Some Basic Questions about MultiChannel Audio
Some Basic Questions about MultiChannel Audio
- Subject: Some Basic Questions about MultiChannel Audio
- From: Mark Coniglio <email@hidden>
- Date: Tue, 14 Mar 2006 09:50:15 -0500
Hi,
I'm adding CoreAudio support to my software Isadora. All of the CA
plugins appear as modules in my program, my user interface is
essentially serving as a graphic front end to a AUGrpah.
But there are some basic issues that I can't seem to wrap my head
around, even after reviewing the CA docs this morning.
1) Sound output routing. After my question yesterday, I was
successfully able to change the sound output routing of the
DefaultOutputUnit so that a stereo stream could be sent to any output
on my MOTU 828. But, then I tried to change the number of input
busses, so that I could feed in more pairs of channels, I found out
the property isn't writable on the Default Output Unit.
This makes me assume that I need to set the input format of the
output unit to, let's say, four channels, and then give an four
channel stream to the output unit so I can route the channels. But
how do I take two stereo audio streams, and combine them into a four
channel stream so I can route all of the stuff individually? Is the
AUMerger useful here? It's default behavior, upon receiving two
stereo streams is to output a stereo stream. (No docs on that
AUMerger, seemingly, so I'm a little lost on that one.)
E.g., let's say the user is playing six sound files. Three are mixed
down to stereo using the stereo mixer, three more are mixed down with
a second stereo mixer. I want to be able to merge those two stereo
streams into a single four channel stream.
2) Multi-channel sound files. So, let's say I have a four-channel
sound file. And I would like the user to manipulate each of these
channels as individual mono streams. How do I pull those channels
apart for individual processing, and the recombine them to send them
to the output device
3) It also seems that some AU's don't want to accept mono inputs. Do
I need to use a format converter to convert the mono to stereo, and
then back again after the output?
Well, there's more. But that's a good start. Thanks in advance for the help.
Best Wishes,
Mark
--
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Mark Coniglio, Artistic Co-Director | email@hidden
Troika Ranch Dance Theater | http://www.troikaranch.org
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