FCP 24 AND 30 FPS Audio Bug

Noiz2

Noiz2

Sound Ninja
This is really a FCP issue but since it appears as an audio issue and sound guys are the ones that found it and have to deal with it...

In FCP if your working in a true 24 FPS OR a true 30 FPS timeline any audio you bring in to the time line will be played back slow in FCP.

This showed up first with RED footage shot at 24 rather than 23.98. Not that many low budget RED films yet so you don't see it too often below a certain budget point. BUT the Cannon 5D Mk II shoots TRUE 30 frame video (only option) and that is being used by a lot of low budget filmmakers.

The best workaround for the Cannon is to convert the footage to 29.97 before you edit. You will need to convert it anyway since it shoots H.264 and you can't really edit with that. Make a custom compressor setting and convert the video to 29.97 and the audio to 48K. After that everybody's happy.

If your the sound guy and it's too late the only real option is to out put a WAV file and run it through Sebsky Tools. You can google it. The company that made it is DOA but the tool was always free and it's archived on a number of sites and I will put it on mine when I get around to it. Anyway you take your WAV file and use the "bwf2qt" tool to wrap the WAV file in a MOV file and set the frame rate to 24. FCP will bring this in as the same speed as the video and it should all play back in sync.

The reason for 24 even if your in a 30 time line is that 30 and 24 are both "film speeds". The whole problem comes from FCP making assumptions about workflow and has decided to "correct" your audio for you behind your back. There doesn't seem to be any way to turn off this bad behavior and it's been in FCP since at least V6. The only "fix" is to lie to FCP so it won't try to fix what ain't broke.
Cheers
SK

Scott Koue
www.scottkouesound.com
http://imdb.com/name/nm0468138/
 
Noiz - Does your audio sound notably slow - as in your voic sounds much lower? Or does it sound slightly slower?

I note this because I was having a problem a couple of weeks ago where FCP just started playing 48k stuff at 44.1. I trashed my prefs and it fixed the problem.


It could also be your audio interface has popped to 44.1 (My Motu Traveler did a couple of times) and I had to go into Utilities to fix it.
 
Chadfish said:
Noiz - Does your audio sound notably slow - as in your voic sounds much lower? Or does it sound slightly slower?

I note this because I was having a problem a couple of weeks ago where FCP just started playing 48k stuff at 44.1. I trashed my prefs and it fixed the problem.


It could also be your audio interface has popped to 44.1 (My Motu Traveler did a couple of times) and I had to go into Utilities to fix it.
Click to expand...

No this is a fairly well documented bug (Apple supposedly told one post house it was an intended "feature"). The problem "may" be with capture settings not matching the sequence settings but it's not fixable after the fact. I was told by a canadian friend (the one Apple told it was a feature) that this applies to all .0 frame rates so PAL sequences are also vulnerable.

It's a pull up issue. And it becomes worse because FCP SRC on the fly so the standard work flow of using pulled up sample rates doesn't work. FCP "corrects" the SR and THEN pulls down the audio.
 
mcgeedigital said:
http://brucesharpe.blogspot.com/2009/06/dslr-dual-system-audio-999-solution.html

Creating a new FCPro preset solves this problem.
Click to expand...

This looks like it would also work. The catch would be for projects that are already started. I'm not sure how you would convert them.

The other little snag is that often the problem doesn't show up till you go to audio post. I was talking to some folks last night who are experienced professional pix editors and they were going "it's not really a problem because your only using a short clip at a time so the drift is minuscule. I had to point out that when they get the mixed track back from post it's an hour and a half clip and it's WAY off.

But thanks for the link I forwarded it to the guy doing this project. I'll link it on the DUC but as I said I think it's too late by the time we usually see it.
 
Also a new thing on the block is GRINDER from Red Giant that will preprocess Cannon footage and solve the non standard frame rate issue. It's in public beta and is looking good. BUT this of course needs to happen before the picture edit. So pass this on to the picture department if you can get to them before they start to edit.
 
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