diff options
| -rw-r--r-- | scripts/_notch_bank.lua | 64 |
1 files changed, 51 insertions, 13 deletions
diff --git a/scripts/_notch_bank.lua b/scripts/_notch_bank.lua index d5662c72f6..68c1942c5a 100644 --- a/scripts/_notch_bank.lua +++ b/scripts/_notch_bank.lua @@ -7,6 +7,15 @@ ardour { description = [[An Example Filter Plugin]] } +------------------------------------------------------------------- +-- this is a quick/dirty example filter: no de-click, no de-zipper, +-- no latency reporting,... +------------------------------------------------------------------- + +-- configuration +local max_stages = 100 + +-- plugin i/o ports function dsp_ioconfig () return { @@ -15,29 +24,42 @@ function dsp_ioconfig () } end +-- plugin control ports 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 }, + { ["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 sample_rate = 0 -local chn = 0 -- channel count -local max_stages = 100 +local chn = 0 -- configured channel count +local sample_rate = 0 -- configured 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 ()) + + -- 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 @@ -46,36 +68,52 @@ function dsp_configure (ins, outs) 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) - 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 as array + -- ctrl[1] .. corresponds to the parameters given in in dsp_params() - local ctrl = CtrlPorts:array() -- get control parameters + -- 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] - for c = 1, chn do - for i = 1, max_stages do + -- re-compute the filter coefficients for all filters + for c = 1, chn do -- for each channel + for i = 1, max_stages do -- and for each filter stage + -- the parameters are type, frequency, quality(bandwidth), gain + -- see http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:DSP:Biquad + -- for a list of available types, see + -- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR.DSP.Biquad.Type 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 + -- limit the number of process stages + local limit = math.floor (sample_rate / ( 2 * freq )) -- at most up to SR / 2 + local stages = math.floor (ctrl['3']) -- current user-set parameter + if stages < 1 then stages = 1 end -- at least one stage... if stages > max_stages then stages = max_stages end 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 not ins[c]:sameinstance (outs[c]) then ARDOUR.DSP.copy_vector (outs[c], outs[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 |