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4349 | Serge | 1 | /* |
2 | * Copyright (c) 2013 Nicolas George |
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3 | * |
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4 | * This file is part of FFmpeg. |
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5 | * |
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6 | * FFmpeg is free software; you can redistribute it and/or |
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7 | * modify it under the terms of the GNU Lesser General Public License |
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8 | * as published by the Free Software Foundation; either |
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9 | * version 2.1 of the License, or (at your option) any later version. |
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10 | * |
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11 | * FFmpeg is distributed in the hope that it will be useful, |
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12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | * GNU Lesser General Public License for more details. |
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15 | * |
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16 | * You should have received a copy of the GNU Lesser General Public License |
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17 | * along with FFmpeg; if not, write to the Free Software Foundation, Inc., |
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18 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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19 | */ |
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20 | |||
21 | #include |
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22 | |||
23 | #include "libavutil/avassert.h" |
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24 | #include "libavutil/channel_layout.h" |
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25 | #include "libavutil/opt.h" |
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26 | #include "audio.h" |
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27 | #include "avfilter.h" |
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28 | #include "internal.h" |
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29 | |||
30 | typedef struct { |
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31 | const AVClass *class; |
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32 | double frequency; |
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33 | double beep_factor; |
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34 | int samples_per_frame; |
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35 | int sample_rate; |
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36 | int64_t duration; |
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37 | int16_t *sin; |
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38 | int64_t pts; |
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39 | uint32_t phi; ///< current phase of the sine (2pi = 1<<32) |
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40 | uint32_t dphi; ///< phase increment between two samples |
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41 | unsigned beep_period; |
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42 | unsigned beep_index; |
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43 | unsigned beep_length; |
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44 | uint32_t phi_beep; ///< current phase of the beep |
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45 | uint32_t dphi_beep; ///< phase increment of the beep |
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46 | } SineContext; |
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47 | |||
48 | #define CONTEXT SineContext |
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49 | #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM |
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50 | |||
51 | #define OPT_GENERIC(name, field, def, min, max, descr, type, deffield, ...) \ |
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52 | { name, descr, offsetof(CONTEXT, field), AV_OPT_TYPE_ ## type, \ |
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53 | { .deffield = def }, min, max, FLAGS, __VA_ARGS__ } |
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54 | |||
55 | #define OPT_INT(name, field, def, min, max, descr, ...) \ |
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56 | OPT_GENERIC(name, field, def, min, max, descr, INT, i64, __VA_ARGS__) |
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57 | |||
58 | #define OPT_DBL(name, field, def, min, max, descr, ...) \ |
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59 | OPT_GENERIC(name, field, def, min, max, descr, DOUBLE, dbl, __VA_ARGS__) |
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60 | |||
61 | #define OPT_DUR(name, field, def, min, max, descr, ...) \ |
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62 | OPT_GENERIC(name, field, def, min, max, descr, DURATION, str, __VA_ARGS__) |
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63 | |||
64 | static const AVOption sine_options[] = { |
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65 | OPT_DBL("frequency", frequency, 440, 0, DBL_MAX, "set the sine frequency"), |
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66 | OPT_DBL("f", frequency, 440, 0, DBL_MAX, "set the sine frequency"), |
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67 | OPT_DBL("beep_factor", beep_factor, 0, 0, DBL_MAX, "set the beep fequency factor"), |
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68 | OPT_DBL("b", beep_factor, 0, 0, DBL_MAX, "set the beep fequency factor"), |
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69 | OPT_INT("sample_rate", sample_rate, 44100, 1, INT_MAX, "set the sample rate"), |
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70 | OPT_INT("r", sample_rate, 44100, 1, INT_MAX, "set the sample rate"), |
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71 | OPT_DUR("duration", duration, 0, 0, INT64_MAX, "set the audio duration"), |
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72 | OPT_DUR("d", duration, 0, 0, INT64_MAX, "set the audio duration"), |
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73 | OPT_INT("samples_per_frame", samples_per_frame, 1024, 0, INT_MAX, "set the number of samples per frame"), |
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74 | {NULL} |
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75 | }; |
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76 | |||
77 | AVFILTER_DEFINE_CLASS(sine); |
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78 | |||
79 | #define LOG_PERIOD 15 |
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80 | #define AMPLITUDE 4095 |
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81 | #define AMPLITUDE_SHIFT 3 |
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82 | |||
83 | static void make_sin_table(int16_t *sin) |
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84 | { |
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85 | unsigned half_pi = 1 << (LOG_PERIOD - 2); |
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86 | unsigned ampls = AMPLITUDE << AMPLITUDE_SHIFT; |
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87 | uint64_t unit2 = (uint64_t)(ampls * ampls) << 32; |
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88 | unsigned step, i, c, s, k, new_k, n2; |
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89 | |||
90 | /* Principle: if u = exp(i*a1) and v = exp(i*a2), then |
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91 | exp(i*(a1+a2)/2) = (u+v) / length(u+v) */ |
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92 | sin[0] = 0; |
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93 | sin[half_pi] = ampls; |
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94 | for (step = half_pi; step > 1; step /= 2) { |
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95 | /* k = (1 << 16) * amplitude / length(u+v) |
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96 | In exact values, k is constant at a given step */ |
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97 | k = 0x10000; |
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98 | for (i = 0; i < half_pi / 2; i += step) { |
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99 | s = sin[i] + sin[i + step]; |
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100 | c = sin[half_pi - i] + sin[half_pi - i - step]; |
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101 | n2 = s * s + c * c; |
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102 | /* Newton's method to solve n² * k² = unit² */ |
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103 | while (1) { |
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104 | new_k = (k + unit2 / ((uint64_t)k * n2) + 1) >> 1; |
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105 | if (k == new_k) |
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106 | break; |
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107 | k = new_k; |
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108 | } |
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109 | sin[i + step / 2] = (k * s + 0x7FFF) >> 16; |
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110 | sin[half_pi - i - step / 2] = (k * c + 0x8000) >> 16; |
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111 | } |
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112 | } |
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113 | /* Unshift amplitude */ |
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114 | for (i = 0; i <= half_pi; i++) |
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115 | sin[i] = (sin[i] + (1 << (AMPLITUDE_SHIFT - 1))) >> AMPLITUDE_SHIFT; |
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116 | /* Use symmetries to fill the other three quarters */ |
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117 | for (i = 0; i < half_pi; i++) |
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118 | sin[half_pi * 2 - i] = sin[i]; |
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119 | for (i = 0; i < 2 * half_pi; i++) |
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120 | sin[i + 2 * half_pi] = -sin[i]; |
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121 | } |
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122 | |||
123 | static av_cold int init(AVFilterContext *ctx) |
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124 | { |
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125 | SineContext *sine = ctx->priv; |
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126 | |||
127 | if (!(sine->sin = av_malloc(sizeof(*sine->sin) << LOG_PERIOD))) |
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128 | return AVERROR(ENOMEM); |
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129 | sine->dphi = ldexp(sine->frequency, 32) / sine->sample_rate + 0.5; |
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130 | make_sin_table(sine->sin); |
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131 | |||
132 | if (sine->beep_factor) { |
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133 | sine->beep_period = sine->sample_rate; |
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134 | sine->beep_length = sine->beep_period / 25; |
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135 | sine->dphi_beep = ldexp(sine->beep_factor * sine->frequency, 32) / |
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136 | sine->sample_rate + 0.5; |
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137 | } |
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138 | |||
139 | return 0; |
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140 | } |
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141 | |||
142 | static av_cold void uninit(AVFilterContext *ctx) |
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143 | { |
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144 | SineContext *sine = ctx->priv; |
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145 | |||
146 | av_freep(&sine->sin); |
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147 | } |
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148 | |||
149 | static av_cold int query_formats(AVFilterContext *ctx) |
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150 | { |
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151 | SineContext *sine = ctx->priv; |
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152 | static const int64_t chlayouts[] = { AV_CH_LAYOUT_MONO, -1 }; |
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153 | int sample_rates[] = { sine->sample_rate, -1 }; |
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154 | static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_S16, |
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155 | AV_SAMPLE_FMT_NONE }; |
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156 | |||
157 | ff_set_common_formats (ctx, ff_make_format_list(sample_fmts)); |
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158 | ff_set_common_channel_layouts(ctx, avfilter_make_format64_list(chlayouts)); |
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159 | ff_set_common_samplerates(ctx, ff_make_format_list(sample_rates)); |
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160 | return 0; |
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161 | } |
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162 | |||
163 | static av_cold int config_props(AVFilterLink *outlink) |
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164 | { |
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165 | SineContext *sine = outlink->src->priv; |
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166 | sine->duration = av_rescale(sine->duration, sine->sample_rate, AV_TIME_BASE); |
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167 | return 0; |
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168 | } |
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169 | |||
170 | static int request_frame(AVFilterLink *outlink) |
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171 | { |
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172 | SineContext *sine = outlink->src->priv; |
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173 | AVFrame *frame; |
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174 | int i, nb_samples = sine->samples_per_frame; |
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175 | int16_t *samples; |
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176 | |||
177 | if (sine->duration) { |
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178 | nb_samples = FFMIN(nb_samples, sine->duration - sine->pts); |
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179 | av_assert1(nb_samples >= 0); |
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180 | if (!nb_samples) |
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181 | return AVERROR_EOF; |
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182 | } |
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183 | if (!(frame = ff_get_audio_buffer(outlink, nb_samples))) |
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184 | return AVERROR(ENOMEM); |
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185 | samples = (int16_t *)frame->data[0]; |
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186 | |||
187 | for (i = 0; i < nb_samples; i++) { |
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188 | samples[i] = sine->sin[sine->phi >> (32 - LOG_PERIOD)]; |
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189 | sine->phi += sine->dphi; |
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190 | if (sine->beep_index < sine->beep_length) { |
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191 | samples[i] += sine->sin[sine->phi_beep >> (32 - LOG_PERIOD)] << 1; |
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192 | sine->phi_beep += sine->dphi_beep; |
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193 | } |
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194 | if (++sine->beep_index == sine->beep_period) |
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195 | sine->beep_index = 0; |
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196 | } |
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197 | |||
198 | frame->pts = sine->pts; |
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199 | sine->pts += nb_samples; |
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200 | return ff_filter_frame(outlink, frame); |
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201 | } |
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202 | |||
203 | static const AVFilterPad sine_outputs[] = { |
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204 | { |
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205 | .name = "default", |
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206 | .type = AVMEDIA_TYPE_AUDIO, |
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207 | .request_frame = request_frame, |
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208 | .config_props = config_props, |
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209 | }, |
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210 | { NULL } |
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211 | }; |
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212 | |||
213 | AVFilter avfilter_asrc_sine = { |
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214 | .name = "sine", |
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215 | .description = NULL_IF_CONFIG_SMALL("Generate sine wave audio signal."), |
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216 | .query_formats = query_formats, |
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217 | .init = init, |
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218 | .uninit = uninit, |
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219 | .priv_size = sizeof(SineContext), |
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220 | .inputs = NULL, |
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221 | .outputs = sine_outputs, |
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222 | .priv_class = &sine_class, |
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223 | };><>>>><>>>><>=>>><>><>><>><>>>>32) |