Robin Gareus
6f0e0000e6
* allow non-realtime bulk transfers * debug mode, dump .syx file * add some comments and references
307 lines
9.7 KiB
Lua
307 lines
9.7 KiB
Lua
ardour {
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["type"] = "EditorAction",
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name = "Scala to MIDI Tuning",
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license = "MIT",
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author = "Ardour Team",
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description = [[Read scala (.scl) tuning from a file, generate MIDI tuning standard (MTS) messages and send them to a MIDI port]]
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}
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function factory () return function ()
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-- return table of all MIDI tracks, and all instrument plugins.
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--
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-- MidiTrack::write_immediate_event() injects MIDI events to the track's input
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-- PluginInsert::write_immediate_event() sends events directly to a plugin
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function midi_targets ()
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local rv = {}
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for r in Session:get_tracks():iter() do
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if not r:to_track():isnil() then
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local mtr = r:to_track():to_midi_track()
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if not mtr:isnil() then
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rv["Track: '" .. r:name() .. "'"] = mtr
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end
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end
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local i = 0;
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while true do
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local proc = r:nth_plugin (i)
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if proc:isnil () then break end
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local pi = proc:to_plugininsert ()
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if pi:is_instrument () then
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rv["Track: '" .. r:name() .. "' | Plugin: '" .. pi:name() .. "'"] = pi
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end
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i = i + 1
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end
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end
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return rv
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end
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function log2 (v)
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return math.log (v) / math.log (2)
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end
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-- calculate MIDI note-number and cent-offset for a given frequency
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--
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-- "The first byte of the frequency data word specifies the nearest equal-tempered
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-- semitone below the frequency. The next two bytes (14 bits) specify the fraction
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-- of 100 cents above the semitone at which the frequency lies."
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--
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-- 68 7F 7F = 439.9984 Hz
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-- 69 00 00 = 440.0000 Hz
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-- 69 00 01 = 440.0016 Hz
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--
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-- NB. 7F 7F 7F = no change (reserved)
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--
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function freq_to_mts (hz)
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local note = math.floor (12. * log2 (hz / 440) + 69.0)
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local freq = 440.0 * 2.0 ^ ((note - 69) / 12);
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local cent = 1200.0 * log2 (hz / freq)
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-- fixup rounding errors
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if cent >= 99.99 then
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note = note + 1
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cent = 0
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end
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if cent < 0 then
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cent = 0
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end
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return note, cent
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end
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local dialog_options = {
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{ type = "file", key = "file", title = "Select .scl file" },
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{ type = "checkbox", key = "bulk", default = false, title = "Bulk Transfer (not realtime)" },
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{ type = "dropdown", key = "tx", title = "MIDI SysEx Target", values = midi_targets () }
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}
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local rv = LuaDialog.Dialog ("Select Scala File and MIDI Taget", dialog_options):run ()
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dialog_options = nil -- drop references (track, plugins, shared ptr)
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collectgarbage () -- and release the references immediately
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if not rv then return end -- user cancelled
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-- read the scl file
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local freqtbl = {}
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local ln = 0
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local expected_len = 0
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local f = io.open (rv["file"], "r")
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if not f then
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LuaDialog.Message ("Scala to MTS", "File Not Found", LuaDialog.MessageType.Error, LuaDialog.ButtonType.Close):run ()
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return
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end
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-- parse scala file and convert all intervals to cents
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-- http://www.huygens-fokker.org/scala/scl_format.html
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freqtbl[1] = 0.0 -- implicit
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for line in f:lines () do
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line = string.gsub (line, "%s", "") -- remove all whitespace
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if line:sub(0,1) == '!' then goto nextline end -- comment
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ln = ln + 1
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if ln < 2 then goto nextline end -- name
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if ln < 3 then
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expected_len = tonumber (line) -- number of notes on scale
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if expected_len < 1 or expected_len > 256 then break end -- invalid file
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goto nextline
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end
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local cents
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if string.find (line, ".", 1, true) then
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cents = tonumber (line)
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else
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local n, d = string.match(line, "(%d+)/(%d+)")
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if n then
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cents = 1200 * log2 (n / d)
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else
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local n = tonumber (line)
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cents = 1200 * log2 (n)
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end
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end
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--print ("SCL", ln - 2, cents)
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freqtbl[ln - 1] = cents
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::nextline::
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end
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f:close ()
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-- We need at least one interval.
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-- While legal in scl, single note scales are not useful here.
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if expected_len < 1 or expected_len + 2 ~= ln then
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LuaDialog.Message ("Scala to MTS", "Invalid or unusable scale file.", LuaDialog.MessageType.Error, LuaDialog.ButtonType.Close):run ()
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return
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end
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assert (expected_len + 2 == ln)
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assert (expected_len > 0)
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-----------------------------------------------------------------------------
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-- TODO consider reading a .kbm file or make these configurable in the dialog
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-- http://www.huygens-fokker.org/scala/help.htm#mappings
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local ref_note = 69 -- Reference note for which frequency is given
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local ref_freq = 440.0 -- Frequency to tune the above note to
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local ref_root = 60 -- root-note of the scale, note where the first entry of the scale is mapped to
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local note_start = 0
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local note_end = 127
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-----------------------------------------------------------------------------
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-- prepare sending data
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local send_bulk = rv['bulk']
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local tx = rv["tx"] -- output port
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local parser = ARDOUR.RawMidiParser () -- construct a MIDI parser
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local checksum = 0
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if send_bulk then
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note_start = 0
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note_end = 127
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end
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--local dump = io.open ("/tmp/dump.syx", "wb")
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-- helper function to send MIDI
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function tx_midi (syx, len, hdr)
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for b = 1, len do
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--dump:write (string.char(syx:byte (b)))
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-- calculate checksum, xor of all payload data
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-- (excluding the 0xf0, 0xf7, and the checksum field)
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if b >= hdr then
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checksum = checksum ~ syx:byte (b)
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end
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-- parse message to C/C++ uint8_t* array (Validate message correctness. This
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-- also returns C/C++ uint8_t* array for direct use with write_immediate_event.)
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if parser:process_byte (syx:byte (b)) then
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tx:write_immediate_event (parser:buffer_size (), parser:midi_buffer ())
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-- Slow things down a bit to ensure that no messages as lost.
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-- Physical MIDI is sent at 31.25kBaud.
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-- Every message is sent as 10bit message on the wire,
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-- so every MIDI byte needs 320usec.
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ARDOUR.LuaAPI.usleep (400 * parser:buffer_size ())
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end
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end
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end
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-- show progress dialog
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local pdialog = LuaDialog.ProgressWindow ("Scala to MIDI Tuning", true)
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pdialog:progress (0, "Tuning");
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-- calculate frequency at ref_root
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local delta = ref_note - ref_root
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local delta_octv = math.floor (delta / expected_len)
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local delta_note = delta % expected_len
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-- inverse mapping, ref_note will have the specified frequency in the target scale,
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-- while the scale itself will start at ref_root
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local ref_base = ref_freq * 2 ^ ((freqtbl[delta_note + 1] + freqtbl[expected_len + 1] * delta_octv) / -1200)
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if send_bulk then
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-- MIDI Tuning message
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-- http://technogems.blogspot.com/2018/07/using-midi-tuning-specification-mts.html
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-- http://www.ludovico.net/download/materiale_didattico/midi/08_midi_tuning.pdf
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local syx = string.char (
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0xf0, 0x7e, -- non-realtime sysex
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0x00, -- target-id
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0x08, 0x01, -- tuning, bulk dump reply
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0x00, -- tuning program number 0 to 127 in hexadecimal
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-- 16 chars name (zero padded)
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0x53, 0x63, 0x6C, 0x2D, 0x4D, 0x54, 0x53, 0x00, -- Scl-MTS
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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)
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tx_midi (syx, 22, 1)
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end
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-- iterate over MIDI notes
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for nn = note_start, note_end do
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if pdialog:canceled () then break end
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-- calculate the note relative to kbm's ref_root
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delta = nn - ref_root
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delta_octv = math.floor (delta / expected_len)
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delta_note = delta % expected_len
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-- calculate the frequency of the note according to the scl
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local fq = ref_base * 2 ^ ((freqtbl[delta_note + 1] + freqtbl[expected_len + 1] * delta_octv) / 1200)
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-- and then convert this frequency to the MIDI note number (and cent offset)
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local base, cent = freq_to_mts (fq)
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-- MTS uses two MIDI bytes (2^14) for cents
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local cc = math.floor (163.83 * cent + 0.5) | 0
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local cent_msb = (cc >> 7) & 127
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local cent_lsb = cc & 127
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--[[
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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)",
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nn, delta_octv, delta_note, fq, base, cent, base, cent_msb, cent_lsb))
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--]]
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if (base < 0 or base > 127) then
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if send_bulk then
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if base < 0 then
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base = 0
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else
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base = 127
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end
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cent_msb = 0
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cent_lsb = 0
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else
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-- skip out of bounds MIDI notes
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goto continue
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end
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end
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if send_bulk then
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local syx = string.char (
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base, -- semitone (MIDI note number to retune to, unit is 100 cents)
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cent_msb, -- MSB of fractional part (1/128 semitone = 100/128 cents = .78125 cent units)
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cent_lsb, -- LSB of fractional part (1/16384 semitone = 100/16384 cents = .0061 cent units)
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0xf7
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)
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tx_midi (syx, 3, 0)
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else
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checksum = 0x07 -- really unused
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-- MIDI Tuning message
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-- http://www.microtonal-synthesis.com/MIDItuning.html
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local syx = string.char (
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0xf0, 0x7f, -- realtime sysex
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0x7f, -- target-id
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0x08, 0x02, -- tuning, note change request
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0x00, -- tuning program number 0 to 127 in hexadecimal
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0x01, -- number of notes to be changed
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nn, -- note number to be changed
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base, -- semitone (MIDI note number to retune to, unit is 100 cents)
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cent_msb, -- MSB of fractional part (1/128 semitone = 100/128 cents = .78125 cent units)
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cent_lsb, -- LSB of fractional part (1/16384 semitone = 100/16384 cents = .0061 cent units)
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0xf7
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)
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tx_midi (syx, 12, 0)
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end
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-- show progress
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pdialog:progress (nn / 127, string.format ("Note %d freq: %.2f (%d + %d)", nn, fq, base, cc))
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if pdialog:canceled () then break end
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::continue::
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end
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if send_bulk and not pdialog:canceled () then
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tx_midi (string.char ((checksum & 127), 0xf7), 2, 2)
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end
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-- hide modal progress dialog and destroy it
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pdialog:done ();
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--dump:close ()
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end end
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-- simple icon
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function icon (params) return function (ctx, width, height, fg)
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ctx:set_source_rgba (ARDOUR.LuaAPI.color_to_rgba (fg))
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local txt = Cairo.PangoLayout (ctx, "ArdourMono ".. math.ceil(math.min (width, height) * .45) .. "px")
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txt:set_text ("SCL\nMTS")
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local tw, th = txt:get_pixel_size ()
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ctx:move_to (.5 * (width - tw), .5 * (height - th))
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txt:show_in_cairo_context (ctx)
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end end
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