|
| 1 | +/* |
| 2 | + * Generates a synthetic stereo sound |
| 3 | + * NOTE: No floats are used to guarantee a bit exact output. |
| 4 | + * |
| 5 | + * Copyright (c) 2002 Fabrice Bellard |
| 6 | + * |
| 7 | + * This file is part of FFmpeg. |
| 8 | + * |
| 9 | + * FFmpeg is free software; you can redistribute it and/or |
| 10 | + * modify it under the terms of the GNU Lesser General Public |
| 11 | + * License as published by the Free Software Foundation; either |
| 12 | + * version 2.1 of the License, or (at your option) any later version. |
| 13 | + * |
| 14 | + * FFmpeg is distributed in the hope that it will be useful, |
| 15 | + * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 17 | + * Lesser General Public License for more details. |
| 18 | + * |
| 19 | + * You should have received a copy of the GNU Lesser General Public |
| 20 | + * License along with FFmpeg; if not, write to the Free Software |
| 21 | + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 22 | + */ |
| 23 | + |
| 24 | +#include <stdlib.h> |
| 25 | +#include <stdio.h> |
| 26 | + |
| 27 | +#define MAX_CHANNELS 8 |
| 28 | + |
| 29 | +static unsigned int myrnd(unsigned int *seed_ptr, int n) |
| 30 | +{ |
| 31 | + unsigned int seed, val; |
| 32 | + |
| 33 | + seed = *seed_ptr; |
| 34 | + seed = (seed * 314159) + 1; |
| 35 | + if (n == 256) { |
| 36 | + val = seed >> 24; |
| 37 | + } else { |
| 38 | + val = seed % n; |
| 39 | + } |
| 40 | + *seed_ptr = seed; |
| 41 | + return val; |
| 42 | +} |
| 43 | + |
| 44 | +#define FRAC_BITS 16 |
| 45 | +#define FRAC_ONE (1 << FRAC_BITS) |
| 46 | + |
| 47 | +#define COS_TABLE_BITS 7 |
| 48 | + |
| 49 | +/* integer cosinus */ |
| 50 | +static const unsigned short cos_table[(1 << COS_TABLE_BITS) + 2] = { |
| 51 | + 0x8000, 0x7ffe, 0x7ff6, 0x7fea, 0x7fd9, 0x7fc2, 0x7fa7, 0x7f87, |
| 52 | + 0x7f62, 0x7f38, 0x7f0a, 0x7ed6, 0x7e9d, 0x7e60, 0x7e1e, 0x7dd6, |
| 53 | + 0x7d8a, 0x7d3a, 0x7ce4, 0x7c89, 0x7c2a, 0x7bc6, 0x7b5d, 0x7aef, |
| 54 | + 0x7a7d, 0x7a06, 0x798a, 0x790a, 0x7885, 0x77fb, 0x776c, 0x76d9, |
| 55 | + 0x7642, 0x75a6, 0x7505, 0x7460, 0x73b6, 0x7308, 0x7255, 0x719e, |
| 56 | + 0x70e3, 0x7023, 0x6f5f, 0x6e97, 0x6dca, 0x6cf9, 0x6c24, 0x6b4b, |
| 57 | + 0x6a6e, 0x698c, 0x68a7, 0x67bd, 0x66d0, 0x65de, 0x64e9, 0x63ef, |
| 58 | + 0x62f2, 0x61f1, 0x60ec, 0x5fe4, 0x5ed7, 0x5dc8, 0x5cb4, 0x5b9d, |
| 59 | + 0x5a82, 0x5964, 0x5843, 0x571e, 0x55f6, 0x54ca, 0x539b, 0x5269, |
| 60 | + 0x5134, 0x4ffb, 0x4ec0, 0x4d81, 0x4c40, 0x4afb, 0x49b4, 0x486a, |
| 61 | + 0x471d, 0x45cd, 0x447b, 0x4326, 0x41ce, 0x4074, 0x3f17, 0x3db8, |
| 62 | + 0x3c57, 0x3af3, 0x398d, 0x3825, 0x36ba, 0x354e, 0x33df, 0x326e, |
| 63 | + 0x30fc, 0x2f87, 0x2e11, 0x2c99, 0x2b1f, 0x29a4, 0x2827, 0x26a8, |
| 64 | + 0x2528, 0x23a7, 0x2224, 0x209f, 0x1f1a, 0x1d93, 0x1c0c, 0x1a83, |
| 65 | + 0x18f9, 0x176e, 0x15e2, 0x1455, 0x12c8, 0x113a, 0x0fab, 0x0e1c, |
| 66 | + 0x0c8c, 0x0afb, 0x096b, 0x07d9, 0x0648, 0x04b6, 0x0324, 0x0192, |
| 67 | + 0x0000, 0x0000, |
| 68 | +}; |
| 69 | + |
| 70 | +#define CSHIFT (FRAC_BITS - COS_TABLE_BITS - 2) |
| 71 | + |
| 72 | +static int int_cos(int a) |
| 73 | +{ |
| 74 | + int neg, v, f; |
| 75 | + const unsigned short *p; |
| 76 | + |
| 77 | + a = a & (FRAC_ONE - 1); /* modulo 2 * pi */ |
| 78 | + if (a >= (FRAC_ONE / 2)) |
| 79 | + a = FRAC_ONE - a; |
| 80 | + neg = 0; |
| 81 | + if (a > (FRAC_ONE / 4)) { |
| 82 | + neg = -1; |
| 83 | + a = (FRAC_ONE / 2) - a; |
| 84 | + } |
| 85 | + p = cos_table + (a >> CSHIFT); |
| 86 | + /* linear interpolation */ |
| 87 | + f = a & ((1 << CSHIFT) - 1); |
| 88 | + v = p[0] + (((p[1] - p[0]) * f + (1 << (CSHIFT - 1))) >> CSHIFT); |
| 89 | + v = (v ^ neg) - neg; |
| 90 | + v = v << (FRAC_BITS - 15); |
| 91 | + return v; |
| 92 | +} |
| 93 | + |
| 94 | +FILE *outfile; |
| 95 | + |
| 96 | +static void put_sample(int v) |
| 97 | +{ |
| 98 | + fputc(v & 0xff, outfile); |
| 99 | + fputc((v >> 8) & 0xff, outfile); |
| 100 | +} |
| 101 | + |
| 102 | +int main(int argc, char **argv) |
| 103 | +{ |
| 104 | + int i, a, v, j, f, amp, ampa; |
| 105 | + unsigned int seed = 1; |
| 106 | + int tabf1[MAX_CHANNELS], tabf2[MAX_CHANNELS]; |
| 107 | + int taba[MAX_CHANNELS]; |
| 108 | + int sample_rate = 44100; |
| 109 | + int nb_channels = 2; |
| 110 | + |
| 111 | + if (argc < 2 || argc > 4) { |
| 112 | + printf("usage: %s file [<sample rate> [<channels>]]\n" |
| 113 | + "generate a test raw 16 bit audio stream\n" |
| 114 | + "default: 44100 Hz stereo\n", argv[0]); |
| 115 | + exit(1); |
| 116 | + } |
| 117 | + |
| 118 | + if (argc > 2) { |
| 119 | + sample_rate = atoi(argv[2]); |
| 120 | + if (sample_rate <= 0) { |
| 121 | + fprintf(stderr, "invalid sample rate: %d\n", sample_rate); |
| 122 | + return 1; |
| 123 | + } |
| 124 | + } |
| 125 | + |
| 126 | + if (argc > 3) { |
| 127 | + nb_channels = atoi(argv[3]); |
| 128 | + if (nb_channels < 1 || nb_channels > MAX_CHANNELS) { |
| 129 | + fprintf(stderr, "invalid number of channels: %d\n", nb_channels); |
| 130 | + return 1; |
| 131 | + } |
| 132 | + } |
| 133 | + |
| 134 | + outfile = fopen(argv[1], "wb"); |
| 135 | + if (!outfile) { |
| 136 | + perror(argv[1]); |
| 137 | + return 1; |
| 138 | + } |
| 139 | + |
| 140 | + /* 1 second of single freq sinus at 1000 Hz */ |
| 141 | + a = 0; |
| 142 | + for(i=0;i<1 * sample_rate;i++) { |
| 143 | + v = (int_cos(a) * 10000) >> FRAC_BITS; |
| 144 | + for(j=0;j<nb_channels;j++) |
| 145 | + put_sample(v); |
| 146 | + a += (1000 * FRAC_ONE) / sample_rate; |
| 147 | + } |
| 148 | + |
| 149 | + /* 1 second of varing frequency between 100 and 10000 Hz */ |
| 150 | + a = 0; |
| 151 | + for(i=0;i<1 * sample_rate;i++) { |
| 152 | + v = (int_cos(a) * 10000) >> FRAC_BITS; |
| 153 | + for(j=0;j<nb_channels;j++) |
| 154 | + put_sample(v); |
| 155 | + f = 100 + (((10000 - 100) * i) / sample_rate); |
| 156 | + a += (f * FRAC_ONE) / sample_rate; |
| 157 | + } |
| 158 | + |
| 159 | + /* 0.5 second of low amplitude white noise */ |
| 160 | + for(i=0;i<sample_rate / 2;i++) { |
| 161 | + v = myrnd(&seed, 20000) - 10000; |
| 162 | + for(j=0;j<nb_channels;j++) |
| 163 | + put_sample(v); |
| 164 | + } |
| 165 | + |
| 166 | + /* 0.5 second of high amplitude white noise */ |
| 167 | + for(i=0;i<sample_rate / 2;i++) { |
| 168 | + v = myrnd(&seed, 65535) - 32768; |
| 169 | + for(j=0;j<nb_channels;j++) |
| 170 | + put_sample(v); |
| 171 | + } |
| 172 | + |
| 173 | + /* 1 second of unrelated ramps for each channel */ |
| 174 | + for(j=0;j<nb_channels;j++) { |
| 175 | + taba[j] = 0; |
| 176 | + tabf1[j] = 100 + myrnd(&seed, 5000); |
| 177 | + tabf2[j] = 100 + myrnd(&seed, 5000); |
| 178 | + } |
| 179 | + for(i=0;i<1 * sample_rate;i++) { |
| 180 | + for(j=0;j<nb_channels;j++) { |
| 181 | + v = (int_cos(taba[j]) * 10000) >> FRAC_BITS; |
| 182 | + put_sample(v); |
| 183 | + f = tabf1[j] + (((tabf2[j] - tabf1[j]) * i) / sample_rate); |
| 184 | + taba[j] += (f * FRAC_ONE) / sample_rate; |
| 185 | + } |
| 186 | + } |
| 187 | + |
| 188 | + /* 2 seconds of 500 Hz with varying volume */ |
| 189 | + a = 0; |
| 190 | + ampa = 0; |
| 191 | + for(i=0;i<2 * sample_rate;i++) { |
| 192 | + for(j=0;j<nb_channels;j++) { |
| 193 | + amp = ((FRAC_ONE + int_cos(ampa)) * 5000) >> FRAC_BITS; |
| 194 | + if (j & 1) |
| 195 | + amp = 10000 - amp; |
| 196 | + v = (int_cos(a) * amp) >> FRAC_BITS; |
| 197 | + put_sample(v); |
| 198 | + a += (500 * FRAC_ONE) / sample_rate; |
| 199 | + ampa += (2 * FRAC_ONE) / sample_rate; |
| 200 | + } |
| 201 | + } |
| 202 | + |
| 203 | + fclose(outfile); |
| 204 | + return 0; |
| 205 | +} |
0 commit comments