23.98 vs 24

Hi, I'm looking for a little advice on our post production workflow. We shot a 35mm film and got the transfers done in 24@25 PAL since we were abroad and that was all we could get. We then used the 24@25 easy setup to slow the PAL down and create 24p sequences. Now, however, we are getting our color corrected re-transfers done at 23.98 to HDCam. 23.98 is not 24p, correct? So I'm wondering if my audio is going to be messed up. Can anyone explain the difference between 23.98 (23.976) and 24? I'm just worried the sync will drift when we do the final mix.

Dan
Final Cut 5.1.2
Mac Pro
XRaid

<<<I'm just worried the sync will drift when we do the final mix.>>>

Probably.

Most movie cameras run at 24.00 even, and when projected in a movie house, all is well--everything matches up. The physical film is slowed down slightly in a telecine session to 23.976 because the frames match up evenly to NTSC television 29.97--in 3/5 frames or 3:2 pulldown.

3:2 allows the telecine process to "hide" the frame differences accurately and evenly. 3:2 is pretty to look at. There is another way to hide the differences called Advanced Pulldown. Advanced pulldown doesn't look as good as straight 3:2 in real life, but it allows a return to 23.976 much more accurately if you need that.

Anyway, if you don't do this little speed change and dance, the conformance between the two framerates would happen at random and give much more disturbing, jittery presentation.

Getting back and forth between 24.00 and 23.976 (rounded off to 23.98) can be very amusing. Compressor can do the actual conversion, but to my knowledge, can't also conform the times and duration. You have to do that manually with an abbacus, toes, and a pile of rounded stones.

Koz

If you are transferring to HDCAM @ 23.976 there won't be the 3:2 pulldown that Koz mentions but there will be the slowdown. So the transfer tapes won't sync to your onset audio.

Theoretically though, you should be able to capture the HDCAM into FCP and conform the clips to true 24fps. If that works then syncing audio shouldn't be a problem. If you are finishing on HD you are going to have to bite the slowdown issue at some point as all HD in North America is broadcast at 29.97.

The big question is how are you going to get your HDCAM footage into FCP?
Blackmagic/Kona or ?
And what do you plan on finishing on, film or HD?
Were your original sequences at 24fps or 23.976 or 25. (Caveat:I am not too familiar with the 24@25 workflow.)
Was your audio recorded at an even frame rate (24 or 30) or a pulldown frame rate (23.976 or 29.97)?






As an aside, can't HDCAM record/play true 24fps native without any slowdown? I thought that was one of the tricks you payed the big bucks for on those decks. On the same topic do either the BM or Kona cards allow for a true 24fps capture. It's one of those things I remember reading about but never thought I would come across.

ak
Sleeplings, AWAKE!

I see, thanks for the explanaition, I'm pretty sure I can now make sense of the problem I am in. The sequence we did our edit in was at 24fps, not 23.98... and the sound was recorded at 24fps as well. So, when I get back these HDCam tapes at 23.98, I'm going to have a sync problem with my mixed 24fps audio mix. Can I use CinemaTools to conform these HD clips to true 24 when I redigitize them? Then I will sync it up with my sound mix, and finally, at the end of the project, I will export the project at 1080i59.94 for Festivals.

Dan