OMF and AAF - Help for Video Producers

Great video is two parts; great visuals and great sounds. The way to make good production audio even better is to transfer your project out of the video editing software and into a sound engineer’s audio workstation aka the audio mixer. People usually accomplish this is with OMF or AAF interchange file formats.

OMF vs AAF

Both these interchange formats accomplish a transfer between video and audio workstations but they have differences. OMF is more common, older, and widely supported. It has a 2GB file size limit and doesn’t support the transfer of some project data like track names and automation (with a few exceptions). The 2GB limit might sound like a deal breaker but OMF doesn’t have to encapsulate the audio. I’ve successfully translated OMFs of feature films on several occasions. So if the 2GB limit seems like a problem, you might just need to change some settings.

AAF is the newer interchange format and solves OMF’s limitation of size but is not as widely supported. Which one to use will depend on your specific metrics and the audio person’s software of choice. The truth…. Nothing this convenient is perfect and there are potential problems you will encounter with both.

Problems creating OMF and AAF

Interchange files don’t always work as advertised. I’ve seen many problem files, even from experienced editors who have sent other working OMF or AAF sessions. Depending on the program used (FCP, FCPX, Premiere, etc) or how you arranged audio clips within the project, it’s tricky to create an interchange session that translates perfectly.

How to Export OMF from Adobe Premiere

Update: As of 2014, Premiere has dramatically improved the OMF export function. Most projects exported from Premiere’s file menu are translating perfectly. That said… much of the information below can still be helpful.

A few potential problems Premiere can encounter are listed here. If you know of others please comment and I’ll update this list.

• Starting a project in FCP and moving it into Premiere.
• Using Nested Audio clips
• Using Premiere to split stereo recordings into mono or dual mono.

For Premiere users, try the built in export process but if you have problems the best solution is to use Adobe Audition to create the OMF. Here’s how.

1. In the project window of Premiere select the desired sequence, right click, and chose “Edit in Adobe Audition” and then chose “sequence”. Doing this brings up a dialogue box asking where to save.  (Just so you know Premiere will create its own subfolder with the name of the sequence, so there was no need to create a new folder.)
2. Under the “Selection” bar chose “Entire sequence” but only if you have a clean timeline with no added bits and pieces.
3. Choose 5 seconds worth of handles. That’s usually enough for your audio person to manage the edit and find some patching material if needed.
4. Don’t bother checking “export Preview video” if you have already created a reference picture. I usually recommend doing this separately.
5. Finally, check all three “Render Audio Clip Effects” and “Send clip volume Keyframe Metadata” and “Open in Adobe Audition.”
6. Once Audition opens up, go to the “File” tab. Go to “Export” and from there you can export either an either encapsulated or referenced OMF.

This process has worked for my clients. The OMF created from this process translates very well in Pro Tools, Nuendo, and Cubase. I haven’t tested this with other DAW platforms.

Premiere OMF Settings Reference:

• Encapsulate With this setting, Premiere Pro exports an OMF file containing the project metadata and all the audio for the selected sequence. Encapsulated OMF files typically are large.
• Separate Audio With this setting, Premiere Pro exports individual mono AIF files into an _omfiMediaFiles folder. The folder name contains the OMF filename. Using AIF files assures maximum compatibility with legacy audio systems.
• Copy Complete Audio Files With this setting, Premiere Pro exports audio for the entirety of each clip used in the sequence, no matter how many times the clip is used nor how many parts of the clip are used.
• Trim Audio Files With this setting, Premiere Pro exports only the portions of each clip that are used in the sequence: the clip instances. You can choose to export each clip instance with extra length, handles, added to the start and end of the file.

Premiere and AAF?

Despite being new on the scene, AAF suffers from it’s own quirks. Since Audition doesn’t support AAF, the workaround above won’t help. Personally I’ve not seen an AAF problem with Premiere but the boards are full of complaints and errors. One documented issue is using “Merged Clips” in your session. Here are some points regarding AAF.

• The AAF files exported by Premiere Pro are compatible with the Avid Media Composer family of editing products. These AAF files have not been tested with other AAF importers.
• Transitions should appear only between two clips, not adjacent to the beginning or end of a clip. Each clip must be at least the same length as the transition.
• If a clip has a transition at both its In and Out points, the clip must be at least the same length as both transitions combined.
• When naming clips and sequences in Premiere Pro, avoid using special characters, accented characters, or characters that affect the parsing of an XML file. Some characters to avoid include /, >, <, ®, and ü.
• AAF files exported from Premiere Pro and imported into Avid Media Composer do not automatically relink to the source footage. To relink the footage, use the Batch Import option in Avid Media Composer.

Note: In Premiere Pro CS5.5 and later, merged clips are not supported when exporting an AAF file.

OMF AND AAF with FCP7 and FCPX

Final Cut Pro 7 has the ability to create OMF but this was removed for FCPX. While there may be some Apple-centric solution, most of my experience has been that 3rd-party software does the best job. FCP7 would often create OMF files that wouldn’t open or had poor sync issues once translated. We found that using FCP7 and Automatic Duck to create OMF (v2.0) compliant files worked best.

As for FCPX, I’ve read that many people are using X2Pro or the Xto7 App for creating interchange files. Here’s another workaround method for FCPX. I’m not sure I’d recommend this over X2Pro but it just illustrates the adage “more than one way to skin a cat” applies for interchange format workflows.

FCPX OMF Workaround from Jef Gibbons.

Wrap-up

One more mention for 3rd part applications…. AAtranslator is a program that boasts interchange management between all major media platforms; Avid, FCP, Premiere, and most every audio program.

I’d like to hear your experiences and workflow methods. Please leave a comment with any suggestions, corrections, or additions.