Re: [linux-audio-dev] processing plugin standard wrapper

On Monday 12 February 2007 21:34:08 Stefano D'Angelo wrote:
> > Well, that's our intent in CLAM[1]. The goal is that CLAM should be able
> > to run a given processing algorithm transparently under several backends.
> > Currently we support, to some extend, PortAudio, Jack, Alsa, and VST. The
> > first three backends can be used with a Qt Designer interface. We still
> > have to face several fronts: Unifying the interface to fit all the
> > backends, incorporating more backends (some work on Ladspa has been
> > done), and enabling Qt GUI's to more backends (notably VST).
>
> Well, I think I've not understood what you mean: Jack, Alsa and
> PortAudio are not sound processing plugin formats... can you explain
> it easier please? (I'm sorry, I'm not a native English speaker)

They are not plugin systems, you're right, but if you have a processing
algorithm encapsulated in a way that it describes itself (number of ports,
controls... then you can build wrappers (what we call backends) that maps
this algorithm to a given plugin system (ladspa, vst...) but also to a given
underlaying audio system api (portaudio, alsa, directx..)

For example, if i want my algorithm to be a Laspa plugin, i could use a Ladspa
backend, that compiles as library, that maps connection topology of the
processing algorithm to a Ladspa descriptor and when it is called, it just
feeds data to and from the ports and executes the algorithm. A Jack backend
should be very similar but it compiles as an application and publishes the
ports as Jack ports to the server. And so on. Of course, there is a lot of
work on handling each backend singularities such as JACK server availability,
api/device enumeration in portaudio...

In short, the intended result is that the developer designs the algoritm once
and then it can be used as any kind of plugin (what you asked for, didn't
you?), and not just plugins but also standalone application.

We also provide a way of relating a qt interface to certain parts of the
algorithm. This is already available for standalone applications backends[1]
(JAck, PA, Alsa..) but we want to provide that also for plugin systems such
as VST.

[1] http://iua-share.upf.es/wikis/clam/index.php/Network_Editor_tutorial

I hope to have explained myself better, but feel free to ask me more
information if you are interested in.

David.
Received on Tue Feb 13 08:15:02 2007