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Diffstat (limited to 'share/scripts/notch_bank.lua')
| -rw-r--r-- | share/scripts/notch_bank.lua | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/share/scripts/notch_bank.lua b/share/scripts/notch_bank.lua new file mode 100644 index 0000000000..76901920d9 --- /dev/null +++ b/share/scripts/notch_bank.lua @@ -0,0 +1,125 @@ +ardour { + ["type"] = "dsp", + name = "a-Notch Bank", + category = "Filter", + license = "MIT", + author = "Ardour Lua Task Force", + description = [[Notch Filter Bank; useful to remove noise with a harmonic spectum (e.g, mains hum, GSM signals, charge-pump noise, etc). +Note: this plugin is not suitable to be automated, it is intended for static noise only.]] +} + +------------------------------------------------------------------ +-- this is a quick/dirty example filter: no de-click, no de-zipper +------------------------------------------------------------------- + +-- configuration +local max_stages = 100 + +-- plugin i/o ports +function dsp_ioconfig () + return + { + -- allow any number of I/O as long as port-count matches + { audio_in = -1, audio_out = -1}, + } +end + +-- plugin control ports +function dsp_params () + return + { + { ["type"] = "input", name = "Base Freq", min = 10, max = 2000, 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 = max_stages, default = 8.0, integer = true }, + } +end + +-- plugin instance state +local filters = {} -- the biquad filter instances +local chn = 0 -- configured channel count +local sample_rate = 0 -- configured sample-rate +local limit = 0 -- max number of stages (given freq & sample-rate) + +-- cached control ports (keep track of changed) +local freq = 0 +local qual = 0 + +-- dsp_init is called once when instantiating the plugin +function dsp_init (rate) + -- remember the sample-rate + sample_rate = rate +end + +-- dsp_configure is called every time when the channel-count +-- changes, and at least once at the beginning. +function dsp_configure (ins, outs) + assert (ins:n_audio () == outs:n_audio ()) + + -- explicit cleanup + filters = {} + collectgarbage () + + -- remember audio-channels + chn = ins:n_audio () + + -- set up filter instances for all channels + for c = 1, chn do + filters[c] = {} + for i = 1, max_stages do + filters[c][i] = ARDOUR.DSP.Biquad (sample_rate) + end + end +end + +-- the actual process function, called every cycle +-- ins, outs are audio-data arrays +-- http://manual.ardour.org/lua-scripting/class_reference/#C:FloatArray +-- n_samples are the number of samples to process +function dsp_run (ins, outs, n_samples) + -- make sure input and output count matches... + assert (#ins == #outs) + -- ...and matches the configured number of channels + assert (#ins == chn) + + local ctrl = CtrlPorts:array () -- get control parameters as array + -- ctrl[] .. correspond to the parameters given in in dsp_params() + + -- test if the plugin-parameters have changed + if freq ~= ctrl[1] or qual ~= ctrl[2] then + -- remember current settings + freq = ctrl[1] + qual = ctrl[2] + -- calc max number of states to configure/process + limit = math.floor (sample_rate / (2 * freq)) -- at most up to SR / 2 + if limit > max_stages then limit = max_stages end + + -- re-compute the filter coefficients for all filters + for c = 1, chn do -- for each channel + for i = 1, limit do -- and for each filter stage + -- see http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:DSP:Biquad + -- and for a list of available types, see + -- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR.DSP.Biquad.Type + -- the parameters are type, frequency, quality(bandwidth), gain + filters[c][i]:compute (ARDOUR.DSP.BiquadType.Notch, freq * i, qual * i, 0) + end + end + end + + -- limit the number of process stages + local stages = math.floor (ctrl['3']) -- current user-set parameter + if stages < 1 then stages = 1 end -- at least one stage... + if stages > limit then stages = limit end + + -- process all channels + for c = 1, chn do + -- when not processing in-place, copy the data from input to output first + if ins[c] ~= outs[c] then + ARDOUR.DSP.copy_vector (outs[c], ins[c], n_samples) + end + + -- run all stages, in-place on the output buffer + for i = 1, stages do + filters[c][i]:run (outs[c], n_samples) + end + end +end |