Re: AudioUnitParameterUnit requests
Re: AudioUnitParameterUnit requests
- Subject: Re: AudioUnitParameterUnit requests
- From: Marc Poirier <email@hidden>
- Date: Sat, 19 Oct 2002 00:29:11 +0200 (CEST)
Right, sometimes, even if the host does provide tempo info, you won't want
to use it. For example, consider the situation where you're using one of
today's modern-day sequencer/multitracker/virtual-acoustic music apps
(Logbase, Cubic, Digital Tools, etc.). Most of these work on the notion
of bars and tempo, even if that might be irrelavant to your music. In
this case, you just want to record some live instrument playing and
whatnot, you've got an idea of what the tempo is, but you haven't changed
set it in your song file because doing that would misalign the segments of
your recording, or for whatever reason, basically you just don't bother
handling the tempo/bars side of things in your song file, but you want to
set it explicitly for an effect because you kind of know what the tempo
is. I'm sure there are other cases where you might want to override the
host tempo in an effect, too.
I've always had my effects enter auto-tempo mode (if possible) when you
set the tempo paramter to its minimum, but having that separate
use-host-tempo boolean parameter would be cleaner, and I personally
wouldn't mind making the change to conform to the proposed guildelines...
Marc
On Fri, 18 Oct 2002, Bill Stewart wrote:
>
Just getting this clear in my own mind:)
>
>
I would imagine that if an AU publishes this parameter unit, AND the AU has
>
the ability to follow tempo changes from the host, then the AU would also
>
publish a boolean property (in our example)
>
>
Filter LFO Tempo (== 60->180)
>
Fliter LFO Beats (==0->4?)
>
Filter LFO Independent Tempo (T/F)
>
(or Filter LFO Track Host Temp (T/F))
>
>
(either way is fine)
>
>
Then, if the user wants the unit to track host tempo and it can, then the
>
"Filter LFO Tempo" above would become a read only parameter?
>
>
(And this would need to be somewhat dynamic in the AU as:
>
(1) Some hosts may not support tempo
>
(2) Some usage scenarios might not have a tempo
>
>
So - typically, we'd expect the HostCallback property that sets this
>
callback for tempo, to be done before the AU's UI (or hopefully before the
>
AU is initialized - though that can't always be guaranteed) is shown - so
>
the AU couldn't code this parameter directly (as it can with most other
>
parameters), but would have to determine the action of the parameter
>
dynamically...
>
>
(And also - setting a tempo parameter if the "track host tempo" parameter is
>
set, would then fail)
>
>
The reason I'd like to get clear on this, is that we're trying to spec out a
>
validation tool for audio units to ensure some consistency of behaviour - so
>
I think I'd like to understand how users/AU writers expect this to behave)
>
>
Thanks
>
>
Bill
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