1 files changed, 106 insertions, 0 deletions
diff --git a/servers/audio/effects/eq.h b/servers/audio/effects/eq.h
new file mode 100644
index 0000000000..2c4668cd0b
--- /dev/null
+++ b/servers/audio/effects/eq.h
@@ -0,0 +1,106 @@
+//
+// C++ Interface: eq
+//
+// Description:
+//
+//
+// Author: reduzio@gmail.com (C) 2006
+//
+// Copyright: See COPYING file that comes with this distribution
+//
+//
+#ifndef EQ_FILTER_H
+#define EQ_FILTER_H
+
+
+#include "typedefs.h"
+#include "vector.h"
+
+
+/**
+@author Juan Linietsky
+*/
+
+class EQ {
+public:
+
+	enum Preset {
+
+		PRESET_6_BANDS,
+		PRESET_8_BANDS,
+		PRESET_10_BANDS,
+		PRESET_21_BANDS,
+		PRESET_31_BANDS
+	};
+
+
+
+	class BandProcess {
+
+	friend class EQ;
+		float c1,c2,c3;
+		struct History {
+			float a1,a2,a3;
+			float b1,b2,b3;
+
+		} history;
+
+	public:
+
+		inline void process_one(float & p_data);
+
+		BandProcess();
+	};
+
+private:
+	struct Band {
+
+		float freq;
+		float c1,c2,c3;
+	};
+
+	Vector<Band> band;
+
+	float mix_rate;
+
+	void recalculate_band_coefficients();
+
+public:
+
+
+	void set_mix_rate(float p_mix_rate);
+
+	int get_band_count() const;
+	void set_preset_band_mode(Preset p_preset);
+	void set_bands(const Vector<float>& p_bands);
+	BandProcess get_band_processor(int p_band) const;
+	float get_band_frequency(int p_band);
+
+	EQ();
+	~EQ();
+
+};
+
+
+/* Inline Function */
+
+inline void EQ::BandProcess::process_one(float & p_data) {
+
+
+	history.a1=p_data;
+
+	history.b1=	c1 * ( history.a1 - history.a3 )
+			+ c3 * history.b2
+			- c2 * history.b3;
+
+	p_data = history.b1;
+
+	history.a3=history.a2;
+	history.a2=history.a1;
+	history.b3=history.b2;
+	history.b2=history.b1;
+
+}
+
+
+#endif