As composers, we are all accustomed to delivering audio (and sometimes even video) information under many different circumstances and in many configurations. As an audio engineer, I am often on the receiving end of this information, and I’ve seen just about every disaster you can imagine.

You are going to see a lot this month about “delivery”—stems, dubs, pre dubs, etc. I want to jump in and give you some info on two delivery formats that you may or may not be too familiar with, in hopes that they will help give you a more solid method for getting your content shipped around the world.

I want to talk to you about the OMF and AAF file formats. You may need to deliver your projects in one of these formats at one time or another in addition to stems, or may receive one of these projects with video, temp music, etc. These files formats are not perfect and may need additional work when receiving one of them. However, learning to utilize each of them can make your deliveries a little more headache-free as well as more efficient on your time. That being said, if you are working on a fairly uncomplicated project, in the end, it may ultimately be simpler to just bounce your tracks individually or to stems based on your clients needs.

Definitions
OMF (Open Media Framework, also known as OMFI—Open Media Framework Interchange) is a platform-independent file format intended for transfer of digital media between different software applications. It was developed by Avid in 1994.

The OMF file format is typically used to exchange data with Digidesign Pro Tools software. The OMF format only supports the exchange of audio data (audio media and the use of this audio media in a project)—MIDI and automation data is ignored when using the export functions. (Pro Tools LE and HD need the Optional DigiTranslator software (~$500) to use OMF or AAF)

AAF is the Advanced Authoring Format (AAF), and was developed by the Advanced Media Workflow Association in 2000 to expand on the OMF framework. AAF was created to help address the problem of multi-vendor, cross-platform interoperability for computer-based digital video production.

Wikipedia describes AAF in two parts:

1) Audio, video, still image, graphics, text, animation, music, and other forms of multimedia data. In AAF, this kind of data is called essence data.

2) Data that provides information on how to combine or modify individual sections of essence data or that provides supplementary information about essence data. In AAF this is called metadata. The metadata in an AAF file can provide the information needed to combine and modify the sections of essence data in the AAF file to produce a complete multimedia program.

What You Should Know
OMF/AAF files are platform independent and include metadata, along with the audio and video data, and were originally developed with video editing programs from video post-production facilities. Audio could then be edited and cleaned up, mixed and sent back to the video house with the final video for final layback. You can use these formats for audio-to-audio type scenarios, but be aware that originally the formats where designed to be more a one-way workflow, rather than a back-and-forth one.

The metadata included in the project file is very generic in nature. It does not store any information on plug-ins, or routing of your internal busses. It does not store MIDI tracks, regions and tempo maps. However, track automation and fades are supported, but may not transfer perfectly. Therefore, you may have to consolidate all of your regions before sending the final project or print/bounce your tracks to stems.

Also, save your midi tracks to SMF or bounce them to audio tracks/stems. These SMF’s will include the tempo information of the session.

You will also have the option of (embedding) keeping your audio files within the project or keeping them in their external location. In most cases, having the audio with the project or sequence makes file management easy. File size, can be an issue with embedded files. Pro Tools, for example, cannot read an embedded OMF or AAF larger than 2 GB. Consult your DAW’s documentation for OMF/AAF instructions and limitations.

Try to use BWF (Broadcast Wave files) if you do not currently, for the best compatibility. You may have to convert your audio files prior to exporting the OMF/AAF.

Documentation
Careful marking and documentation is key when using OMF or AAF formats. Make sure to name all tracks, regions, etc. before exporting. Track and session notes/comments do not translate, so write down your session information like (tempo, frame rate, timecode offset, etc) in a text file or PDF and include it with the OMF/AAF project.

Check your DAW’s documentation for exporting/importing OMF/AAF files. Different options are offered, such as converting 24 bit to 16 bit, exporting names, etc.

Conclusion
OMF and AAF may give you many options, but as mentioned above there are many options and potential tweaks that may need to be handled. However, if your client asks for delivery of one of these formats, hopefully you will be armed with more information to be able to deliver.
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RANDY KNAUB is an audio engineer, producer, songwriter, keyboardist, and music technologist. He composes music and sound bites at his northern California studio, and works with local artists recording demos and CDs as well as pursuing corporate multimedia clients. Randy also consults for and beta tests for numerous music software and hardware manufacturers. His clients range from Martin Marietta, McDonalds, The United Way, Colorado Lottery, Visual Communications Group, and Jeppesen. You can find his SCOREcast bio (and links to his other sites) here.