Deva Sound Files and Damaged Resource Forks

A lot of sound recording for film and television is moving to the Deva II hard disk recorder. They’ve been around for several years but if the recent conversations I’ve had with production mixers are any indication, we fear change.

Actually I think post-production sound tends to embrace new technologies, but lets face it when you’re on the set or on location with a production, you’ve got one chance to get that recording right. So I don’t blame mixers for being a bit hesitant to jump on the non-linear digital bandwagon.

Here’s the problem:

The Deva II mirrors to a DVD-RAM disk as it records to a hard drive. Those DVD-RAM disks become the sound rolls for the production. There are two sizes of DVD-RAM disks–2.6 GB per side and 4.7 GB per side. The older 2.6 GB drives are not compatible with 4.7 GB disks.

The Deva II formats in MS-DOS FAT16 format, but if you set it to record Sound Designer II (SD2) files, these are Macintosh files with resource forks. In post-production, if you use a SCSI DVD-RAM drive, there is software that can be installed in OS 9 to give you proper access to the SD2 files. No problem.

Unfortunately SCSI DVD-RAM drives are no longer made and have not been made for about a year or so. There is a very limited supply of rental SCSI DVD-RAM drives in Los Angeles. Only Firewire DVD-RAM drives are available for purchase now. Plus according to Apple, OS 9 has been dead for about a year and half. All new Macintoshes only boot into OS X.

Thankfully OS X comes with drivers for DVD-RAM drives built-in. Plus it supports the MSDOS FAT16 format. So if you buy a Firewire DVD-RAM drive, plug it into your OS X-based Macintosh, and insert a DVD-RAM disk from a Deva II, it will pop up on your desktop. No additional software needed.

There is a problem with this. Apple’s implementation of the MSDOS FAT16 filesystem under OS X does not properly deal with resource forks. They get stripped out of the file and appear under another directory as separate files. For something like SD2 files, this means that you lose your source timecode information which is critical for doing an auto-assembly of you production dialogue track.

The easiest solution is to record all the production sound on the Deva II in the Broadcast Wave (BWF) format. This is a flat file with no resource fork so there is no problem with losing timecode. Plus Digidesign Pro Tools, the digital audio workstation that most of us in the post-production sound industry use, fully supports the BWF format.

This solution is not always available. Often you get sound rolls from the production after shooting has wrapped and there was no conversation with the production mixer. It might be in SD2 format and there’s nothing you can do to change it at that point.

I’ve developed an AppleScript that makes use of two other programs–ToggleFork and Resploder–to fix this problem. Take your DVD-RAM disk. Insert it into your Firewire DVD-RAM drive under OS X. Copy the entire disk (including all folders) over to your working hard drive (it can be SCSI, Firewire, internal, it doesn’t matter). Run my “Deva SD2 Fix” AppleScript and point to the folder that contains the Deva sound files when you are prompted. That’s it. It’s pretty simple and only take a minute or so to fix an entire sound roll.

Let me know if you have any problems with this.

Download Deva SD2 Fix.
Download ToggleFork from me.
Download Resploder from me.

NOTE: I didn’t write ToggleFork or Resploder. Other people did. Also, Apple released OS X 10.3.3 yesterday. It’s possible that MSDOS FAT16 resource fork bug was fixed in this release. I’ve been in touch with Apple trying to get this fixed for many months now. I haven’t had a chance to try out the new OS software and see if it now works.