Add library to normalize speech level (Sendevolumenregler SVoR)

Note: This lib has no user yet.

src/test/Makefile.am

@@ -2,6 +2,7 @@ AM_CPPFLAGS = -Wall -g $(all_includes)
 
 noinst_PROGRAMS = \
 	test_filter \
+	test_sendevolumenregler \
 	test_compandor \
 	test_emphasis \
 	test_dms \
@@ -37,6 +38,13 @@ test_filter_LDADD += \
 	$(SOAPY_LIBS)
 endif
 
+test_sendevolumenregler_SOURCES = test_sendevolumenregler.c
+
+test_sendevolumenregler_LDADD = \
+	$(COMMON_LA) \
+	$(top_builddir)/src/libsendevolumenregler/libsendevolumenregler.a \
+	-lm
+
 test_compandor_SOURCES = dummy.x test_compandor.c
 
 test_compandor_LDADD = \

src/test/test_sendevolumenregler.c

@@ -0,0 +1,105 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <math.h>
+#include <string.h>
+#include "../libsample/sample.h"
+#include "../libsendevolumenregler/sendevolumenregler.h"
+
+#define level2db(level)		(20 * log10(level))
+#define db2level(db)		pow(10, (double)db / 20.0)
+
+#define SAMPLERATE		48000
+#define ABWAERTS_DBS		(2.6 / 0.020) /* 2.6 dB in 20 ms */
+#define AUFWAERTS_DBS		4.3
+#define MINIMUM_DB		-16.0
+#define MAXIMUM_DB		2.6
+
+static double test_frequency[3] = { 1000.0, 4000.0, 300.0 };
+
+static sample_t samples_plus4db[SAMPLERATE];
+static sample_t samples_minus20db[SAMPLERATE];
+static sample_t samples_0db[SAMPLERATE];
+
+/* generate 2 samples: one with -4 dB, the other with -16 dB */
+static void generate_test_sample(double test_frequency)
+{
+	int i;
+	double value;
+
+	for (i = 0; i < SAMPLERATE; i++) {
+		value = cos(2.0 * M_PI * test_frequency / (double)SAMPLERATE * i);
+		samples_plus4db[i] = value * db2level(4);
+		samples_minus20db[i] = value * db2level(-20);
+		samples_0db[i] = value;
+	}
+}
+
+static void check_level(sample_t *samples, const char *desc, double target_db, int when)
+{
+	int i;
+	double last = 0.0, envelope = 0.0;
+	int up = 0;
+	double factor;
+
+	for (i = 0; i < when; i++) {
+//puts(debug_amplitude(samples[i]));
+		if (last < samples[i]) {
+			up = 1;
+		} else if (last > samples[i]) {
+			if (up) {
+				envelope = last;
+			}
+			up = 0;
+		}
+#if 0
+		if ((i % (SAMPLERATE/(SAMPLERATE/100))) == 0)
+			printf("%s: envelope = %.4f (val=%.4f) (when=%d ms)\n", desc, level2db(envelope), envelope, i * 1000 / SAMPLERATE);
+#endif
+		last = samples[i];
+	}
+	factor = envelope / db2level(target_db);
+	printf("%s: envelope after %d ms is %.4f db (factor %.4f)\n", desc, i * 1000 / SAMPLERATE, level2db(envelope), factor);
+	if (factor > 1.1 || factor < 0.9) {
+		printf("**** ERROR: we expected a factor close to 1.0\n");
+	}
+}
+
+int main(void)
+{
+	sendevolumenregler_t state;
+	sample_t samples[SAMPLERATE * 2];
+	int f;
+
+	for (f = 0; f < 3; f++) {
+		printf("Testing frequency %.0f Hz:\n", test_frequency[f]);
+		generate_test_sample(test_frequency[f]);
+
+		/* increment low level */
+		memcpy(samples, samples_minus20db, SAMPLERATE * sizeof(sample_t));
+
+		init_sendevolumenregler(&state, SAMPLERATE, ABWAERTS_DBS, AUFWAERTS_DBS, MAXIMUM_DB, MINIMUM_DB, 1.0);
+		sendevolumenregler(&state, samples, SAMPLERATE);
+
+		check_level(samples, "aufwaerts (-20 dB)", AUFWAERTS_DBS - 20.0, 1000 * SAMPLERATE / 1000);
+
+		/* decrement high level */
+		memcpy(samples, samples_plus4db, SAMPLERATE * sizeof(sample_t));
+
+		init_sendevolumenregler(&state, SAMPLERATE, ABWAERTS_DBS, AUFWAERTS_DBS, MAXIMUM_DB, MINIMUM_DB, 1.0);
+		sendevolumenregler(&state, samples, SAMPLERATE);
+
+		check_level(samples, "abwaerts (+4 dB)", MAXIMUM_DB / 2.0, 10 * SAMPLERATE / 1000);
+		check_level(samples, "abwaerts (+4 dB)", 0.0, 20 * SAMPLERATE / 1000);
+
+		/* 0 DB */
+		memcpy(samples, samples_0db, SAMPLERATE * sizeof(sample_t));
+
+		init_sendevolumenregler(&state, SAMPLERATE, ABWAERTS_DBS, AUFWAERTS_DBS, MAXIMUM_DB, MINIMUM_DB, 1.0);
+		check_level(samples, "unaffected level", 0.0, 1000 * SAMPLERATE / 1000);
+
+		puts("");
+	}
+
+	return 0;
+}
+