update notch-bank to variable i/o, increase max stages to 100

scripts/_notch_bank.lua

@@ -10,7 +10,8 @@ ardour {
 function dsp_ioconfig ()
 	return
 	{
-		{ audio_in = 1, audio_out = 1},
+		-- allow any number of I/O as long as port-count matches
+		{ audio_in = -1, audio_out = -1},
 	}
 end
 
@@ -19,45 +20,64 @@ function dsp_params ()
 	{
 		{ ["type"] = "input", name = "Base Freq", min = 10, max = 1000, default = 100, unit="Hz", logarithmic = true },
 		{ ["type"] = "input", name = "Quality", min = 1.0, max = 16.0, default = 8.0 },
-		{ ["type"] = "input", name = "Stages", min = 1.0, max = 20, default = 6.0, integer = true },
+		{ ["type"] = "input", name = "Stages", min = 1.0, max = 100, default = 8.0, integer = true },
 	}
 end
 
 local filters = {} -- the biquad filter instances
+local sample_rate = 0
+local chn = 0 -- channel count
+local max_stages = 100
 local freq = 0
-local bw = 0
+local qual = 0
 
 function dsp_init (rate)
-	for i = 1,20 do
-		filters[i] = ARDOUR.DSP.Biquad (rate)
+	sample_rate = rate
+end
+
+function dsp_configure (ins, outs)
+	assert (ins:n_audio () == outs:n_audio ())
+	chn = ins:n_audio ()
+	for c = 1, chn do
+		filters[c] = {}
+		for i = 1, max_stages do
+			filters[c][i] = ARDOUR.DSP.Biquad (sample_rate)
+		end
 	end
 end
 
 function dsp_run (ins, outs, n_samples)
-	assert (#outs == 1)
+	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
-	if freq ~= ctrl[1] or bw ~= ctrl[2] then
+	if freq ~= ctrl[1] or qual ~= ctrl[2] then
 		freq = ctrl[1]
-		bw = ctrl[2]
-		for i = 1,20 do
-			filters[i]:compute (ARDOUR.DSP.BiquadType.Notch, freq * i, bw, 0)
+		qual = ctrl[2]
+		for c = 1, chn do
+			for i = 1, max_stages do
+				filters[c][i]:compute (ARDOUR.DSP.BiquadType.Notch, freq * i, qual, 0)
+			end
 		end
 	end
 
-	if not ins[1]:sameinstance (outs[1]) then
-		ARDOUR.DSP.copy_vector (outs[1], outs[1], n_samples)
-	end
-
+	local limit = math.floor (sample_rate / ( 2 * freq ))
 	local stages = math.floor (ctrl['3'])
-	if stages < 1 then stages = 1; end
-	if stages > 20 then stages = 20; end
+	if stages < 1 then stages = 1 end
+	if stages > max_stages then stages = max_stages end
+	if stages > limit then stages = limit end
+
+	-- process all channels
+	for c = 1, chn do
+		if not ins[c]:sameinstance (outs[c]) then
+			ARDOUR.DSP.copy_vector (outs[c], outs[c], n_samples)
+		end
 
 		for i = 1, stages do
-		filters[i]:run (outs[1], n_samples)
+			filters[c][i]:run (outs[c], n_samples)
+		end
 	end
 end