FFmpeg
mux.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2003 Fabrice Bellard
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a copy
5  * of this software and associated documentation files (the "Software"), to deal
6  * in the Software without restriction, including without limitation the rights
7  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8  * copies of the Software, and to permit persons to whom the Software is
9  * furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20  * THE SOFTWARE.
21  */
22 
23 /**
24  * @file libavformat muxing API usage example
25  * @example mux.c
26  *
27  * Generate a synthetic audio and video signal and mux them to a media file in
28  * any supported libavformat format. The default codecs are used.
29  */
30 
31 #include <stdlib.h>
32 #include <stdio.h>
33 #include <string.h>
34 #include <math.h>
35 
36 #include <libavutil/avassert.h>
38 #include <libavutil/opt.h>
39 #include <libavutil/mathematics.h>
40 #include <libavutil/timestamp.h>
41 #include <libavcodec/avcodec.h>
42 #include <libavformat/avformat.h>
43 #include <libswscale/swscale.h>
45 
46 #define STREAM_DURATION 10.0
47 #define STREAM_FRAME_RATE 25 /* 25 images/s */
48 #define STREAM_PIX_FMT AV_PIX_FMT_YUV420P /* default pix_fmt */
49 
50 #define SCALE_FLAGS SWS_BICUBIC
51 
52 // a wrapper around a single output AVStream
53 typedef struct OutputStream {
56 
57  /* pts of the next frame that will be generated */
58  int64_t next_pts;
60 
63 
65 
66  float t, tincr, tincr2;
67 
68  struct SwsContext *sws_ctx;
70 } OutputStream;
71 
72 static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt)
73 {
75 
76  printf("pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
77  av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
78  av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
80  pkt->stream_index);
81 }
82 
85 {
86  int ret;
87 
88  // send the frame to the encoder
89  ret = avcodec_send_frame(c, frame);
90  if (ret < 0) {
91  fprintf(stderr, "Error sending a frame to the encoder: %s\n",
92  av_err2str(ret));
93  exit(1);
94  }
95 
96  while (ret >= 0) {
97  ret = avcodec_receive_packet(c, pkt);
98  if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
99  break;
100  else if (ret < 0) {
101  fprintf(stderr, "Error encoding a frame: %s\n", av_err2str(ret));
102  exit(1);
103  }
104 
105  /* rescale output packet timestamp values from codec to stream timebase */
107  pkt->stream_index = st->index;
108 
109  /* Write the compressed frame to the media file. */
112  /* pkt is now blank (av_interleaved_write_frame() takes ownership of
113  * its contents and resets pkt), so that no unreferencing is necessary.
114  * This would be different if one used av_write_frame(). */
115  if (ret < 0) {
116  fprintf(stderr, "Error while writing output packet: %s\n", av_err2str(ret));
117  exit(1);
118  }
119  }
120 
121  return ret == AVERROR_EOF ? 1 : 0;
122 }
123 
124 /* Add an output stream. */
126  const AVCodec **codec,
127  enum AVCodecID codec_id)
128 {
129  AVCodecContext *c;
130  int i;
131 
132  /* find the encoder */
133  *codec = avcodec_find_encoder(codec_id);
134  if (!(*codec)) {
135  fprintf(stderr, "Could not find encoder for '%s'\n",
136  avcodec_get_name(codec_id));
137  exit(1);
138  }
139 
140  ost->tmp_pkt = av_packet_alloc();
141  if (!ost->tmp_pkt) {
142  fprintf(stderr, "Could not allocate AVPacket\n");
143  exit(1);
144  }
145 
146  ost->st = avformat_new_stream(oc, NULL);
147  if (!ost->st) {
148  fprintf(stderr, "Could not allocate stream\n");
149  exit(1);
150  }
151  ost->st->id = oc->nb_streams-1;
152  c = avcodec_alloc_context3(*codec);
153  if (!c) {
154  fprintf(stderr, "Could not alloc an encoding context\n");
155  exit(1);
156  }
157  ost->enc = c;
158 
159  switch ((*codec)->type) {
160  case AVMEDIA_TYPE_AUDIO:
161  c->sample_fmt = (*codec)->sample_fmts ?
162  (*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;
163  c->bit_rate = 64000;
164  c->sample_rate = 44100;
165  if ((*codec)->supported_samplerates) {
166  c->sample_rate = (*codec)->supported_samplerates[0];
167  for (i = 0; (*codec)->supported_samplerates[i]; i++) {
168  if ((*codec)->supported_samplerates[i] == 44100)
169  c->sample_rate = 44100;
170  }
171  }
173  ost->st->time_base = (AVRational){ 1, c->sample_rate };
174  break;
175 
176  case AVMEDIA_TYPE_VIDEO:
177  c->codec_id = codec_id;
178 
179  c->bit_rate = 400000;
180  /* Resolution must be a multiple of two. */
181  c->width = 352;
182  c->height = 288;
183  /* timebase: This is the fundamental unit of time (in seconds) in terms
184  * of which frame timestamps are represented. For fixed-fps content,
185  * timebase should be 1/framerate and timestamp increments should be
186  * identical to 1. */
187  ost->st->time_base = (AVRational){ 1, STREAM_FRAME_RATE };
188  c->time_base = ost->st->time_base;
189 
190  c->gop_size = 12; /* emit one intra frame every twelve frames at most */
191  c->pix_fmt = STREAM_PIX_FMT;
192  if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
193  /* just for testing, we also add B-frames */
194  c->max_b_frames = 2;
195  }
196  if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
197  /* Needed to avoid using macroblocks in which some coeffs overflow.
198  * This does not happen with normal video, it just happens here as
199  * the motion of the chroma plane does not match the luma plane. */
200  c->mb_decision = 2;
201  }
202  break;
203 
204  default:
205  break;
206  }
207 
208  /* Some formats want stream headers to be separate. */
209  if (oc->oformat->flags & AVFMT_GLOBALHEADER)
211 }
212 
213 /**************************************************************/
214 /* audio output */
215 
216 static AVFrame *alloc_audio_frame(enum AVSampleFormat sample_fmt,
217  const AVChannelLayout *channel_layout,
218  int sample_rate, int nb_samples)
219 {
221  if (!frame) {
222  fprintf(stderr, "Error allocating an audio frame\n");
223  exit(1);
224  }
225 
226  frame->format = sample_fmt;
227  av_channel_layout_copy(&frame->ch_layout, channel_layout);
228  frame->sample_rate = sample_rate;
229  frame->nb_samples = nb_samples;
230 
231  if (nb_samples) {
232  if (av_frame_get_buffer(frame, 0) < 0) {
233  fprintf(stderr, "Error allocating an audio buffer\n");
234  exit(1);
235  }
236  }
237 
238  return frame;
239 }
240 
241 static void open_audio(AVFormatContext *oc, const AVCodec *codec,
242  OutputStream *ost, AVDictionary *opt_arg)
243 {
244  AVCodecContext *c;
245  int nb_samples;
246  int ret;
247  AVDictionary *opt = NULL;
248 
249  c = ost->enc;
250 
251  /* open it */
252  av_dict_copy(&opt, opt_arg, 0);
253  ret = avcodec_open2(c, codec, &opt);
254  av_dict_free(&opt);
255  if (ret < 0) {
256  fprintf(stderr, "Could not open audio codec: %s\n", av_err2str(ret));
257  exit(1);
258  }
259 
260  /* init signal generator */
261  ost->t = 0;
262  ost->tincr = 2 * M_PI * 110.0 / c->sample_rate;
263  /* increment frequency by 110 Hz per second */
264  ost->tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
265 
267  nb_samples = 10000;
268  else
269  nb_samples = c->frame_size;
270 
271  ost->frame = alloc_audio_frame(c->sample_fmt, &c->ch_layout,
272  c->sample_rate, nb_samples);
274  c->sample_rate, nb_samples);
275 
276  /* copy the stream parameters to the muxer */
278  if (ret < 0) {
279  fprintf(stderr, "Could not copy the stream parameters\n");
280  exit(1);
281  }
282 
283  /* create resampler context */
284  ost->swr_ctx = swr_alloc();
285  if (!ost->swr_ctx) {
286  fprintf(stderr, "Could not allocate resampler context\n");
287  exit(1);
288  }
289 
290  /* set options */
291  av_opt_set_chlayout (ost->swr_ctx, "in_chlayout", &c->ch_layout, 0);
292  av_opt_set_int (ost->swr_ctx, "in_sample_rate", c->sample_rate, 0);
293  av_opt_set_sample_fmt(ost->swr_ctx, "in_sample_fmt", AV_SAMPLE_FMT_S16, 0);
294  av_opt_set_chlayout (ost->swr_ctx, "out_chlayout", &c->ch_layout, 0);
295  av_opt_set_int (ost->swr_ctx, "out_sample_rate", c->sample_rate, 0);
296  av_opt_set_sample_fmt(ost->swr_ctx, "out_sample_fmt", c->sample_fmt, 0);
297 
298  /* initialize the resampling context */
299  if ((ret = swr_init(ost->swr_ctx)) < 0) {
300  fprintf(stderr, "Failed to initialize the resampling context\n");
301  exit(1);
302  }
303 }
304 
305 /* Prepare a 16 bit dummy audio frame of 'frame_size' samples and
306  * 'nb_channels' channels. */
308 {
309  AVFrame *frame = ost->tmp_frame;
310  int j, i, v;
311  int16_t *q = (int16_t*)frame->data[0];
312 
313  /* check if we want to generate more frames */
314  if (av_compare_ts(ost->next_pts, ost->enc->time_base,
315  STREAM_DURATION, (AVRational){ 1, 1 }) > 0)
316  return NULL;
317 
318  for (j = 0; j <frame->nb_samples; j++) {
319  v = (int)(sin(ost->t) * 10000);
320  for (i = 0; i < ost->enc->ch_layout.nb_channels; i++)
321  *q++ = v;
322  ost->t += ost->tincr;
323  ost->tincr += ost->tincr2;
324  }
325 
326  frame->pts = ost->next_pts;
327  ost->next_pts += frame->nb_samples;
328 
329  return frame;
330 }
331 
332 /*
333  * encode one audio frame and send it to the muxer
334  * return 1 when encoding is finished, 0 otherwise
335  */
337 {
338  AVCodecContext *c;
339  AVFrame *frame;
340  int ret;
341  int dst_nb_samples;
342 
343  c = ost->enc;
344 
346 
347  if (frame) {
348  /* convert samples from native format to destination codec format, using the resampler */
349  /* compute destination number of samples */
350  dst_nb_samples = av_rescale_rnd(swr_get_delay(ost->swr_ctx, c->sample_rate) + frame->nb_samples,
352  av_assert0(dst_nb_samples == frame->nb_samples);
353 
354  /* when we pass a frame to the encoder, it may keep a reference to it
355  * internally;
356  * make sure we do not overwrite it here
357  */
358  ret = av_frame_make_writable(ost->frame);
359  if (ret < 0)
360  exit(1);
361 
362  /* convert to destination format */
363  ret = swr_convert(ost->swr_ctx,
364  ost->frame->data, dst_nb_samples,
365  (const uint8_t **)frame->data, frame->nb_samples);
366  if (ret < 0) {
367  fprintf(stderr, "Error while converting\n");
368  exit(1);
369  }
370  frame = ost->frame;
371 
372  frame->pts = av_rescale_q(ost->samples_count, (AVRational){1, c->sample_rate}, c->time_base);
373  ost->samples_count += dst_nb_samples;
374  }
375 
376  return write_frame(oc, c, ost->st, frame, ost->tmp_pkt);
377 }
378 
379 /**************************************************************/
380 /* video output */
381 
383 {
384  AVFrame *picture;
385  int ret;
386 
387  picture = av_frame_alloc();
388  if (!picture)
389  return NULL;
390 
391  picture->format = pix_fmt;
392  picture->width = width;
393  picture->height = height;
394 
395  /* allocate the buffers for the frame data */
396  ret = av_frame_get_buffer(picture, 0);
397  if (ret < 0) {
398  fprintf(stderr, "Could not allocate frame data.\n");
399  exit(1);
400  }
401 
402  return picture;
403 }
404 
405 static void open_video(AVFormatContext *oc, const AVCodec *codec,
406  OutputStream *ost, AVDictionary *opt_arg)
407 {
408  int ret;
409  AVCodecContext *c = ost->enc;
410  AVDictionary *opt = NULL;
411 
412  av_dict_copy(&opt, opt_arg, 0);
413 
414  /* open the codec */
415  ret = avcodec_open2(c, codec, &opt);
416  av_dict_free(&opt);
417  if (ret < 0) {
418  fprintf(stderr, "Could not open video codec: %s\n", av_err2str(ret));
419  exit(1);
420  }
421 
422  /* allocate and init a re-usable frame */
423  ost->frame = alloc_picture(c->pix_fmt, c->width, c->height);
424  if (!ost->frame) {
425  fprintf(stderr, "Could not allocate video frame\n");
426  exit(1);
427  }
428 
429  /* If the output format is not YUV420P, then a temporary YUV420P
430  * picture is needed too. It is then converted to the required
431  * output format. */
432  ost->tmp_frame = NULL;
433  if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
434  ost->tmp_frame = alloc_picture(AV_PIX_FMT_YUV420P, c->width, c->height);
435  if (!ost->tmp_frame) {
436  fprintf(stderr, "Could not allocate temporary picture\n");
437  exit(1);
438  }
439  }
440 
441  /* copy the stream parameters to the muxer */
443  if (ret < 0) {
444  fprintf(stderr, "Could not copy the stream parameters\n");
445  exit(1);
446  }
447 }
448 
449 /* Prepare a dummy image. */
450 static void fill_yuv_image(AVFrame *pict, int frame_index,
451  int width, int height)
452 {
453  int x, y, i;
454 
455  i = frame_index;
456 
457  /* Y */
458  for (y = 0; y < height; y++)
459  for (x = 0; x < width; x++)
460  pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
461 
462  /* Cb and Cr */
463  for (y = 0; y < height / 2; y++) {
464  for (x = 0; x < width / 2; x++) {
465  pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
466  pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
467  }
468  }
469 }
470 
472 {
473  AVCodecContext *c = ost->enc;
474 
475  /* check if we want to generate more frames */
476  if (av_compare_ts(ost->next_pts, c->time_base,
477  STREAM_DURATION, (AVRational){ 1, 1 }) > 0)
478  return NULL;
479 
480  /* when we pass a frame to the encoder, it may keep a reference to it
481  * internally; make sure we do not overwrite it here */
482  if (av_frame_make_writable(ost->frame) < 0)
483  exit(1);
484 
485  if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
486  /* as we only generate a YUV420P picture, we must convert it
487  * to the codec pixel format if needed */
488  if (!ost->sws_ctx) {
489  ost->sws_ctx = sws_getContext(c->width, c->height,
491  c->width, c->height,
492  c->pix_fmt,
493  SCALE_FLAGS, NULL, NULL, NULL);
494  if (!ost->sws_ctx) {
495  fprintf(stderr,
496  "Could not initialize the conversion context\n");
497  exit(1);
498  }
499  }
500  fill_yuv_image(ost->tmp_frame, ost->next_pts, c->width, c->height);
501  sws_scale(ost->sws_ctx, (const uint8_t * const *) ost->tmp_frame->data,
502  ost->tmp_frame->linesize, 0, c->height, ost->frame->data,
503  ost->frame->linesize);
504  } else {
505  fill_yuv_image(ost->frame, ost->next_pts, c->width, c->height);
506  }
507 
508  ost->frame->pts = ost->next_pts++;
509 
510  return ost->frame;
511 }
512 
513 /*
514  * encode one video frame and send it to the muxer
515  * return 1 when encoding is finished, 0 otherwise
516  */
518 {
519  return write_frame(oc, ost->enc, ost->st, get_video_frame(ost), ost->tmp_pkt);
520 }
521 
523 {
524  avcodec_free_context(&ost->enc);
525  av_frame_free(&ost->frame);
526  av_frame_free(&ost->tmp_frame);
527  av_packet_free(&ost->tmp_pkt);
528  sws_freeContext(ost->sws_ctx);
529  swr_free(&ost->swr_ctx);
530 }
531 
532 /**************************************************************/
533 /* media file output */
534 
535 int main(int argc, char **argv)
536 {
537  OutputStream video_st = { 0 }, audio_st = { 0 };
538  const AVOutputFormat *fmt;
539  const char *filename;
540  AVFormatContext *oc;
541  const AVCodec *audio_codec, *video_codec;
542  int ret;
543  int have_video = 0, have_audio = 0;
544  int encode_video = 0, encode_audio = 0;
545  AVDictionary *opt = NULL;
546  int i;
547 
548  if (argc < 2) {
549  printf("usage: %s output_file\n"
550  "API example program to output a media file with libavformat.\n"
551  "This program generates a synthetic audio and video stream, encodes and\n"
552  "muxes them into a file named output_file.\n"
553  "The output format is automatically guessed according to the file extension.\n"
554  "Raw images can also be output by using '%%d' in the filename.\n"
555  "\n", argv[0]);
556  return 1;
557  }
558 
559  filename = argv[1];
560  for (i = 2; i+1 < argc; i+=2) {
561  if (!strcmp(argv[i], "-flags") || !strcmp(argv[i], "-fflags"))
562  av_dict_set(&opt, argv[i]+1, argv[i+1], 0);
563  }
564 
565  /* allocate the output media context */
566  avformat_alloc_output_context2(&oc, NULL, NULL, filename);
567  if (!oc) {
568  printf("Could not deduce output format from file extension: using MPEG.\n");
569  avformat_alloc_output_context2(&oc, NULL, "mpeg", filename);
570  }
571  if (!oc)
572  return 1;
573 
574  fmt = oc->oformat;
575 
576  /* Add the audio and video streams using the default format codecs
577  * and initialize the codecs. */
578  if (fmt->video_codec != AV_CODEC_ID_NONE) {
579  add_stream(&video_st, oc, &video_codec, fmt->video_codec);
580  have_video = 1;
581  encode_video = 1;
582  }
583  if (fmt->audio_codec != AV_CODEC_ID_NONE) {
584  add_stream(&audio_st, oc, &audio_codec, fmt->audio_codec);
585  have_audio = 1;
586  encode_audio = 1;
587  }
588 
589  /* Now that all the parameters are set, we can open the audio and
590  * video codecs and allocate the necessary encode buffers. */
591  if (have_video)
592  open_video(oc, video_codec, &video_st, opt);
593 
594  if (have_audio)
595  open_audio(oc, audio_codec, &audio_st, opt);
596 
597  av_dump_format(oc, 0, filename, 1);
598 
599  /* open the output file, if needed */
600  if (!(fmt->flags & AVFMT_NOFILE)) {
601  ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE);
602  if (ret < 0) {
603  fprintf(stderr, "Could not open '%s': %s\n", filename,
604  av_err2str(ret));
605  return 1;
606  }
607  }
608 
609  /* Write the stream header, if any. */
610  ret = avformat_write_header(oc, &opt);
611  if (ret < 0) {
612  fprintf(stderr, "Error occurred when opening output file: %s\n",
613  av_err2str(ret));
614  return 1;
615  }
616 
617  while (encode_video || encode_audio) {
618  /* select the stream to encode */
619  if (encode_video &&
620  (!encode_audio || av_compare_ts(video_st.next_pts, video_st.enc->time_base,
621  audio_st.next_pts, audio_st.enc->time_base) <= 0)) {
622  encode_video = !write_video_frame(oc, &video_st);
623  } else {
624  encode_audio = !write_audio_frame(oc, &audio_st);
625  }
626  }
627 
628  av_write_trailer(oc);
629 
630  /* Close each codec. */
631  if (have_video)
632  close_stream(oc, &video_st);
633  if (have_audio)
634  close_stream(oc, &audio_st);
635 
636  if (!(fmt->flags & AVFMT_NOFILE))
637  /* Close the output file. */
638  avio_closep(&oc->pb);
639 
640  /* free the stream */
642 
643  return 0;
644 }
simple assert() macros that are a bit more flexible than ISO C assert().
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
Libavcodec external API header.
Main libavformat public API header.
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:468
#define AVFMT_GLOBALHEADER
Format wants global header.
Definition: avformat.h:478
int avformat_alloc_output_context2(AVFormatContext **ctx, const AVOutputFormat *oformat, const char *format_name, const char *filename)
Allocate an AVFormatContext for an output format.
int avio_open(AVIOContext **s, const char *url, int flags)
Create and initialize a AVIOContext for accessing the resource indicated by url.
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:624
int avio_closep(AVIOContext **s)
Close the resource accessed by the AVIOContext *s, free it and set the pointer pointing to it to NULL...
Public libavutil channel layout APIs header.
static AVFormatContext * fmt_ctx
static int width
Definition: demux_decode.c:40
static AVPacket * pkt
Definition: demux_decode.c:55
static enum AVPixelFormat pix_fmt
Definition: demux_decode.c:41
static int height
Definition: demux_decode.c:40
static AVFrame * frame
Definition: demux_decode.c:54
int avcodec_parameters_from_context(AVCodecParameters *par, const AVCodecContext *codec)
Fill the parameters struct based on the values from the supplied codec context.
int avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options)
Initialize the AVCodecContext to use the given AVCodec.
const char * avcodec_get_name(enum AVCodecID id)
Get the name of a codec.
#define AV_CODEC_CAP_VARIABLE_FRAME_SIZE
Audio encoder supports receiving a different number of samples in each call.
Definition: codec.h:125
const AVCodec * avcodec_find_encoder(enum AVCodecID id)
Find a registered encoder with a matching codec ID.
#define AV_CODEC_FLAG_GLOBAL_HEADER
Place global headers in extradata instead of every keyframe.
Definition: avcodec.h:317
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: codec_id.h:49
AVCodecContext * avcodec_alloc_context3(const AVCodec *codec)
Allocate an AVCodecContext and set its fields to default values.
void avcodec_free_context(AVCodecContext **avctx)
Free the codec context and everything associated with it and write NULL to the provided pointer.
@ AV_CODEC_ID_NONE
Definition: codec_id.h:50
@ AV_CODEC_ID_MPEG1VIDEO
Definition: codec_id.h:53
@ AV_CODEC_ID_MPEG2VIDEO
preferred ID for MPEG-1/2 video decoding
Definition: codec_id.h:54
int avcodec_receive_packet(AVCodecContext *avctx, AVPacket *avpkt)
Read encoded data from the encoder.
int avcodec_send_frame(AVCodecContext *avctx, const AVFrame *frame)
Supply a raw video or audio frame to the encoder.
void av_packet_free(AVPacket **pkt)
Free the packet, if the packet is reference counted, it will be unreferenced first.
AVPacket * av_packet_alloc(void)
Allocate an AVPacket and set its fields to default values.
void av_packet_rescale_ts(AVPacket *pkt, AVRational tb_src, AVRational tb_dst)
Convert valid timing fields (timestamps / durations) in a packet from one timebase to another.
void avformat_free_context(AVFormatContext *s)
Free an AVFormatContext and all its streams.
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
av_warn_unused_result int avformat_write_header(AVFormatContext *s, AVDictionary **options)
Allocate the stream private data and write the stream header to an output media file.
int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
Write a packet to an output media file ensuring correct interleaving.
int av_write_trailer(AVFormatContext *s)
Write the stream trailer to an output media file and free the file private data.
void av_dump_format(AVFormatContext *ic, int index, const char *url, int is_output)
Print detailed information about the input or output format, such as duration, bitrate,...
#define AV_CHANNEL_LAYOUT_STEREO
int av_channel_layout_copy(AVChannelLayout *dst, const AVChannelLayout *src)
Make a copy of a channel layout.
void av_dict_free(AVDictionary **m)
Free all the memory allocated for an AVDictionary struct and all keys and values.
struct AVDictionary AVDictionary
Definition: dict.h:94
int av_dict_copy(AVDictionary **dst, const AVDictionary *src, int flags)
Copy entries from one AVDictionary struct into another.
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
#define AVERROR_EOF
End of file.
Definition: error.h:57
#define av_err2str(errnum)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: error.h:121
#define AVERROR(e)
Definition: error.h:45
int av_frame_get_buffer(AVFrame *frame, int align)
Allocate new buffer(s) for audio or video data.
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
int av_frame_make_writable(AVFrame *frame)
Ensure that the frame data is writable, avoiding data copy if possible.
int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b)
Compare two timestamps each in its own time base.
int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding rnd) av_const
Rescale a 64-bit integer with specified rounding.
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const
Rescale a 64-bit integer by 2 rational numbers.
@ AV_ROUND_UP
Round toward +infinity.
Definition: mathematics.h:83
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:55
@ AV_SAMPLE_FMT_FLTP
float, planar
Definition: samplefmt.h:66
@ AV_SAMPLE_FMT_S16
signed 16 bits
Definition: samplefmt.h:58
void sws_freeContext(struct SwsContext *swsContext)
Free the swscaler context swsContext.
int sws_scale(struct SwsContext *c, const uint8_t *const srcSlice[], const int srcStride[], int srcSliceY, int srcSliceH, uint8_t *const dst[], const int dstStride[])
Scale the image slice in srcSlice and put the resulting scaled slice in the image in dst.
struct SwsContext * sws_getContext(int srcW, int srcH, enum AVPixelFormat srcFormat, int dstW, int dstH, enum AVPixelFormat dstFormat, int flags, SwsFilter *srcFilter, SwsFilter *dstFilter, const double *param)
Allocate and return an SwsContext.
struct SwrContext SwrContext
The libswresample context.
Definition: swresample.h:189
int64_t swr_get_delay(struct SwrContext *s, int64_t base)
Gets the delay the next input sample will experience relative to the next output sample.
void swr_free(struct SwrContext **s)
Free the given SwrContext and set the pointer to NULL.
int swr_convert(struct SwrContext *s, uint8_t **out, int out_count, const uint8_t **in, int in_count)
Convert audio.
int swr_init(struct SwrContext *s)
Initialize context after user parameters have been set.
struct SwrContext * swr_alloc(void)
Allocate SwrContext.
int av_opt_set_int(void *obj, const char *name, int64_t val, int search_flags)
int av_opt_set_chlayout(void *obj, const char *name, const AVChannelLayout *layout, int search_flags)
int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags)
#define M_PI
Definition: mathematics.h:52
static AVFrame * alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
Definition: mux.c:382
static void open_video(AVFormatContext *oc, const AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
Definition: mux.c:405
static void add_stream(OutputStream *ost, AVFormatContext *oc, const AVCodec **codec, enum AVCodecID codec_id)
Definition: mux.c:125
static AVFrame * get_video_frame(OutputStream *ost)
Definition: mux.c:471
int main(int argc, char **argv)
Definition: mux.c:535
static int write_video_frame(AVFormatContext *oc, OutputStream *ost)
Definition: mux.c:517
static AVFrame * get_audio_frame(OutputStream *ost)
Definition: mux.c:307
static void open_audio(AVFormatContext *oc, const AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
Definition: mux.c:241
static int write_audio_frame(AVFormatContext *oc, OutputStream *ost)
Definition: mux.c:336
static int write_frame(AVFormatContext *fmt_ctx, AVCodecContext *c, AVStream *st, AVFrame *frame, AVPacket *pkt)
Definition: mux.c:83
static AVFrame * alloc_audio_frame(enum AVSampleFormat sample_fmt, const AVChannelLayout *channel_layout, int sample_rate, int nb_samples)
Definition: mux.c:216
static void close_stream(AVFormatContext *oc, OutputStream *ost)
Definition: mux.c:522
#define SCALE_FLAGS
Definition: mux.c:50
static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt)
Definition: mux.c:72
static void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height)
Definition: mux.c:450
#define STREAM_DURATION
Definition: mux.c:46
#define STREAM_FRAME_RATE
Definition: mux.c:47
#define STREAM_PIX_FMT
Definition: mux.c:48
AVOptions.
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
@ AV_PIX_FMT_YUV420P
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:66
An AVChannelLayout holds information about the channel layout of audio data.
main external API structure.
Definition: avcodec.h:426
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:635
int width
picture width / height.
Definition: avcodec.h:598
AVChannelLayout ch_layout
Audio channel layout.
Definition: avcodec.h:2054
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:1050
int max_b_frames
maximum number of B-frames between non-B-frames Note: The output will be delayed by max_b_frames+1 re...
Definition: avcodec.h:697
int mb_decision
macroblock decision mode
Definition: avcodec.h:898
int64_t bit_rate
the average bitrate
Definition: avcodec.h:476
const struct AVCodec * codec
Definition: avcodec.h:435
int sample_rate
samples per second
Definition: avcodec.h:1034
int gop_size
the number of pictures in a group of pictures, or 0 for intra_only
Definition: avcodec.h:620
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented.
Definition: avcodec.h:548
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:506
enum AVCodecID codec_id
Definition: avcodec.h:436
int frame_size
Number of samples per channel in an audio frame.
Definition: avcodec.h:1062
AVCodec.
Definition: codec.h:184
int capabilities
Codec capabilities.
Definition: codec.h:203
Format I/O context.
Definition: avformat.h:1104
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1160
AVIOContext * pb
I/O context.
Definition: avformat.h:1146
const struct AVOutputFormat * oformat
The output container format.
Definition: avformat.h:1123
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1172
This structure describes decoded (raw) audio or video data.
Definition: frame.h:330
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:410
int64_t pts
Presentation timestamp in time_base units (time when frame should be shown to user).
Definition: frame.h:437
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:351
int width
Definition: frame.h:402
int height
Definition: frame.h:402
int linesize[AV_NUM_DATA_POINTERS]
For video, a positive or negative value, which is typically indicating the size in bytes of each pict...
Definition: frame.h:375
int sample_rate
Sample rate of the audio data.
Definition: frame.h:516
AVChannelLayout ch_layout
Channel layout of the audio data.
Definition: frame.h:723
int format
format of the frame, -1 if unknown or unset Values correspond to enum AVPixelFormat for video frames,...
Definition: frame.h:417
enum AVCodecID video_codec
default video codec
Definition: avformat.h:519
enum AVCodecID audio_codec
default audio codec
Definition: avformat.h:518
int flags
can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS,...
Definition: avformat.h:527
This structure stores compressed data.
Definition: packet.h:351
int stream_index
Definition: packet.h:376
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:392
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:367
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed.
Definition: packet.h:373
Rational number (pair of numerator and denominator).
Definition: rational.h:58
Stream structure.
Definition: avformat.h:838
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:861
int id
Format-specific stream ID.
Definition: avformat.h:850
int index
stream index in AVFormatContext
Definition: avformat.h:844
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented.
Definition: avformat.h:877
float tincr2
Definition: mux.c:66
AVFrame * frame
Definition: mux.c:61
int samples_count
Definition: mux.c:59
struct SwrContext * swr_ctx
Definition: mux.c:69
AVFrame * tmp_frame
Definition: mux.c:62
AVPacket * tmp_pkt
Definition: mux.c:64
struct SwsContext * sws_ctx
Definition: mux.c:68
int64_t next_pts
Definition: mux.c:58
float t
Definition: mux.c:66
AVStream * st
Definition: mux.c:54
AVCodecContext * enc
Definition: mux.c:55
float tincr
Definition: mux.c:66
libswresample public header
external API header
timestamp utils, mostly useful for debugging/logging purposes
#define av_ts2str(ts)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: timestamp.h:54
#define av_ts2timestr(ts, tb)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: timestamp.h:76
static AVStream * ost