Subject: Re: [linux-audio-dev] questions to be resolved
From: Paul Davis (pbd_AT_Op.Net)
Date: Tue May 22 2001 - 22:52:42 EEST
>That is quite easy. Lets say someone has a synth unit that they have
>programmed and one of the things they do is add/remove plugins during
>playback. Or better yet, maybe its a vocal recording and at different
>parts of the song different plugins are used.
Both of these would not be handled in the real world by using a UI to
create and connect these things as you went along. Instead, you'd be
changing the parameters of the plugins (e.g. their output gains) so
that no longer did anything to the signal. That doesn't involve any
change in the graph.
Also, please be careful about confusing LAAGA and LADSPA. Although
there is no hard line between them, FX algorithms are best thought of
in LADSPA terms, not LAAGA ones, IMHO.
>occur :) I think Abramo's suggestion at least in theory is very valid.
As has been noted, you can't leave the engine running
>"Since the time required for changes in the signal graph can/could cause
> an xrun situation, use a dual graph system where the graph is switched
> only at a point where it is ready to be used"
The graph is not a standalone entity that can be copied. It is an
implicit feature of the interconnections between objects with "real
world" semantics. If there is a Port labelled "Channel 1" on a Plugin
called "ALSA I/O", you can't just go blindly creating a duplicate Port
or Plugin for the purposes of making the graph change be double buffered.
Maybe there is a way to make the graph into an explicit object, at
which point, the "double buffered" approach would work.
--p
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