static void audiogen(void *data, enum AVSampleFormat sample_fmt, int channels, int sample_rate, int nb_samples) { int i, ch, k; double v, f, a, ampa; double tabf1[SWR_CH_MAX]; double tabf2[SWR_CH_MAX]; double taba[SWR_CH_MAX]; unsigned static rnd; #define PUT_SAMPLE set(data, ch, k, channels, sample_fmt, v); #define uint_rand(x) (x = x * 1664525 + 1013904223) #define dbl_rand(x) (uint_rand(x)*2.0 / (double)UINT_MAX - 1) k = 0; /* 1 second of single freq sinus at 1000 Hz */ a = 0; for (i = 0; i < 1 * sample_rate && k < nb_samples; i++, k++) { v = sin(a) * 0.30; for (ch = 0; ch < channels; ch++) PUT_SAMPLE a += M_PI * 1000.0 * 2.0 / sample_rate; } /* 1 second of varying frequency between 100 and 10000 Hz */ a = 0; for (i = 0; i < 1 * sample_rate && k < nb_samples; i++, k++) { v = sin(a) * 0.30; for (ch = 0; ch < channels; ch++) PUT_SAMPLE f = 100.0 + (((10000.0 - 100.0) * i) / sample_rate); a += M_PI * f * 2.0 / sample_rate; } /* 0.5 second of low amplitude white noise */ for (i = 0; i < sample_rate / 2 && k < nb_samples; i++, k++) { v = dbl_rand(rnd) * 0.30; for (ch = 0; ch < channels; ch++) PUT_SAMPLE } /* 0.5 second of high amplitude white noise */ for (i = 0; i < sample_rate / 2 && k < nb_samples; i++, k++) { v = dbl_rand(rnd); for (ch = 0; ch < channels; ch++) PUT_SAMPLE } /* 1 second of unrelated ramps for each channel */ for (ch = 0; ch < channels; ch++) { taba[ch] = 0; tabf1[ch] = 100 + uint_rand(rnd) % 5000; tabf2[ch] = 100 + uint_rand(rnd) % 5000; } for (i = 0; i < 1 * sample_rate && k < nb_samples; i++, k++) { for (ch = 0; ch < channels; ch++) { v = sin(taba[ch]) * 0.30; PUT_SAMPLE f = tabf1[ch] + (((tabf2[ch] - tabf1[ch]) * i) / sample_rate); taba[ch] += M_PI * f * 2.0 / sample_rate; } } /* 2 seconds of 500 Hz with varying volume */ a = 0; ampa = 0; for (i = 0; i < 2 * sample_rate && k < nb_samples; i++, k++) { for (ch = 0; ch < channels; ch++) { double amp = (1.0 + sin(ampa)) * 0.15; if (ch & 1) amp = 0.30 - amp; v = sin(a) * amp; PUT_SAMPLE a += M_PI * 500.0 * 2.0 / sample_rate; ampa += M_PI * 2.0 / sample_rate; } } }