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ardour {
["type"] = "dsp",
name = "Notch Bank",
category = "Example",
license = "MIT",
author = "Ardour Lua Task Force",
description = [[An Example Filter Plugin]]
}
function dsp_ioconfig ()
return
{
-- allow any number of I/O as long as port-count matches
{ audio_in = -1, audio_out = -1},
}
end
function dsp_params ()
return
{
{ ["type"] = "input", name = "Base Freq", min = 10, max = 1000, default = 100, unit="Hz", logarithmic = true },
{ ["type"] = "input", name = "Quality", min = 1.0, max = 100.0, default = 8.0, logarithmic = true },
{ ["type"] = "input", name = "Stages", min = 1.0, max = 100, default = 8.0, integer = true },
}
end
local filters = {} -- the biquad filter instances
local sample_rate = 0
local chn = 0 -- channel count
local max_stages = 100
local freq = 0
local qual = 0
function dsp_init (rate)
sample_rate = rate
end
function dsp_configure (ins, outs)
assert (ins:n_audio () == outs:n_audio ())
chn = ins:n_audio ()
for c = 1, chn do
filters[c] = {}
for i = 1, max_stages do
filters[c][i] = ARDOUR.DSP.Biquad (sample_rate)
end
end
end
function dsp_run (ins, outs, n_samples)
assert (#ins == chn)
assert (n_samples < 8192)
-- this is quick/dirty: no declick, no de-zipper, no latency reporting,...
-- and no documentation :)
local ctrl = CtrlPorts:array() -- get control parameters
if freq ~= ctrl[1] or qual ~= ctrl[2] then
freq = ctrl[1]
qual = ctrl[2]
for c = 1, chn do
for i = 1, max_stages do
filters[c][i]:compute (ARDOUR.DSP.BiquadType.Notch, freq * i, qual, 0)
end
end
end
local limit = math.floor (sample_rate / ( 2 * freq ))
local stages = math.floor (ctrl['3'])
if stages < 1 then stages = 1 end
if stages > max_stages then stages = max_stages end
if stages > limit then stages = limit end
-- process all channels
for c = 1, chn do
if not ins[c]:sameinstance (outs[c]) then
ARDOUR.DSP.copy_vector (outs[c], outs[c], n_samples)
end
for i = 1, stages do
filters[c][i]:run (outs[c], n_samples)
end
end
end
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