prototype polyphonic audio to midi script

scripts/_vamp_audio_to_midi.lua

@@ -0,0 +1,43 @@
+ardour { ["type"] = "EditorAction", name = "Vamp Audio to MIDI" }
+
+function factory () return function ()
+	local sel = Editor:get_selection ()
+	local sr = Session:nominal_frame_rate ()
+	local tm = Session:tempo_map ()
+	local vamp = ARDOUR.LuaAPI.Vamp ("libardourvampplugins:qm-transcription", sr)
+
+	local ar = nil
+	local mr = nil
+	for r in sel.regions:regionlist ():iter () do
+		if r:to_midiregion():isnil() then
+			ar = r
+		else
+			mr = r:to_midiregion()
+		end
+	end
+	-- analyze audio from selected audio region to selected midi region
+	assert (ar and mr)
+
+	vamp:analyze (ar:to_readable (), 0, nil)
+	local fl = vamp:plugin ():getRemainingFeatures ():at (0)
+	if fl and fl:size() > 0 then
+		local mm = mr:midi_source(0):model()
+		local midi_command = mm:new_note_diff_command ("Audio2Midi")
+		for f in fl:iter () do
+			local ft = Vamp.RealTime.realTime2Frame (f.timestamp, sr / 2)
+			local fd = Vamp.RealTime.realTime2Frame (f.duration, sr / 2)
+			local fn = f.values:at (0)
+
+			local bs = tm:exact_beat_at_frame (ft, 0)
+			local be = tm:exact_beat_at_frame (ft + fd, 0)
+
+			local pos = Evoral.Beats (bs)
+			local len = Evoral.Beats (be - bs)
+
+			local note = ARDOUR.LuaAPI.new_noteptr (1, pos, len, fn, 0x7f)
+			midi_command:add (note)
+
+		end
+		mm:apply_command (Session, midi_command)
+	end
+end end