ardour/ardour
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enforce range of HP/LP

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We must not assume that the host sends values within the the range
nor that the enum is always an integer.
This commit is contained in:
Robin Gareus 2016-07-19 19:26:05 +02:00
parent 2e933a6414
commit 2e789e34e7
1 changed files with 27 additions and 4 deletions
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31
scripts/HiAndLowPass.lua
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@ -53,6 +53,7 @@ local cur = {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 lpf_chunk = 0 -- chunk size for audio processing when interpolating parameters
local max_freq = 20000
local mem = nil -- memory x-fade buffer
@ -60,11 +61,16 @@ function dsp_init (rate)
-- allocate some mix-buffer
mem = ARDOUR.DSP.DspShm (8192)
-- max allowed cut-off frequency
max_freq = .499 * rate
-- create a table of objects to share with the GUI
local tbl = {}
tbl['samplerate'] = rate
tbl['max_freq'] = max_freq
self:table ():set (tbl)
-- Parameter smoothing: we want to filter out parameter changes that are
-- faster than 15Hz, and interpolate between parameter values.
-- For performance reasons, we want to ensure that two consecutive values
@ -113,6 +119,21 @@ function dsp_configure (ins, outs)
end
end
function santize_params (ctrl)
-- don't allow manual cross-fades. enforce enums
ctrl[1] = math.floor(ctrl[1] + .5)
ctrl[4] = math.floor(ctrl[4] + .5)
-- high pass, clamp range
ctrl[2] = math.min (max_freq, math.max (5, ctrl[2]))
ctrl[3] = math.min (6, math.max (0.1, ctrl[3]))
-- low pass, clamp range
ctrl[5] = math.min (max_freq, math.max (20, ctrl[5]))
ctrl[6] = math.min (6, math.max (0.1, ctrl[6]))
return ctrl
end
-- helper functions for parameter interpolation
function param_changed (ctrl)
for p = 1,6 do
@ -158,6 +179,7 @@ end
function dsp_run (ins, outs, n_samples)
assert (n_samples < 8192)
assert (#ins == chn)
local ctrl = santize_params (CtrlPorts:array ())
local changed = false
local siz = n_samples
@ -166,13 +188,13 @@ function dsp_run (ins, outs, n_samples)
-- if a parameter was changed, process at most lpf_chunk samples
-- at a time and interpolate parameters until the current settings
-- match the target values
if param_changed (CtrlPorts:array ()) then
if param_changed (ctrl) then
changed = true
siz = lpf_chunk
end
while n_samples > 0 do
if changed then apply_params (CtrlPorts:array ()) end
if changed then apply_params (ctrl) end
if siz > n_samples then siz = n_samples end
local ho = math.floor(cur[1])
@ -304,11 +326,12 @@ function render_inline (ctx, w, max_h)
filt = {}
filt['hp'] = ARDOUR.DSP.Biquad (tbl['samplerate'])
filt['lp'] = ARDOUR.DSP.Biquad (tbl['samplerate'])
max_freq = tbl['max_freq']
end
local ctrl = santize_params (CtrlPorts:array ())
-- set filter coefficients if they have changed
if param_changed (CtrlPorts:array ()) then
local ctrl = CtrlPorts:array ()
if param_changed (ctrl) then
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)