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Steps in Sound Post Production, Part 1
By Carmen Borgia

When producing a film or video project, there are a number of sound elements that you may need over the life of the project. Here is a brief description of the steps that are likely to be involved. Projects that move through multiple frame rates may have additional steps. This description is centered on the Pro Tools digital audio workstation.

Production sound
This is sound which is recorded when you shoot the project, usually a 2 track format. Varieties of tape formats include DAT, 1/4Ē tape, and video tape. Hard disk and random access formats include Deva, Fostex DVD, Aaton and others.

Sound editing during the picture edit
The production sound gets loaded into a non-linear editing system (NLE) such as Final Cut Pro, Avid, Premiere and others. Some systems, notably Final Cut and Avid are friendlier to doing sound work in other systems, which in our case will be Pro Tools.

The production sound is typically one or two tracks; once in the NLE there are many more tracks available. This feature is useful for adding more sound and for organizing the sound so that it can be mixed. In the old days, we tended to do minimal sound work in the picture editing system and then do a sound edit where effects and music were added. These days the sound edit can happen during a picture edit in the NLE or there can be a separate edit in Pro Tools depending upon the needs of the project. Documentaries and other less-complicated forms are frequently prepared in the NLE by the picture editor. Narrative features often have a separate sound edit in Pro Tools to allow for more involved dialogue, music and effects work.

An edit that is properly prepared for mixing can be anywhere from a few tracks to a hundred or more. A typical track layout for documentaries uses between 10 and 24 tracks. Simple narrative features fall between 24 and 40 tracks. More complex projects requiring detailed sound design and 5.1 finishes will usually use more tracks.

OMF export
Letís say that you have 16 tracks of sound in your Final Cut Pro system. Youíve got 8 tracks of dialogue that have been arranged by scene and the kind of microphone used. There are 4 tracks of effects to add a bit of atmosphere and there are 4 tracks of music (2 stereo pairs). Youíve taken the sound work as far as you can in Final Cut and you want to give it to a person with a Pro Tools system to make it better by mixing it. There is a way to transfer your existing sound work intact from Final Cut to Pro Tools called an OMF export. This means that if you have 16 tracks of audio in your picture edit, those same 16 tracks can be turned into a Pro Tools session, including the audio media. This is the fastest, simplest and most efficient method of getting your sound into Pro Tools.

I cannot give you a click by click guide to doing an OMF export, as systems vary; you will have to consult your manuals for that. Hereís an FAQ:

Can every NLE system do an OMF export?
No. The system must support OMF exports as part of the software. Final Cut Pro and Avid support OMF exporting and importing as a standard feature. Pro Tools supports OMF exports and imports, but you have to purchase a special software upgrade to make it work. If you are in doubt, consult the manufacturer of the NLE.

What is included in the OMF export?
Audio regions on the timeline are included. Clip based gain and those little triangular rendered fades are included. Effects are not included. Picture is not included.

Are there any particulars to the OMF export that I should know?
Yes. If there is an option, exports should be type 2. Exports should be embedded, in which all of the audio media gets rendered into a big fat file. The sample rate of the export should match the sample rate of the NLE, which is often 48 kHz. You should specify generous handles for the audio; letís say 300 frames, which are used to help smooth everything out in the mix. You should generally not process the sound in any way prior to mix; donít use equalizers, compressors or other effects.

How do I get the OMF to the sound person?
Export the OMF to a firewire drive and bring us the firewire drive. You can also burn it to CD or DVD. Weíve also received OMFís by FTP and on Ipods.

Can the OMF get screwed up?
The OMF usually works well. When there are problems they are in one of two areas: the export was done improperly or there is some transfer issue, like the hard drive not mounting or the CD not being readable. Good practice means getting the OMF to your sound folks a few days in advance of the mix so that the export can be redone if necessary.

Sound editing in a Pro Tools system
Once we get the OMF, we can go to work in Pro Tools. It is possible to do more detailed dialogue work here as well as adding more sound effects: hard effects like doors slamming, phones ringing and ambience effects. Pro Tools is great for additional sound design work. If the job is particularly detailed or complex, several Pro Tools systems may be utilized; one for dialogue, one for foleys, one for other effects, etc. The sound editors or the audio post production supervisor will usually figure out who gets what.

Music composition and editing
Somewhere in this process, music is either composed or edited. If a composer is creating original music, they will use their own recording system which may be Pro Tools or any other high-quality music recording system.


Carmen Borgia is the head of audio services for DuArt Film & Video in New York City. He oversees a post production sound department that provides mixing, sound design, restoration, transfer and printmastering. His department caters to independent projects in all formats from mono optical up to digital 5.1.

Editorís note: Part 2 will be in our October issue. If anyone has any questions, please submit them to cborgia@duart.com. Carmen will do his best to answer your queries.


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