Subject: Re: [linux-audio-dev] [ardour] custom graphics + MIDI control for LADSPA plugins
From: Paul Barton-Davis (pbd_AT_Op.Net)
Date: Wed Nov 22 2000 - 17:46:53 EET
>Wow, cool. Hopefully, it will someday be possible to hook up a MIDI
>knob box work as mixing console faders, so that one can adjust mix
>levels (and effects parameters, and other things) while listening, then
>later edit the MIDI data graphically and play it all back. This could
>either be handled directly by Ardour, or a sequencer/mixer that is
>hooked up to control Ardour.
in theory, this should be easy. in practice, its not quite so
simple. the central problem is that you need either of these two
configurations ("FIFO/Sequencer" means either a FIFO or the ALSA Sequencer):
MIDI Port -> MIDI Sequencer app -> FIFO/Sequencer -> Ardour
|
V
stored MIDI data
OR
MIDI Port -> Ardour
|
V
stored MIDI data
The second one allows for "replay" only when the stored data is reused
as in:
stored MIDI data -> MIDI Sequencer app -> FIFO/Sequencer -> Ardour
i don't know if any MIDI sequencers exist that do "passthru" of MIDI
data as shown in the first example, and the second one is clearly a
hack, not a very good one at that. even in the first case, we have
latency issues as well.
once again, the best solution from a performance point of view would
appear to be the monolithic one that hides the original source of
any "control events" and uses a native event list:
MIDI Port -> ARDOUR:MIDI-Handler -> ARDOUR:EventSequencer -> Ardour:Core
^ |
| |
X Server -> ARDOUR:X-Event-Handler -+ |
|
V
stored event data
but this is a lot of work :)
--p
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