Re: Matrix Mixer and Number of Channels Per Bus
Re: Matrix Mixer and Number of Channels Per Bus
- Subject: Re: Matrix Mixer and Number of Channels Per Bus
- From: William Stewart <email@hidden>
- Date: Tue, 27 Feb 2007 15:55:59 -0800
On 27/02/2007, at 12:34 AM, Mark Coniglio wrote:
Hi,
I am having a bit of trouble understanding how to control the
number of input channels to a Matrix Mixer.
In my app, the user can specify the number of input channels for
each input bus, as well as the source sound file that plays into a
given bus. But it seems that, regardless of what the number of
input channels I set for a given bus on the Matrix Mixer, it
automatically reverts to the number of channels supplied by the
input source.
For example: user specifies 4 input channels on bus 1 of Matrix
Mixer. Then connects a sound file player playing a stereo file to
that bus.
1) Open the graph
2) Along with other initializations, I call AudioUnitSetProperty
with kAudioUnitProperty_StreamFormat to set the number bus 1 to
four input channels.
3) Create the connections between the nodes
4) Initialize the graph
5) run it
The channel count for input bus 1 reverts to 2 (matching the input
source), even though I explicitly set it to 4.
If you are going to set the format of just one side of a connection,
then the source AU of the connection is the one that matters - so in
this case, set the format of the file player to 4 channels. What is
happening in your place is that when the connection is made, the
mixer sees that the source's output doesn't match its input format,
so it sets its input format to match the source (the file player's
output)
I tried setting the channel count _after_ creating the connections,
and after initing the graph, but it had no effect.
You would actually be seeing an error here I think - connection
already exists.
Bill
I feel like I must be doing something in the wrong order... or
maybe this is just the way it works.
Any help?
Thanks in advance,
Mark
--
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Mark Coniglio, Artistic Co-Director | email@hidden
Troika Ranch Dance Theater | http://www.troikaranch.org
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