stereo synth / music device bug?
stereo synth / music device bug?
- Subject: stereo synth / music device bug?
- From: Christopher Corbell <email@hidden>
- Date: Sat, 14 Dec 2002 22:19:30 -0800
I'm stuck on a misbehavior of the V1 stereo synth unit with
V1 music device components. I've spent a good deal of time
trying to find a cause in my code and haven't found it yet, maybe
someone else has seen a similar problem... If it is a bug I'll file
a bug report but I'm rather hoping it isn't as I need the functionality.
I have created cocoa wrappers for AudioUnit, AUGraph, etc. and
I'm creating a graph that sets up a stereo mixer with the default output
unit. The idea is a multitrack, mixable sound synth - MusicDevice
units output to distinct input busses of the stereo mixer.
The misbehavior is, if I add more than three MusicDevices, everything
gets 'strange'. The app begins responding sluggishly, playing of
instrument
sounds is mangled (it sounds like sounds are being rendered at a
much lower frequency), and eventually the app can hang. However
if I limit myself to three MusicDevices everything works perfectly
including
mixing through the mixer unit. If I create the graph with four music
devices,
the problem is there, and if I then remove one at runtime and update
the graph the
problem goes away and things return to normal.
I checked the mixer properties and the # of busses is 64 so I don't
think
it should be exceeding the mixer's capabilities. CAShow() on the graph
looks fine, identical for both the good and bad cases except of course
that
there's one more MusicDevice unit.
Has anyone seen behavior like this, and if so is it something I'm likely
doing wrong? I've tried changing placement of AUGraph open/initialize
calls relative to node setup, tried calling update more and less
frequently,
and other superstitious things stopping just short of live sacrifice to
the
unknown code gods.
Here's a dump of the graph that works, the bad graph just has one more
music node going to bus 3 of the mixer:
AudioUnitGraph 0x9810000:
Member Nodes:
node 1: desc aunt mixr smxr, instance 0x810000 O I
node 2: desc aunt out def , instance 0x810001 O I
node 3: desc aunt musd , instance 0x810002 O I
node 4: desc aunt musd , instance 0x810003 O I
node 5: desc aunt musd , instance 0x810004 O I
Connections:
node 1 bus 0 => node 2 bus 0
node 3 bus 0 => node 1 bus 0
node 4 bus 0 => node 1 bus 1
node 5 bus 0 => node 1 bus 2
Events to be updated:
CurrentState:
mLastUpdateError=0, eventsToProcess=F, isRunning=T
Thanks for any help or advice.
- Chris
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