Subject: Re: [linux-audio-dev] File interchange with ProTools?
From: Paul Winkler (slinkp23_AT_yahoo.com)
Date: Mon Aug 07 2000 - 14:35:55 EEST
Kevin Hremeviuc wrote:
> I agree that using an interchange file format is a
> good idea. If it's a standardised format, then just
> maybe it's been done from a holistic view point
> (probably wishful thinking on my part).
Well, it's at least done from a point of view that lets several
major manufacturers agree on it... don't know how "holistic" that
would be. My quick searching has turned up some articles where
people mention "foot-dragging" by Avid since they control the
ProTools format and they like making money by licensing it, whereas
they don't make anything from OMFI. But customers are demanding open
interchanges, very loudly.
> I haven't had a look at the links mentioned yet, but
> does this include midi and audio used together (as per
> cubase and cakewalk (and Mac oriented studio
> sequencers))? Because I would like to use audio and
> midi together i.e. midi instruments playing in synch
> with audio, as well as midi controllers assigned to
> audio real time effects. A file interchange format
> that encompasses this would be ideal.
For OMFI you can get the general idea from their promotional blather
at
http://www.avid.com/3rdparty/omfi/whatis/omfibrochure.html
Note that there's no mention of MIDI on this page. :-(
For AAF, I found this excerpt from
http://www.AAFassociation.org/techinfo/whitepaper.html
"The Advanced Authoring Format is a structured container for media
and metadata that
provides a single object-oriented model to interchange a broad
variety of media types
including video, audio, still images, graphics, text, MIDI files,
animation,
^^^^^^ ^^^^^^^^^^^
compositional
information and event triggers. The AAF format contains the media
assets and
preserves their file-specific intrinsic information, as well as the
authoring information
(in- and out-point, volume, pan, time and frame markers, etc.)
involving those media
assets and any interactions between them."
As for AES-31, I hadn't heard about it so I went looking. This
turned up some interesting facts:
--The EDL for AES-31 is in ASCII rather than binary, which is nice
for developers and end-users alike. Compare this to OMFI which uses
a binary EDL.
--It costs $40 to get the AES-31 spec either electronically or in
print.
http://global.ihs.com/doc_detail.cfm?COUNTRY_CODE=US&LANG_CODE=ENGL&document_name=AES31-3
--The spec for the ASCII information is finished, but they're still
talking about a standard media and filesystem, I guess so people can
treat an AES-31 media (e.g. jazz disk or portable hard drive) as a
black box which can plug into any supporting DAW and know it will
work. Sounds like they might settle on FAT-32 and SCSI. We probably
don't need to worry about that so much, and indeed some
manufacturers have plunged ahead and already implement the existing
spec.
-- I can't find anything about MIDI in the pages I've seen on
AES-31. I think it's only meant for audio with some sort of time
code.
--AES-31 is partly intended to make some vague parts of OMFI
standardized, such as what precisely a crossfade means. Video
post-production people might not be bothered so much of crossfades
sound slightly different on two different machines, but it's driving
the audio engineers nuts.
In summary, OMFI and AAF are intended for multi-media applications
such as video post-production, so they support many types of data
including a bunch we're probably not concerned with. AES-31 is
specifically intended for digital audio workstations and only deals
with audio.
--
................. paul winkler ..................
slinkP arts: music, sound, illustration, design, etc.
web page: http://www.slinkp.com
A member of ARMS: http://www.reacharms.com
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