24 fps HD to 29.97 and Back

[All Ears]

This is a question which has been raised on the DUC, but I haven't been able to find and answer. I'm about to start working on a project which was shot on 24fps HD. The picture was bumped to DVCAM and then loaded into Avid for the offline. I received the OMF's from Avid at 29.97 fps. I will eventually deliver the mix as files to be loaded back into the Avid. The picture will then be onlined back to 24fps. The audio was recorded directly to the camera (Panasonic) for the most part. Some 2nd camera shots were recorded to DAT. Don't know if that info is relevant.
My questions are:
What kind of pullup or pulldown do I have to consider and at what stage?
Should I even be delivering files or would I be better off going to DAT and doing the pulldown myself?
Basically, how are we going to conform my 29.97 mix to their 24 online?
Sorry, I know some of this is probably audio post 101, but what can I say. Thanks

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[douglas roberts]

I received the OMF's from Avid at 29.97 fps. I will eventually deliver the mix as files to be loaded back into the Avid. The picture will then be onlined back to 24fps. The audio was recorded directly to the camera (Panasonic) for the most part. Some 2nd camera shots were recorded to DAT. Don't know if that info is relevant.
My questions are:
What kind of pullup or pulldown do I have to consider and at what stage?

Ok I'll take a shot at this and you can all shoot me down in flames if I'm wrong
The OMF's were at 29.97 and the video you're working to is at the same rate so so far you're ok.
If the 2nd camera dats were recorded at 30fps you'll need to pull those down to 29.97 to work with that material. This is the murky bit for me but intuition tells me that seeing as 24 frame picture will run in sync with 30 frame audio you could pull up your session up to 30 before bouncing the files...likewise if your making a DAT...
Any more takers?

[All Ears]

I had heard that 24p cameras actually record audio at 60 (5.9***)frames. Is this why you said that 30 frame audio will play in sync with 24 frame video? Don't quite get that? Also, I'm still unclear about the process. Would I wait for the online to be created and then layback to the master? Or if I deliver files (which would be preferable), will the video guys be able to incorporate my files into the online master?

[douglas roberts]

I had heard that 24p cameras actually record audio at 60 (5.9***)frames. Is this why you said that 30 frame audio will play in sync with 24 frame video?

If you're taking audio from the OMF that references audio that has been previously digitized into the Avid from whatever source (direct from the HD masters or from the DV dubs) and is running at 29.97 and is in sync with your reference video then there's not much to worry about there. In film land they shoot the film at 24 frames and the audio at 30 frames and they are in sync, it's only when they transfer to video (29.97) that the audio get's pulled down the .01% from 30 to 29.97.
So from that standpoint I was assuming (wild guessing) that if you made bounces at 30 frames they'd be in sync with video that's running at 24 frames...this is where I could be way off base !

Don't quite get that? Also, I'm still unclear about the process. Would I wait for the online to be created and then layback to the master?

Well if they make a video output from the online it will be now running at 29.97 and you can layback audio to that just fine without any pull up's.

Or if I deliver files (which would be preferable), will the video guys be able to incorporate my files into the online master?

I guess the question I would ask the video wonks is whether the video is actually running at 24 or 29.97 frames and what they need from you, I often get asked to deliver bounced AIFF 29.97 48k files (with a sync pop that they can line up) that get loaded back into the Avid and they layoff the picture and my mix at the same time to the master.
Anyone got any other thoughts

[All Ears]

Thanks for the tips dougals, you've cleared up some things. Still a little unclear on some things though, and it may be because I'm using the incorrect terms. When I say they will online at 24fps, I mean they will take the EDL that the Avid generates and create their master using the original 24p tapes. That is why I am wondering how they will incorporate my 29.97 audio files. Will they create the HD master, and expect me to do the pullup and lay back to that HD master? If so, and I do pull my session up to 30 will I be able to lock an HD deck runnning at 24 to my session running at pulled up 30 to do the layback? Does that even make sense? Sorry to beat this horse. Usually I do what Dougals explained, I deliver the AIFF's and they create the master from the Avid output. But this is different and I just want to make sure I am delivering what will be needed, so I don't look like a fool.

[potatohead]

I bet your 24p HD camera tapes (and the eventual HD online master) are actually 23.976fps which means the 29.97 DVCAM downconverts are actually not "pulled down" per se. In this case, your Standard Def tapes (and subsequent Avid offline edit) have the exact same timebase as the originals (and the HD online) so your sound edit/mix will not need to be "pulled up" in any way to sync back to the originals.

What I'm saying is that if you make 48k soundfiles referenced to the 29.97 offline video, those soundfiles should sync up perfectly to a 48l/23.976fps HD online session (like an Avid Symphony online) that can import 48k soundfiles.

Hope this helps.