Subject: Re: [linux-audio-dev] ladspa diff
From: Jesse Chappell (jesse_AT_essej.net)
Date: Fri Sep 12 2003 - 18:46:04 EEST
Paul Davis wrote on Fri, 12-Sep-2003:
> >Well, I'm *half* paying attention...
> >
> >So we're essentially saying that the momentary thing is a trigger that
> >operates on 0->positive but not positive->0. I must admit I'm not 100% clear
> >about the randomisable case from the text.
> >
> >Do we have example plugins for the two cases?
>
> sooperlooper is the example for the momentary case. in that case, your
> definition isn't quite correct. a momentary control is one that only
> causes something to happen when its value transitions between any two
> meaningful values. this means that it needs to be reset to a
> meaningless value after being set to any meaningful value. this is
> required so that "pressing the button twice" does what the user expects.
> its actually slightly more complex than that at the code level.
>
> the more i try to explain this, the less convinced i am that we should
> add it. it requires the definition of a meaningless value, for a
> start, which will require warping/overloading the meaning of some
> other value (e.g. using the default as the meaningless value).
I agree, I do not think a momentary hint would really help in this specialized
case. Sooperlooper will never be a ladspa plugin that any generic
host can use. The better solution to the SL problem is audio-rate
control ports. Then we get sample accurate control, and can easily
specify the "off" value in the plugin's custom semantics.
So the hint we *really* need is the audio-rate control port (or
the control-hinted audio port :)
> however, jesse tried to come up with a way of modelling this kind of
> control with existing LADSPA options and couldn't do it. the "requires
> reset after every use" is hard to do without it.
The audio rate control port would fix this, but again, only a
custom host could use this plugin, which I'm fine with... apps
to use it are on the way.
jlc
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