Subject: Re: my take on the "virtual studio" (monolith vs plugins) ... was Re: [linux-audio-dev] ardour, LADSPA, a marriage
From: Paul Barton-Davis (pbd_AT_Op.Net)
Date: Fri Nov 17 2000 - 19:04:05 EET
>Of course transport control, metering and all the other fancy stuff has to be
>implemented within the app. (and as said it's far from trivial getting
>the job done in an elegant and efficient way)
This depends. In my head right now, I am convinced that the host has
to run synchronously with the audio interface. That means that even if
it uses some kind of non-LADSPA plugin for this (I'm thinking of
AlsaPlayer and XMMS here), its operation is intimately caught up with
audio i/o. That in turn means that h/w monitoring *has* be done here,
since layers above this presumably should not understand the details
of how to do this. It also means that metering (the measurement, not
the display) is most efficiently done here as well. Theoretically, you
could attach a plugin to the stream, but then other plugins that
needed meter values would have to know about this plugin - not good.
>Yes this abstract discussion may sound boring, because there is neither
>a precise plan nor working code available.
I don't think its boring. I just prefer writing code, and I find that
having worked on a real system that does a substantial fraction of
what we're talking about here helps me think about things much more
clearly.
>That's fine, but what I am interested in, is the inter-application routing:
>you can implement the internal routing schemes you like
>(within ardour), but what the proposed API should allow is to manage
>the routing of data from/to connectors (ins/outs) an application decides
>to publish.
What makes you think you know what I'm doing ?
The scheme I'm working is designed around LADSPA. Its designed to
allow *any* LADSPA plugin, whether its a complex system like the top
layers of Ardour, or something very simple, to be connected to
ins/outs and other plugins. The top level of ardour (from the "Tape"
object on up) will be "reduced" to a LADSPA plugin. The current
ALSA::MultiChannelDevice object will vanish (not go away), hidden by
this "host/router/patch-bay". I will finesse the GUI issue right now,
because I have to. You could write EVO as a LADSPA plugin (sans GUI),
and it would show up as just another set of inputs and outputs. And
now, I don't want to talk about it anymore because I have other things
to do :)
--p
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