In a perfect digital world, collaboration with other electronic musicians would be a simple matter. Sessions would be passed seamlessly between DAWs. Unfortunately, you don't live in that world, and you probably won't — at least for a while. There are accepted standards such as Broadcast Wave (BWF) and Standard MIDI Files (SMFs), but what about your audio edits? That's what OMF and AAF files are for, though they're not perfect yet.
FIG. 1: OMF and AAF provide the common ground for different DAWs to transfer session data back and forth for collaboration.
The Open Media Framework (OMF) is an interchange format devised by Avid in 1994. The Advanced Authoring Format (AAF) was developed by the Advanced Media Workflow Association (www.aafassociation.org) in 2000 to expand on OMF. Both enable a DAW or nonlinear video editor to export essential session parameters along with audio and video data in a format that can be read by another DAW or video editor. All of the major DAWs support OMF, and most support AAF, although Digidesign Pro Tools LE and HD require the $495 DigiTranslator add-on in order to use either OMF or AAF. (Pro Tools M-Powered does not support DigiTranslator.)
OMF and AAF provide a platform-independent file structure for describing media data, namely video and audio files, and metadata, or information about these files and how they are arranged in a project (see Fig. 1 and “Step-by-Step Instructions” on p. 64). In a common post-production scenario, the edited video session is exported as an OMF or AAF sequence and sent to the audio team to be imported into their DAW of choice. After cleanup, editing, ADR, sweetening, and mixing, a final mix is sent back to be integrated with the final video. Note that OMF/AAF in this case is a one-way street. The video-centric roots of OMF/AAF and the downstream-only perspective, as far as audio is concerned, limit its use in music production scenarios.
Because they are generic, OMF and AAF don't describe complex program-specific parameters such as plug-ins and internal busing. Track automation, fades, and slip-edits are described, but they may not translate perfectly. MIDI tracks, regions, and even tempo maps are not provided for in OMF/AAF sequences.
To make OMF work for you, then, you must approach it with realistic expectations. Do not expect to be able to take an Apple Logic mix that is 90 percent ready to fly and move it into Pro Tools for the final touches. Even if you had used only plug-ins that are available within both hosts, the routing and plug-in settings would not translate. OMF and AAF, however, are useful during tracking and overdubbing. For example, sending an OMF version of a Nuendo session to a Sonar studio for vocal editing and tuning should work just fine.
From your DAW's Save As or Export function, choose OMF or AAF. Which is better? During informal testing with my Full Sail compatriots, we had great success moving OMF sequences between all the major DAWs until we tried to go between Pro Tools and Steinberg Nuendo. Fortunately, an AAF version of the same session translated perfectly between those two. Based on this, you might be inclined to trust AAF more, but alas, not all DAWs support AAF. Whenever possible, export both formats.
If you don't ordinarily use BWF files, convert to that format on export for best compatibility. You will most likely have the option of embedding audio files into the sequence or leaving the audio external, as in most DAWs. Embedding creates simpler file management, as there is only one file to keep track of. It also facilitates the workflow for some DAWs. For example, Cakewalk Sonar can extract information about the audio's sample rate and bit depth from an embedded OMF but requires you to enter that information manually otherwise. File size, however, can be an issue with embedded files. Pro Tools, for one, cannot read an embedded OMF or AAF larger than 2 GB.
MIDI tracks do not export at all, so save them as an SMF. Even if your original session has no MIDI tracks, saving an SMF enables you to transmit tempo information to the destination DAW.
Document everything! Name all tracks, regions, and files before exporting. Track and session comments won't translate, so write down critical session information and tracking notes — tempo, frame rate, timecode offset, and so on — in a plain text file, and include that file with the OMF. If you plan ahead and allow time for surprises, OMF and AAF can be highly effective in bridging the gap between different applications.
Click here to see step-by-step instructions on moving projects between DAWs using OMF.
STEP 1: In Sonar, export the project as an OMF sequence (File, Export, OMF).
STEP 2: Choosing to embed audio within the OMF file helps avoid any file and path name confusion in the target DAW.
STEP 3: Save the project as a Type 1 Standard MIDI File (File, Save As) to convey tempo information.
STEP 4: In Logic, open the Standard MIDI File (File, Open).
STEP 5: Import the OMF sequence and choose a folder for the audio files (File, Import).
STEP 6: The essential content of the Sonar project is now the basis of a Logic song, ready for overdubs, further sequencing, editing, and mixing.
Brian Smithers would like to thank his colleagues at Full Sail Real World Education for their hard-won expertise on OMF and AAF.