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livetrax/scripts/_midifilter.lua
Julien "_FrnchFrgg_" RIVAUD 3b1a6a350e Simplify _midifilter.lua example
Instead of and-ing the first byte to extract the event type, it is
simpler and easier to understand to bitwise-shift it, so that we don't
get the result as a multiple of 2^4, but as values corresponding to the
MIDI specification.

Currently, a guard is put against events with completely empty data,
though maybe ardour discards those earlier on since that would not be
valid MIDI.
2017-07-14 15:16:33 +02:00

40 lines
976 B
Lua

ardour {
["type"] = "dsp",
name = "Midi Filter",
category = "Example", -- "Utility"
license = "MIT",
author = "Ardour Lua Task Force",
description = [[An Example Midi Filter for prototyping.]]
}
function dsp_ioconfig ()
return { { midi_in = 1, midi_out = 1, audio_in = 0, audio_out = 0}, }
end
function dsp_run (_, _, n_samples)
assert (type(midiin) == "table")
assert (type(midiout) == "table")
local cnt = 1;
function tx_midi (time, data)
midiout[cnt] = {}
midiout[cnt]["time"] = time;
midiout[cnt]["data"] = data;
cnt = cnt + 1;
end
-- for each incoming midi event
for _,b in pairs (midiin) do
local t = b["time"] -- t = [ 1 .. n_samples ]
local d = b["data"] -- get midi-event
local event_type
if #d == 0 then event_type = -1 else event_type = d[1] >> 4 end
if (#d == 3 and event_type == 9) then -- note on
tx_midi (t, d)
elseif (#d == 3 and event_type = 8) then -- note off
tx_midi (t, d)
end
end
end