-----Original Message-----
From: Stefan Gretscher [mailto:email@hidden]
Sent: 06 February 2007 15:06
To: Muon Software Ltd - Dave
Cc: email@hidden
Subject: Re: Garageband 3/audio units odd behaviour
Hi Dave,
unlike in VST world, AU hosts are not required to process all
AUs all
the time.
Instead, AUs are based on a pull-output model, and that implies that
if the
audio data produced by a given AU is not needed at a certain
point in
time
(for example while the engine is not running or if a track is
muted),
the host
can skip rendering that AU (i.e. not pull its output) in order to
save CPU.
Best,
Stefan
Am 06.02.2007 um 15:40 schrieb Muon Software Ltd - Dave:
I'm testing a PPC audio unit we're developing for a client in as
many hosts
as possible and have come across something odd specifically in
Garageband 3.
The AU in question is built from the same code as the VST and
Standalone
versions of our product and assumes that there is a separate audio
and GUI
thread in all hosts. Because of this assumption, in some
cases when
the user
alters certain settings in the GUI we simply make a note of that
request and
leave it down to the next render cycle when it would be
thread-safe
to act
upon that request.
What seems to be happening in GB3 (but not in any other AU host
tested) is
that the audio rendering thread doesn't seem to start when the
application
is first loaded, which seems to break our plugin in some new and
interesting
ways.
So far the only work arounds that I've found to get the the audio
thread to
start running are:-
1. run the transport or...
2. open the musical typing keyboard or piano keyboard window and
play a note
or...
3. Show editor and click in the vertical piano keyboard on
the left
side
Is this normal behaviour? Any suggestions?
Regards
Dave Waugh
Muon Software Ltd
www.muon-software.com
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Stefan Gretscher
plug-in development & 3rd party developer support
phone: (+49)-4101-495-586 (Central European Time)
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