Third generation DSP for maximiser

Signed-off-by: Damien Zammit <damien@zamaudio.com>

3 files changed, 50 insertions, 70 deletions

diff --git a/plugins/ZaMaximX2/ZaMaximX2Plugin.cpp b/plugins/ZaMaximX2/ZaMaximX2Plugin.cpp
index d6a8396..c206879 100644
--- a/plugins/ZaMaximX2/ZaMaximX2Plugin.cpp
+++ b/plugins/ZaMaximX2/ZaMaximX2Plugin.cpp
@@ -42,7 +42,7 @@ void ZaMaximX2Plugin::initParameter(uint32_t index, Parameter& parameter)
         parameter.unit       = "ms";
         parameter.ranges.def = 25.0f;
         parameter.ranges.min = 1.0f;
-        parameter.ranges.max = 100.0f;
+        parameter.ranges.max = 500.0f;
         break;
     case paramCeiling:
         parameter.hints      = kParameterIsAutomable;
@@ -97,8 +97,8 @@ void ZaMaximX2Plugin::loadProgram(uint32_t index)
 {
 	switch(index) {
 	case 0:
-		release = 25.0;
-		ceiling = -3.0;
+		release = 150.0;
+		ceiling = -0.5;
 		thresdb = 0.0;
 		gainred = 0.0;
 		outlevel = -45.0;
@@ -166,14 +166,12 @@ void ZaMaximX2Plugin::activate()
     gainred = 0.0f;
     outlevel = -45.0f;
     for (i = 0; i < MAX_SAMPLES; i++) {
-    	cn[0][i] = z[0][i] = emaxn[0][i] = 0.f;
-    	cn[1][i] = z[1][i] = emaxn[1][i] = 0.f;
+    	z[0][i] = 0.f;
+    	z[1][i] = 0.f;
     }
     posz[0] = posz[1] = 0;
-    pose[0] = pose[1] = 0;
-    posc[0] = posc[1] = 0;
-    emax_old[0] = emax_old[1] = 0.f;
-    eavg_old[0] = eavg_old[1] = 0.f;
+    smoothold[0] = smoothold[1] = 0.f;
+    envold[0] = envold[1] = 0.f;
 }
 
 void ZaMaximX2Plugin::deactivate()
@@ -242,80 +240,64 @@ double ZaMaximX2Plugin::maxsample(double in[])
 void ZaMaximX2Plugin::run(const float** inputs, float** outputs, uint32_t frames)
 {
 	uint32_t i;
-	double N = (float)MAX_SAMPLES;
-	double M = (float)MAX_SAMPLES;
 	double absx[2];
 	double c[2];
-	double xmax[2];
-	double emax[2];
-	double eavg[2];
-	double g[2];
 	double srate = getSampleRate();
-	double alpha = 1.0001;
-	double aa = 1. - pow( (alpha - 1.f) / alpha,  1. / ( N + 1. ) );
-	double a;
-	double beta = 0.f;
-	for (i = 0; i < M; i++) {
-		beta += pow(1. - aa, N + 1. - i);
-	}
-	beta /= M;
+	double tau = exp(-1000. / (release*srate));
+	double env[2];
+	double smooth[2];
+	double targetgain = from_dB(ceiling);
 
 	double inL, inR;
 
 	for (i = 0; i < frames; i++) {
 		inL = inputs[0][i];
 		inR = inputs[1][i];
+		
+		// input
 		absx[0] = MAX(fabs(inL), fabs(inR));
-		c[0] = MAX(absx[0], (absx[0]-beta*eavg_old[0]) / (1. - beta));
-		pushsample(&cn[0][0], sanitize_denormal(c[0]), &posc[0]);
-		xmax[0] = maxsample(&cn[0][0]);
-
-		if (xmax[0] < emaxn[0][pose[0]]) {
-			a = 1000 / (release * srate);
+		
+		// Envelope extractor
+		if (envold[0] > absx[0]) {
+			env[0] = tau * envold[0] + (1. - tau) * absx[0];
 		} else {
-			a = aa;
+			env[0] = absx[0];
 		}
-		emax[0] = a*xmax[0] + (1. - a)*emaxn[0][pose[0]];
-		pushsample(&emaxn[0][0], sanitize_denormal(emax[0]), &pose[0]);
-		eavg[0] = avgall(&emaxn[0][0]);
-		if (eavg[0] == 0.f) {
-			g[0] = 1.;
+		if (envold[1] > absx[0]) {
+			env[1] = tau * envold[1] + (1. - tau) * absx[0];
 		} else {
-			g[0] = MIN(1., from_dB(thresdb) / eavg[0]);
+			env[1] = absx[0];
 		}
-
-		absx[1] = absx[0];
-		c[1] = MAX(absx[1], (absx[1]-beta*eavg_old[1]) / (1. - beta));
-		pushsample(&cn[1][0], sanitize_denormal(c[1]), &posc[1]);
-		xmax[1] = maxsample(&cn[1][0]);
-
-		if (xmax[1] < emaxn[1][pose[1]]) {
-			a = 1000 / (release * srate);
+		
+		// control gain calculator
+		c[0] = 1. / (1. / targetgain + (1. - 1. / targetgain)*env[0]);
+		c[0] *= MIN(1., env[0] / from_dB(thresdb));
+		c[1] = 1. / (1. / targetgain + (1. - 1. / targetgain)*env[1]);
+		c[1] *= MIN(1., env[1] / from_dB(thresdb));
+
+		// smoother
+		if (c[0] > smoothold[0]) {
+			smooth[0] = smoothold[0]*tau + c[0]*(1.-tau);
 		} else {
-			a = aa;
+			smooth[0] = c[0];
 		}
-		emax[1] = a*xmax[1] + (1. - a)*emaxn[1][pose[1]];
-		pushsample(&emaxn[1][0], sanitize_denormal(emax[1]), &pose[1]);
-		eavg[1] = avgall(&emaxn[1][0]);
-		if (eavg[1] == 0.f) {
-			g[1] = 1.;
+		if (c[1] > smoothold[1]) {
+			smooth[1] = smoothold[1]*tau + c[1]*(1.-tau);
 		} else {
-			g[1] = MIN(1., from_dB(thresdb) / eavg[1]);
+			smooth[1] = c[1];
 		}
 
-		gainred = MAX(-to_dB(g[0]), -to_dB(g[1]));
-
-		outputs[0][i] = (float)clip(normalise(z[0][posz[0]] * g[0], 0.));
-		outputs[1][i] = (float)clip(normalise(z[1][posz[1]] * g[1], 0.));
+		outputs[0][i] = (float)clip(normalise(z[0][posz[0]] * smooth[0], 0.));
+		outputs[1][i] = (float)clip(normalise(z[1][posz[1]] * smooth[1], 0.));
 
-		outlevel = to_dB(MAX(fabs(eavg[0]), fabs(eavg[1]))) + (ceiling - thresdb);
+		outlevel = to_dB(MAX(fabs(outputs[0][i]), fabs(outputs[1][i]))) + (ceiling - thresdb);
 		pushsample(&z[0][0], sanitize_denormal(inL), &posz[0]);
 		pushsample(&z[1][0], sanitize_denormal(inR), &posz[1]);
 
-		emax_old[0] = sanitize_denormal(emax[0]);
-		eavg_old[0] = sanitize_denormal(eavg[0]);
-		emax_old[1] = sanitize_denormal(emax[1]);
-		eavg_old[1] = sanitize_denormal(eavg[1]);
+		smoothold[0] = sanitize_denormal(smooth[0]);
+		smoothold[1] = sanitize_denormal(smooth[1]);
+		envold[0] = sanitize_denormal(env[0]);
+		envold[1] = sanitize_denormal(env[1]);
 	}
 }
 
diff --git a/plugins/ZaMaximX2/ZaMaximX2Plugin.hpp b/plugins/ZaMaximX2/ZaMaximX2Plugin.hpp
index feff4f5..c5b1782 100644
--- a/plugins/ZaMaximX2/ZaMaximX2Plugin.hpp
+++ b/plugins/ZaMaximX2/ZaMaximX2Plugin.hpp
@@ -121,12 +121,10 @@ protected:
 
 private:
     float release,ceiling,thresdb,gainred,outlevel;//parameters
-    int pose[2], posz[2], posc[2];
-    double cn[2][MAX_SAMPLES];
-    double emaxn[2][MAX_SAMPLES];
+    int posz[2];
     double z[2][MAX_SAMPLES];
-    double emax_old[2];
-    double eavg_old[2];
+    double smoothold[2];
+    double envold[2];
 };
 
 // -----------------------------------------------------------------------
diff --git a/plugins/ZaMaximX2/ZaMaximX2UI.cpp b/plugins/ZaMaximX2/ZaMaximX2UI.cpp
index d62378f..03e6150 100644
--- a/plugins/ZaMaximX2/ZaMaximX2UI.cpp
+++ b/plugins/ZaMaximX2/ZaMaximX2UI.cpp
@@ -47,9 +47,9 @@ ZaMaximX2UI::ZaMaximX2UI()
     fKnobRelease = new ImageKnob(this, knobImage);
     fKnobRelease->setAbsolutePos(27, 46);
     fKnobRelease->setId(ZaMaximX2Plugin::paramRelease);
-    fKnobRelease->setRange(1.0f, 100.0f);
+    fKnobRelease->setRange(1.0f, 500.0f);
     fKnobRelease->setStep(1.0f);
-    fKnobRelease->setDefault(25.0f);
+    fKnobRelease->setDefault(150.0f);
     fKnobRelease->setRotationAngle(240);
     fKnobRelease->setCallback(this);
 
@@ -67,7 +67,7 @@ ZaMaximX2UI::ZaMaximX2UI()
     fKnobCeiling->setId(ZaMaximX2Plugin::paramCeiling);
     fKnobCeiling->setRange(-30.0f, 0.0f);
     fKnobCeiling->setStep(0.1f);
-    fKnobCeiling->setDefault(-3.0f);
+    fKnobCeiling->setDefault(-0.5f);
     fKnobCeiling->setRotationAngle(240);
     fKnobCeiling->setCallback(this);
 
@@ -112,9 +112,9 @@ void ZaMaximX2UI::programLoaded(uint32_t index)
 {
 	switch(index) {
 	case 0:
-		fKnobRelease->setValue(1.0f);
+		fKnobRelease->setValue(150.0f);
 		fKnobThresh->setValue(0.0f);
-		fKnobCeiling->setValue(-6.0f);
+		fKnobCeiling->setValue(-0.5f);
 		break;
 	}
 }