Subject: RE: [linux-audio-dev] A new audio plugin API ?
From: Dr. Matthias Nagorni (mana_AT_suse.de)
Date: Tue May 14 2002 - 12:34:09 EEST
On Mon, 13 May 2002, Richard W.E. Furse wrote:
> > 4) LADSPA_IS_PORT_DYNAMIC
> I don't understand this. Are we just saying this is an array? If so, I think
> this goes beyond LADSPA's scope.
Yes. In principle one could use audio ports for this purpose. I was
thinking of ports that accept e.g. LFO and envelope input.
> > 5) LADSPA_HINT_LOW_FREQ, LADSPA_HINT_HIGH_FREQ
> I don't quite understand this, but hopefully this could be handled by clear
> labelling for the user.
It might make a difference to DSP routines whether a signal is in the
audio frequency range or in the LFO range of say 0..50 Hz.
> and one control (or perhaps audio) output port. The input port selects which
> synth control is required (1 for frequency, 2 for gate etc, 3 for velocity,
> 4 for modulation wheel or whatever).
Still I don't know how the host should extract this information from an
arbitrary plugin: 1) The plugin does synthesis and therefore provides ports
for frequency, gate and velocity.
2) Which port is the frequency/gate/velocity port ?
These ports should not show up as sliders/toggles in
the GUI but should be available as "external" ports
of the LADSPA plugin module.
In the organ plugin of cmt I just identify the frequency/gate/velocity
ports by their name. But there is no naming convention, so this could fail
in other synth plugins. Also some synth plugins might allow dynamic
frequency/velocity input with LFOs and envelopes. In this case you would
either need arrays or use audio ports.
Matthias
-- Dr. Matthias Nagorni SuSE GmbH Deutschherrnstr. 15-19 phone: +49 911 74053375 D - 90429 Nuernberg fax : +49 911 74053483
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