[LV2] should plugins somehow indicate whether they support MPE?

Stefan Westerfeld stefan at space.twc.de
Sat Jun 17 04:04:06 PDT 2017


I don't know if that affects other plugins (yet), but the next version of
SpectMorph will support MPE (Multidimensional Polyphonic Expression). That way
a host can change parameters individually of notes that are already playing.
What I implemented so far in SpectMorph is changing the pitch. Unlike
conventional pitch-bend messages, this allows users to bend each note
individually. So you could slide from a C major chord to D minor. Obviously in
this case, a per-note-pitch UI like Bitwig provides - which I used for
developing and testing - makes sense.

In VST, my plugin reacts to a new canDo("MPE"), to indicate to hosts with MPE
support that MPE messages should be sent (like per-note pitch bend). Bitwig for
instance will not send any MPE messages to the plugin unless this canDo is

Since MPE is midi-only, my LV2 plugin will automatically support MPE now.  I
wonder if it should somehow in the plugin description indicate that it does.

I don't know any LV2 host that supports MPE so far, so if the LV2 strategy for
MPE would be wait until we have at least one host which supports MPE, and then
discuss negotiation, that would be ok for me, too.

MPE spec:


   Cu... Stefan
Stefan Westerfeld, http://space.twc.de/~stefan

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