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Boris Riabov
DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 12, 2012 at 1:48:59 am

This is regarding correct audio/video sync...

- I'm editing 23.98 clips (reverse-telecined from 29.97).
- Under Item Properties...
Vid Rate: 23.98
TC: Rate: 24
- I had sound recorded independently at 24fps to 48Khz, 24 Bit .Wav Files. FCP - however - gives them the TC Rate of 30.

What would be the best way to ensure sync between the two?

- Would it make sense to 'Merge' original 29.97 video and 30TC audio - export through FCP - and reverse telecine both video/audio in Cinema Tools? What would be the correct audio settings for that process?

- Would slowing the audio down in FCP instead be more feasible?

Thank You,
Boris


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Michael Gissing
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 12, 2012 at 2:54:47 am

This second half of this tutorial explains the correct process for importing wav files into FCP to avoid the wrong frame rate being stamped on files. This sync problem is extremely common and discussed here at least once a week, sometimes more.

http://library.creativecow.net/lyon_matt/fixing-fcp-assets/1


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Boris Riabov
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 12, 2012 at 3:13:36 am

Thanks!

It's very helpful.
I'm just curious - for entering new audio time code in the XML and for editing with 23.876 clips - I would enter 24 correct?
I wouldn't enter 23.98 for audio time-code because that only applies to frame rates I'm assuming.
This is referring to the following line in the guide: "It can be a whole number such as 24, 25 or 30."

-Boris


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Matt Lyon
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 12, 2012 at 7:48:03 pm

Hi Boris,

Is this the same project as your earlier post? The super16 shoot?

If you ran your camera at 24.00 fps, then you need to apply a speed change to your audio before you start synching. You can do this in "realtime" in FCP, but without sample-level accuracy, so I prefer to run all my sound through ProTools or Audacity and "bake in" the speed change (aka pulldown).

You should definitely reverse telecine your video FIRST. Then import into FCP. Then import your processed sound, then do the sync and clip merge.

But follow my advice in the second half of my tutorial (about setting your sequence presets) so FCP interprets your sound files properly when you import them.

hth,

Matt Lyon
Editor
Toronto


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Boris Riabov
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 12, 2012 at 8:53:48 pm

Hello Matt,

I've been reading your post, and I have some questions about your guide.

If I am already working from an XML file (imported from Cinema Tools to Batch Capture miniDV tapes (no audio) at 29.97fps, perform the reverse telecine, offline and reconnect clips in FCP to the 23.98 clips, could I import just an audio xml?

When you recommend opening another, new project and importing the 'fixed' XML, I am afraid of doing so because my old project is connected to Cinema Tools, etc. I am afraid of loosing synchronization between the two, and having problems with exporting an EDL properly (timeline, negative cut list, window burns match up, etc).

I did shoot film 24fps and audio was recorded at 48.0Khz, 24-Bit Intiger. When I do merge the reverse telecine clips and the imported audio (simply through Import-Files), it does in fact give me the time-code rate of thirty. I know this is wrong, and will cause sync problems.

I need to get the audio to 24 TC.

Is there any guide that would let me batch pull down all my audio to 24 through Pro Tools?
Would I still need to figure out how to tell FCP to interpret that audio properly as well, upon importing after Pro Tools?

Would it make sense, instead, to be picture-locked (which I am, at 29.97fps, too long to explain, I had the wrong workflow but am re-editing, after miniDV recapture, etc. clip by clip in 23.98), and export the XML of the entire sequence and changing the TC of all the 'merged' clips in the timeline once editing is complete?

Thank you for all of your help!

Sincerely,
- Boris


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Boris Riabov
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 12, 2012 at 9:03:34 pm

It seems, I absolutely must change the audio logging TC rate of 30 through XML?

-Boris


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Matt Lyon
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 12, 2012 at 9:28:10 pm

Hi Boris, I understand more now... you basically are re-conforming your project from 29.97 to 23.976?

But that raises a larger question. Did your audio stay in sync with picture during the first edit? Theoretically, if you didn't do the audio pull down at that point, then the clips would have been drifting out of sync. It is possible your sound recordist was already applying the pulldown, so there is no need to do it again.

Also, you don't HAVE to change the audio TC to 24 in order for things to stay in sync. In fact, your audio should absolutely maintain the timecode of the original recordings. This is important if your mixer has to reconform from the the original files.

FCP can mix 23.976 video with timebase 30 audio, you just have to make sure your settings are correct when you import the files (which is what the second half of my guide is all about).

Are you rebuilding your timeline from scratch? Or are you hoping to conform the video and marry the old sound to it?

Matt Lyon
Editor
Toronto


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Boris Riabov
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 12, 2012 at 10:01:14 pm

Hello Matt,

Because I edited previously at 29.97fps, straight from the miniDV tape, and the audio was at 30TC, I believe everything was in sync, although I may be completely wrong and my eyes were fooling me, with the audio, in fact, slowly drifting!

Yes, I am rebuilding from scratch, matching the sequences clip by clip through the key-frame window burns, which isn't too difficult, only time consuming - my own fault for not doing it properly the first time and editing in 23.98fps right off the bat.
I am seeing that the clips in both timelines (29.97fps, 23.98fps) are pretty much identical in length, so I am on my way to maintaining proper visual picture lock and identical edits between shots in both sequences.

I currently have my new timeline setup in the photo below. I realized that the Sequence Preset Editor allows me to set the TC Rate, but I'm assuming it has nothing to do audio?

What I'd prefer to do, is resync only the takes that are in my 23.98fps picture-locked timeline, merge clips, and drop them into the sequence, clip by clip - this way I can double check sync of every clip (tedious, I know), and make sure the edits are the same.

I'm still having some difficulty with the XML workflow. Should I export the XML of an empty sequence and change the TC (text-edit) and reimport it? Should I import before I resync, and merge?
I'm already working off an XML (from Cinema Tools).



-Boris


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Boris Riabov
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 12, 2012 at 10:19:56 pm

I think I got it.

I will re-sync the 29fps clips, video/audio/merge, place them in the 23.98 fps timeline, and have my picture-locked timeline.

I will then export an XML of the entire 23.98 sequence, open it with text-edit and make the changes like you said, reopen another FCP project, import the sequence. I did this for three clips, and the green bars have gone away - and it seems to be in sync.

This process seems to be easier than going through Pro-Tools. What are your thoughts?

Sincerely,
Boris


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Boris Riabov
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 12, 2012 at 10:24:51 pm

Final Question!

Does this process at all conflict with how I need to export my OMF for my sound designer?
Should I also layer in the score, temp SFX before I do the XML workflow? Or could I add them in the new project after all the clip audio/video is properly synched?

-Boris


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Matt Lyon
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 12, 2012 at 11:16:03 pm

Hey Boris, there's a lot of information here so I hope I'm getting everything straight :)

First off, based on you other post, if you are still seeing interlaced fields in your footage after you ran the reverse telecine, that means it didn't work properly. You need to run the batch again, and find the correct settings that work with your material.

FCP is actually designed to automatically apply audio pulldown in certain situations (you can read about it in the Cinema Tools manual. In fact, I highly recommend reading the whole thing if you haven't already).
So it actually sounds like this worked in your favor, since that is what is likely kept your audio and video in sync during your first go around.

I don't like working that way. My preference is to bake the speed change in. I'm not aware of any specific tutorials for doing this in protools, but I'm sure they are out there.

So I'm still not sure why you need the xml route? My way of going about this would be:

reverse telecine the footage
apply pulldown to the audio
start a new FCP project
import all audio and video
sync a long clip, make a merged clip, and very there is no drift
throw a few clips on the timeline and very you can export a valid pull list with keycode via Cinema Tools (I assume that is what you'll be giving to the lab to recapture you're selects?)
rebuild your edit, picture and camera sound
rebuild your temp score and sfx
export deliverables for sound folks and the online folks

hth,

Matt Lyon
Editor
Toronto


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Matt Lyon
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 12, 2012 at 11:53:24 pm

[Matt Lyon] "sync a long clip, make a merged clip, and very there is no drift"

sorry that should read: VERIFY there is no drift...

Matt Lyon
Editor
Toronto


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Boris Riabov
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 13, 2012 at 12:46:02 am

Great!

1. I'll get to it; I'll try to reverse telecine clips again (I had followed the Cinema Tools manual which told me to choose Field 2 according to the A-B-C-D-D 29.97fps letters on my window burn).

2. I guess I should go through all the settings to see which ones give me no interlaced footage - meaning each letter can be properly read A-B-C-D - and the footage is not interlaced.

3. I guess I will do the audio pulldown through Pro-Tools?
I will read-up on the automatic audio pulldown in FCP and I will read the entire Cinema Tools guide. I think I've covered about half of it so far!
I spoke to one of the sound guys at my university and he told me Pro-Tools lets you conform the audio when you import it (I imagine I'll be doing pull-down on all those .wav clips to 24TC?)

4. Should do the audio pull down to my .aiff music score files? I also have .aiff voiceover audio files.

5. When I export an OMF should I tell my sound designer to work in 23.98? 24TC In Pro-Tools? Or does frame rate does not matter at this point?

6. Perfoming Pull Down = Bake In?

I really, really appreciate all your help. It's great to hear concrete advice after reading up on so many 'recommendations' and work-flows.


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Matt Lyon
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 13, 2012 at 8:46:32 pm

sorry, been crunching at work today so I couldn't write sooner...

1. You may need to play around with the reverse telecine settings in Cinema Tools to find the combo that works, but start with:

Capture mode: Field 1 - Field 2
Fields: Style 1:AA
conform to 23.98 (don't ever change this)
standard upper/lower: ON (unless nothing else works)

Usually, a telecine session will export an ALE file where every clip starts on a 00 frame, and every 00 frame is an "A" frame.

2. correct. when you read proper A/B/C/D letters, you're reverse telecine worked

3. The pulldown doesn't change the timebase of the audio, it just makes the audio play slower (since your video footage has been slowed down from 24.00 to 23.976 fps during the telecine). So the speed change should be 23.976/24.00 (aka 0.999%)

4. You only need to apply the pulldown to sound that was recorded while cameras were rolling.

5. Your sound guy should work at 23.976. It sounds like you are finishing on HD, which will be at 23.976 ... so everything will stay in sync. If you finish on film at 24.00, then you need to apply a pullup to the final mix to maintain sync.

6. By "bake in," I mean to say that the audio tracks are processed and re-exported with the speed change applied so they are permanently altered, as opposed to having FCP do the speed change "on the fly." (in a sense, the opposite of a "non-destructive" effect)

Matt Lyon
Editor
Toronto


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Boris Riabov
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 13, 2012 at 10:20:44 pm

Hello Matt,

Thanks for the help!
I'm just having an issue with Pro-Tools; when I open my new session and try to import my stereo .wav files so I can do the SRC pulldown, Pro-Tools converts them to mono files, and converts each file into two in its own folder.
When I import them, FCP still gives me the green bar in the audio :(
Is there any way to tell Pro-Tools to keep the .wav files in stereo for re-import back into FCP?

-Boris


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Boris Riabov
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 13, 2012 at 10:39:17 pm

Also,
I see that when I'm cutting my 23.98 picture-lock time line based off my 23.97 timeline, matching up the window burns, and even by what's in the frame itself, the run time of the 23.98 clips are shorter anywhere from one-five tenths of a second.
I imagine this to be appropriate, due to the reverse telecine, but I just wanted to check if this was any cause for concern.

-Boris


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Matt Lyon
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 13, 2012 at 11:21:36 pm

hmm ... I'm not enough of a ProTools guy to be able to explain how to do that of the top of my head, but I'm pretty sure there must be a way.

If you are still getting the green bars, there could be a number of things going on. Make sure ProTools is actually rendering a new file at 48000 hz, rather then just changing the sample rate to 47952, which is one way of applying pulldown, but not really FCP friendly.

[Boris Riabov] "I see that when I'm cutting my 23.98 picture-lock time line based off my 23.97 timeline,"

I assume you mean 29.97 timeline?

as for the clip lengths: are you sure they are actually shorter? remember that the timebase is different. So frame number 12@24fps is equivalent to frame 15@30 fps

Matt Lyon
Editor
Toronto


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Boris Riabov
Re: DV NTSC 48KHz - 23.98 Editing Sequence Preset - Audio Sync...
on Mar 15, 2012 at 12:55:46 am

Yes!
Duh!

I'm still figuring out the Pro Tools. I figure I'm just going to sync everything with the audio and just match the timelines by window burns - and either do the XML audio fix after I'm done matching my 23.98 timeline to my 29.97 timeline frame by frame - or simply reconnect the audio to my Pro Tools pulled-down audio, when I figure out how to export them properly as stereo and for FCP to recognized them as 47.952.

-Boris


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