ardour { ["type"] = "EditorAction", name = "Scala to MIDI Tuning", license = "MIT", author = "Ardour Team", description = [[Read scala (.scl) tuning from a file, generate MIDI tuning standard (MTS) messages and send them to a MIDI port]] } 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 function freq_to_mts (hz) local note = math.floor (12. * log2 (hz / 440) + 69.0) local freq = 440.0 * 2.0 ^ ((note - 69) / 12); assert (freq > note) local cent = 1200.0 * log2 (hz / freq) return note, cent end local dialog_options = { { type = "file", key = "file", title = "Select .scl file" }, { type = "dropdown", key = "tx", title = "MIDI SysEx Target", values = midi_targets () } } local rv = LuaDialog.Dialog ("Select Scala File and MIDI Taget", 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 -- read the scl file local freqtbl = {} local ln = 0 local expected_len = 0 local f = io.open (rv["file"], "r") if not f then LuaDialog.Message ("Scala to MTS", "File Not Found", LuaDialog.MessageType.Error, LuaDialog.ButtonType.Close):run () return end -- parse scala file and convert all intervals to cents -- http://www.huygens-fokker.org/scala/scl_format.html freqtbl[1] = 0.0 -- implicit for line in f:lines () do line = string.gsub (line, "%s", "") -- remove all whitespace if line:sub(0,1) == '!' then goto nextline end -- comment ln = ln + 1 if ln < 2 then goto nextline end -- name if ln < 3 then expected_len = tonumber (line) -- number of notes on scale if expected_len < 1 or expected_len > 256 then break end -- invalid file goto nextline end local cents if string.find (line, ".", 1, true) then cents = tonumber (line) else local n, d = string.match(line, "(%d+)/(%d+)") if n then cents = 1200 * log2 (n / d) else local n = tonumber (line) cents = 1200 * log2 (n) end end --print ("SCL", ln - 2, cents) freqtbl[ln - 1] = cents ::nextline:: end f:close () -- We need at least one interval. -- While legal in scl, single note scales are not useful here. if expected_len < 1 or expected_len + 2 ~= ln then LuaDialog.Message ("Scala to MTS", "Invalid or unusable scale file.", LuaDialog.MessageType.Error, LuaDialog.ButtonType.Close):run () return end assert (expected_len + 2 == ln) assert (expected_len > 0) -- TODO consider reading a .kbm file or make these configurable in the dialog -- http://www.huygens-fokker.org/scala/help.htm#mappings local ref_root = 60 -- middle C local ref_note = 69 -- A4 local ref_freq = 440.0 -- calculate frequency at ref_root local delta = ref_note - ref_root local delta_octv = math.floor (delta / expected_len) local delta_note = delta % expected_len local ref_base = ref_freq * 2 ^ ((freqtbl[delta_note + 1] + freqtbl[expected_len + 1] * delta_octv) / -1200) -- prepare sending data local tx = rv["tx"] -- output port local parser = ARDOUR.RawMidiParser () -- construct a MIDI parser -- show progress dialog local pdialog = LuaDialog.ProgressWindow ("Scala to MIDI Tuning", true) pdialog:progress (0, "Tuning"); -- iterate over all MIDI notes for nn = 0, 127 do if pdialog:canceled () then break end -- calculate the note relative to kbm's ref_root delta = nn - ref_root delta_octv = math.floor (delta / expected_len) delta_note = delta % expected_len -- calculate the frequency of the note according to the scl local fq = ref_base * 2 ^ ((freqtbl[delta_note + 1] + freqtbl[expected_len + 1] * delta_octv) / 1200) -- 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_lsb = (cc >> 7) & 127 local cent_msb = cc & 127 --print ("MIDI Note:", nn, "scale-note:", delta_note, "Octave:", delta_octv, "-> Freq:", fq, "= note:", base, "+", cent, "cents (", cc, ")") if (base < 0 or base > 127) then -- skip out of bounds MIDI notes goto continue end -- MIDI Tuning message -- http://www.microtonal-synthesis.com/MIDItuning.html local syx = string.char ( 0xf0, 0x7f, -- realtime sysex 0x7f, -- target-id 0x08, 0x02, -- tuning, note change request 0x00, -- tuning program number 0 to 127 in hexadecimal 0x01, -- number of notes to be changed nn, -- note number to be changed 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 ) -- 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.) for b = 1, 12 do if parser:process_byte (syx:byte (b)) then tx:write_immediate_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 -- 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 -- hide modal progress dialog and destroy it pdialog:done (); 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 ("SCL\nMTS") local tw, th = txt:get_pixel_size () ctx:move_to (.5 * (width - tw), .5 * (height - th)) txt:show_in_cairo_context (ctx) end end