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asrc_sine.c
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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"
25 #include "libavutil/eval.h"
26 #include "libavutil/opt.h"
27 #include "audio.h"
28 #include "avfilter.h"
29 #include "internal.h"
30 
31 typedef struct {
32  const AVClass *class;
33  double frequency;
34  double beep_factor;
38  int64_t duration;
39  int16_t *sin;
40  int64_t pts;
41  uint32_t phi; ///< current phase of the sine (2pi = 1<<32)
42  uint32_t dphi; ///< phase increment between two samples
43  unsigned beep_period;
44  unsigned beep_index;
45  unsigned beep_length;
46  uint32_t phi_beep; ///< current phase of the beep
47  uint32_t dphi_beep; ///< phase increment of the beep
48 } SineContext;
49 
50 #define CONTEXT SineContext
51 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
52 
53 #define OPT_GENERIC(name, field, def, min, max, descr, type, deffield, ...) \
54  { name, descr, offsetof(CONTEXT, field), AV_OPT_TYPE_ ## type, \
55  { .deffield = def }, min, max, FLAGS, __VA_ARGS__ }
56 
57 #define OPT_INT(name, field, def, min, max, descr, ...) \
58  OPT_GENERIC(name, field, def, min, max, descr, INT, i64, __VA_ARGS__)
59 
60 #define OPT_DBL(name, field, def, min, max, descr, ...) \
61  OPT_GENERIC(name, field, def, min, max, descr, DOUBLE, dbl, __VA_ARGS__)
62 
63 #define OPT_DUR(name, field, def, min, max, descr, ...) \
64  OPT_GENERIC(name, field, def, min, max, descr, DURATION, str, __VA_ARGS__)
65 
66 #define OPT_STR(name, field, def, min, max, descr, ...) \
67  OPT_GENERIC(name, field, def, min, max, descr, STRING, str, __VA_ARGS__)
68 
69 static const AVOption sine_options[] = {
70  OPT_DBL("frequency", frequency, 440, 0, DBL_MAX, "set the sine frequency",),
71  OPT_DBL("f", frequency, 440, 0, DBL_MAX, "set the sine frequency",),
72  OPT_DBL("beep_factor", beep_factor, 0, 0, DBL_MAX, "set the beep frequency factor",),
73  OPT_DBL("b", beep_factor, 0, 0, DBL_MAX, "set the beep frequency factor",),
74  OPT_INT("sample_rate", sample_rate, 44100, 1, INT_MAX, "set the sample rate",),
75  OPT_INT("r", sample_rate, 44100, 1, INT_MAX, "set the sample rate",),
76  OPT_DUR("duration", duration, 0, 0, INT64_MAX, "set the audio duration",),
77  OPT_DUR("d", duration, 0, 0, INT64_MAX, "set the audio duration",),
78  OPT_STR("samples_per_frame", samples_per_frame, "1024", 0, 0, "set the number of samples per frame",),
79  {NULL}
80 };
81 
83 
84 #define LOG_PERIOD 15
85 #define AMPLITUDE 4095
86 #define AMPLITUDE_SHIFT 3
87 
88 static void make_sin_table(int16_t *sin)
89 {
90  unsigned half_pi = 1 << (LOG_PERIOD - 2);
91  unsigned ampls = AMPLITUDE << AMPLITUDE_SHIFT;
92  uint64_t unit2 = (uint64_t)(ampls * ampls) << 32;
93  unsigned step, i, c, s, k, new_k, n2;
94 
95  /* Principle: if u = exp(i*a1) and v = exp(i*a2), then
96  exp(i*(a1+a2)/2) = (u+v) / length(u+v) */
97  sin[0] = 0;
98  sin[half_pi] = ampls;
99  for (step = half_pi; step > 1; step /= 2) {
100  /* k = (1 << 16) * amplitude / length(u+v)
101  In exact values, k is constant at a given step */
102  k = 0x10000;
103  for (i = 0; i < half_pi / 2; i += step) {
104  s = sin[i] + sin[i + step];
105  c = sin[half_pi - i] + sin[half_pi - i - step];
106  n2 = s * s + c * c;
107  /* Newton's method to solve n² * k² = unit² */
108  while (1) {
109  new_k = (k + unit2 / ((uint64_t)k * n2) + 1) >> 1;
110  if (k == new_k)
111  break;
112  k = new_k;
113  }
114  sin[i + step / 2] = (k * s + 0x7FFF) >> 16;
115  sin[half_pi - i - step / 2] = (k * c + 0x8000) >> 16;
116  }
117  }
118  /* Unshift amplitude */
119  for (i = 0; i <= half_pi; i++)
120  sin[i] = (sin[i] + (1 << (AMPLITUDE_SHIFT - 1))) >> AMPLITUDE_SHIFT;
121  /* Use symmetries to fill the other three quarters */
122  for (i = 0; i < half_pi; i++)
123  sin[half_pi * 2 - i] = sin[i];
124  for (i = 0; i < 2 * half_pi; i++)
125  sin[i + 2 * half_pi] = -sin[i];
126 }
127 
128 static const char *const var_names[] = {
129  "n",
130  "pts",
131  "t",
132  "TB",
133  NULL
134 };
135 
136 enum {
142 };
143 
145 {
146  int ret;
147  SineContext *sine = ctx->priv;
148 
149  if (!(sine->sin = av_malloc(sizeof(*sine->sin) << LOG_PERIOD)))
150  return AVERROR(ENOMEM);
151  sine->dphi = ldexp(sine->frequency, 32) / sine->sample_rate + 0.5;
152  make_sin_table(sine->sin);
153 
154  if (sine->beep_factor) {
155  sine->beep_period = sine->sample_rate;
156  sine->beep_length = sine->beep_period / 25;
157  sine->dphi_beep = ldexp(sine->beep_factor * sine->frequency, 32) /
158  sine->sample_rate + 0.5;
159  }
160 
163  NULL, NULL, NULL, NULL, 0, sine);
164  if (ret < 0)
165  return ret;
166 
167  return 0;
168 }
169 
171 {
172  SineContext *sine = ctx->priv;
173 
176  av_freep(&sine->sin);
177 }
178 
180 {
181  SineContext *sine = ctx->priv;
182  static const int64_t chlayouts[] = { AV_CH_LAYOUT_MONO, -1 };
183  int sample_rates[] = { sine->sample_rate, -1 };
184  static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_S16,
188  int ret;
189 
190  formats = ff_make_format_list(sample_fmts);
191  if (!formats)
192  return AVERROR(ENOMEM);
193  ret = ff_set_common_formats (ctx, formats);
194  if (ret < 0)
195  return ret;
196 
197  layouts = avfilter_make_format64_list(chlayouts);
198  if (!layouts)
199  return AVERROR(ENOMEM);
200  ret = ff_set_common_channel_layouts(ctx, layouts);
201  if (ret < 0)
202  return ret;
203 
204  formats = ff_make_format_list(sample_rates);
205  if (!formats)
206  return AVERROR(ENOMEM);
207  return ff_set_common_samplerates(ctx, formats);
208 }
209 
210 static av_cold int config_props(AVFilterLink *outlink)
211 {
212  SineContext *sine = outlink->src->priv;
213  sine->duration = av_rescale(sine->duration, sine->sample_rate, AV_TIME_BASE);
214  return 0;
215 }
216 
217 static int request_frame(AVFilterLink *outlink)
218 {
219  SineContext *sine = outlink->src->priv;
220  AVFrame *frame;
221  double values[VAR_VARS_NB] = {
222  [VAR_N] = outlink->frame_count,
223  [VAR_PTS] = sine->pts,
224  [VAR_T] = sine->pts * av_q2d(outlink->time_base),
225  [VAR_TB] = av_q2d(outlink->time_base),
226  };
227  int i, nb_samples = lrint(av_expr_eval(sine->samples_per_frame_expr, values, sine));
228  int16_t *samples;
229 
230  if (nb_samples <= 0) {
231  av_log(sine, AV_LOG_WARNING, "nb samples expression evaluated to %d, "
232  "defaulting to 1024\n", nb_samples);
233  nb_samples = 1024;
234  }
235 
236  if (sine->duration) {
237  nb_samples = FFMIN(nb_samples, sine->duration - sine->pts);
238  av_assert1(nb_samples >= 0);
239  if (!nb_samples)
240  return AVERROR_EOF;
241  }
242  if (!(frame = ff_get_audio_buffer(outlink, nb_samples)))
243  return AVERROR(ENOMEM);
244  samples = (int16_t *)frame->data[0];
245 
246  for (i = 0; i < nb_samples; i++) {
247  samples[i] = sine->sin[sine->phi >> (32 - LOG_PERIOD)];
248  sine->phi += sine->dphi;
249  if (sine->beep_index < sine->beep_length) {
250  samples[i] += sine->sin[sine->phi_beep >> (32 - LOG_PERIOD)] << 1;
251  sine->phi_beep += sine->dphi_beep;
252  }
253  if (++sine->beep_index == sine->beep_period)
254  sine->beep_index = 0;
255  }
256 
257  frame->pts = sine->pts;
258  sine->pts += nb_samples;
259  return ff_filter_frame(outlink, frame);
260 }
261 
262 static const AVFilterPad sine_outputs[] = {
263  {
264  .name = "default",
265  .type = AVMEDIA_TYPE_AUDIO,
266  .request_frame = request_frame,
267  .config_props = config_props,
268  },
269  { NULL }
270 };
271 
273  .name = "sine",
274  .description = NULL_IF_CONFIG_SMALL("Generate sine wave audio signal."),
275  .query_formats = query_formats,
276  .init = init,
277  .uninit = uninit,
278  .priv_size = sizeof(SineContext),
279  .inputs = NULL,
280  .outputs = sine_outputs,
281  .priv_class = &sine_class,
282 };
#define NULL
Definition: coverity.c:32
int ff_set_common_channel_layouts(AVFilterContext *ctx, AVFilterChannelLayouts *layouts)
A helper for query_formats() which sets all links to the same list of channel layouts/sample rates...
Definition: formats.c:549
const char * s
Definition: avisynth_c.h:768
AVFilter ff_asrc_sine
Definition: asrc_sine.c:272
This structure describes decoded (raw) audio or video data.
Definition: frame.h:184
AVOption.
Definition: opt.h:245
#define OPT_INT(name, field, def, min, max, descr,...)
Definition: asrc_sine.c:57
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
Main libavfilter public API header.
uint32_t dphi_beep
phase increment of the beep
Definition: asrc_sine.c:47
static const AVOption sine_options[]
Definition: asrc_sine.c:69
static enum AVSampleFormat formats[]
Definition: avresample.c:163
#define AMPLITUDE
Definition: asrc_sine.c:85
uint32_t phi_beep
current phase of the beep
Definition: asrc_sine.c:46
int av_expr_parse(AVExpr **expr, const char *s, const char *const *const_names, const char *const *func1_names, double(*const *funcs1)(void *, double), const char *const *func2_names, double(*const *funcs2)(void *, double, double), int log_offset, void *log_ctx)
Parse an expression.
Definition: eval.c:658
AVFilterFormats * ff_make_format_list(const int *fmts)
Create a list of supported formats.
Definition: formats.c:283
const char * name
Pad name.
Definition: internal.h:59
AVFILTER_DEFINE_CLASS(sine)
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1189
#define av_cold
Definition: attributes.h:82
#define av_malloc(s)
AVOptions.
int64_t pts
Presentation timestamp in time_base units (time when frame should be shown to user).
Definition: frame.h:268
Definition: eval.c:149
int64_t duration
Definition: movenc.c:63
static AVFrame * frame
static double av_q2d(AVRational a)
Convert an AVRational to a double.
Definition: rational.h:104
#define AVERROR_EOF
End of file.
Definition: error.h:55
static av_cold int init(AVFilterContext *ctx)
Definition: asrc_sine.c:144
#define av_log(a,...)
char * samples_per_frame
Definition: asrc_sine.c:35
#define LOG_PERIOD
Definition: asrc_sine.c:84
A filter pad used for either input or output.
Definition: internal.h:53
int ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
A helper for query_formats() which sets all links to the same list of formats.
Definition: formats.c:568
AVFrame * ff_get_audio_buffer(AVFilterLink *link, int nb_samples)
Request an audio samples buffer with a specific set of permissions.
Definition: audio.c:65
#define AVERROR(e)
Definition: error.h:43
int sample_rate
Definition: asrc_sine.c:37
AVExpr * samples_per_frame_expr
Definition: asrc_sine.c:36
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
void * priv
private data for use by the filter
Definition: avfilter.h:322
double frequency
Definition: asrc_sine.c:33
simple assert() macros that are a bit more flexible than ISO C assert().
static const int sample_rates[]
Definition: dcaenc.h:32
unsigned beep_length
Definition: asrc_sine.c:45
audio channel layout utility functions
#define av_assert1(cond)
assert() equivalent, that does not lie in speed critical code.
Definition: avassert.h:53
int64_t av_rescale(int64_t a, int64_t b, int64_t c)
Rescale a 64-bit integer with rounding to nearest.
Definition: mathematics.c:129
int64_t pts
Definition: asrc_sine.c:40
#define AV_TIME_BASE
Internal time base represented as integer.
Definition: avutil.h:248
#define FFMIN(a, b)
Definition: common.h:96
AVFormatContext * ctx
Definition: movenc.c:48
static const AVFilterPad outputs[]
Definition: af_afftfilt.c:386
A list of supported channel layouts.
Definition: formats.h:85
double beep_factor
Definition: asrc_sine.c:34
sample_rate
static const AVFilterPad inputs[]
Definition: af_afftfilt.c:376
static int request_frame(AVFilterLink *outlink)
Definition: asrc_sine.c:217
static const AVFilterPad sine_outputs[]
Definition: asrc_sine.c:262
AVFilterChannelLayouts * avfilter_make_format64_list(const int64_t *fmts)
Definition: formats.c:303
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
void av_expr_free(AVExpr *e)
Free a parsed expression previously created with av_expr_parse().
Definition: eval.c:318
#define OPT_DBL(name, field, def, min, max, descr,...)
Definition: asrc_sine.c:60
static const char *const var_names[]
Definition: asrc_sine.c:128
Describe the class of an AVClass context structure.
Definition: log.h:67
Filter definition.
Definition: avfilter.h:144
const char * name
Filter name.
Definition: avfilter.h:148
static void make_sin_table(int16_t *sin)
Definition: asrc_sine.c:88
enum MovChannelLayoutTag * layouts
Definition: mov_chan.c:434
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:198
static av_cold void uninit(AVFilterContext *ctx)
Definition: asrc_sine.c:170
unsigned beep_period
Definition: asrc_sine.c:43
int64_t duration
Definition: asrc_sine.c:38
signed 16 bits
Definition: samplefmt.h:61
static double c[64]
#define AMPLITUDE_SHIFT
Definition: asrc_sine.c:86
static av_cold int config_props(AVFilterLink *outlink)
Definition: asrc_sine.c:210
double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
Evaluate a previously parsed expression.
Definition: eval.c:713
uint32_t phi
current phase of the sine (2pi = 1<<32)
Definition: asrc_sine.c:41
A list of supported formats for one end of a filter link.
Definition: formats.h:64
uint32_t dphi
phase increment between two samples
Definition: asrc_sine.c:42
#define lrint
Definition: tablegen.h:53
static av_cold int query_formats(AVFilterContext *ctx)
Definition: asrc_sine.c:179
int16_t * sin
Definition: asrc_sine.c:39
An instance of a filter.
Definition: avfilter.h:307
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:701
unsigned beep_index
Definition: asrc_sine.c:44
#define av_freep(p)
#define OPT_STR(name, field, def, min, max, descr,...)
Definition: asrc_sine.c:66
internal API functions
#define AV_CH_LAYOUT_MONO
for(j=16;j >0;--j)
int ff_set_common_samplerates(AVFilterContext *ctx, AVFilterFormats *samplerates)
Definition: formats.c:556
simple arithmetic expression evaluator
#define OPT_DUR(name, field, def, min, max, descr,...)
Definition: asrc_sine.c:63