Video is 44KHz, Sound is 44.1

Question

Level 1

127 points

Video is 44KHz, Sound is 44.1

I taped a performance (one long shot, one close up) with two different camcorders with the idea that one would have better sound and the other would be a long shot.

I did not realize that the close-up camera, records at 44.1.

I'm assuming the audio will drift, or do I change capture settings for audio between one and other? Not sure how to do this. I thought use the 44.1 as the "master" and just capture the long shot without audio, but do I convert it so the speed won't drift?

My capture settings in FCP are for 48 since the camera I usually use has that setting. Should I convert it from 44.1 to 48 in something like itunes?

Any help or references much appreciated.

thanks
enzosf

iBook G4 1.25G/G5 2 Gig DP 1.5Gig RAM, Mac OS X (10.4)

Posted on Sep 25, 2006 9:23 PM

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Answer 1

Sep 26, 2006 12:16 AM in response to Enzo Lombard

Okay -- there are 3 different audio sample rates I'll be talking about here: camera settings, FCP capture settings, and sequence settings.

Your settings in FCP for CAPTURING a clip should match the settings the CAMERA used to record that clip.

That means you'll end up with captured clips from the "long" camera with audio at whatever the sample rate for that camera was and from the "close-up" camera at 44.1kHz.

As for the audio sample rate settings for the FCP SEQUENCE -- it doesn't really matter to FCP what settings you use for the sequence, although I'd use 48kHz (but mostly out of superstition.) That said, you will want to set the sequence audio sample rate to match the highest of the clips you captured to retain at least the quality of that clip in the sequence.

FCP is designed to recognize differences like this in clips so the audio won't (read: shouldn't) drift. When you use the differing clips in a sequence, FCP will force them to match to the settings in the sequence and will render whichever clip(s) have a different audio format.

To change capture settings, I would advise setting up two different camera profiles (called "presets" in FCP). To do this, go to Final Cut Pro->Audio/Video Settings, click on the Capture Presets tab.

Next, find a preset that's closest to the settings of your camera (do them one at a time). If you used a typical DV camera, then you'll probably just want to use DV NTSC 48kHz. Click on it and hit "edit." FCP won't let you change the settings for that preset (it's locked), but it will copy the preset for you and let you edit the copy. Rename it to the name of your camera and make sure the settings match how the clip was recorded. If you need more detailed help on this, check the FCP manual.

Hope this helps.

Cheers,
SA

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Answer 2

Sep 26, 2006 9:02 AM in response to Scott Andrews

"FCP is designed to recognize differences like this in clips so the audio won't (read: shouldn't) drift. "

While this statement is correct, I still have doubts whether the 44.1 clip will sync up to your other cameras.

Everything Scott said is true, but what I would suggest is, after capturing the 44.1 camera as 44.1, close FCP and open that clip in Soundtrack Pro. Resample it as 48khz and save it. Reopen FCP and make sure that clip now reads 48khz.

Click Here and scroll down a ways. I typed a long explanation of why the clip actually needs to be resampled. This particular explanation pertains to 12 bit vs. 16 bit, but the same theory applies to 48khz vs. 44.1khz.

Judging by your post, if you're syncing to another audio source that has been delivered on audio CD, you'll need to resample that as well. Resample so everything you're working with is 48khz.

FCP is designed to work with other bit depths & frequencies, but often it does so by slightly speeding up or slowing down footage to fit in the settings of your sequence. Generally, this is fine, unless you're trying to sync multiple angles and a sound source.

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Answer 3

Sep 27, 2006 2:08 AM in response to thrillcat editorial

I'll definitely second that suggestion.

I've also used Quicktime Player to resample clips to 48kHz before, too, and seem to get better results in FCP by resampling in general.

Seems like anything you can do to take the load off of FCP, the better off you'll be for it.

Cheers,
SA

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Answer 4

Enzo Lombard Author

Level 1

127 points

Sep 27, 2006 10:33 PM in response to Scott Andrews

Thanks for this. I created a new capture for the 44.1, captured both clips at their respective settings. Set the project / sequence preset to 48 KHz and dropped both clips in and had absolutely no problems. That's a first. I went 20 - 30 minutes into the show and once i synced the two clips (by playing audio on both until I lined them up) it matched perfectly all the way through.

Thanks so much. Sorry I tried to post earlier but I think the boards were down because I could get the discussion boards for a few hours.

thanks again
enzosf

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