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Minor fixes to compandor

This commit is contained in:
Andreas Eversberg 2017-06-24 10:09:22 +02:00
parent a12329a884
commit 085ceb9173
4 changed files with 44 additions and 29 deletions
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12
src/common/compandor.c
View File

@ -1,4 +1,4 @@
/* Compandor to use various networks like C-Netz / NMT / AMPS
/* Compandor to use various networks like C-Netz / NMT / AMPS / TACS
*
* (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
* All Rights Reserved
@ -46,7 +46,7 @@ static double sqrt_tab[10000];
* Hopefully this is correct
*
*/
void init_compandor(compandor_t *state, int samplerate, double attack_ms, double recovery_ms, double unaffected_level)
void init_compandor(compandor_t *state, double samplerate, double attack_ms, double recovery_ms, double unaffected_level)
{
int i;
@ -56,10 +56,10 @@ void init_compandor(compandor_t *state, int samplerate, double attack_ms, double
state->c.envelope = 1.0;
state->e.peak = 1.0;
state->e.envelope = 1.0;
state->c.step_up = pow(COMPRESS_ATTACK_FACTOR, 1000.0 / attack_ms / (double)samplerate);
state->c.step_down = pow(COMPRESS_RECOVERY_FACTOR, 1000.0 / recovery_ms / (double)samplerate);
state->e.step_up = pow(EXPAND_ATTACK_FACTOR, 1000.0 / attack_ms / (double)samplerate);
state->e.step_down = pow(EXPAND_RECOVERY_FACTOR, 1000.0 / recovery_ms / (double)samplerate);
state->c.step_up = pow(COMPRESS_ATTACK_FACTOR, 1000.0 / attack_ms / samplerate);
state->c.step_down = pow(COMPRESS_RECOVERY_FACTOR, 1000.0 / recovery_ms / samplerate);
state->e.step_up = pow(EXPAND_ATTACK_FACTOR, 1000.0 / attack_ms / samplerate);
state->e.step_down = pow(EXPAND_RECOVERY_FACTOR, 1000.0 / recovery_ms / samplerate);
state->c.unaffected = unaffected_level;
state->e.unaffected = unaffected_level;

2
src/common/compandor.h
View File

@ -15,7 +15,7 @@ typedef struct compandor {
} e;
} compandor_t;
void init_compandor(compandor_t *state, int samplerate, double attack_ms, double recovery_ms, double unaffected_level);
void init_compandor(compandor_t *state, double samplerate, double attack_ms, double recovery_ms, double unaffected_level);
void compress_audio(compandor_t *state, sample_t *samples, int num);
void expand_audio(compandor_t *state, sample_t *samples, int num);

7
src/test/Makefile.am
View File

@ -19,11 +19,16 @@ test_filter_LDADD = \
$(SOAPY_LIBS) \
-lm
test_compandor_SOURCES = test_compandor.c
test_compandor_SOURCES = \
test_compandor.c \
dummy.c
test_compandor_LDADD = \
$(COMMON_LA) \
$(top_builddir)/src/common/libcommon.a \
$(ALSA_LIBS) \
$(UHD_LIBS) \
$(SOAPY_LIBS) \
-lm
test_emphasis_SOURCES = test_emphasis.c dummy.c

52
src/test/test_compandor.c
View File

@ -11,7 +11,6 @@
#define SAMPLERATE 48000
#define ATTACK_MS 15.0
#define RECOVERY_MS 15.0
#define UNAFFECTED 10000.0
static double test_frequency[3] = { 2000.0, 4000.0, 1000.0 };
@ -29,24 +28,26 @@ static void generate_test_sample(double test_frequency)
for (i = 0; i < SAMPLERATE; i++) {
value = cos(2.0 * M_PI * test_frequency / (double)SAMPLERATE * i);
samples_4db[i] = (int)(UNAFFECTED * value * db2level(-4));
samples_16db[i] = (int)(UNAFFECTED * value * db2level(-16));
samples_2db[i] = (int)(UNAFFECTED * value * db2level(-2));
samples_8db[i] = (int)(UNAFFECTED * value * db2level(-8));
samples_0db[i] = (int)(UNAFFECTED * value);
samples_4db[i] = value * db2level(-4);
samples_16db[i] = value * db2level(-16);
samples_2db[i] = value * db2level(-2);
samples_8db[i] = value * db2level(-8);
samples_0db[i] = value;
}
}
static void check_level(sample_t *samples, double duration, const char *desc, double target_db)
{
int i;
int last = 0, envelop = 0;
double last = 0.0, envelop = 0.0;
int up = 0;
double factor;
int when = (int)((double)SAMPLERATE + (double)SAMPLERATE * duration / 1000.0 + 0.5);
//printf("%d %d\n", SAMPLERATE, when);
for (i = 0; i < when; i++) {
//puts(debug_amplitude(samples[i]));
if (last < samples[i]) {
up = 1;
} else if (last > samples[i]) {
@ -57,12 +58,12 @@ static void check_level(sample_t *samples, double duration, const char *desc, do
}
#if 0
if (i >= (SAMPLERATE-(SAMPLERATE/100)) && (i % (SAMPLERATE/(SAMPLERATE/10))) == 0)
printf("%s: envelop = %.4f (when=%d)\n", desc, level2db((double)envelop / UNAFFECTED), i);
printf("%s: envelop = %.4f (val=%.4f) (when=%d)\n", desc, level2db(envelop), envelop, i);
#endif
last = samples[i];
}
factor = (envelop / UNAFFECTED) / db2level(target_db);
printf("%s: envelop after the instance of %.1f ms is %.4f db factor =%.4f\n", desc, duration, level2db((double)envelop / UNAFFECTED), factor);
factor = envelop / db2level(target_db);
printf("%s: envelop after the instance of %.1f ms is %.4f db factor =%.4f\n", desc, duration, level2db(envelop), factor);
}
int main(void)
@ -71,47 +72,56 @@ int main(void)
sample_t samples[SAMPLERATE * 2];
int f;
init_compandor(&cstate, SAMPLERATE, ATTACK_MS, RECOVERY_MS, UNAFFECTED);
init_compandor(&cstate, SAMPLERATE, ATTACK_MS, RECOVERY_MS, 1.0);
for (f = 0; f < 3; f++) {
/* -16 and -4 dB */
printf("Testing frequency %.0f Hz:\n", test_frequency[f]);
generate_test_sample(test_frequency[f]);
#if 0
check_level(samples_0db, -100.0, "generate sample with 0db", 0.0);
check_level(samples_2db, -100.0, "generate sample with -2db", -2.0);
check_level(samples_4db, -100.0, "generate sample with -4db", -4.0);
check_level(samples_8db, -100.0, "generate sample with -8db", -8.0);
check_level(samples_16db, -100.0, "generate sample with -16db", -16.0);
#endif
/* low to high transition */
memcpy(samples, samples_16db, SAMPLERATE * 2);
memcpy(samples + SAMPLERATE, samples_4db, SAMPLERATE * 2);
memcpy(samples, samples_16db, SAMPLERATE * sizeof(sample_t));
memcpy(samples + SAMPLERATE, samples_4db, SAMPLERATE * sizeof(sample_t));
compress_audio(&cstate, samples, SAMPLERATE * 2);
check_level(samples, ATTACK_MS, "compressor attack", -2.0);
/* high to low transition */
memcpy(samples, samples_4db, SAMPLERATE * 2);
memcpy(samples + SAMPLERATE, samples_16db, SAMPLERATE * 2);
memcpy(samples, samples_4db, SAMPLERATE * sizeof(sample_t));
memcpy(samples + SAMPLERATE, samples_16db, SAMPLERATE * sizeof(sample_t));
compress_audio(&cstate, samples, SAMPLERATE * 2);
check_level(samples, RECOVERY_MS, "compressor recovery", -8.0);
/* low to high transition */
memcpy(samples, samples_8db, SAMPLERATE * 2);
memcpy(samples + SAMPLERATE, samples_2db, SAMPLERATE * 2);
memcpy(samples, samples_8db, SAMPLERATE * sizeof(sample_t));
memcpy(samples + SAMPLERATE, samples_2db, SAMPLERATE * sizeof(sample_t));
expand_audio(&cstate, samples, SAMPLERATE * 2);
check_level(samples, ATTACK_MS, "expander attack", -4.0);
/* high to low transition */
memcpy(samples, samples_2db, SAMPLERATE * 2);
memcpy(samples + SAMPLERATE, samples_8db, SAMPLERATE * 2);
memcpy(samples, samples_2db, SAMPLERATE * sizeof(sample_t));
memcpy(samples + SAMPLERATE, samples_8db, SAMPLERATE * sizeof(sample_t));
expand_audio(&cstate, samples, SAMPLERATE * 2);
check_level(samples, RECOVERY_MS, "expander recovery", -16.0);
/* 0 DB */
memcpy(samples, samples_0db, SAMPLERATE * 2);
memcpy(samples + SAMPLERATE, samples_0db, SAMPLERATE * 2);
memcpy(samples, samples_0db, SAMPLERATE * sizeof(sample_t));
memcpy(samples + SAMPLERATE, samples_0db, SAMPLERATE * sizeof(sample_t));
check_level(samples, RECOVERY_MS, "unaffected level", 0.0);