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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 {
42 
43  int64_t next_pts;
44 
45  /* set by filter_frame() to signal an output frame to request_frame() */
48 
49 static av_cold int init(AVFilterContext *ctx, const char *args)
50 {
51  ResampleContext *s = ctx->priv;
52 
53  if (args) {
54  int ret = av_dict_parse_string(&s->options, args, "=", ":", 0);
55  if (ret < 0) {
56  av_log(ctx, AV_LOG_ERROR, "error setting option string: %s\n", args);
57  return ret;
58  }
59 
60  /* do not allow the user to override basic format options */
61  av_dict_set(&s->options, "in_channel_layout", NULL, 0);
62  av_dict_set(&s->options, "out_channel_layout", NULL, 0);
63  av_dict_set(&s->options, "in_sample_fmt", NULL, 0);
64  av_dict_set(&s->options, "out_sample_fmt", NULL, 0);
65  av_dict_set(&s->options, "in_sample_rate", NULL, 0);
66  av_dict_set(&s->options, "out_sample_rate", NULL, 0);
67  }
68 
69  return 0;
70 }
71 
72 static av_cold void uninit(AVFilterContext *ctx)
73 {
74  ResampleContext *s = ctx->priv;
75 
76  if (s->avr) {
78  avresample_free(&s->avr);
79  }
80  av_dict_free(&s->options);
81 }
82 
84 {
85  AVFilterLink *inlink = ctx->inputs[0];
86  AVFilterLink *outlink = ctx->outputs[0];
87 
90  AVFilterFormats *in_samplerates = ff_all_samplerates();
91  AVFilterFormats *out_samplerates = ff_all_samplerates();
94 
95  ff_formats_ref(in_formats, &inlink->out_formats);
96  ff_formats_ref(out_formats, &outlink->in_formats);
97 
98  ff_formats_ref(in_samplerates, &inlink->out_samplerates);
99  ff_formats_ref(out_samplerates, &outlink->in_samplerates);
100 
101  ff_channel_layouts_ref(in_layouts, &inlink->out_channel_layouts);
102  ff_channel_layouts_ref(out_layouts, &outlink->in_channel_layouts);
103 
104  return 0;
105 }
106 
107 static int config_output(AVFilterLink *outlink)
108 {
109  AVFilterContext *ctx = outlink->src;
110  AVFilterLink *inlink = ctx->inputs[0];
111  ResampleContext *s = ctx->priv;
112  char buf1[64], buf2[64];
113  int ret;
114 
115  if (s->avr) {
116  avresample_close(s->avr);
117  avresample_free(&s->avr);
118  }
119 
120  if (inlink->channel_layout == outlink->channel_layout &&
121  inlink->sample_rate == outlink->sample_rate &&
122  (inlink->format == outlink->format ||
125  av_get_planar_sample_fmt(inlink->format) ==
126  av_get_planar_sample_fmt(outlink->format))))
127  return 0;
128 
129  if (!(s->avr = avresample_alloc_context()))
130  return AVERROR(ENOMEM);
131 
132  if (s->options) {
133  AVDictionaryEntry *e = NULL;
134  while ((e = av_dict_get(s->options, "", e, AV_DICT_IGNORE_SUFFIX)))
135  av_log(ctx, AV_LOG_VERBOSE, "lavr option: %s=%s\n", e->key, e->value);
136 
137  av_opt_set_dict(s->avr, &s->options);
138  }
139 
140  av_opt_set_int(s->avr, "in_channel_layout", inlink ->channel_layout, 0);
141  av_opt_set_int(s->avr, "out_channel_layout", outlink->channel_layout, 0);
142  av_opt_set_int(s->avr, "in_sample_fmt", inlink ->format, 0);
143  av_opt_set_int(s->avr, "out_sample_fmt", outlink->format, 0);
144  av_opt_set_int(s->avr, "in_sample_rate", inlink ->sample_rate, 0);
145  av_opt_set_int(s->avr, "out_sample_rate", outlink->sample_rate, 0);
146 
147  if ((ret = avresample_open(s->avr)) < 0)
148  return ret;
149 
150  outlink->time_base = (AVRational){ 1, outlink->sample_rate };
152 
153  av_get_channel_layout_string(buf1, sizeof(buf1),
154  -1, inlink ->channel_layout);
155  av_get_channel_layout_string(buf2, sizeof(buf2),
156  -1, outlink->channel_layout);
157  av_log(ctx, AV_LOG_VERBOSE,
158  "fmt:%s srate:%d cl:%s -> fmt:%s srate:%d cl:%s\n",
159  av_get_sample_fmt_name(inlink ->format), inlink ->sample_rate, buf1,
160  av_get_sample_fmt_name(outlink->format), outlink->sample_rate, buf2);
161 
162  return 0;
163 }
164 
165 static int request_frame(AVFilterLink *outlink)
166 {
167  AVFilterContext *ctx = outlink->src;
168  ResampleContext *s = ctx->priv;
169  int ret = 0;
170 
171  s->got_output = 0;
172  while (ret >= 0 && !s->got_output)
173  ret = ff_request_frame(ctx->inputs[0]);
174 
175  /* flush the lavr delay buffer */
176  if (ret == AVERROR_EOF && s->avr) {
177  AVFilterBufferRef *buf;
179  outlink->sample_rate,
180  ctx->inputs[0]->sample_rate,
181  AV_ROUND_UP);
182 
183  if (!nb_samples)
184  return ret;
185 
186  buf = ff_get_audio_buffer(outlink, AV_PERM_WRITE, nb_samples);
187  if (!buf)
188  return AVERROR(ENOMEM);
189 
190  ret = avresample_convert(s->avr, buf->extended_data,
191  buf->linesize[0], nb_samples,
192  NULL, 0, 0);
193  if (ret <= 0) {
195  return (ret == 0) ? AVERROR_EOF : ret;
196  }
197 
198  buf->pts = s->next_pts;
199  return ff_filter_frame(outlink, buf);
200  }
201  return ret;
202 }
203 
204 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *buf)
205 {
206  AVFilterContext *ctx = inlink->dst;
207  ResampleContext *s = ctx->priv;
208  AVFilterLink *outlink = ctx->outputs[0];
209  int ret;
210 
211  if (s->avr) {
212  AVFilterBufferRef *buf_out;
213  int delay, nb_samples;
214 
215  /* maximum possible samples lavr can output */
216  delay = avresample_get_delay(s->avr);
217  nb_samples = av_rescale_rnd(buf->audio->nb_samples + delay,
218  outlink->sample_rate, inlink->sample_rate,
219  AV_ROUND_UP);
220 
221  buf_out = ff_get_audio_buffer(outlink, AV_PERM_WRITE, nb_samples);
222  if (!buf_out) {
223  ret = AVERROR(ENOMEM);
224  goto fail;
225  }
226 
227  ret = avresample_convert(s->avr, buf_out->extended_data,
228  buf_out->linesize[0], nb_samples,
229  buf->extended_data, buf->linesize[0],
230  buf->audio->nb_samples);
231  if (ret <= 0) {
232  avfilter_unref_buffer(buf_out);
233  if (ret < 0)
234  goto fail;
235  }
236 
238 
239  if (s->next_pts == AV_NOPTS_VALUE) {
240  if (buf->pts == AV_NOPTS_VALUE) {
241  av_log(ctx, AV_LOG_WARNING, "First timestamp is missing, "
242  "assuming 0.\n");
243  s->next_pts = 0;
244  } else
245  s->next_pts = av_rescale_q(buf->pts, inlink->time_base,
246  outlink->time_base);
247  }
248 
249  if (ret > 0) {
250  buf_out->audio->nb_samples = ret;
251  if (buf->pts != AV_NOPTS_VALUE) {
252  buf_out->pts = av_rescale_q(buf->pts, inlink->time_base,
253  outlink->time_base) -
254  av_rescale(delay, outlink->sample_rate,
255  inlink->sample_rate);
256  } else
257  buf_out->pts = s->next_pts;
258 
259  s->next_pts = buf_out->pts + buf_out->audio->nb_samples;
260 
261  ret = ff_filter_frame(outlink, buf_out);
262  s->got_output = 1;
263  }
264 
265 fail:
267  } else {
268  buf->format = outlink->format;
269  ret = ff_filter_frame(outlink, buf);
270  s->got_output = 1;
271  }
272 
273  return ret;
274 }
275 
277  {
278  .name = "default",
279  .type = AVMEDIA_TYPE_AUDIO,
280  .filter_frame = filter_frame,
281  .min_perms = AV_PERM_READ
282  },
283  { NULL }
284 };
285 
287  {
288  .name = "default",
289  .type = AVMEDIA_TYPE_AUDIO,
290  .config_props = config_output,
291  .request_frame = request_frame
292  },
293  { NULL }
294 };
295 
297  .name = "resample",
298  .description = NULL_IF_CONFIG_SMALL("Audio resampling and conversion."),
299  .priv_size = sizeof(ResampleContext),
300 
301  .init = init,
302  .uninit = uninit,
304 
305  .inputs = avfilter_af_resample_inputs,
306  .outputs = avfilter_af_resample_outputs,
307 };