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