tests/audiogen.c

   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 NB_CHANNELS 2
  28 #define FE 44100
  29
  30 static unsigned int myrnd(unsigned int *seed_ptr, int n)
  31 {
  32     unsigned int seed, val;
  33
  34     seed = *seed_ptr;
  35     seed = (seed * 314159) + 1;
  36     if (n == 256) {
  37         val = seed >> 24;
  38     } else {
  39         val = seed % n;
  40     }
  41     *seed_ptr = seed;
  42     return val;
  43 }
  44
  45 #define FRAC_BITS 16
  46 #define FRAC_ONE (1 << FRAC_BITS)
  47
  48 #define COS_TABLE_BITS 7
  49
  50 /* integer cosinus */
  51 static const unsigned short cos_table[(1 << COS_TABLE_BITS) + 2] = {
  52  0x8000, 0x7ffe, 0x7ff6, 0x7fea, 0x7fd9, 0x7fc2, 0x7fa7, 0x7f87,
  53  0x7f62, 0x7f38, 0x7f0a, 0x7ed6, 0x7e9d, 0x7e60, 0x7e1e, 0x7dd6,
  54  0x7d8a, 0x7d3a, 0x7ce4, 0x7c89, 0x7c2a, 0x7bc6, 0x7b5d, 0x7aef,
  55  0x7a7d, 0x7a06, 0x798a, 0x790a, 0x7885, 0x77fb, 0x776c, 0x76d9,
  56  0x7642, 0x75a6, 0x7505, 0x7460, 0x73b6, 0x7308, 0x7255, 0x719e,
  57  0x70e3, 0x7023, 0x6f5f, 0x6e97, 0x6dca, 0x6cf9, 0x6c24, 0x6b4b,
  58  0x6a6e, 0x698c, 0x68a7, 0x67bd, 0x66d0, 0x65de, 0x64e9, 0x63ef,
  59  0x62f2, 0x61f1, 0x60ec, 0x5fe4, 0x5ed7, 0x5dc8, 0x5cb4, 0x5b9d,
  60  0x5a82, 0x5964, 0x5843, 0x571e, 0x55f6, 0x54ca, 0x539b, 0x5269,
  61  0x5134, 0x4ffb, 0x4ec0, 0x4d81, 0x4c40, 0x4afb, 0x49b4, 0x486a,
  62  0x471d, 0x45cd, 0x447b, 0x4326, 0x41ce, 0x4074, 0x3f17, 0x3db8,
  63  0x3c57, 0x3af3, 0x398d, 0x3825, 0x36ba, 0x354e, 0x33df, 0x326e,
  64  0x30fc, 0x2f87, 0x2e11, 0x2c99, 0x2b1f, 0x29a4, 0x2827, 0x26a8,
  65  0x2528, 0x23a7, 0x2224, 0x209f, 0x1f1a, 0x1d93, 0x1c0c, 0x1a83,
  66  0x18f9, 0x176e, 0x15e2, 0x1455, 0x12c8, 0x113a, 0x0fab, 0x0e1c,
  67  0x0c8c, 0x0afb, 0x096b, 0x07d9, 0x0648, 0x04b6, 0x0324, 0x0192,
  68  0x0000, 0x0000,
  69 };
  70
  71 #define CSHIFT (FRAC_BITS - COS_TABLE_BITS - 2)
  72
  73 static int int_cos(int a)
  74 {
  75     int neg, v, f;
  76     const unsigned short *p;
  77
  78     a = a & (FRAC_ONE - 1); /* modulo 2 * pi */
  79     if (a >= (FRAC_ONE / 2))
  80         a = FRAC_ONE - a;
  81     neg = 0;
  82     if (a > (FRAC_ONE / 4)) {
  83         neg = -1;
  84         a = (FRAC_ONE / 2) - a;
  85     }
  86     p = cos_table + (a >> CSHIFT);
  87     /* linear interpolation */
  88     f = a & ((1 << CSHIFT) - 1);
  89     v = p[0] + (((p[1] - p[0]) * f + (1 << (CSHIFT - 1))) >> CSHIFT);
  90     v = (v ^ neg) - neg;
  91     v = v << (FRAC_BITS - 15);
  92     return v;
  93 }
  94
  95 FILE *outfile;
  96
  97 static void put_sample(int v)
  98 {
  99     fputc(v & 0xff, outfile);
 100     fputc((v >> 8) & 0xff, outfile);
 101 }
 102
 103 int main(int argc, char **argv)
 104 {
 105     int i, a, v, j, f, amp, ampa;
 106     unsigned int seed = 1;
 107     int tabf1[NB_CHANNELS], tabf2[NB_CHANNELS];
 108     int taba[NB_CHANNELS];
 109
 110     if (argc != 2) {
 111         printf("usage: %s file\n"
 112                "generate a test raw 16 bit stereo audio stream\n", argv[0]);
 113         exit(1);
 114     }
 115
 116     outfile = fopen(argv[1], "wb");
 117     if (!outfile) {
 118         perror(argv[1]);
 119         return 1;
 120     }
 121
 122     /* 1 second of single freq sinus at 1000 Hz */
 123     a = 0;
 124     for(i=0;i<1 * FE;i++) {
 125         v = (int_cos(a) * 10000) >> FRAC_BITS;
 126         for(j=0;j<NB_CHANNELS;j++)
 127             put_sample(v);
 128         a += (1000 * FRAC_ONE) / FE;
 129     }
 130
 131     /* 1 second of varing frequency between 100 and 10000 Hz */
 132     a = 0;
 133     for(i=0;i<1 * FE;i++) {
 134         v = (int_cos(a) * 10000) >> FRAC_BITS;
 135         for(j=0;j<NB_CHANNELS;j++)
 136             put_sample(v);
 137         f = 100 + (((10000 - 100) * i) / FE);
 138         a += (f * FRAC_ONE) / FE;
 139     }
 140
 141     /* 0.5 second of low amplitude white noise */
 142     for(i=0;i<FE / 2;i++) {
 143         v = myrnd(&seed, 20000) - 10000;
 144         for(j=0;j<NB_CHANNELS;j++)
 145             put_sample(v);
 146     }
 147
 148     /* 0.5 second of high amplitude white noise */
 149     for(i=0;i<FE / 2;i++) {
 150         v = myrnd(&seed, 65535) - 32768;
 151         for(j=0;j<NB_CHANNELS;j++)
 152             put_sample(v);
 153     }
 154
 155     /* stereo : 2 unrelated ramps */
 156     for(j=0;j<NB_CHANNELS;j++) {
 157         taba[j] = 0;
 158         tabf1[j] = 100 + myrnd(&seed, 5000);
 159         tabf2[j] = 100 + myrnd(&seed, 5000);
 160     }
 161     for(i=0;i<1 * FE;i++) {
 162         for(j=0;j<NB_CHANNELS;j++) {
 163             v = (int_cos(taba[j]) * 10000) >> FRAC_BITS;
 164             put_sample(v);
 165             f = tabf1[j] + (((tabf2[j] - tabf1[j]) * i) / FE);
 166             taba[j] += (f * FRAC_ONE) / FE;
 167         }
 168     }
 169
 170     /* stereo 500 Hz with varying volume */
 171     a = 0;
 172     ampa = 0;
 173     for(i=0;i<2 * FE;i++) {
 174         for(j=0;j<NB_CHANNELS;j++) {
 175             amp = ((FRAC_ONE + int_cos(ampa)) * 5000) >> FRAC_BITS;
 176             if (j & 1)
 177                 amp = 10000 - amp;
 178             v = (int_cos(a) * amp) >> FRAC_BITS;
 179             put_sample(v);
 180             a += (500 * FRAC_ONE) / FE;
 181             ampa += (2 * FRAC_ONE) / FE;
 182         }
 183     }
 184
 185     fclose(outfile);
 186     return 0;
 187 }