Subject: Re: [linux-audio-dev] A new audio plugin API ?
From: Dr. Matthias Nagorni (mana_AT_suse.de)
Date: Tue May 14 2002 - 12:08:00 EEST
On Mon, 13 May 2002, Steve Harris wrote:
> > > > 7) Type of integer port int not float
> > > Don't think it helps much, in some cases there is a fine line between
> > > integer and non-integer ports, eg. "mode" of diode_1185
> > It makes the code for the GUI routines simpler. If integer port variables
> > are int, their pointer can be directly passed to the integer GUI element.
>
> OK, I see why that helps, but I'm still not convinced.
So you would like to have ports where some int values have special
meanings like "half wave" or "full wave" but you still would like to allow
non-int input to these ports, right ? Then you perhaps would like to be
able to attach also a descriptive string array to this kind of port.
> I'm a modular synthesist at heart, so I don't like the idea of making
> things like aftertough first class signal types. The aftertouch out on
> the MIDI "module" could be wired to any input port on any module. Its just
> a singal.
Yes, of course. My mistake. Of course the host should supply a MIDI to CV
converter module with CV, gate, frequency and aftertouch outputs (maybe
also pitch- and modwheel, although I treat them as "normal" controller
in my synth).
> Advantages are that the class graph is extensible, and isn't confined
> to a single tree structure natively, but can be flattened to one.
I understand. This way plugins can be members of several categories.
> > What about the frequently discussed arrays ? I have seen from your code
> > that you just use audio ports whenever you need arrays. I would prefer to
> > distinguish between audio and control ports.
>
> Yes and no, generally, where I have used audio ports, its because thats
> what they are. There isn't really any difference between an audio rate
> control port and an audio rate audio port. Sometimes it is helpful to mark
> them as different, but you should never be prevented or discouraged from
> wiring one to the other.
I agree. But what about e.g. envelope and LFO signals ? Probably it is
relevant for some DSP routines to know whether a signal is in the audio
frequency range or in the e.g. 0..50 Hz LFO range. Anyhow there should be
a hint to the host whether it should create a slider for the port.
You will not want to have a slider for e.g. the audio in of canyon delay.
However in the case of e.g. a square wave synthesis plugin it should be
possible to control the pulsewidth both dynamically via an audio input port
and statically with a slider (which can be the offset to the signal of the
audio input).
Matthias
-- Dr. Matthias Nagorni SuSE GmbH Deutschherrnstr. 15-19 phone: +49 911 74053375 D - 90429 Nuernberg fax : +49 911 74053483
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