{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},
};
(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.
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;
* @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.
*/
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)