livetrax/scripts/_vamp_audio_to_midi.lua

ardour { ["type"] = "EditorAction", name = "Vamp Audio to MIDI",
description = "analyze audio from selected audio region to selected midi region" }

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 midi_region
	local audio_regions = {}
	local start_time = Session:current_end_frame ()
	local end_time = Session:current_start_frame ()
	for r in sel.regions:regionlist ():iter () do
		if r:to_midiregion():isnil() then
			local st = r:position()
			local ln = r:length()
			local et = st + ln
			if st < start_time then
				start_time = st
			end
			if et > end_time then
				end_time = et
			end
			table.insert(audio_regions, r) 
		else
			midi_region = r:to_midiregion()
		end
	end
	assert (audio_regions and midi_region)
	midi_region:set_initial_position(start_time)
	midi_region:set_length(end_time - start_time, 0)

	for i,ar in pairs(audio_regions) do
		local a_off = ar:position ()
		local b_off = 4.0 * midi_region:pulse () - midi_region:start_beats ()

		vamp:analyze (ar:to_readable (), 0, nil)
		local fl = vamp:plugin ():getRemainingFeatures ():at (0)
		if fl and fl:size() > 0 then
			local mm = midi_region: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)
				local fd = Vamp.RealTime.realTime2Frame (f.duration, sr)
				local fn = f.values:at (0)

				local bs = tm:exact_qn_at_frame (a_off + ft, 0)
				local be = tm:exact_qn_at_frame (a_off + ft + fd, 0)

				local pos = Evoral.Beats (bs - b_off)
				local len = Evoral.Beats (be - bs)
				local note = ARDOUR.LuaAPI.new_noteptr (1, pos, len, fn + 1, 0x7f)
				midi_command:add (note)
			end
			mm:apply_command (Session, midi_command)
		end
	end
end end