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 -- -- "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 = "file", key = "file", title = "Select .scl file" }, { type = "checkbox", key = "bulk", default = false, title = "Bulk Transfer (not realtime)" }, { 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_note = 69 -- Reference note for which frequency is given local ref_freq = 440.0 -- Frequency to tune the above note to local ref_root = 60 -- root-note of the scale, note where the first entry of the scale is mapped to local note_start = 0 local note_end = 127 ----------------------------------------------------------------------------- -- prepare sending data local send_bulk = rv['bulk'] local tx = rv["tx"] -- output port local parser = ARDOUR.RawMidiParser () -- construct a MIDI parser local checksum = 0 if send_bulk then note_start = 0 note_end = 127 end --local dump = io.open ("/tmp/dump.syx", "wb") -- 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 ("Scala to MIDI Tuning", true) pdialog:progress (0, "Tuning"); -- 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 -- inverse mapping, ref_note will have the specified frequency in the target scale, -- while the scale itself will start at ref_root local ref_base = ref_freq * 2 ^ ((freqtbl[delta_note + 1] + freqtbl[expected_len + 1] * delta_octv) / -1200) if send_bulk then -- 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) end -- iterate over MIDI notes for nn = note_start, note_end 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_msb = (cc >> 7) & 127 local cent_lsb = cc & 127 --[[ print (string.format ("MIDI-Note %3d | Octv: %+d Note: %2d -> Freq: %8.2f Hz = note: %3d + %6.3f ct (0x%02x 0x%02x 0x%02x)", nn, delta_octv, delta_note, fq, base, cent, base, cent_msb, cent_lsb)) --]] if (base < 0 or base > 127) then if send_bulk then if base < 0 then base = 0 else base = 127 end cent_msb = 0 cent_lsb = 0 else -- skip out of bounds MIDI notes goto continue end end if send_bulk then 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) else checksum = 0x07 -- really unused -- 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 ) tx_midi (syx, 12, 0) 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 if send_bulk and 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 ("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