AU parameter notify vs. writing automation
AU parameter notify vs. writing automation
- Subject: AU parameter notify vs. writing automation
- From: Marc Poirier <email@hidden>
- Date: Sun, 1 Dec 2002 15:58:30 +0100 (CET)
After the thread last week about how to get hosts to write automation data
after parameter changes, now I have the opposite question: how can how
make sure that hosts won't write automation data when a parameter changes?
Is there a way to change a parameter value, notify listeners, but not
trigger the recording of automation data?
Here's an example of when you'd want to do this (this is when I want to do
it): You have a plugin where you allow the user to assign MIDI CCs to
control parameters. A MIDI CC message arrives and now you want to make
the value change for the corresponding parameter. After changing the
value, you want to notify listeners so that the GUI updates to reflect the
change and so that anyone else knows about the new value, but you don't
want automation to be recorded for that change. The host will already be
recording the MIDI messages, and those in effect are the automation data.
If you were to have both MIDI messages and regular parameter automation
data recorded, then what happens when the user wants to edit the MIDI
messages? She's left with conflicting MIDI and regular parameter
automation data.
In VST it's easy, you either use setParameter or setParameterAutomated,
the latter of which triggers host automation recording (a little bit too
easy, though, because VST actually has no system for listeners and
notifying them whatsoever). So is this sort of thing possible in AU
world?
Thanks,
Marc
_______________________________________________
coreaudio-api mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/coreaudio-api
Do not post admin requests to the list. They will be ignored.