FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
aeval.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2011 Stefano Sabatini
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
8  * License 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 GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * eval audio source
24  */
25 
26 #include "libavutil/avassert.h"
27 #include "libavutil/avstring.h"
29 #include "libavutil/eval.h"
30 #include "libavutil/opt.h"
31 #include "libavutil/parseutils.h"
32 #include "avfilter.h"
33 #include "audio.h"
34 #include "internal.h"
35 
36 static const char * const var_names[] = {
37  "ch", ///< the value of the current channel
38  "n", ///< number of frame
39  "nb_in_channels",
40  "nb_out_channels",
41  "t", ///< timestamp expressed in seconds
42  "s", ///< sample rate
43  NULL
44 };
45 
46 enum var_name {
54 };
55 
56 typedef struct {
57  const AVClass *class;
60  int64_t chlayout;
61  char *chlayout_str;
62  int nb_channels; ///< number of output channels
63  int nb_in_channels; ///< number of input channels
64  int same_chlayout; ///< set output as input channel layout
65  int64_t pts;
67  char *exprs;
68  int nb_samples; ///< number of samples per requested frame
69  int64_t duration;
70  uint64_t n;
71  double var_values[VAR_VARS_NB];
72  double *channel_values;
74 } EvalContext;
75 
76 static double val(void *priv, double ch)
77 {
78  EvalContext *eval = priv;
79  return eval->channel_values[FFMIN((int)ch, eval->nb_in_channels-1)];
80 }
81 
82 static double (* const aeval_func1[])(void *, double) = { val, NULL };
83 static const char * const aeval_func1_names[] = { "val", NULL };
84 
85 #define OFFSET(x) offsetof(EvalContext, x)
86 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
87 
88 static const AVOption aevalsrc_options[]= {
89  { "exprs", "set the '|'-separated list of channels expressions", OFFSET(exprs), AV_OPT_TYPE_STRING, {.str = NULL}, .flags = FLAGS },
90  { "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 0, INT_MAX, FLAGS },
91  { "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 0, INT_MAX, FLAGS },
92  { "sample_rate", "set the sample rate", OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX, FLAGS },
93  { "s", "set the sample rate", OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX, FLAGS },
94  { "duration", "set audio duration", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64 = -1}, -1, INT64_MAX, FLAGS },
95  { "d", "set audio duration", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64 = -1}, -1, INT64_MAX, FLAGS },
96  { "channel_layout", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
97  { "c", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
98  { NULL }
99 };
100 
101 AVFILTER_DEFINE_CLASS(aevalsrc);
102 
104  int expected_nb_channels)
105 {
106  EvalContext *eval = ctx->priv;
107  char *args1 = av_strdup(eval->exprs);
108  char *expr, *last_expr, *buf;
109  double (* const *func1)(void *, double) = NULL;
110  const char * const *func1_names = NULL;
111  int i, ret = 0;
112 
113  if (!args1)
114  return AVERROR(ENOMEM);
115 
116  if (!eval->exprs) {
117  av_log(ctx, AV_LOG_ERROR, "Channels expressions list is empty\n");
118  return AVERROR(EINVAL);
119  }
120 
121  if (!strcmp(ctx->filter->name, "aeval")) {
122  func1 = aeval_func1;
123  func1_names = aeval_func1_names;
124  }
125 
126 #define ADD_EXPRESSION(expr_) do { \
127  if (!av_dynarray2_add((void **)&eval->expr, &eval->nb_channels, \
128  sizeof(*eval->expr), NULL)) { \
129  ret = AVERROR(ENOMEM); \
130  goto end; \
131  } \
132  eval->expr[eval->nb_channels-1] = NULL; \
133  ret = av_expr_parse(&eval->expr[eval->nb_channels - 1], expr_, \
134  var_names, func1_names, func1, \
135  NULL, NULL, 0, ctx); \
136  if (ret < 0) \
137  goto end; \
138  } while (0)
139 
140  /* reset expressions */
141  for (i = 0; i < eval->nb_channels; i++) {
142  av_expr_free(eval->expr[i]);
143  eval->expr[i] = NULL;
144  }
145  av_freep(&eval->expr);
146  eval->nb_channels = 0;
147 
148  buf = args1;
149  while (expr = av_strtok(buf, "|", &buf)) {
150  ADD_EXPRESSION(expr);
151  last_expr = expr;
152  }
153 
154  if (expected_nb_channels > eval->nb_channels)
155  for (i = eval->nb_channels; i < expected_nb_channels; i++)
156  ADD_EXPRESSION(last_expr);
157 
158  if (expected_nb_channels > 0 && eval->nb_channels != expected_nb_channels) {
159  av_log(ctx, AV_LOG_ERROR,
160  "Mismatch between the specified number of channel expressions '%d' "
161  "and the number of expected output channels '%d' for the specified channel layout\n",
162  eval->nb_channels, expected_nb_channels);
163  ret = AVERROR(EINVAL);
164  goto end;
165  }
166 
167 end:
168  av_free(args1);
169  return ret;
170 }
171 
172 static av_cold int init(AVFilterContext *ctx)
173 {
174  EvalContext *eval = ctx->priv;
175  int ret = 0;
176 
177  if (eval->chlayout_str) {
178  if (!strcmp(eval->chlayout_str, "same") && !strcmp(ctx->filter->name, "aeval")) {
179  eval->same_chlayout = 1;
180  } else {
181  ret = ff_parse_channel_layout(&eval->chlayout, NULL, eval->chlayout_str, ctx);
182  if (ret < 0)
183  return ret;
184 
186  if (ret < 0)
187  return ret;
188  }
189  } else {
190  /* guess channel layout from nb expressions/channels */
191  if ((ret = parse_channel_expressions(ctx, -1)) < 0)
192  return ret;
193 
195  if (!eval->chlayout && eval->nb_channels <= 0) {
196  av_log(ctx, AV_LOG_ERROR, "Invalid number of channels '%d' provided\n",
197  eval->nb_channels);
198  return AVERROR(EINVAL);
199  }
200  }
201 
202  if (eval->sample_rate_str)
203  if ((ret = ff_parse_sample_rate(&eval->sample_rate, eval->sample_rate_str, ctx)))
204  return ret;
205  eval->n = 0;
206 
207  return ret;
208 }
209 
210 static av_cold void uninit(AVFilterContext *ctx)
211 {
212  EvalContext *eval = ctx->priv;
213  int i;
214 
215  for (i = 0; i < eval->nb_channels; i++) {
216  av_expr_free(eval->expr[i]);
217  eval->expr[i] = NULL;
218  }
219  av_freep(&eval->expr);
220 }
221 
222 static int config_props(AVFilterLink *outlink)
223 {
224  EvalContext *eval = outlink->src->priv;
225  char buf[128];
226 
227  outlink->time_base = (AVRational){1, eval->sample_rate};
228  outlink->sample_rate = eval->sample_rate;
229 
230  eval->var_values[VAR_S] = eval->sample_rate;
232  eval->var_values[VAR_NB_OUT_CHANNELS] = outlink->channels;
233 
234  av_get_channel_layout_string(buf, sizeof(buf), 0, eval->chlayout);
235 
236  av_log(outlink->src, AV_LOG_VERBOSE,
237  "sample_rate:%d chlayout:%s duration:%"PRId64"\n",
238  eval->sample_rate, buf, eval->duration);
239 
240  return 0;
241 }
242 
244 {
245  EvalContext *eval = ctx->priv;
247  int64_t chlayouts[] = { eval->chlayout ? eval->chlayout : FF_COUNT2LAYOUT(eval->nb_channels) , -1 };
248  int sample_rates[] = { eval->sample_rate, -1 };
249 
250  ff_set_common_formats (ctx, ff_make_format_list(sample_fmts));
253 
254  return 0;
255 }
256 
257 static int request_frame(AVFilterLink *outlink)
258 {
259  EvalContext *eval = outlink->src->priv;
260  AVFrame *samplesref;
261  int i, j;
262  int64_t t = av_rescale(eval->n, AV_TIME_BASE, eval->sample_rate);
263 
264  if (eval->duration >= 0 && t >= eval->duration)
265  return AVERROR_EOF;
266 
267  samplesref = ff_get_audio_buffer(outlink, eval->nb_samples);
268  if (!samplesref)
269  return AVERROR(ENOMEM);
270 
271  /* evaluate expression for each single sample and for each channel */
272  for (i = 0; i < eval->nb_samples; i++, eval->n++) {
273  eval->var_values[VAR_N] = eval->n;
274  eval->var_values[VAR_T] = eval->var_values[VAR_N] * (double)1/eval->sample_rate;
275 
276  for (j = 0; j < eval->nb_channels; j++) {
277  *((double *) samplesref->extended_data[j] + i) =
278  av_expr_eval(eval->expr[j], eval->var_values, NULL);
279  }
280  }
281 
282  samplesref->pts = eval->pts;
283  samplesref->sample_rate = eval->sample_rate;
284  eval->pts += eval->nb_samples;
285 
286  return ff_filter_frame(outlink, samplesref);
287 }
288 
289 #if CONFIG_AEVALSRC_FILTER
290 static const AVFilterPad aevalsrc_outputs[] = {
291  {
292  .name = "default",
293  .type = AVMEDIA_TYPE_AUDIO,
294  .config_props = config_props,
295  .request_frame = request_frame,
296  },
297  { NULL }
298 };
299 
300 AVFilter ff_asrc_aevalsrc = {
301  .name = "aevalsrc",
302  .description = NULL_IF_CONFIG_SMALL("Generate an audio signal generated by an expression."),
303  .query_formats = query_formats,
304  .init = init,
305  .uninit = uninit,
306  .priv_size = sizeof(EvalContext),
307  .inputs = NULL,
308  .outputs = aevalsrc_outputs,
309  .priv_class = &aevalsrc_class,
310 };
311 
312 #endif /* CONFIG_AEVALSRC_FILTER */
313 
314 #define OFFSET(x) offsetof(EvalContext, x)
315 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
316 
317 static const AVOption aeval_options[]= {
318  { "exprs", "set the '|'-separated list of channels expressions", OFFSET(exprs), AV_OPT_TYPE_STRING, {.str = NULL}, .flags = FLAGS },
319  { "channel_layout", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
320  { "c", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
321  { NULL }
322 };
323 
324 AVFILTER_DEFINE_CLASS(aeval);
325 
327 {
328  AVFilterFormats *formats = NULL;
330  AVFilterLink *inlink = ctx->inputs[0];
331  AVFilterLink *outlink = ctx->outputs[0];
332  EvalContext *eval = ctx->priv;
333  static const enum AVSampleFormat sample_fmts[] = {
335  };
336 
337  // inlink supports any channel layout
338  layouts = ff_all_channel_counts();
339  ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);
340 
341  if (eval->same_chlayout) {
342  layouts = ff_all_channel_counts();
343  if (!layouts)
344  return AVERROR(ENOMEM);
345  ff_set_common_channel_layouts(ctx, layouts);
346  } else {
347  // outlink supports only requested output channel layout
348  layouts = NULL;
349  ff_add_channel_layout(&layouts,
350  eval->out_channel_layout ? eval->out_channel_layout :
352  ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts);
353  }
354 
355  formats = ff_make_format_list(sample_fmts);
356  if (!formats)
357  return AVERROR(ENOMEM);
358  ff_set_common_formats(ctx, formats);
359 
360  formats = ff_all_samplerates();
361  if (!formats)
362  return AVERROR(ENOMEM);
363  ff_set_common_samplerates(ctx, formats);
364 
365  return 0;
366 }
367 
368 static int aeval_config_output(AVFilterLink *outlink)
369 {
370  AVFilterContext *ctx = outlink->src;
371  EvalContext *eval = ctx->priv;
372  AVFilterLink *inlink = ctx->inputs[0];
373  int ret;
374 
375  if (eval->same_chlayout) {
376  eval->chlayout = inlink->channel_layout;
377 
378  if ((ret = parse_channel_expressions(ctx, inlink->channels)) < 0)
379  return ret;
380  }
381 
382  eval->n = 0;
383  eval->nb_in_channels = eval->var_values[VAR_NB_IN_CHANNELS] = inlink->channels;
384  eval->var_values[VAR_NB_OUT_CHANNELS] = outlink->channels;
385  eval->var_values[VAR_S] = inlink->sample_rate;
386  eval->var_values[VAR_T] = NAN;
387 
389  inlink->channels, sizeof(*eval->channel_values));
390  if (!eval->channel_values)
391  return AVERROR(ENOMEM);
392 
393  return 0;
394 }
395 
396 #define TS2T(ts, tb) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts)*av_q2d(tb))
397 
398 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
399 {
400  EvalContext *eval = inlink->dst->priv;
401  AVFilterLink *outlink = inlink->dst->outputs[0];
402  int nb_samples = in->nb_samples;
403  AVFrame *out;
404  double t0;
405  int i, j;
406 
407  /* do volume scaling in-place if input buffer is writable */
408  out = ff_get_audio_buffer(outlink, nb_samples);
409  if (!out)
410  return AVERROR(ENOMEM);
411  av_frame_copy_props(out, in);
412 
413  t0 = TS2T(in->pts, inlink->time_base);
414 
415  /* evaluate expression for each single sample and for each channel */
416  for (i = 0; i < nb_samples; i++, eval->n++) {
417  eval->var_values[VAR_N] = eval->n;
418  eval->var_values[VAR_T] = t0 + i * (double)1/inlink->sample_rate;
419 
420  for (j = 0; j < inlink->channels; j++)
421  eval->channel_values[j] = *((double *) in->extended_data[j] + i);
422 
423  for (j = 0; j < outlink->channels; j++) {
424  eval->var_values[VAR_CH] = j;
425  *((double *) out->extended_data[j] + i) =
426  av_expr_eval(eval->expr[j], eval->var_values, eval);
427  }
428  }
429 
430  av_frame_free(&in);
431  return ff_filter_frame(outlink, out);
432 }
433 
434 #if CONFIG_AEVAL_FILTER
435 
436 static const AVFilterPad aeval_inputs[] = {
437  {
438  .name = "default",
439  .type = AVMEDIA_TYPE_AUDIO,
440  .filter_frame = filter_frame,
441  },
442  { NULL }
443 };
444 
445 static const AVFilterPad aeval_outputs[] = {
446  {
447  .name = "default",
448  .type = AVMEDIA_TYPE_AUDIO,
449  .config_props = aeval_config_output,
450  },
451  { NULL }
452 };
453 
454 AVFilter ff_af_aeval = {
455  .name = "aeval",
456  .description = NULL_IF_CONFIG_SMALL("Filter audio signal according to a specified expression."),
457  .query_formats = aeval_query_formats,
458  .init = init,
459  .uninit = uninit,
460  .priv_size = sizeof(EvalContext),
461  .inputs = aeval_inputs,
462  .outputs = aeval_outputs,
463  .priv_class = &aeval_class,
464 };
465 
466 #endif /* CONFIG_AEVAL_FILTER */