On Thu, Oct 16, 2014 at 1:44 PM, Phil CM <philcm@gnu.org> wrote:

I think you're confused. The host doesn't put a plugin on a MIDI channel. It delivers MIDI events to the plugin which might be on any channel.

But in Qtractor I do have a choice of what MIDI channel (or any/omni, for that matter) I'm sending signal to on that particular track... So, no? No way for the plugin to retrieve any info from the host (I mean specific info, not just instantiated, port enum et al) I guess it makes sense since it would introduce a breaking point. Sorry, I don't really speak english, I'm just persuaded I do.

That is a host-specific issue. The part of the LV2 specification and the existing extensions don't describe that functionality. As far as the plugin is concerned, it just gets MIDI events. If the host is filtering some of them, the plugin has no way to determine this programmatically.

Wow, not even the very channel it's broadcasting on in readable? Does that mean that I have to implement a MIDI channel selection in my synth? There is no way to go around this?

Again, you're confused. The host doesn't control what the plugin does when it generates MIDI. The host *might* filter messages from the plugin based on some user preference, or it might not. It sounds as if you need an LV2 extension so that the host and plugin can exchange information on preferred MIDI channel(s). This isn't part of the core LV2 specification. The host is free to deliver zero, one or more MIDI channels to the plugin; the plugin can use any channels it wants, but the host might throw away zero, one or more channels.

Sounds as if you want the host to allow the user to select a channel and then have the plugin know about that choice. Not part LV2, and also not part of AudioUnits or the VST plugin APIs.