Re: 64bit processing possible?
Re: 64bit processing possible?
- Subject: Re: 64bit processing possible?
- From: Evan Olcott <email@hidden>
- Date: Wed, 29 Jul 2009 14:27:10 -0500
On Jul 29, 2009, at 2:04 PM, email@hidden
wrote:
The best next step here is for some industrious developer to create a
double-precision AU host and go from there. It's a bit of a chicken-
and-egg situation, but it would seem to start the ball rolling.
Coming from the host-development side (which we do with a small
handful of our products, Rax in particular), I can tell you that we
HAVE tried this and researched it, and our roadblock in the end is the
AUHAL drivers. Even if we WERE able to make the entirety of the stream
double precision, not only would we lose access to almost every
commercial AU, it seems to be brought down to (at least) single-
precision internally the AUHAL. We have yet to come across an AUHAL
driver that supports a 64-bit AudioBasicStreamDescription as the input
format. The drivers we've analyzed seem to convert their data streams
to 24-bit integer on the outgoing side, so they take the single
precision and convert that to a more efficient data stream. 64-bits
with multiple channels is a pretty hot data stream - takes a wide pipe
to push that all through.
That said, it's not like we've seen every driver out there. If there
IS a double-precision clean AUHAL driver out there (that can be used
by third-party developers like us), please let us know - we'd look
forward to working with it. We'll be the guinea pig if it gets double-
precision AUs written.
Also note: the 64-bit operating system will effectively obsolete VST
support, as their interfaces are written (almost always) in Carbon.
Carbon libraries are not available to apps that are 64-bit clean. We
are going down the 64-bit clean path, as every app eventually will,
and Carbon.framework will be unavailable. So unless someone
(Steinberg?) finds a way to update the VST libraries to not access
Carbon.framework, update their headers to properly use the 64-bit
memory access (does VST3 do this?) and to use Cocoa GUIs instead of
Carbon (up to the individual developers), VST plugs are a dead end.
Audio Units seem to be the only path forward. If someone could prove
me wrong, we would really really like to know.
Ev
Senior Software Developer
Audiofile Engineering
http://www.audiofile-engineering.com/
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