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audiotestsrc: Add support for generating gaussian white noise

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This patch adds support for stationary white Gaussian noise.
The Box-Muller algorithm is used to generate pairs of independent
normally-distributed random numbers.

Fixes bug #586519.
This commit is contained in:
Kipp Cannon 2009-06-21 12:27:37 +02:00 committed by Sebastian Dröge
parent 0ed6ec3902
commit 620391b300
2 changed files with 48 additions and 3 deletions
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45
gst/audiotestsrc/gstaudiotestsrc.c
View file

@ -130,10 +130,12 @@ gst_audiostestsrc_wave_get_type (void)
{GST_AUDIO_TEST_SRC_WAVE_SAW, "Saw", "saw"},
{GST_AUDIO_TEST_SRC_WAVE_TRIANGLE, "Triangle", "triangle"},
{GST_AUDIO_TEST_SRC_WAVE_SILENCE, "Silence", "silence"},
{GST_AUDIO_TEST_SRC_WAVE_WHITE_NOISE, "White noise", "white-noise"},
{GST_AUDIO_TEST_SRC_WAVE_WHITE_NOISE, "White uniform noise", "white-noise"},
{GST_AUDIO_TEST_SRC_WAVE_PINK_NOISE, "Pink noise", "pink-noise"},
{GST_AUDIO_TEST_SRC_WAVE_SINE_TAB, "Sine table", "sine-table"},
{GST_AUDIO_TEST_SRC_WAVE_TICKS, "Periodic Ticks", "ticks"},
{GST_AUDIO_TEST_SRC_WAVE_GAUSSIAN_WHITE_NOISE, "White Gaussian noise",
"gaussian"},
{0, NULL, NULL},
};
@ -780,6 +782,44 @@ static ProcessFunc tick_funcs[] = {
(ProcessFunc) gst_audio_test_src_create_tick_double
};
/* Gaussian white noise using Box-Muller algorithm. unit variance
* normally-distributed random numbers are generated in pairs as the real
* and imaginary parts of a compex random variable with
* uniformly-distributed argument and \chi^{2}-distributed modulus.
*/
#define DEFINE_GAUSSIAN_WHITE_NOISE(type,scale) \
static void \
gst_audio_test_src_create_gaussian_white_noise_##type (GstAudioTestSrc * src, g##type * samples) \
{ \
gint i, c; \
gdouble amp = (src->volume * scale); \
\
for (i = 0; i < src->generate_samples_per_buffer * src->channels; ) { \
for (c = 0; c < src->channels; ++c) { \
gdouble mag = sqrt (-2 * log (1.0 - g_random_double ())); \
gdouble phs = g_random_double_range (0.0, M_PI_M2); \
\
samples[i++] = (g##type) (amp * mag * cos (phs)); \
if (++c >= src->channels) \
break; \
samples[i++] = (g##type) (amp * mag * sin (phs)); \
} \
} \
}
DEFINE_GAUSSIAN_WHITE_NOISE (int16, 32767.0);
DEFINE_GAUSSIAN_WHITE_NOISE (int32, 2147483647.0);
DEFINE_GAUSSIAN_WHITE_NOISE (float, 1.0);
DEFINE_GAUSSIAN_WHITE_NOISE (double, 1.0);
static ProcessFunc gaussian_white_noise_funcs[] = {
(ProcessFunc) gst_audio_test_src_create_gaussian_white_noise_int16,
(ProcessFunc) gst_audio_test_src_create_gaussian_white_noise_int32,
(ProcessFunc) gst_audio_test_src_create_gaussian_white_noise_float,
(ProcessFunc) gst_audio_test_src_create_gaussian_white_noise_double
};
/*
* gst_audio_test_src_change_wave:
* Assign function pointer of wave genrator.
@ -823,6 +863,9 @@ gst_audio_test_src_change_wave (GstAudioTestSrc * src)
gst_audio_test_src_init_sine_table (src);
src->process = tick_funcs[src->format];
break;
case GST_AUDIO_TEST_SRC_WAVE_GAUSSIAN_WHITE_NOISE:
src->process = gaussian_white_noise_funcs[src->format];
break;
default:
GST_ERROR ("invalid wave-form");
break;

6
gst/audiotestsrc/gstaudiotestsrc.h
View file

@ -45,10 +45,11 @@ G_BEGIN_DECLS
* @GST_AUDIO_TEST_SRC_WAVE_SAW: a saw wave
* @GST_AUDIO_TEST_SRC_WAVE_TRIANGLE: a tringle wave
* @GST_AUDIO_TEST_SRC_WAVE_SILENCE: silence
* @GST_AUDIO_TEST_SRC_WAVE_WHITE_NOISE: white noise
* @GST_AUDIO_TEST_SRC_WAVE_WHITE_NOISE: white uniform noise
* @GST_AUDIO_TEST_SRC_WAVE_PINK_NOISE: pink noise
* @GST_AUDIO_TEST_SRC_WAVE_SINE_TAB: sine wave using a table
* @GST_AUDIO_TEST_SRC_WAVE_TICKS: periodic ticks
* @GST_AUDIO_TEST_SRC_WAVE_GAUSSIAN_WHITE_NOISE: white (zero mean) Gaussian noise; volume sets the standard deviation of the noise in units of the range of values of the sample type, e.g. volume=0.1 produces noise with a standard deviation of 0.1*32767=3277 with 16-bit integer samples, or 0.1*1.0=0.1 with floating-point samples.
*
* Different types of supported sound waves.
*/
@ -61,7 +62,8 @@ typedef enum {
GST_AUDIO_TEST_SRC_WAVE_WHITE_NOISE,
GST_AUDIO_TEST_SRC_WAVE_PINK_NOISE,
GST_AUDIO_TEST_SRC_WAVE_SINE_TAB,
GST_AUDIO_TEST_SRC_WAVE_TICKS
GST_AUDIO_TEST_SRC_WAVE_TICKS,
GST_AUDIO_TEST_SRC_WAVE_GAUSSIAN_WHITE_NOISE
} GstAudioTestSrcWave;
#define PINK_MAX_RANDOM_ROWS (30)