Re: Need help with the MatrixMixer
Re: Need help with the MatrixMixer
- Subject: Re: Need help with the MatrixMixer
- From: Robert Grant <email@hidden>
- Date: Sun, 16 Nov 2003 16:12:12 -0500
Chris - I'm not using V1 units - never have - never will ;-)
More info:
Apparently if the RenderCallbackProc isn't set for each input bus then
the MatrixMixer will not produce noise. I discovered this with the
MatrixMixerTest. I connected a synth node to input bus 0 using the
AUGraphConnectNodeInput. I commented out the callback proc property
setup because I didn't want it to mess with my synth input. Started up
the graph and even though noise was passing through the mixer
(indicated by the level meters) nothing was coming out of the speakers.
Re-enabling the callback proc (along with the synth input) made sound
come out of the speakers (and the callback still gets called!) This
doesn't make sense to me... why should the mixer want to pull from a
callback proc when it's been connected through the graph to another
node?
So back in my project I set a dummy input proc (just returns noErr) and
connected a synth to bus 0 and lo and behold I get a sound, but if (as
I need to do) I connect the mixer input to a subgraph (which contains
just a GenericOutputUnit and a GraphicEQ) the callback proc is no
longer called. And even if I connect a synth to the subgraph I get
nothing.
Obviously there are some delicate rules that must be followed to get
this thing to work, so....
Any guidance available?
Thanks,
Robert.
On Nov 16, 2003, at 2:34 PM, Robert Grant wrote:
Here's my simple graph - where the mdaX: Test effect should produce a
simple sine tone - which it does in Rax and will if I don't connect
the matrix mixer.
AudioUnitGraph 0x9810000:
Member Nodes:
node 1: desc auou def appl, instance 0x850000 O I
node 2: desc aumx mxmx appl, instance 0x820001 O I
node 3: desc aufx Test mdaX, instance 0x860003 O I
Connections:
node 2 bus 0 => node 3 bus 0
node 3 bus 0 => node 1 bus 0
Events to be updated:
CurrentState:
mLastUpdateError=0, eventsToProcess=F, isRunning=T
The matrix mixer is configured to have two 2-channel input buses and 1
2-channel output bus.
Really stumbling in the dark....
Robert.
On Nov 16, 2003, at 1:49 PM, Robert Grant wrote:
More updates:
It turns out that having the MatrixMixer in my graph causes the
OutputUnit to become silent - even if I have the handy MDA TestTone
effect between the mixer and the OutputUnit!
If I connect a synth to the TestTone and then to the output it works
fine.
How could the MatrixMixer do that - is it returning an error perhaps?
The output unit doesn't seem to be complaining though.... Which
raises a question - if one of the nodes in the graph returns an error
during rendering how would we be informed?
Robert.
On Nov 16, 2003, at 9:09 AM, Robert Grant wrote:
Well some progress has been made: I've added some metering and the
output channel is getting data but still there's silence, here's a
sample line of output from output channel 0 of the matrix mixer
(post is: kMatrixMixerParam_PostAveragePower)
output channel 0 post: -9.66, level: 1.00
Now I've fiddling with things like Global volume and output enabling
and seen that these change the "post" level so I'm sure that a
signal is getting to the DefaultOutputUnit, and yet I'm not getting
a peep.
I can get a peep out the StereoMixer - so I know my inputs and
outputs are good.
Any suggestions?
Thanks,
Robert.
On Nov 15, 2003, at 7:48 PM, Robert Grant wrote:
I'm having a hard time getting sound to pass through the matrix
mixer. I'm basing what I'm doing on the MatrixMixerTest example app
and everything seems to be wired up OK - I'm definitely getting my
synths pulled on, but no sound.
There seems to be a variety of different places where levels need
to be set and I'm setting them all I think. Here's what I've got:
set the input level for each channel on each input bus:
kMatrixMixerParam_Volume, kAudioUnitScope_Input
enable each input bus
kMatrixMixerParam_Enable, kAudioUnitScope_Input
set the level of each intersection within the matrix
kMatrixMixerParam_Volume, kAudioUnitScope_Global
Some more explication on addressing these intersections would be
good.
set the level of each output channel on each output bus
kMatrixMixerParam_Volume, kAudioUnitScope_Output
set the global level of the mixer
kMatrixMixerParam_Volume, kAudioUnitScope_Global, 0xFFFFFFFF
Enable each output bus
kMatrixMixerParam_Enable, kAudioUnitScope_Output
Anyone else messing with the Matrix?
Robert.
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