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af_afade.c
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1 /*
2  * Copyright (c) 2013 Paul B Mahol
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  * fade audio filter
24  */
25 
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  int type;
34  int curve;
35  int nb_samples;
36  int64_t start_sample;
37  double duration;
38  double start_time;
39 
40  void (*fade_samples)(uint8_t **dst, uint8_t * const *src,
41  int nb_samples, int channels, int direction,
42  int64_t start, int range, int curve);
43 } AudioFadeContext;
44 
45 enum CurveType { TRI, QSIN, ESIN, HSIN, LOG, PAR, QUA, CUB, SQU, CBR };
46 
47 #define OFFSET(x) offsetof(AudioFadeContext, x)
48 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
49 
50 static const AVOption afade_options[] = {
51  { "type", "set the fade direction", OFFSET(type), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 1, FLAGS, "type" },
52  { "t", "set the fade direction", OFFSET(type), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 1, FLAGS, "type" },
53  { "in", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 0 }, 0, 0, FLAGS, "type" },
54  { "out", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1 }, 0, 0, FLAGS, "type" },
55  { "start_sample", "set expression of sample to start fading", OFFSET(start_sample), AV_OPT_TYPE_INT64, {.i64 = 0 }, 0, INT64_MAX, FLAGS },
56  { "ss", "set expression of sample to start fading", OFFSET(start_sample), AV_OPT_TYPE_INT64, {.i64 = 0 }, 0, INT64_MAX, FLAGS },
57  { "nb_samples", "set expression for fade duration in samples", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 44100}, 1, INT32_MAX, FLAGS },
58  { "ns", "set expression for fade duration in samples", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 44100}, 1, INT32_MAX, FLAGS },
59  { "start_time", "set expression of second to start fading", OFFSET(start_time), AV_OPT_TYPE_DOUBLE, {.dbl = 0. }, 0, 7*24*60*60,FLAGS },
60  { "st", "set expression of second to start fading", OFFSET(start_time), AV_OPT_TYPE_DOUBLE, {.dbl = 0. }, 0, 7*24*60*60,FLAGS },
61  { "duration", "set expression for fade duration in seconds", OFFSET(duration), AV_OPT_TYPE_DOUBLE, {.dbl = 0. }, 0, 24*60*60, FLAGS },
62  { "d", "set expression for fade duration in seconds", OFFSET(duration), AV_OPT_TYPE_DOUBLE, {.dbl = 0. }, 0, 24*60*60, FLAGS },
63  { "curve", "set expression for fade curve", OFFSET(curve), AV_OPT_TYPE_INT, {.i64 = TRI }, TRI, CBR, FLAGS, "curve" },
64  { "c", "set expression for fade curve", OFFSET(curve), AV_OPT_TYPE_INT, {.i64 = TRI }, TRI, CBR, FLAGS, "curve" },
65  { "tri", "linear slope", 0, AV_OPT_TYPE_CONST, {.i64 = TRI }, 0, 0, FLAGS, "curve" },
66  { "qsin", "quarter of sine wave", 0, AV_OPT_TYPE_CONST, {.i64 = QSIN }, 0, 0, FLAGS, "curve" },
67  { "esin", "exponential sine wave", 0, AV_OPT_TYPE_CONST, {.i64 = ESIN }, 0, 0, FLAGS, "curve" },
68  { "hsin", "half of sine wave", 0, AV_OPT_TYPE_CONST, {.i64 = HSIN }, 0, 0, FLAGS, "curve" },
69  { "log", "logarithmic", 0, AV_OPT_TYPE_CONST, {.i64 = LOG }, 0, 0, FLAGS, "curve" },
70  { "par", "inverted parabola", 0, AV_OPT_TYPE_CONST, {.i64 = PAR }, 0, 0, FLAGS, "curve" },
71  { "qua", "quadratic", 0, AV_OPT_TYPE_CONST, {.i64 = QUA }, 0, 0, FLAGS, "curve" },
72  { "cub", "cubic", 0, AV_OPT_TYPE_CONST, {.i64 = CUB }, 0, 0, FLAGS, "curve" },
73  { "squ", "square root", 0, AV_OPT_TYPE_CONST, {.i64 = SQU }, 0, 0, FLAGS, "curve" },
74  { "cbr", "cubic root", 0, AV_OPT_TYPE_CONST, {.i64 = CBR }, 0, 0, FLAGS, "curve" },
75  {NULL},
76 };
77 
78 AVFILTER_DEFINE_CLASS(afade);
79 
80 static av_cold int init(AVFilterContext *ctx, const char *args)
81 {
82  AudioFadeContext *afade = ctx->priv;
83  int ret;
84 
85  afade->class = &afade_class;
86  av_opt_set_defaults(afade);
87 
88  if ((ret = av_set_options_string(afade, args, "=", ":")) < 0)
89  return ret;
90 
91  if (INT64_MAX - afade->nb_samples < afade->start_sample)
92  return AVERROR(EINVAL);
93 
94  return 0;
95 }
96 
97 static int query_formats(AVFilterContext *ctx)
98 {
99  AVFilterFormats *formats;
100  AVFilterChannelLayouts *layouts;
101  static const enum AVSampleFormat sample_fmts[] = {
102  AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S16P,
103  AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S32P,
104  AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_FLTP,
105  AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_DBLP,
106  AV_SAMPLE_FMT_NONE
107  };
108 
109  layouts = ff_all_channel_layouts();
110  if (!layouts)
111  return AVERROR(ENOMEM);
112  ff_set_common_channel_layouts(ctx, layouts);
113 
114  formats = ff_make_format_list(sample_fmts);
115  if (!formats)
116  return AVERROR(ENOMEM);
117  ff_set_common_formats(ctx, formats);
118 
119  formats = ff_all_samplerates();
120  if (!formats)
121  return AVERROR(ENOMEM);
122  ff_set_common_samplerates(ctx, formats);
123 
124  return 0;
125 }
126 
127 static double fade_gain(int curve, int64_t index, int range)
128 {
129  double gain;
130 
131  gain = FFMAX(0.0, FFMIN(1.0, 1.0 * index / range));
132 
133  switch (curve) {
134  case QSIN:
135  gain = sin(gain * M_PI / 2.0);
136  break;
137  case ESIN:
138  gain = 1.0 - cos(M_PI / 4.0 * (pow(2.0*gain - 1, 3) + 1));
139  break;
140  case HSIN:
141  gain = (1.0 - cos(gain * M_PI)) / 2.0;
142  break;
143  case LOG:
144  gain = pow(0.1, (1 - gain) * 5.0);
145  break;
146  case PAR:
147  gain = (1 - (1 - gain) * (1 - gain));
148  break;
149  case QUA:
150  gain *= gain;
151  break;
152  case CUB:
153  gain = gain * gain * gain;
154  break;
155  case SQU:
156  gain = sqrt(gain);
157  break;
158  case CBR:
159  gain = cbrt(gain);
160  break;
161  }
162 
163  return gain;
164 }
165 
166 #define FADE_PLANAR(name, type) \
167 static void fade_samples_## name ##p(uint8_t **dst, uint8_t * const *src, \
168  int nb_samples, int channels, int dir, \
169  int64_t start, int range, int curve) \
170 { \
171  int i, c; \
172  \
173  for (i = 0; i < nb_samples; i++) { \
174  double gain = fade_gain(curve, start + i * dir, range); \
175  for (c = 0; c < channels; c++) { \
176  type *d = (type *)dst[c]; \
177  const type *s = (type *)src[c]; \
178  \
179  d[i] = s[i] * gain; \
180  } \
181  } \
182 }
183 
184 #define FADE(name, type) \
185 static void fade_samples_## name (uint8_t **dst, uint8_t * const *src, \
186  int nb_samples, int channels, int dir, \
187  int64_t start, int range, int curve) \
188 { \
189  type *d = (type *)dst[0]; \
190  const type *s = (type *)src[0]; \
191  int i, c, k = 0; \
192  \
193  for (i = 0; i < nb_samples; i++) { \
194  double gain = fade_gain(curve, start + i * dir, range); \
195  for (c = 0; c < channels; c++, k++) \
196  d[k] = s[k] * gain; \
197  } \
198 }
199 
200 FADE_PLANAR(dbl, double)
201 FADE_PLANAR(flt, float)
202 FADE_PLANAR(s16, int16_t)
203 FADE_PLANAR(s32, int32_t)
204 
205 FADE(dbl, double)
206 FADE(flt, float)
207 FADE(s16, int16_t)
208 FADE(s32, int32_t)
209 
210 static int config_output(AVFilterLink *outlink)
211 {
212  AVFilterContext *ctx = outlink->src;
213  AudioFadeContext *afade = ctx->priv;
214  AVFilterLink *inlink = ctx->inputs[0];
215 
216  switch (inlink->format) {
217  case AV_SAMPLE_FMT_DBL: afade->fade_samples = fade_samples_dbl; break;
218  case AV_SAMPLE_FMT_DBLP: afade->fade_samples = fade_samples_dblp; break;
219  case AV_SAMPLE_FMT_FLT: afade->fade_samples = fade_samples_flt; break;
220  case AV_SAMPLE_FMT_FLTP: afade->fade_samples = fade_samples_fltp; break;
221  case AV_SAMPLE_FMT_S16: afade->fade_samples = fade_samples_s16; break;
222  case AV_SAMPLE_FMT_S16P: afade->fade_samples = fade_samples_s16p; break;
223  case AV_SAMPLE_FMT_S32: afade->fade_samples = fade_samples_s32; break;
224  case AV_SAMPLE_FMT_S32P: afade->fade_samples = fade_samples_s32p; break;
225  }
226 
227  if (afade->duration)
228  afade->nb_samples = afade->duration * inlink->sample_rate;
229  if (afade->start_time)
230  afade->start_sample = afade->start_time * inlink->sample_rate;
231 
232  return 0;
233 }
234 
235 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *buf)
236 {
237  AudioFadeContext *afade = inlink->dst->priv;
238  AVFilterLink *outlink = inlink->dst->outputs[0];
239  int nb_samples = buf->audio->nb_samples;
240  AVFilterBufferRef *out_buf;
241  int64_t cur_sample = av_rescale_q(buf->pts, (AVRational){1, outlink->sample_rate}, outlink->time_base);
242 
243  if ((!afade->type && (afade->start_sample + afade->nb_samples < cur_sample)) ||
244  ( afade->type && (cur_sample + afade->nb_samples < afade->start_sample)))
245  return ff_filter_frame(outlink, buf);
246 
247  if (buf->perms & AV_PERM_WRITE) {
248  out_buf = buf;
249  } else {
250  out_buf = ff_get_audio_buffer(inlink, AV_PERM_WRITE, nb_samples);
251  if (!out_buf)
252  return AVERROR(ENOMEM);
253  out_buf->pts = buf->pts;
254  }
255 
256  if ((!afade->type && (cur_sample + nb_samples < afade->start_sample)) ||
257  ( afade->type && (afade->start_sample + afade->nb_samples < cur_sample))) {
258  av_samples_set_silence(out_buf->extended_data, 0, nb_samples,
259  out_buf->audio->channels, out_buf->format);
260  } else {
261  int64_t start;
262 
263  if (!afade->type)
264  start = cur_sample - afade->start_sample;
265  else
266  start = afade->start_sample + afade->nb_samples - cur_sample;
267 
268  afade->fade_samples(out_buf->extended_data, buf->extended_data,
269  nb_samples, buf->audio->channels,
270  afade->type ? -1 : 1, start,
271  afade->nb_samples, afade->curve);
272  }
273 
274  if (buf != out_buf)
275  avfilter_unref_buffer(buf);
276 
277  return ff_filter_frame(outlink, out_buf);
278 }
279 
280 static const AVFilterPad avfilter_af_afade_inputs[] = {
281  {
282  .name = "default",
283  .type = AVMEDIA_TYPE_AUDIO,
284  .filter_frame = filter_frame,
285  },
286  { NULL }
287 };
288 
289 static const AVFilterPad avfilter_af_afade_outputs[] = {
290  {
291  .name = "default",
292  .type = AVMEDIA_TYPE_AUDIO,
293  .config_props = config_output,
294  },
295  { NULL }
296 };
297 
298 AVFilter avfilter_af_afade = {
299  .name = "afade",
300  .description = NULL_IF_CONFIG_SMALL("Fade in/out input audio."),
301  .query_formats = query_formats,
302  .priv_size = sizeof(AudioFadeContext),
303  .init = init,
304  .inputs = avfilter_af_afade_inputs,
305  .outputs = avfilter_af_afade_outputs,
306  .priv_class = &afade_class,
307 };
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