[linux-audio-dev] LADSPA: proposition for polyphonic use of plugins

[Steve Harris]

On Mon, Nov 17, 2003 at 02:14:41 +0100, Alfons Adriaensen wrote:
> I'd like to propose an extension of the LADSPA specs, or more correctly, a
> particular interpretation of the current specs, in order to support the use of
> plugins in a 'polyphonic' context.

FWIW, I dont think this is the correct way to support polyphony in a
modular system. It works ok for special puprpose soft-synth plugins, but
LADSPA is missing other things to make that viable.

Other modular systems I've seen have a polyphonic block, eg:

                         -------------------
in -> mono processing -> | poly processing | -> mono processing -> out
                         -------------------

The poly processing block is repeated once for each voice (with duplicates
of its inputs, and its outouts mixed), and the mono sections only exist
once per patch.

The division between mono and poly sections can either be a magic module,
or a flagged subpatch. In the simple case (everything is duplicated per
voice) the poly processing block is the whole patch, but often LFOs and
things exist globally.

This works well, and doesnt break the "module" metaphor.

- Steve