## ffmpeg / tests / audiogen.c @ 3a74415d

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1 | 51133a7d | Fabrice Bellard | ```
/*
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2 | ```
* Generates a synthetic stereo sound
``` |
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3 | ```
* NOTE: no floats are used to guaranty a bit exact output.
``` |
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4 | eebfba2e | Diego Biurrun | ```
*
``` |

5 | ```
* Copyright (c) 2002 Fabrice Bellard
``` |
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6 | ```
*
``` |
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7 | ```
* This file is part of FFmpeg.
``` |
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8 | ```
*
``` |
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9 | ```
* FFmpeg is free software; you can redistribute it and/or
``` |
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10 | ```
* modify it under the terms of the GNU Lesser General Public
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11 | ```
* License as published by the Free Software Foundation; either
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12 | ```
* version 2.1 of the License, or (at your option) any later version.
``` |
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13 | ```
*
``` |
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14 | ```
* FFmpeg is distributed in the hope that it will be useful,
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15 | ```
* but WITHOUT ANY WARRANTY; without even the implied warranty of
``` |
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16 | ```
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
``` |
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17 | ```
* Lesser General Public License for more details.
``` |
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18 | ```
*
``` |
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19 | ```
* You should have received a copy of the GNU Lesser General Public
``` |
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20 | ```
* License along with FFmpeg; if not, write to the Free Software
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21 | ```
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
``` |
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22 | 51133a7d | Fabrice Bellard | ```
*/
``` |

23 | eebfba2e | Diego Biurrun | |

24 | 51133a7d | Fabrice Bellard | #include <stdlib.h> |

25 | #include <stdio.h> |
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26 | |||

27 | #define NB_CHANNELS 2 |
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28 | #define FE 44100 |
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29 | |||

30 | static unsigned int myrnd(unsigned int *seed_ptr, int n) |
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31 | { |
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32 | unsigned int seed, val; |
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33 | |||

34 | seed = *seed_ptr; |
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35 | seed = (seed * 314159) + 1; |
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36 | if (n == 256) { |
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37 | ```
val = seed >> 24;
``` |
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38 | ```
} else {
``` |
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39 | val = seed % n; |
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40 | } |
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41 | *seed_ptr = seed; |
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42 | ```
return val;
``` |
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43 | } |
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44 | |||

45 | #define FRAC_BITS 16 |
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46 | #define FRAC_ONE (1 << FRAC_BITS) |
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47 | |||

48 | #define COS_TABLE_BITS 7 |
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49 | |||

50 | ```
/* integer cosinus */
``` |
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51 | static const unsigned short cos_table[(1 << COS_TABLE_BITS) + 2] = { |
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52 | 0x8000, 0x7ffe, 0x7ff6, 0x7fea, 0x7fd9, 0x7fc2, 0x7fa7, 0x7f87, |
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53 | 0x7f62, 0x7f38, 0x7f0a, 0x7ed6, 0x7e9d, 0x7e60, 0x7e1e, 0x7dd6, |
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54 | 0x7d8a, 0x7d3a, 0x7ce4, 0x7c89, 0x7c2a, 0x7bc6, 0x7b5d, 0x7aef, |
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55 | 0x7a7d, 0x7a06, 0x798a, 0x790a, 0x7885, 0x77fb, 0x776c, 0x76d9, |
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56 | 0x7642, 0x75a6, 0x7505, 0x7460, 0x73b6, 0x7308, 0x7255, 0x719e, |
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57 | 0x70e3, 0x7023, 0x6f5f, 0x6e97, 0x6dca, 0x6cf9, 0x6c24, 0x6b4b, |
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58 | 0x6a6e, 0x698c, 0x68a7, 0x67bd, 0x66d0, 0x65de, 0x64e9, 0x63ef, |
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59 | 0x62f2, 0x61f1, 0x60ec, 0x5fe4, 0x5ed7, 0x5dc8, 0x5cb4, 0x5b9d, |
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60 | 0x5a82, 0x5964, 0x5843, 0x571e, 0x55f6, 0x54ca, 0x539b, 0x5269, |
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61 | 0x5134, 0x4ffb, 0x4ec0, 0x4d81, 0x4c40, 0x4afb, 0x49b4, 0x486a, |
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62 | 0x471d, 0x45cd, 0x447b, 0x4326, 0x41ce, 0x4074, 0x3f17, 0x3db8, |
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63 | 0x3c57, 0x3af3, 0x398d, 0x3825, 0x36ba, 0x354e, 0x33df, 0x326e, |
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64 | 0x30fc, 0x2f87, 0x2e11, 0x2c99, 0x2b1f, 0x29a4, 0x2827, 0x26a8, |
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65 | 0x2528, 0x23a7, 0x2224, 0x209f, 0x1f1a, 0x1d93, 0x1c0c, 0x1a83, |
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66 | 0x18f9, 0x176e, 0x15e2, 0x1455, 0x12c8, 0x113a, 0x0fab, 0x0e1c, |
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67 | 0x0c8c, 0x0afb, 0x096b, 0x07d9, 0x0648, 0x04b6, 0x0324, 0x0192, |
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68 | 0x0000, 0x0000, |
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69 | }; |
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70 | |||

71 | #define CSHIFT (FRAC_BITS - COS_TABLE_BITS - 2) |
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72 | |||

73 | static int int_cos(int a) |
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74 | { |
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75 | ```
int neg, v, f;
``` |
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76 | const unsigned short *p; |
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77 | |||

78 | a = a & (FRAC_ONE - 1); /* modulo 2 * pi */ |
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79 | if (a >= (FRAC_ONE / 2)) |
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80 | a = FRAC_ONE - a; |
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81 | ```
neg = 0;
``` |
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82 | if (a > (FRAC_ONE / 4)) { |
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83 | ```
neg = -1;
``` |
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84 | ```
a = (FRAC_ONE / 2) - a;
``` |
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85 | } |
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86 | p = cos_table + (a >> CSHIFT); |
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87 | ```
/* linear interpolation */
``` |
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88 | f = a & ((1 << CSHIFT) - 1); |
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89 | v = p[0] + (((p[1] - p[0]) * f + (1 << (CSHIFT - 1))) >> CSHIFT); |
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90 | v = (v ^ neg) - neg; |
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91 | ```
v = v << (FRAC_BITS - 15);
``` |
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92 | ```
return v;
``` |
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93 | } |
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94 | |||

95 | FILE *outfile; |
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96 | |||

97 | void put_sample(int v) |
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98 | { |
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99 | ```
fputc(v & 0xff, outfile);
``` |
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100 | fputc((v >> 8) & 0xff, outfile); |
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101 | } |
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102 | |||

103 | int main(int argc, char **argv) |
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104 | { |
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105 | ```
int i, a, v, j, f, amp, ampa;
``` |
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106 | unsigned int seed = 1; |
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107 | ```
int tabf1[NB_CHANNELS], tabf2[NB_CHANNELS];
``` |
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108 | ```
int taba[NB_CHANNELS];
``` |
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109 | |||

110 | if (argc != 2) { |
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111 | ```
printf("usage: %s file\n"
``` |
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112 | "generate a test raw 16 bit stereo audio stream\n", argv[0]); |
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113 | ```
exit(1);
``` |
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114 | } |
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115 | 115329f1 | Diego Biurrun | |

116 | baf23f0c | Mike Melanson | outfile = fopen(argv[1], "wb"); |

117 | 51133a7d | Fabrice Bellard | ```
if (!outfile) {
``` |

118 | ```
perror(argv[1]);
``` |
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119 | return 1; |
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120 | } |
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121 | |||

122 | ```
/* 1 second of single freq sinus at 1000 Hz */
``` |
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123 | ```
a = 0;
``` |
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124 | for(i=0;i<1 * FE;i++) { |
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125 | ```
v = (int_cos(a) * 10000) >> FRAC_BITS;
``` |
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126 | for(j=0;j<NB_CHANNELS;j++) |
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127 | put_sample(v); |
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128 | ```
a += (1000 * FRAC_ONE) / FE;
``` |
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129 | } |
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130 | |||

131 | ```
/* 1 second of varing frequency between 100 and 10000 Hz */
``` |
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132 | ```
a = 0;
``` |
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133 | for(i=0;i<1 * FE;i++) { |
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134 | ```
v = (int_cos(a) * 10000) >> FRAC_BITS;
``` |
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135 | for(j=0;j<NB_CHANNELS;j++) |
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136 | put_sample(v); |
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137 | f = 100 + (((10000 - 100) * i) / FE); |
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138 | a += (f * FRAC_ONE) / FE; |
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139 | } |
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140 | 115329f1 | Diego Biurrun | |

141 | 51133a7d | Fabrice Bellard | ```
/* 0.5 second of low amplitude white noise */
``` |

142 | for(i=0;i<FE / 2;i++) { |
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143 | v = myrnd(&seed, 20000) - 10000; |
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144 | for(j=0;j<NB_CHANNELS;j++) |
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145 | put_sample(v); |
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146 | } |
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147 | |||

148 | ```
/* 0.5 second of high amplitude white noise */
``` |
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149 | for(i=0;i<FE / 2;i++) { |
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150 | v = myrnd(&seed, 65535) - 32768; |
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151 | for(j=0;j<NB_CHANNELS;j++) |
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152 | put_sample(v); |
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153 | } |
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154 | |||

155 | ```
/* stereo : 2 unrelated ramps */
``` |
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156 | for(j=0;j<NB_CHANNELS;j++) { |
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157 | ```
taba[j] = 0;
``` |
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158 | tabf1[j] = 100 + myrnd(&seed, 5000); |
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159 | tabf2[j] = 100 + myrnd(&seed, 5000); |
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160 | } |
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161 | for(i=0;i<1 * FE;i++) { |
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162 | for(j=0;j<NB_CHANNELS;j++) { |
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163 | ```
v = (int_cos(taba[j]) * 10000) >> FRAC_BITS;
``` |
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164 | put_sample(v); |
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165 | f = tabf1[j] + (((tabf2[j] - tabf1[j]) * i) / FE); |
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166 | taba[j] += (f * FRAC_ONE) / FE; |
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167 | } |
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168 | } |
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169 | 115329f1 | Diego Biurrun | |

170 | 51133a7d | Fabrice Bellard | ```
/* stereo 500 Hz with varying volume */
``` |

171 | ```
a = 0;
``` |
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172 | ```
ampa = 0;
``` |
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173 | for(i=0;i<2 * FE;i++) { |
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174 | for(j=0;j<NB_CHANNELS;j++) { |
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175 | ```
amp = ((FRAC_ONE + int_cos(ampa)) * 5000) >> FRAC_BITS;
``` |
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176 | if (j & 1) |
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177 | ```
amp = 10000 - amp;
``` |
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178 | v = (int_cos(a) * amp) >> FRAC_BITS; |
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179 | put_sample(v); |
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180 | ```
a += (500 * FRAC_ONE) / FE;
``` |
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181 | ```
ampa += (2 * FRAC_ONE) / FE;
``` |
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182 | } |
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183 | } |
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184 | |||

185 | fclose(outfile); |
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186 | return 0; |
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187 | } |