authoring program. Will it matter at all whether or not you put it on the DVD as 24p, 30p or 60i?

The reason I am asking is because I don't yet fully understand how the DVD player could turn the signal into either NTSC for the TV. Or, do those new progressive scan players simply play it in 24p. I guess that may be a question that has been addessed in a different thread or may need a new one. One of your threads had a brief discussion about that but it was not quite comprehensive enough.