Oasis Digital Audio Post Production

OMF Output And Delivery (Detailed)

1. Preparing For OMF Transfer

Make a copy of the final sequence (or sub out an audio-only sequence) and place it in a new bin designated for OMF transfer. Remove all video tracks from the duplicate OMF sequence. Ensure that all media in the sequence is online. If any media is off-line during the OMF export, the transfer may fail.

Remove all audio EQ and compression effects from the sequence. Render all audio dissolves in the sequence. Any un-rendered audio effects remaining in the sequence could cause the OMF transfer to fail. OMF files may be delivered on a Firewire drive, CDR, or DVD-R. Delivery is also accepted over FTP/email (please call us before though) If multiple sequences are to be exported, create an appropriately named folder AFTER each export to ensure that all media will remain separate. However, complete each export in its entirety before outputting an additional sequence.

2. OMF Export

Open the bin containing the prepared sequence. Select the sequence and choose “Consolidate” from the Clip menu. In the Consolidate dialogue box, make the following settings:

1. DO NOT Select: Delete original media files when done.
2. DO NOT Select: Skip media files already on target disk
3. Select: Appropriate target delivery disk
4. Handle Length: 150 frames usually works just fine
5. DO NOT Select: Consolidate all clips in a group edit.
6. Click “OK” to begin consolidation.
   

Immediately after consolidation, make sure the sequence is still selected in the bin, and select “Export” from the File menu. DO NOT move the OMFI MediaFiles folder that has just been consolidated on the target drive. The sequence that is pending export is now re-linked to the media that has been consolidated to the target drive; relocating or hiding that media will bring it off-line and the export will fail.

3. In the Export dialogue box, choose the following settings:

1. Select: OMFI Compositions Only
2. Select: SD2 Format Audio
3. Export as: OMFI 2.0

Click OK to continue. In the Save dialogue box, save the OMFI file to the target OMF delivery drive. You will be prompted to name the OMF sequence upon export. Please export a version 2.0 sequence, naming each appropriately. Following this final export step, the OMFI MediaFiles folder can be moved. It can now be placed in an appropriately named folder with the exported OMF sequences. Thus, if subsequent sequences must be output, the media for those sequences will remain separate and hidden. This is to prevent all the media for several separate shows from being consolidated to a single OMFI MediaFiles folder. Once again, DO NOT move the media until you have completed the export process.

4. OMF Tool

Oasis Digital can convert the OMFI file to a Pro Tools session and re-link all consolidated audio. However, you can check Media Composer Version 9 and previous exported sequences by using Digidesign’s OMF Tool. This downloadable utility will convert the OMF sequence into a Pro Tools session (www.digidesign.com > support > downloads > OMF Tool.). (Sequences exported from Version 5 of Media Composer can only be translated with the older OMF Tool 1.12).

If any media was off-line during the export, or if any portion of the output failed, the OMF Tool will indicate so during conversion. This can eliminate a tremendous amount of wasted time and effort by ensuring that an OMF export has been successful prior to its delivery to our facility. Please DO NOT remove any media from the AVID until we have confirmed that the OMFI to Pro Tools transfer was completed successfully.

These steps should ensure that an OMF sequence and its corresponding media are successfully delivered for conversion to a Pro Tools session.

5. If the OMF export fails

Double check to make sure that all media is online, and that the entire sequence has been rendered and is free of Plug-In effects. Pro Tools’ native file format is SD2 (as of 2005 it has become WAV). Any media in the sequence that has not been digitized as SD2 (or WAV) files, must be converted. This conversion is performed automatically upon export of the OMF sequence. A folder entitled “Exported Audio Media” will be placed on the target drive of the exported sequence. Make sure that this folder accompanies the OMF transfer to Oasis Digital. Often times, one chunk of corrupt media can cause an entire OMF transfer to fail. Splitting the sequence and performing separate transfers can sometimes solve the problem. Be sure to place the OMFI MediaFiles in appropriate folders during each transfer to ensure that all media remains separate.

6. AIFC Export

If none of these steps provide a successful transfer, an AIFC Export is another option. This process bypasses the consolidation process completely. It results in a single, massive file that contains the requisite data to extract a sequence and its corresponding media upon conversion. Because a handle length cannot be specified, all digitized media that is used in the sequence will be transferred in its entirety. The AIFC export is a single step process.
Select the sequence in the bin, and choose “export” in the file menu. The dialogue box will vary depending upon the version of Media Composer you are using.

1. Select: OMFI Composition, standard AIFC, audio only.
2. Version: OMFI 2.0 Select: With Media.
3. Make sure the target drive can accommodate a rather large (1-2 GB) export.
   

7. Media Composer Version 10

Because Version 10 software allows multiple file digitization formats within a single sequence, and does not default to Sound Designer II in its General Settings, the standard OMF export process usually fails. For this reason, Version 10 offers an “AVID Links” option directly beneath the “export” option on the File menu. Simply select the sequence to be exported (making certain it contains NO video layers), and choose “AVID Links” under the File menu. Select Digidesign Pro Tools and Embed Media in OMF file. This is basically an AIFC export, so handle length is not an option. You will not need to consolidate any media, because it will be embedded in the OMF sequence. Again, make sure the target drive can accommodate a rather large export.

Exporting your sequence from FCP

Highlight your sequence in the Browser and click File > Export > Audio to OMF  

1. Set the Sample Rate to 48k and 16-bit (which is the default)
2. Set Handle Length to 00:00:05.00
3. Be sure to turn OFF "Include Crossfade Transitions"
4. Click OK

Save the File using a short descriptive filename (keeping the ".OMF" extension) to your removable firewire drive or DVD/CD for delivery to Oasis Digital.

The .OMF file which is created contains all of your project audio, sequence timecode information. None of your audio mixing from Final Cut will transfer (volume changes, EQs, effects, etc).

OMF has an internal limit of 2 GB. This translates into ROUGHLY 6 tracks of mono, 16-bit audio, each one-hour long. (A 16-bit mono audio clip is roughly 5 MB per minute.)

If you try to export only part of a sequence to an OMF file, setting In's and Out's won't work. Using OMF always exports the entire sequence, regardless of how In's and Out's are set.

Consequently, if your OMF file threatens to be larger than 2 GB, turn off some of the Track Visibility lights on the far left of your Timeline. Only tracks who's visibility lights are lit (glowing green) will be exported. Then, export in sections, where each OMF file is, say, tracks 1 thru 6 and the second section is tracks 7 thru 12.

Audio Help Guide

This page is dedicated to helping you achieve the best possible sound for your project before you bring it to us.

1. Common Issues

One of the most common issues we come across in audio post is low or almost flat lined sound files. This is easily corrected in the mix but is time consuming and can result in a noticeable quality loss. The two predominant causes for this are low recording levels by the production sound mixer and overly cautious digitizing into the AVID.

Be aware that the audio level meters on an AVID are of the PEAK kind. They do not reflect the “denseness” of the sound just the peaks. They will bounce around a lot, often way into the red areas, this is fine, don’t panic! As long as the little “peak” or “overload” indicators do not flash you are safe. Take some deep breaths and try to relax, do not be tempted to adjust, or worse, ride the levels for this.

2.Digitizing from Analog

When digitizing audio from analog tape sources try to keep the signal path as direct as possible. Directly out of the recorder into the AVID if possible. If you must route signal through a mixer prior to the AVID make sure it is set up correctly. This is a very common source of all kinds of bad audio.

The trim pots at the top of the channel should be kept all the way down (fully anti clockwise) this is the “line level” audio setting. If you are recording a microphone, maybe for a scratch v/o track, this trim pot will be turned to about the three o’clock position and is then at “mic level”. The faders should then have a full range of motion, with unity being about three quarters of the way up. If the faders are typically at the bottom quarter or less of their range your audio will probably tend to sound thin, crispy or even distorted.

Check on the mixer to make sure you are not double bussed. Those little buttons usually just above or beside each channel fader are for routing the audio out of the mixer. If your audio sounds phasey it could be being bussed out into the AVID and then where the AVID returns back into the mixer being bussed again back into the AVID, the resulting time delay causes the audio to be slightly out of sync and therefore phases.

3. Microphone tips

Please try to keep mic choices as consistent as possible, or give us the ability to choose. Switching between a lavalier and boom will generally sound bad (unless it’s for perspective). If you edit to the production mix or “line cut audio” please know that there is little we can do with it. We can’t un-bake the cake. Likewise, reverb can only be added. It is nearly impossible to remove ambience from an echoey location without making it sound equally bad in some other way. If someone is not mic’d then we probably will not be able to hear them, I know this sounds obvious but you’d be surprised!

Try to budget for a good audio mixer and then let him do his job. Don’t force him to bury mic’s under layers of clothes unless absolutely necessary, it can sound muffled, hard to understand and in some cases scratchy. A good audio mixer will not be scared or intimidated to hold up production for a few minutes while he fixes a problem, after all he wants the same thing you do, good clean audio. Please try to check the audio levels off tape before moving on to the next shot or location… if it is too low, distorted, or didn’t make it to tape at least you will know in advance and possibly be able to re shoot or do some pickups. Bare in mind that these issues are very often not fixable in post.

4. Ambience and Room Tone

One other thing we often come across while doing the dialog cleanup pass is the need for ambience or “room tone”. Whenever possible try to get at least a minute of silence for this, record it from whatever mic or mic’s you were using for the scene so that it matches, and make sure the editor knows where it is. If it doesn’t make it into the OMFI we will probably never see it in post.

5. Organizing Your Tracks

When organizing your tracks prior to the shoot it sometimes helps to have a “mics only mix” this is generally pretty easy for the production mixer to provide and is a good compromise between getting every single mic of a multi mic shoot as an iso, and everything mixed together in a “line cut”. Even a combination can work well; "host ISO" and "mic's only mix (minus host ISO)" for instance would work well. Of course if it’s possible to get iso mic choices picked by the editor in the OMFI that would be very nice, thank you!

6. One Last Thing

One last thing, the audio that you digitize into the AVID is the same audio that comes to us in the OMFI, and the same audio that airs.

Please be gentle with it… We’d much rather be spending our time (and your dime) mixing than fixing