[linux-audio-user] Jammin as a ladspa plugin?

[Steve Harris]

On Fri, Jun 18, 2004 at 01:09:33 +0200, Florian Schmidt wrote:
> On Thu, 17 Jun 2004 20:51:36 +0100
> Steve Harris <S.W.Harris at ecs.soton.ac.uk> wrote:
> 
> > > is it even possible?
> > 
> > Not well. You might see a greatly simplified version without linear
> > filters at some point. Its waaaay down my TODO list though.
> 
> i wonder if it's possible to "wrap" jack clients into a ladspa plugin.
> Imagine a ladspa plugin that is also a jack client. I opens two ports in
> the jack graph [one writable one readable, or pairs for stereo, or even
> depending on the context of the ladspa plugin]. All audio that is put into
> the plugin is available on the readable ports and all audio written into
> the writable jack ports is available as output on the ladspa plugin..

Yeah, its possible, I started one, or thought about it extensivly. There
are two cases you need to cover - if the host runs in jack you can just
let it freewheel (with a 1 jack period buffer between them) and it will be
fine, but if the host doesnt run in jack you have to block between having
a full buffer and you doing your jack i/o, to keep everything in sync.

Its kinda nasty either way, but it should work. I didn't get as far as a
reliable way to determine if the host you're loaded into runs in jack.
Thinking about it afresh, if you always have the buffer you can block in
the case when you try to write to the buffer and its not been emptied.

- Steve