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  1. /*
  2.  * Generate a synthetic stereo sound.
  3.  * NOTE: No floats are used to guarantee bitexact 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 <stdint.h>
  26. #include <stdio.h>
  27. #include <string.h>
  28.  
  29. #define MAX_CHANNELS 8
  30.  
  31. static unsigned int myrnd(unsigned int *seed_ptr, int n)
  32. {
  33.     unsigned int seed, val;
  34.  
  35.     seed = *seed_ptr;
  36.     seed = (seed * 314159) + 1;
  37.     if (n == 256) {
  38.         val = seed >> 24;
  39.     } else {
  40.         val = seed % n;
  41.     }
  42.     *seed_ptr = seed;
  43.     return val;
  44. }
  45.  
  46. #define FRAC_BITS 16
  47. #define FRAC_ONE (1 << FRAC_BITS)
  48.  
  49. #define COS_TABLE_BITS 7
  50.  
  51. /* integer cosine */
  52. static const unsigned short cos_table[(1 << COS_TABLE_BITS) + 2] = {
  53.     0x8000, 0x7ffe, 0x7ff6, 0x7fea, 0x7fd9, 0x7fc2, 0x7fa7, 0x7f87,
  54.     0x7f62, 0x7f38, 0x7f0a, 0x7ed6, 0x7e9d, 0x7e60, 0x7e1e, 0x7dd6,
  55.     0x7d8a, 0x7d3a, 0x7ce4, 0x7c89, 0x7c2a, 0x7bc6, 0x7b5d, 0x7aef,
  56.     0x7a7d, 0x7a06, 0x798a, 0x790a, 0x7885, 0x77fb, 0x776c, 0x76d9,
  57.     0x7642, 0x75a6, 0x7505, 0x7460, 0x73b6, 0x7308, 0x7255, 0x719e,
  58.     0x70e3, 0x7023, 0x6f5f, 0x6e97, 0x6dca, 0x6cf9, 0x6c24, 0x6b4b,
  59.     0x6a6e, 0x698c, 0x68a7, 0x67bd, 0x66d0, 0x65de, 0x64e9, 0x63ef,
  60.     0x62f2, 0x61f1, 0x60ec, 0x5fe4, 0x5ed7, 0x5dc8, 0x5cb4, 0x5b9d,
  61.     0x5a82, 0x5964, 0x5843, 0x571e, 0x55f6, 0x54ca, 0x539b, 0x5269,
  62.     0x5134, 0x4ffb, 0x4ec0, 0x4d81, 0x4c40, 0x4afb, 0x49b4, 0x486a,
  63.     0x471d, 0x45cd, 0x447b, 0x4326, 0x41ce, 0x4074, 0x3f17, 0x3db8,
  64.     0x3c57, 0x3af3, 0x398d, 0x3825, 0x36ba, 0x354e, 0x33df, 0x326e,
  65.     0x30fc, 0x2f87, 0x2e11, 0x2c99, 0x2b1f, 0x29a4, 0x2827, 0x26a8,
  66.     0x2528, 0x23a7, 0x2224, 0x209f, 0x1f1a, 0x1d93, 0x1c0c, 0x1a83,
  67.     0x18f9, 0x176e, 0x15e2, 0x1455, 0x12c8, 0x113a, 0x0fab, 0x0e1c,
  68.     0x0c8c, 0x0afb, 0x096b, 0x07d9, 0x0648, 0x04b6, 0x0324, 0x0192,
  69.     0x0000, 0x0000,
  70. };
  71.  
  72. #define CSHIFT (FRAC_BITS - COS_TABLE_BITS - 2)
  73.  
  74. static int int_cos(int a)
  75. {
  76.     int neg, v, f;
  77.     const unsigned short *p;
  78.  
  79.     a = a & (FRAC_ONE - 1); /* modulo 2 * pi */
  80.     if (a >= (FRAC_ONE / 2))
  81.         a = FRAC_ONE - a;
  82.     neg = 0;
  83.     if (a > (FRAC_ONE / 4)) {
  84.         neg = -1;
  85.         a   = (FRAC_ONE / 2) - a;
  86.     }
  87.     p = cos_table + (a >> CSHIFT);
  88.     /* linear interpolation */
  89.     f = a & ((1 << CSHIFT) - 1);
  90.     v = p[0] + (((p[1] - p[0]) * f + (1 << (CSHIFT - 1))) >> CSHIFT);
  91.     v = (v ^ neg) - neg;
  92.     v = v << (FRAC_BITS - 15);
  93.     return v;
  94. }
  95.  
  96. FILE *outfile;
  97.  
  98. static void put16(int16_t v)
  99. {
  100.     fputc( v       & 0xff, outfile);
  101.     fputc((v >> 8) & 0xff, outfile);
  102. }
  103.  
  104. static void put32(uint32_t v)
  105. {
  106.     fputc( v        & 0xff, outfile);
  107.     fputc((v >>  8) & 0xff, outfile);
  108.     fputc((v >> 16) & 0xff, outfile);
  109.     fputc((v >> 24) & 0xff, outfile);
  110. }
  111.  
  112. #define HEADER_SIZE      46
  113. #define FMT_SIZE         18
  114. #define SAMPLE_SIZE       2
  115. #define WFORMAT_PCM  0x0001
  116.  
  117. static void put_wav_header(int sample_rate, int channels, int nb_samples)
  118. {
  119.     int block_align = SAMPLE_SIZE * channels;
  120.     int data_size   = block_align * nb_samples;
  121.  
  122.     fputs("RIFF", outfile);
  123.     put32(HEADER_SIZE + data_size);
  124.     fputs("WAVEfmt ", outfile);
  125.     put32(FMT_SIZE);
  126.     put16(WFORMAT_PCM);
  127.     put16(channels);
  128.     put32(sample_rate);
  129.     put32(block_align * sample_rate);
  130.     put16(block_align);
  131.     put16(SAMPLE_SIZE * 8);
  132.     put16(0);
  133.     fputs("data", outfile);
  134.     put32(data_size);
  135. }
  136.  
  137. int main(int argc, char **argv)
  138. {
  139.     int i, a, v, j, f, amp, ampa;
  140.     unsigned int seed = 1;
  141.     int tabf1[MAX_CHANNELS], tabf2[MAX_CHANNELS];
  142.     int taba[MAX_CHANNELS];
  143.     int sample_rate = 44100;
  144.     int nb_channels = 2;
  145.     char *ext;
  146.  
  147.     if (argc < 2 || argc > 5) {
  148.         printf("usage: %s file [<sample rate> [<channels>] [<random seed>]]\n"
  149.                "generate a test raw 16 bit audio stream\n"
  150.                "If the file extension is .wav a WAVE header will be added.\n"
  151.                "default: 44100 Hz stereo\n", argv[0]);
  152.         exit(1);
  153.     }
  154.  
  155.     if (argc > 2) {
  156.         sample_rate = atoi(argv[2]);
  157.         if (sample_rate <= 0) {
  158.             fprintf(stderr, "invalid sample rate: %d\n", sample_rate);
  159.             return 1;
  160.         }
  161.     }
  162.  
  163.     if (argc > 3) {
  164.         nb_channels = atoi(argv[3]);
  165.         if (nb_channels < 1 || nb_channels > MAX_CHANNELS) {
  166.             fprintf(stderr, "invalid number of channels: %d\n", nb_channels);
  167.             return 1;
  168.         }
  169.     }
  170.  
  171.     if (argc > 4)
  172.         seed = atoi(argv[4]);
  173.  
  174.     outfile = fopen(argv[1], "wb");
  175.     if (!outfile) {
  176.         perror(argv[1]);
  177.         return 1;
  178.     }
  179.  
  180.     if ((ext = strrchr(argv[1], '.')) != NULL && !strcmp(ext, ".wav"))
  181.         put_wav_header(sample_rate, nb_channels, 6 * sample_rate);
  182.  
  183.     /* 1 second of single freq sine at 1000 Hz */
  184.     a = 0;
  185.     for (i = 0; i < 1 * sample_rate; i++) {
  186.         v = (int_cos(a) * 10000) >> FRAC_BITS;
  187.         for (j = 0; j < nb_channels; j++)
  188.             put16(v);
  189.         a += (1000 * FRAC_ONE) / sample_rate;
  190.     }
  191.  
  192.     /* 1 second of varying frequency between 100 and 10000 Hz */
  193.     a = 0;
  194.     for (i = 0; i < 1 * sample_rate; i++) {
  195.         v = (int_cos(a) * 10000) >> FRAC_BITS;
  196.         for (j = 0; j < nb_channels; j++)
  197.             put16(v);
  198.         f  = 100 + (((10000 - 100) * i) / sample_rate);
  199.         a += (f * FRAC_ONE) / sample_rate;
  200.     }
  201.  
  202.     /* 0.5 second of low amplitude white noise */
  203.     for (i = 0; i < sample_rate / 2; i++) {
  204.         v = myrnd(&seed, 20000) - 10000;
  205.         for (j = 0; j < nb_channels; j++)
  206.             put16(v);
  207.     }
  208.  
  209.     /* 0.5 second of high amplitude white noise */
  210.     for (i = 0; i < sample_rate / 2; i++) {
  211.         v = myrnd(&seed, 65535) - 32768;
  212.         for (j = 0; j < nb_channels; j++)
  213.             put16(v);
  214.     }
  215.  
  216.     /* 1 second of unrelated ramps for each channel */
  217.     for (j = 0; j < nb_channels; j++) {
  218.         taba[j]  = 0;
  219.         tabf1[j] = 100 + myrnd(&seed, 5000);
  220.         tabf2[j] = 100 + myrnd(&seed, 5000);
  221.     }
  222.     for (i = 0; i < 1 * sample_rate; i++) {
  223.         for (j = 0; j < nb_channels; j++) {
  224.             v = (int_cos(taba[j]) * 10000) >> FRAC_BITS;
  225.             put16(v);
  226.             f        = tabf1[j] + (((tabf2[j] - tabf1[j]) * i) / sample_rate);
  227.             taba[j] += (f * FRAC_ONE) / sample_rate;
  228.         }
  229.     }
  230.  
  231.     /* 2 seconds of 500 Hz with varying volume */
  232.     a    = 0;
  233.     ampa = 0;
  234.     for (i = 0; i < 2 * sample_rate; i++) {
  235.         for (j = 0; j < nb_channels; j++) {
  236.             amp = ((FRAC_ONE + int_cos(ampa)) * 5000) >> FRAC_BITS;
  237.             if (j & 1)
  238.                 amp = 10000 - amp;
  239.             v = (int_cos(a) * amp) >> FRAC_BITS;
  240.             put16(v);
  241.             a    += (500 * FRAC_ONE) / sample_rate;
  242.             ampa += (2 * FRAC_ONE) / sample_rate;
  243.         }
  244.     }
  245.  
  246.     fclose(outfile);
  247.     return 0;
  248. }
  249.