67 lines
1.9 KiB
Lua
67 lines
1.9 KiB
Lua
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ardour {
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["type"] = "dsp",
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name = "a-Slow-Mute",
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category = "Amplifier",
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license = "MIT",
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author = "Ardour Team",
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description = [[Mute button with slow fade in/out]]
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}
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function dsp_ioconfig ()
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-- -1, -1 = any number of channels as long as input and output count matches
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return { { audio_in = -1, audio_out = -1} }
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end
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function dsp_params ()
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return { { ["type"] = "input", name = "Mute", min = 0, max = 1, default = 0, toggled = true } }
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end
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local cur_gain = 1
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local lpf = 0.002 -- parameter low-pass filter time-constant
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function dsp_init (rate)
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lpf = 100 / rate -- interpolation time constant
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end
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function low_pass_filter_param (old, new, limit)
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if math.abs (old - new) < limit then
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return new
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else
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return old + lpf * (new - old)
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end
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end
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-- the DSP callback function
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-- "ins" and "outs" are http://manual.ardour.org/lua-scripting/class_reference/#C:FloatArray
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function dsp_run (ins, outs, n_samples)
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local ctrl = CtrlPorts:array() -- get control port array
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local target_gain = ctrl[1] > 0 and 0.0 or 1.0; -- when muted, target_gain = 0.0; otherwise use 1.0
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local siz = n_samples -- samples remaining to process
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local off = 0 -- already processed samples
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local changed = false
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-- if the target gain changes, process at most 32 samples at a time,
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-- and interpolate gain until the current settings match the target values
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if cur_gain ~= target_gain then
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changed = true
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siz = 32
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end
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while n_samples > 0 do
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if siz > n_samples then siz = n_samples end
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if changed then
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cur_gain = low_pass_filter_param (cur_gain, target_gain, 0.001)
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end
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for c = 1,#ins do -- process all channels
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if ins[c] ~= outs[c] then
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ARDOUR.DSP.copy_vector (outs[c]:offset (off), ins[c]:offset (off), siz)
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end
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ARDOUR.DSP.apply_gain_to_buffer (outs[c]:offset (off), siz, cur_gain);
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end
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n_samples = n_samples - siz
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off = off + siz
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end
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end
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