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ardour {
["type"] = "dsp",
name = "Simple Amp II",
category = "Example",
license = "MIT",
author = "Ardour Lua Task Force",
description = [[
An Example DSP Plugin for processing audio, to
be used with Ardour's Lua scripting facility.]]
}
-- see amp1.lua
function dsp_ioconfig ()
return { [1] = { audio_in = -1, audio_out = -1}, }
end
function dsp_configure (ins, outs)
audio_ins = ins:n_audio();
local audio_outs = outs:n_audio()
assert (audio_ins == audio_outs)
end
-- this variant modifies the audio data in-place
-- in Ardour's buffer.
--
-- It relies on the fact that by default Ardour requires
-- plugins to process data in-place (zero copy).
--
-- Every assignment directly calls a c-function behind
-- the scenes to get/set the value.
-- It's a bit more efficient than "Amp I" on most systems.
function dsp_runmap (bufs, in_map, out_map, n_samples, offset)
for c = 1,audio_ins do
-- ensure that processing does happen in-place
local ib = in_map:get(ARDOUR.DataType("audio"), c - 1); -- get id of mapped input buffer for given cannel
local ob = out_map:get(ARDOUR.DataType("audio"), c - 1); -- get id of mapped output buffer for given cannel
assert (ib ~= ARDOUR.ChanMapping.Invalid);
assert (ob ~= ARDOUR.ChanMapping.Invalid);
local bi = bufs:get_audio(ib)
local bo = bufs:get_audio(ob)
assert (bi == bo)
local a = bufs:get_audio(ib):data(offset):array() -- get a reference (pointer to array)
for s = 1,n_samples do
a[s] = a[s] * 2; -- modify data in-place (shared with ardour)
end
end
end
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