add early prototype of leveller

Makefile

@@ -5,7 +5,7 @@ FULLNAME = $(DISTNAME)-$(VERSION)
 BIN ?= ./bin
 VST_SDK_DIR ?= .
 
-BOTH = eq eq_const eq_const_T420 eq_const_T420_svf mugi4 noise tube
+BOTH = eq eq_const eq_const_T420 eq_const_T420_svf mugi4 noise tube level
 LADSPA = $(BOTH)
 VST = $(BOTH) delay_test
 

README.md

@@ -18,6 +18,7 @@ crap T420 Speaker Compensation | crap\_eq\_const\_T420 | `0x0DEFAE91` | lenovo t
 crap T420 Speaker Compensation (SVF) | crap\_eq\_const\_T420\_svf | `0x0DEFB3CA` | trying out State Variable Filters (SVFs)
 crap mugi4 (moog-like) | crap\_mugi4 | `0xD8D0D8D0` | nonlinear moog filter implementation: [see reference][moog]
 crap Tube Distortion | crap\_tube | `0x50F7BA11` | static waveshaper with 6x oversampling and parameter smoothing. doesn't actually emulate a tube. not actually for crapping in.
+crap Leveller | crap\_level | `0xAAAAAAAA` | an early prototype of a heavy leveller.
 
 [moog]: https://aaltodoc.aalto.fi/bitstream/handle/123456789/14420/article6.pdf
 

crap/level.hpp

@@ -0,0 +1,190 @@
+#include <string.h>
+#include <math.h>
+
+#include "util.hpp"
+#include "Param.hpp"
+#include "Crap.hpp"
+#include "Buffer2.hpp"
+#include "biquad.hpp"
+
+#define DELAY 1
+static ulong global_delay = 0;
+
+TEMPLATE
+struct Delay {
+	static constexpr ulong size = 4096;
+
+	// needs to be twice the size for a memcpy trick later
+	T buf[size*2];
+	int length, pos;
+
+	inline void
+	setup(int newlen)
+	{
+		pos = 0;
+		length = newlen;
+		for (int i = 0; i < size*2; i++)
+			buf[i] = T(0);
+	};
+
+	inline T
+	delay(T s)
+	{
+		pos--;
+		if (pos <= 0) {
+			memcpy(buf + size, buf, size*sizeof(T));
+			pos = size;
+		}
+		buf[pos] = s;
+		return buf[pos + length];
+	};
+
+	inline T &
+	operator[](int index) {
+		return buf[pos + index];
+	}
+
+	inline const T &
+	operator[](int index) const {
+		return buf[pos + index];
+	}
+};
+
+struct Crap_level
+:public AdjustAll<Buffer2<Crap>> {
+	static constexpr ulong id = 0xAAAAAAAA;
+	static constexpr char label[] = "crap_level";
+	static constexpr char name[] = "crap Leveller";
+	static constexpr char author[] = "Connor Olding";
+	static constexpr char copyright[] = "MIT";
+
+	static constexpr ulong bands = 2;
+	static constexpr ulong parameters = 0;
+
+	v2df sc[BLOCK_SIZE]; // sidechain
+	biquad filters_L[bands];
+	biquad filters_R[bands];
+	ulong window_size;
+	ulong lookahead;
+	double *window;
+	double env, attack, release;
+	Delay<v2df> delay;
+	Delay<double> window_delay;
+
+	Crap_level()
+	{
+		window = NULL;
+	};
+
+	virtual
+	~Crap_level()
+	{
+		if (window)
+			free(window);
+	}
+
+	inline void
+	process2(v2df *buf, ulong rem)
+	{
+		biquad *f0, *f1;
+		f0 = filters_L;
+		f1 = filters_R;
+		memcpy(sc, buf, rem*sizeof(v2df));
+		for (ulong i = 0; i < bands; i++) {
+			biquad_run_block_stereo(f0, f1, sc, rem);
+			f0++;
+			f1++;
+		}
+		double envs[rem];
+		for (ulong i = 0; i < rem; i++)
+			envs[i] = fabs(sc[i][0]) + fabs(sc[i][1]);
+		for (ulong i = 0; i < rem; i++)
+			envs[i] *= 0.5;
+
+		// MaxFIR
+		double applied[window_size];
+		for (ulong i = 0; i < rem; i++) {
+			window_delay.delay(envs[i]);
+			for (ulong j = 0; j < window_size; j++)
+				applied[j] = window[j]*window_delay[j];
+			double max_ = 0;
+			for (ulong j = 0; j < window_size; j++)
+				max_ = fmax(max_, applied[j]);
+			envs[i] = max_;
+		}
+
+		// Follower
+		for (ulong i = 0; i < rem; i++) {
+			env += (envs[i] - env)*(env < envs[i] ? attack : release);
+			env = fmax(0.00001, env);
+			envs[i] = env;
+		}
+		double gains[rem];
+		for (ulong i = 0; i < rem; i++)
+			gains[i] = 0.3991 - 0.01769/(envs[i] + 0.044);
+		for (ulong i = 0; i < rem; i++)
+			gains[i] = fmax(0, gains[i]);
+		for (ulong i = 0; i < rem; i++)
+			gains[i] /= envs[i];
+
+		for (ulong i = 0; i < rem; i++) {
+			v2df gain = v2df(gains[i]);
+			buf[i] = delay.delay(buf[i])*gain;
+		}
+	}
+
+	inline void
+	pause()
+	{}
+
+	inline void
+	resume()
+	{
+		for (int i = 0; i < bands; i++) {
+			biquad_init(&filters_L[i]);
+			biquad_init(&filters_R[i]);
+		}
+		env = 0;
+		delay.setup(lookahead);
+		window_delay.setup(window_size);
+	}
+
+	static inline void
+	construct_params(Param *params)
+	{}
+
+	virtual void
+	adjust_all(Param *params)
+	{
+		biquad *f = filters_L;
+		f[ 0] = biquad_gen(FILT_PEAKING,  50.0,  -10, 4.00, fs);
+		f[ 1] = biquad_gen(FILT_PEAKING,  5000,    5, 4.00, fs);
+		for (int i = 0; i < bands; i++)
+			filters_R[i] = filters_L[i];
+
+		double window_length = fs*0.010/0.60;
+		window_size = round(window_length);
+		lookahead = round(window_length*0.6);
+		global_delay = lookahead;
+
+		if (window)
+			free(window);
+		window = (double *) calloc(window_size, sizeof(double));
+
+		for (int i = 0; i < window_size; i++) {
+			double x = double(i)/window_size;
+			double y = -(x - 0)*(x - 1)*(x + 0.6)/0.288;
+			window[i] = y;
+		}
+
+		attack  = 1 - exp(-1/(fs*0.002));
+		release = 1 - exp(-1/(fs*0.050));
+
+		resume();
+	}
+};
+
+constexpr char Crap_level::label[];
+constexpr char Crap_level::name[];
+constexpr char Crap_level::author[];
+constexpr char Crap_level::copyright[];