[LV2] LV2 Programs extension

David Robillard d at drobilla.net
Fri May 4 09:16:19 PDT 2012

On Fri, 2012-05-04 at 17:08 +0100, Filipe Lopes wrote:
> hey there everyone,
> I've been working a new LV2 extension with Rui (a.k.a. rncbc,
> Qtractor's developer) regarding midi-programs.
> The purpose is simple - allow to plugin to tell the host about his
> midi-programs, and the host to change them on the fly.
> Currently LV2 Presets are managed by the host, and the plugin has no
> control over them.
> Although it is possible to collect all presets related to a plugin and
> map them to ints for this, it's not in any sense pratical.
> (The host would have a lot of work ensuring a session presets 100%
> match another session, as LV2 presets can be changed at anytime by the
> user).

Programs are not at all like presets.  They are more like an enumeration

> A simple and easy solution is a C API similar to the DSSI
> get/select_program.
> The plugin tells the host which midi-programs it has available, and
> allows the host to select one.
> The spec is still in draft and being tested at the moment (although
> already works in it's base form).
> I've reserved a namespace on my page for it (as I don't expect this to
> be fully accepted by we know who...)
> May I preset you, LV2 Programs extension:
> http://kxstudio.sourceforge.net/ns/lv2ext/programs/

Select program with a function is completely silly.  Use MIDI, then
there is no need for that function, or the UI extension whatsoever,
since hosts already need to implemented the ability to send that from
the UI.


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