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author | Robin Gareus <robin@gareus.org> | 2016-07-16 23:05:30 +0200 |
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committer | Robin Gareus <robin@gareus.org> | 2016-07-16 23:05:30 +0200 |
commit | e7a154b9dd8ed43a77424f8624ce61db0fa390d9 (patch) | |
tree | e634e0bd2d0f44ab0e889567457f10af66f05988 /scripts/HiAndLowPass.lua | |
parent | 1a7fd81f4095e3ee8cb42e63c232a51529412846 (diff) |
Hi AND low pass filter -- fresh from the oven werks.
Diffstat (limited to 'scripts/HiAndLowPass.lua')
-rw-r--r-- | scripts/HiAndLowPass.lua | 342 |
1 files changed, 342 insertions, 0 deletions
diff --git a/scripts/HiAndLowPass.lua b/scripts/HiAndLowPass.lua new file mode 100644 index 0000000000..58908edd23 --- /dev/null +++ b/scripts/HiAndLowPass.lua @@ -0,0 +1,342 @@ +ardour { + ["type"] = "dsp", + name = "a-High and Low Pass Filter", + category = "Filter", + license = "MIT", + author = "Ardour Team", + description = [[Example Ardour Lua DSP 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 = "High Pass Steepness", min = 0, max = 4, default = 1, enum = true, scalepoints = + { + ["Off"] = 0, + ["12dB/oct"] = 1, + ["24dB/oct"] = 2, + ["36dB/oct"] = 3, + ["48dB/oct"] = 4, + } + }, + { ["type"] = "input", name = "High Pass Cut off frequency", min = 5, max = 20000, default = 100, unit="Hz", logarithmic = true }, + { ["type"] = "input", name = "High Pass Resonance", min = 0.1, max = 6, default = .707, logarithmic = true }, + + { ["type"] = "input", name = "Low Pass Steepness", min = 0, max = 4, default = 1, enum = true, scalepoints = + { + ["Off"] = 0, + ["12dB/oct"] = 1, + ["24dB/oct"] = 2, + ["36dB/oct"] = 3, + ["48dB/oct"] = 4, + } + }, + { ["type"] = "input", name = "Low Pass Cut off frequency", min = 20, max = 20000, default = 18000, unit="Hz", logarithmic = true }, + { ["type"] = "input", name = "Low Pass Resonance", min = 0.1, max = 6, default = .707, logarithmic = true }, + } +end + +-- these globals are *not* shared between DSP and UI +local hp = {} -- the biquad high-pass filter instances (DSP) +local lp = {} -- the biquad high-pass filter instances (DSP) +local filt = nil -- the biquad filter instance (GUI, response) +local cur = {0, 0, 0, 0, 0, 0, 0} -- current parameters +local lpf = 0.03 -- parameter low-pass filter time-constant +local chn = 0 -- channel/filter count + +local mem = nil -- memory x-fade buffer + +function dsp_init (rate) + -- allocate some mix-buffer + mem = ARDOUR.DSP.DspShm (8192) + + -- create a table of objects to share with the GUI + local tbl = {} + tbl['rb'] = rb + tbl['samplerate'] = rate + self:table ():set (tbl) + + -- interpolation time constant + lpf = 13000 / rate +end + +function dsp_configure (ins, outs) + assert (ins:n_audio () == outs:n_audio ()) + local tbl = self:table ():get () -- get shared memory table + local rate = tbl['samplerate'] + + chn = ins:n_audio () + + for c = 1, chn do + hp[c] = {} + lp[c] = {} + -- initialize filters + -- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:DSP:Biquad + for k = 1,4 do + hp[c][k] = ARDOUR.DSP.Biquad (rate) + lp[c][k] = ARDOUR.DSP.Biquad (rate) + end + end + cur = {0, 0, 0, 0, 0, 0} +end + +-- helper functions for parameter interpolation +function param_changed (ctrl) + for p = 1,6 do + if ctrl[p] ~= cur[p] then + return true + end + end + return false +end + +function low_pass_filter_param (old, new, limit) + if math.abs (old - new) < limit then + return new + else + return old + lpf * (new - old) + end +end + +-- apply parameters, re-compute filter coefficients if needed +function apply_params (ctrl) + if not param_changed (ctrl) then + return + end + + -- low-pass filter ctrl parameter values, smooth transition + cur[1] = low_pass_filter_param (cur[1], ctrl[1], 0.05) -- HP order x-fade + cur[2] = low_pass_filter_param (cur[2], ctrl[2], 1.0) -- HP freq/Hz + cur[3] = low_pass_filter_param (cur[3], ctrl[3], 0.01) -- HP quality + cur[4] = low_pass_filter_param (cur[4], ctrl[4], 0.05) -- LP order x-fade + cur[5] = low_pass_filter_param (cur[5], ctrl[5], 1.0) -- LP freq/Hz + cur[6] = low_pass_filter_param (cur[6], ctrl[6], 0.01) -- LP quality + + for c = 1, chn do + for k = 1,4 do + hp[c][k]:compute (ARDOUR.DSP.BiquadType.HighPass, cur[2], cur[3], 0) + lp[c][k]:compute (ARDOUR.DSP.BiquadType.LowPass, cur[5], cur[6], 0) + end + end +end + + +-- the actual DSP callback +function dsp_run (ins, outs, n_samples) + assert (n_samples < 8192) + local changed = false + local siz = n_samples + local off = 0 + + -- if a parameter was changed, process at most 64 samples at a time + -- and interpolate parameters until the current settings match + -- the target values + if param_changed (CtrlPorts:array ()) then + changed = true + siz = 64 + end + + while n_samples > 0 do + if changed then apply_params (CtrlPorts:array ()) end + if siz > n_samples then siz = n_samples end + + local ho = math.floor(cur[1]) + local lo = math.floor(cur[4]) + local hox = cur[1] + local lox = cur[4] + + -- process all channels + for c = 1, #ins do + + local xfade = hox - ho + assert (xfade >= 0 and xfade < 1) + + ARDOUR.DSP.copy_vector (mem:to_float (off), ins[c]:offset (off), siz) + + -- initialize output + if hox == 0 then + ARDOUR.DSP.copy_vector (outs[c]:offset (off), mem:to_float (off), siz) + else + ARDOUR.DSP.memset (outs[c]:offset (off), 0, siz) + end + + for k = 1,4 do + if xfade > 0 and k > ho and k <= ho + 1 then + ARDOUR.DSP.mix_buffers_with_gain (outs[c]:offset (off), mem:to_float (off), siz, 1 - xfade) + end + + hp[c][k]:run (mem:to_float (off), siz) + + if k == ho and xfade == 0 then + ARDOUR.DSP.copy_vector (outs[c]:offset (off), mem:to_float (off), siz) + elseif k > ho and k <= ho + 1 then + ARDOUR.DSP.mix_buffers_with_gain (outs[c]:offset (off), mem:to_float (off), siz, xfade) + end + end + + -- low pass + xfade = lox - lo + assert (xfade >= 0 and xfade < 1) + + ARDOUR.DSP.copy_vector (mem:to_float (off), outs[c]:offset (off), siz) + + if lox > 0 then + ARDOUR.DSP.memset (outs[c]:offset (off), 0, siz) + end + + for k = 1,4 do + if xfade > 0 and k > lo and k <= lo + 1 then + ARDOUR.DSP.mix_buffers_with_gain (outs[c]:offset (off), mem:to_float (off), siz, 1 - xfade) + end + + lp[c][k]:run (mem:to_float (off), siz) + + if k == lo and xfade == 0 then + ARDOUR.DSP.copy_vector (outs[c]:offset (off), mem:to_float (off), siz) + elseif k > lo and k <= lo + 1 then + ARDOUR.DSP.mix_buffers_with_gain (outs[c]:offset (off), mem:to_float (off), siz, xfade) + end + end + + end + + n_samples = n_samples - siz + off = off + siz + end + + if changed then + -- notify display + self:queue_draw () + end +end + + +------------------------------------------------------------------------------- +--- inline display + +function round (n) + return math.floor (n + .5) +end + +function freq_at_x (x, w) + -- x-axis pixel for given freq, power-scale + return 20 * 1000 ^ (x / w) +end + +function x_at_freq (f, w) + -- frequency at given x-axis pixel + return w * math.log (f / 20.0) / math.log (1000.0) +end + +function db_to_y (db, h) + -- y-axis gain mapping + if db < -60 then db = -60 end + if db > 12 then db = 12 end + return -.5 + round (0.2 * h) - h * db / 60 +end + +function grid_db (ctx, w, h, db) + -- draw horizontal grid line + local y = -.5 + round (db_to_y (db, h)) + ctx:move_to (0, y) + ctx:line_to (w, y) + ctx:stroke () +end + +function grid_freq (ctx, w, h, f) + -- draw vertical grid line + local x = -.5 + round (x_at_freq (f, w)) + ctx:move_to (x, 0) + ctx:line_to (x, h) + ctx:stroke () +end + +function response (ho, lo, f) + local db = ho * filt['hp']:dB_at_freq (f) + return db + lo * filt['lp']:dB_at_freq (f) +end + +function render_inline (ctx, w, max_h) + if not filt then + local tbl = self:table ():get () -- get shared memory table + -- instantiate filter (to calculate the transfer function's response) + filt = {} + filt['hp'] = ARDOUR.DSP.Biquad (tbl['samplerate']) + filt['lp'] = ARDOUR.DSP.Biquad (tbl['samplerate']) + end + + -- set filter coefficients if they have changed + if param_changed (CtrlPorts:array ()) then + local ctrl = CtrlPorts:array () + for k = 1,6 do cur[k] = ctrl[k] end + filt['hp']:compute (ARDOUR.DSP.BiquadType.HighPass, cur[2], cur[3], 0) + filt['lp']:compute (ARDOUR.DSP.BiquadType.LowPass, cur[5], cur[6], 0) + end + + -- calc height of inline display + local h = 1 | math.ceil (w * 9 / 16) -- use 16:9 aspect, odd number of y pixels + if (h > max_h) then h = max_h end -- but at most max-height + + -- ctx is a http://cairographics.org/ context + -- http://manual.ardour.org/lua-scripting/class_reference/#Cairo:Context + + -- clear background + ctx:rectangle (0, 0, w, h) + ctx:set_source_rgba (.2, .2, .2, 1.0) + ctx:fill () + ctx:rectangle (0, 0, w, h) + ctx:clip () + + -- set line width: 1px + -- Note: a cairo pixel at [1,1] spans [0.5->1.5 , 0.5->1.5] + -- hence the offset -0.5 in various move_to(), line_to() calls + ctx:set_line_width (1.0) + + -- draw grid + local dash3 = C.DoubleVector () + local dash2 = C.DoubleVector () + dash2:add ({1, 2}) + dash3:add ({1, 3}) + ctx:set_dash (dash2, 2) -- dotted line + ctx:set_source_rgba (.5, .5, .5, .8) + grid_db (ctx, w, h, 0) + ctx:set_dash (dash3, 2) -- dotted line + ctx:set_source_rgba (.5, .5, .5, .5) + grid_db (ctx, w, h, -12) + grid_db (ctx, w, h, -24) + grid_db (ctx, w, h, -36) + grid_freq (ctx, w, h, 100) + grid_freq (ctx, w, h, 1000) + grid_freq (ctx, w, h, 10000) + ctx:unset_dash () + + local ho = math.floor(cur[1]) + local lo = math.floor(cur[4]) + + -- draw transfer function line + ctx:set_source_rgba (.8, .8, .8, 1.0) + ctx:move_to (-.5, db_to_y (response(ho, lo, freq_at_x (0, w)), h)) + for x = 1,w do + local db = response(ho, lo, freq_at_x (x, w)) + ctx:line_to (-.5 + x, db_to_y (db, h)) + end + ctx:stroke_preserve () + + -- fill area to zero under the curve + ctx:line_to (w, -.5 + round (db_to_y (0, h))) + ctx:line_to (0, -.5 + round (db_to_y (0, h))) + ctx:close_path () + ctx:set_source_rgba (.5, .5, .5, .5) + ctx:fill () + + return {w, h} +end |