Febuary, 2005

[This article was first published in the December, 2004, issue of Larry's Final Cut Pro HD Newsletter]
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Exporting Audio for Post-Production Sweetening

by Larry Jordan
www.larryjordan.biz

Many Final Cut projects can be mixed directly in Final Cut, especially using the new audio mixer that appeared in version 4. However, projects with more complex audio demands are more easily mixed using audio software like ProTools, Logic or Deck. As I am a big ProTools fan, this technique describes what you need to know to move audio out of, then back into, Final Cut Pro.

If you expect to do your final audio mix outside of Final Cut Pro, plan your project accordingly:

1) Change the starting timecode on your sequence to 00:58:30 to give you room to work

2) Add a 1 frame "pop" of audio exactly 2 seconds BEFORE start of first picture on all audio tracks to act as a sync point "just in case"

3) Add a 1 frame "pop" of audio exactly 2 seconds AFTER end of last picture on all audio tracks to act as a sync point "just in case"

4) Checkerboard your audio -- put audio from different scenes on different tracks

5) Don't worry about the mix in Final Cut

6) Give yourself handles where possible

7) Don't export audio until you've locked picture.

Once you have locked picture, that is, you are sure your video timings won't change, you are ready to export your audio.

You can do this one of two ways:

1) Export each pair of tracks as a stereo AIF file

2) Export the entire project audio as an OMF file

AIFFs can be read by any audio editing package. OMFs, which are far more flexible, are generally only readable by audio workstation software; for instance, DigiDesign's ProTools (if you are using ProTools LE you'll also need to purchase the DV Toolkit option ), Bias' Deck, or Apple's Logic.

The benefit to using OMF files is that all clips remain individual clips, so you can move them between tracks, each with separate volume and pan controls, as well as adjusting their in and out points and adding customized fades.

When you export an AIF, all clips on a track get consolidated into one large clip.

To export your audio as a Stereo AIFF

Export all your audio into separate audio pair files, then combine them in your audio editing application.

To do this:

1) Turn off the visibility lights on all but TWO adjacent tracks

2) Select File -> Export -> Audio to AIFFs

3) Name the export file (i.e. "Tracks"). QuickTime will automatically append the actual track numbers to the end of the file name.

4) Specify whether you want the audio exported as a stereo pair (where the odd number channel is panned left and the even number channel is panned right) or as a channel grouped (where both channels are panned center)

5) Repeat this process for all tracks in your project

6) Load the tracks into your audio editing software

7) Make sure the one frame audio pop exactly lines up vertically between all tracks.

8) Mix your audio

To export your audio as an OMF file

1) Make sure all tracks you want to export have their visibility light turned on

2) Select File -> Export -> Audio to OMF

3) Select the sample rate, bit depth and handles (48 kHz, 16 bit are fine, you might give yourself an extra second or two on the handles)

4) Open the OMF audio file in your editing application.

Note that OMF files contain all the audio from your selected sequence, so the files can get fairly large. (There is a 2 GB limit on OMF files, so, if you are doing lots of tracks for a long program, you'll probably want to break you sequences up into individual acts for mixing.

Getting your audio back into Final Cut

Regardless of whether you are exporting as AIF or OMF, you'll need to get your finished audio back to Final Cut. When you are ready, export your final mix as a stereo AIF file.

Then, inside Final Cut, import that final AIF mix into your Browser.

From there,

1) Move the new mix down to two new tracks on your timeline

2) Line up the audio pop just before start of picture on the new mix with the pops that you put into your original audio tracks. I've never had sync drift when I kept files fully digital. However, you can reassure yourself by checking the audio pops at the tail of the project and make sure they still line up.

3) Once everything is sync'd, turn off the visibility of all audio layers EXCEPT your mix and you are ready to output.