diff --git a/share/scripts/pitch_to_mts.lua b/share/scripts/pitch_to_mts.lua
new file mode 100644
index 0000000000..63d68018cb
--- /dev/null
+++ b/share/scripts/pitch_to_mts.lua
@@ -0,0 +1,198 @@
+ardour {
+	["type"]    = "EditorAction",
+	name        = "MIDI Tuning",
+	license     = "MIT",
+	author      = "Ardour Team",
+	description = [[generate MIDI tuning standard (MTS) messages for 12TET pitch changes]]
+}
+
+function factory () return function ()
+
+	-- return table of all MIDI tracks, and all instrument plugins.
+	--
+	-- MidiTrack::write_immediate_event() injects MIDI events to the track's input
+	-- PluginInsert::write_immediate_event() sends events directly to a plugin
+	function midi_targets ()
+		local rv = {}
+		for r in Session:get_tracks():iter() do
+
+			if not r:to_track():isnil() then
+				local mtr = r:to_track():to_midi_track()
+				if not mtr:isnil() then
+					rv["Track: '" .. r:name() .. "'"] = mtr
+				end
+			end
+
+			local i = 0;
+			while true do
+				local proc = r:nth_plugin (i)
+				if proc:isnil () then break end
+				local pi = proc:to_plugininsert ()
+				if pi:is_instrument () then
+					rv["Track: '" .. r:name() .. "' | Plugin: '" .. pi:name() .. "'"] = pi
+				end
+				i = i + 1
+			end
+		end
+		return rv
+	end
+
+	function log2 (v)
+		return math.log (v) / math.log (2)
+	end
+
+	-- calculate MIDI note-number and cent-offset for a given frequency
+	--
+	-- "The first byte of the frequency data word specifies the nearest equal-tempered
+	--  semitone below the frequency. The next two bytes (14 bits) specify the fraction
+	--  of 100 cents above the semitone at which the frequency lies."
+	--
+	-- 68 7F 7F = 439.9984 Hz
+	-- 69 00 00 = 440.0000 Hz
+	-- 69 00 01 = 440.0016 Hz
+	--
+	-- NB. 7F 7F 7F = no change (reserved)
+	--
+	function freq_to_mts (hz)
+		local note = math.floor (12. * log2 (hz / 440) + 69.0)
+		local freq = 440.0 * 2.0 ^ ((note - 69) / 12);
+		local cent = 1200.0 * log2 (hz / freq)
+		-- fixup rounding errors
+		if cent >= 99.99 then
+			note = note + 1
+			cent = 0
+		end
+		if cent < 0 then
+			cent = 0
+		end
+		return note, cent
+	end
+
+	local dialog_options = {
+		{ type = "number", key = "tuning", title = "Tuning A4 (Hz)", min= 220.0, max = 880.0, default = 440.0, digits = 1, step = 0.1 },
+		{ type = "dropdown", key = "tx", title = "MIDI SysEx Target", values = midi_targets () }
+	}
+
+	local rv = LuaDialog.Dialog ("MIDI Tuning", dialog_options):run ()
+	dialog_options = nil -- drop references (track, plugins, shared ptr)
+	collectgarbage () -- and release the references immediately
+
+	if not rv then return end -- user cancelled
+
+	-- prepare sending data
+	local tx = rv["tx"] -- output port
+	local ref_freq = rv["tuning"] -- ref freq (440.0)
+	local parser = ARDOUR.RawMidiParser () -- construct a MIDI parser
+	local checksum = 0
+
+	-- helper function to send MIDI
+	function tx_midi (syx, len, hdr)
+		for b = 1, len do
+			--dump:write (string.char(syx:byte (b)))
+
+			-- calculate checksum, xor of all payload data
+			-- (excluding the 0xf0, 0xf7, and the checksum field)
+			if b >= hdr then
+				checksum = checksum ~ syx:byte (b)
+			end
+
+			-- parse message to C/C++ uint8_t* array (Validate message correctness. This
+			-- also returns C/C++ uint8_t* array for direct use with write_immediate_event.)
+			if parser:process_byte (syx:byte (b)) then
+				tx:write_immediate_event (Evoral.EventType.MIDI_EVENT, parser:buffer_size (), parser:midi_buffer ())
+				-- Slow things down a bit to ensure that no messages as lost.
+				-- Physical MIDI is sent at 31.25kBaud.
+				-- Every message is sent as 10bit message on the wire,
+				-- so every MIDI byte needs 320usec.
+				ARDOUR.LuaAPI.usleep (400 * parser:buffer_size ())
+			end
+		end
+	end
+
+	-- show progress dialog
+	local pdialog = LuaDialog.ProgressWindow ("MIDI Tuning", true)
+	pdialog:progress (0, "Tuning");
+
+	-- MIDI Tuning message
+	-- http://technogems.blogspot.com/2018/07/using-midi-tuning-specification-mts.html
+	-- http://www.ludovico.net/download/materiale_didattico/midi/08_midi_tuning.pdf
+	local syx = string.char (
+	0xf0, 0x7e, -- non-realtime sysex
+	0x00,       -- target-id
+	0x08, 0x01, -- tuning, bulk dump reply
+	0x00,       -- tuning program number 0 to 127 in hexadecimal
+	-- 16 chars name (zero padded)
+	0x53, 0x63, 0x6C, 0x2D, 0x4D, 0x54, 0x53, 0x00,  -- Scl-MTS
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+	)
+	tx_midi (syx, 22, 1)
+
+	-- iterate over MIDI notes
+	for nn = 0, 127 do
+		if pdialog:canceled () then break end
+
+		-- calculate the frequency of the note
+		local fq = ref_freq * 2 ^ ((nn - 69) / 12)
+
+		-- and then convert this frequency to the MIDI note number (and cent offset)
+		local base, cent = freq_to_mts (fq)
+
+		-- MTS uses two MIDI bytes (2^14) for cents
+		local cc = math.floor (163.83 * cent + 0.5) | 0
+		local cent_msb = (cc >> 7) & 127
+		local cent_lsb = cc & 127
+
+		--[[
+		print (string.format ("MIDI-Note %3d | Freq: %8.2f Hz = note: %3d + %6.3f ct (0x%02x 0x%02x 0x%02x)",
+		                      nn, fq, base, cent, base, cent_msb, cent_lsb))
+		--]]
+
+		if (base < 0 or base > 127) then
+			if base < 0 then
+				base = 0
+			else
+				base = 127
+			end
+			cent_msb = 0
+			cent_lsb = 0
+		end
+
+		local syx = string.char (
+			base,       -- semitone (MIDI note number to retune to, unit is 100 cents)
+			cent_msb,   -- MSB of fractional part (1/128 semitone = 100/128 cents = .78125 cent units)
+			cent_lsb,   -- LSB of fractional part (1/16384 semitone = 100/16384 cents = .0061 cent units)
+			0xf7
+		)
+		tx_midi (syx, 3, 0)
+
+		-- show progress
+		pdialog:progress (nn / 127, string.format ("Note %d freq: %.2f (%d + %d)", nn, fq, base, cc))
+		if pdialog:canceled () then break end
+
+		::continue::
+	end
+
+	if not pdialog:canceled () then
+		tx_midi (string.char ((checksum & 127), 0xf7), 2, 2)
+	end
+
+	-- hide modal progress dialog and destroy it
+	pdialog:done ();
+
+	tx = nil
+	parser = nil
+	collectgarbage () -- and release any references
+
+	--dump:close ()
+
+end end
+
+-- simple icon
+function icon (params) return function (ctx, width, height, fg)
+	ctx:set_source_rgba (ARDOUR.LuaAPI.color_to_rgba (fg))
+	local txt = Cairo.PangoLayout (ctx, "ArdourMono ".. math.ceil(math.min (width, height) * .45) .. "px")
+	txt:set_text ("MTS")
+	local tw, th = txt:get_pixel_size ()
+	ctx:move_to (.5 * (width - tw), .5 * (height - th))
+	txt:show_in_cairo_context (ctx)
+end end