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af_resample.c
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1 /*
2  *
3  * This file is part of Libav.
4  *
5  * Libav is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2.1 of the License, or (at your option) any later version.
9  *
10  * Libav is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with Libav; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18  */
19 
20 /**
21  * @file
22  * sample format and channel layout conversion audio filter
23  */
24 
25 #include "libavutil/avassert.h"
26 #include "libavutil/avstring.h"
27 #include "libavutil/common.h"
28 #include "libavutil/dict.h"
29 #include "libavutil/mathematics.h"
30 #include "libavutil/opt.h"
31 
33 
34 #include "audio.h"
35 #include "avfilter.h"
36 #include "formats.h"
37 #include "internal.h"
38 
39 typedef struct ResampleContext {
40  const AVClass *class;
43 
44  int64_t next_pts;
45 
46  /* set by filter_frame() to signal an output frame to request_frame() */
49 
50 static av_cold int init(AVFilterContext *ctx, AVDictionary **opts)
51 {
52  ResampleContext *s = ctx->priv;
53  const AVClass *avr_class = avresample_get_class();
54  AVDictionaryEntry *e = NULL;
55 
56  while ((e = av_dict_get(*opts, "", e, AV_DICT_IGNORE_SUFFIX))) {
57  if (av_opt_find(&avr_class, e->key, NULL, 0,
59  av_dict_set(&s->options, e->key, e->value, 0);
60  }
61 
62  e = NULL;
63  while ((e = av_dict_get(s->options, "", e, AV_DICT_IGNORE_SUFFIX)))
64  av_dict_set(opts, e->key, NULL, 0);
65 
66  /* do not allow the user to override basic format options */
67  av_dict_set(&s->options, "in_channel_layout", NULL, 0);
68  av_dict_set(&s->options, "out_channel_layout", NULL, 0);
69  av_dict_set(&s->options, "in_sample_fmt", NULL, 0);
70  av_dict_set(&s->options, "out_sample_fmt", NULL, 0);
71  av_dict_set(&s->options, "in_sample_rate", NULL, 0);
72  av_dict_set(&s->options, "out_sample_rate", NULL, 0);
73 
74  return 0;
75 }
76 
77 static av_cold void uninit(AVFilterContext *ctx)
78 {
79  ResampleContext *s = ctx->priv;
80 
81  if (s->avr) {
83  avresample_free(&s->avr);
84  }
85  av_dict_free(&s->options);
86 }
87 
89 {
90  AVFilterLink *inlink = ctx->inputs[0];
91  AVFilterLink *outlink = ctx->outputs[0];
92 
95  AVFilterFormats *in_samplerates = ff_all_samplerates();
96  AVFilterFormats *out_samplerates = ff_all_samplerates();
99 
100  ff_formats_ref(in_formats, &inlink->out_formats);
101  ff_formats_ref(out_formats, &outlink->in_formats);
102 
103  ff_formats_ref(in_samplerates, &inlink->out_samplerates);
104  ff_formats_ref(out_samplerates, &outlink->in_samplerates);
105 
106  ff_channel_layouts_ref(in_layouts, &inlink->out_channel_layouts);
107  ff_channel_layouts_ref(out_layouts, &outlink->in_channel_layouts);
108 
109  return 0;
110 }
111 
112 static int config_output(AVFilterLink *outlink)
113 {
114  AVFilterContext *ctx = outlink->src;
115  AVFilterLink *inlink = ctx->inputs[0];
116  ResampleContext *s = ctx->priv;
117  char buf1[64], buf2[64];
118  int ret;
119 
120  if (s->avr) {
121  avresample_close(s->avr);
122  avresample_free(&s->avr);
123  }
124 
125  if (inlink->channel_layout == outlink->channel_layout &&
126  inlink->sample_rate == outlink->sample_rate &&
127  (inlink->format == outlink->format ||
130  av_get_planar_sample_fmt(inlink->format) ==
131  av_get_planar_sample_fmt(outlink->format))))
132  return 0;
133 
134  if (!(s->avr = avresample_alloc_context()))
135  return AVERROR(ENOMEM);
136 
137  if (s->options) {
138  AVDictionaryEntry *e = NULL;
139  while ((e = av_dict_get(s->options, "", e, AV_DICT_IGNORE_SUFFIX)))
140  av_log(ctx, AV_LOG_VERBOSE, "lavr option: %s=%s\n", e->key, e->value);
141 
142  av_opt_set_dict(s->avr, &s->options);
143  }
144 
145  av_opt_set_int(s->avr, "in_channel_layout", inlink ->channel_layout, 0);
146  av_opt_set_int(s->avr, "out_channel_layout", outlink->channel_layout, 0);
147  av_opt_set_int(s->avr, "in_sample_fmt", inlink ->format, 0);
148  av_opt_set_int(s->avr, "out_sample_fmt", outlink->format, 0);
149  av_opt_set_int(s->avr, "in_sample_rate", inlink ->sample_rate, 0);
150  av_opt_set_int(s->avr, "out_sample_rate", outlink->sample_rate, 0);
151 
152  if ((ret = avresample_open(s->avr)) < 0)
153  return ret;
154 
155  outlink->time_base = (AVRational){ 1, outlink->sample_rate };
157 
158  av_get_channel_layout_string(buf1, sizeof(buf1),
159  -1, inlink ->channel_layout);
160  av_get_channel_layout_string(buf2, sizeof(buf2),
161  -1, outlink->channel_layout);
162  av_log(ctx, AV_LOG_VERBOSE,
163  "fmt:%s srate:%d cl:%s -> fmt:%s srate:%d cl:%s\n",
164  av_get_sample_fmt_name(inlink ->format), inlink ->sample_rate, buf1,
165  av_get_sample_fmt_name(outlink->format), outlink->sample_rate, buf2);
166 
167  return 0;
168 }
169 
170 static int request_frame(AVFilterLink *outlink)
171 {
172  AVFilterContext *ctx = outlink->src;
173  ResampleContext *s = ctx->priv;
174  int ret = 0;
175 
176  s->got_output = 0;
177  while (ret >= 0 && !s->got_output)
178  ret = ff_request_frame(ctx->inputs[0]);
179 
180  /* flush the lavr delay buffer */
181  if (ret == AVERROR_EOF && s->avr) {
182  AVFrame *frame;
183  int nb_samples = av_rescale_rnd(avresample_get_delay(s->avr),
184  outlink->sample_rate,
185  ctx->inputs[0]->sample_rate,
186  AV_ROUND_UP);
187 
188  if (!nb_samples)
189  return ret;
190 
191  frame = ff_get_audio_buffer(outlink, nb_samples);
192  if (!frame)
193  return AVERROR(ENOMEM);
194 
195  ret = avresample_convert(s->avr, frame->extended_data,
196  frame->linesize[0], nb_samples,
197  NULL, 0, 0);
198  if (ret <= 0) {
199  av_frame_free(&frame);
200  return (ret == 0) ? AVERROR_EOF : ret;
201  }
202 
203  frame->pts = s->next_pts;
204  return ff_filter_frame(outlink, frame);
205  }
206  return ret;
207 }
208 
209 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
210 {
211  AVFilterContext *ctx = inlink->dst;
212  ResampleContext *s = ctx->priv;
213  AVFilterLink *outlink = ctx->outputs[0];
214  int ret;
215 
216  if (s->avr) {
217  AVFrame *out;
218  int delay, nb_samples;
219 
220  /* maximum possible samples lavr can output */
221  delay = avresample_get_delay(s->avr);
222  nb_samples = av_rescale_rnd(in->nb_samples + delay,
223  outlink->sample_rate, inlink->sample_rate,
224  AV_ROUND_UP);
225 
226  out = ff_get_audio_buffer(outlink, nb_samples);
227  if (!out) {
228  ret = AVERROR(ENOMEM);
229  goto fail;
230  }
231 
232  ret = avresample_convert(s->avr, out->extended_data, out->linesize[0],
233  nb_samples, in->extended_data, in->linesize[0],
234  in->nb_samples);
235  if (ret <= 0) {
236  av_frame_free(&out);
237  if (ret < 0)
238  goto fail;
239  }
240 
242 
243  if (s->next_pts == AV_NOPTS_VALUE) {
244  if (in->pts == AV_NOPTS_VALUE) {
245  av_log(ctx, AV_LOG_WARNING, "First timestamp is missing, "
246  "assuming 0.\n");
247  s->next_pts = 0;
248  } else
249  s->next_pts = av_rescale_q(in->pts, inlink->time_base,
250  outlink->time_base);
251  }
252 
253  if (ret > 0) {
254  out->nb_samples = ret;
255  if (in->pts != AV_NOPTS_VALUE) {
256  out->pts = av_rescale_q(in->pts, inlink->time_base,
257  outlink->time_base) -
258  av_rescale(delay, outlink->sample_rate,
259  inlink->sample_rate);
260  } else
261  out->pts = s->next_pts;
262 
263  s->next_pts = out->pts + out->nb_samples;
264 
265  ret = ff_filter_frame(outlink, out);
266  s->got_output = 1;
267  }
268 
269 fail:
270  av_frame_free(&in);
271  } else {
272  in->format = outlink->format;
273  ret = ff_filter_frame(outlink, in);
274  s->got_output = 1;
275  }
276 
277  return ret;
278 }
279 
280 static const AVClass *resample_child_class_next(const AVClass *prev)
281 {
282  return prev ? NULL : avresample_get_class();
283 }
284 
285 static void *resample_child_next(void *obj, void *prev)
286 {
287  ResampleContext *s = obj;
288  return prev ? NULL : s->avr;
289 }
290 
291 static const AVClass resample_class = {
292  .class_name = "resample",
293  .item_name = av_default_item_name,
294  .version = LIBAVUTIL_VERSION_INT,
295  .child_class_next = resample_child_class_next,
297 };
298 
300  {
301  .name = "default",
302  .type = AVMEDIA_TYPE_AUDIO,
303  .filter_frame = filter_frame,
304  },
305  { NULL }
306 };
307 
309  {
310  .name = "default",
311  .type = AVMEDIA_TYPE_AUDIO,
312  .config_props = config_output,
313  .request_frame = request_frame
314  },
315  { NULL }
316 };
317 
319  .name = "resample",
320  .description = NULL_IF_CONFIG_SMALL("Audio resampling and conversion."),
321  .priv_size = sizeof(ResampleContext),
322  .priv_class = &resample_class,
323 
324  .init_dict = init,
325  .uninit = uninit,
327 
328  .inputs = avfilter_af_resample_inputs,
329  .outputs = avfilter_af_resample_outputs,
330 };