FFmpeg
muxing.c
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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
25  * libavformat API example.
26  *
27  * Output a media file in any supported libavformat format. The default
28  * codecs are used.
29  * @example muxing.c
30  */
31 
32 #include <stdlib.h>
33 #include <stdio.h>
34 #include <string.h>
35 #include <math.h>
36 
37 #include <libavutil/avassert.h>
39 #include <libavutil/opt.h>
40 #include <libavutil/mathematics.h>
41 #include <libavutil/timestamp.h>
42 #include <libavcodec/avcodec.h>
43 #include <libavformat/avformat.h>
44 #include <libswscale/swscale.h>
46 
47 #define STREAM_DURATION 10.0
48 #define STREAM_FRAME_RATE 25 /* 25 images/s */
49 #define STREAM_PIX_FMT AV_PIX_FMT_YUV420P /* default pix_fmt */
50 
51 #define SCALE_FLAGS SWS_BICUBIC
52 
53 // a wrapper around a single output AVStream
54 typedef struct OutputStream {
57 
58  /* pts of the next frame that will be generated */
59  int64_t next_pts;
61 
64 
65  float t, tincr, tincr2;
66 
69 } OutputStream;
70 
71 static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt)
72 {
74 
75  printf("pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
76  av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
77  av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
79  pkt->stream_index);
80 }
81 
83  AVStream *st, AVFrame *frame)
84 {
85  int ret;
86 
87  // send the frame to the encoder
89  if (ret < 0) {
90  fprintf(stderr, "Error sending a frame to the encoder: %s\n",
91  av_err2str(ret));
92  exit(1);
93  }
94 
95  while (ret >= 0) {
96  AVPacket pkt = { 0 };
97 
99  if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
100  break;
101  else if (ret < 0) {
102  fprintf(stderr, "Error encoding a frame: %s\n", av_err2str(ret));
103  exit(1);
104  }
105 
106  /* rescale output packet timestamp values from codec to stream timebase */
107  av_packet_rescale_ts(&pkt, c->time_base, st->time_base);
108  pkt.stream_index = st->index;
109 
110  /* Write the compressed frame to the media file. */
114  if (ret < 0) {
115  fprintf(stderr, "Error while writing output packet: %s\n", av_err2str(ret));
116  exit(1);
117  }
118  }
119 
120  return ret == AVERROR_EOF ? 1 : 0;
121 }
122 
123 /* Add an output stream. */
125  const AVCodec **codec,
126  enum AVCodecID codec_id)
127 {
128  AVCodecContext *c;
129  int i;
130 
131  /* find the encoder */
132  *codec = avcodec_find_encoder(codec_id);
133  if (!(*codec)) {
134  fprintf(stderr, "Could not find encoder for '%s'\n",
136  exit(1);
137  }
138 
139  ost->st = avformat_new_stream(oc, NULL);
140  if (!ost->st) {
141  fprintf(stderr, "Could not allocate stream\n");
142  exit(1);
143  }
144  ost->st->id = oc->nb_streams-1;
145  c = avcodec_alloc_context3(*codec);
146  if (!c) {
147  fprintf(stderr, "Could not alloc an encoding context\n");
148  exit(1);
149  }
150  ost->enc = c;
151 
152  switch ((*codec)->type) {
153  case AVMEDIA_TYPE_AUDIO:
154  c->sample_fmt = (*codec)->sample_fmts ?
155  (*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;
156  c->bit_rate = 64000;
157  c->sample_rate = 44100;
158  if ((*codec)->supported_samplerates) {
159  c->sample_rate = (*codec)->supported_samplerates[0];
160  for (i = 0; (*codec)->supported_samplerates[i]; i++) {
161  if ((*codec)->supported_samplerates[i] == 44100)
162  c->sample_rate = 44100;
163  }
164  }
165  c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
166  c->channel_layout = AV_CH_LAYOUT_STEREO;
167  if ((*codec)->channel_layouts) {
168  c->channel_layout = (*codec)->channel_layouts[0];
169  for (i = 0; (*codec)->channel_layouts[i]; i++) {
170  if ((*codec)->channel_layouts[i] == AV_CH_LAYOUT_STEREO)
171  c->channel_layout = AV_CH_LAYOUT_STEREO;
172  }
173  }
174  c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
175  ost->st->time_base = (AVRational){ 1, c->sample_rate };
176  break;
177 
178  case AVMEDIA_TYPE_VIDEO:
179  c->codec_id = codec_id;
180 
181  c->bit_rate = 400000;
182  /* Resolution must be a multiple of two. */
183  c->width = 352;
184  c->height = 288;
185  /* timebase: This is the fundamental unit of time (in seconds) in terms
186  * of which frame timestamps are represented. For fixed-fps content,
187  * timebase should be 1/framerate and timestamp increments should be
188  * identical to 1. */
190  c->time_base = ost->st->time_base;
191 
192  c->gop_size = 12; /* emit one intra frame every twelve frames at most */
193  c->pix_fmt = STREAM_PIX_FMT;
194  if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
195  /* just for testing, we also add B-frames */
196  c->max_b_frames = 2;
197  }
198  if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
199  /* Needed to avoid using macroblocks in which some coeffs overflow.
200  * This does not happen with normal video, it just happens here as
201  * the motion of the chroma plane does not match the luma plane. */
202  c->mb_decision = 2;
203  }
204  break;
205 
206  default:
207  break;
208  }
209 
210  /* Some formats want stream headers to be separate. */
211  if (oc->oformat->flags & AVFMT_GLOBALHEADER)
212  c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
213 }
214 
215 /**************************************************************/
216 /* audio output */
217 
218 static AVFrame *alloc_audio_frame(enum AVSampleFormat sample_fmt,
219  uint64_t channel_layout,
220  int sample_rate, int nb_samples)
221 {
223  int ret;
224 
225  if (!frame) {
226  fprintf(stderr, "Error allocating an audio frame\n");
227  exit(1);
228  }
229 
230  frame->format = sample_fmt;
231  frame->channel_layout = channel_layout;
232  frame->sample_rate = sample_rate;
233  frame->nb_samples = nb_samples;
234 
235  if (nb_samples) {
237  if (ret < 0) {
238  fprintf(stderr, "Error allocating an audio buffer\n");
239  exit(1);
240  }
241  }
242 
243  return frame;
244 }
245 
246 static void open_audio(AVFormatContext *oc, const AVCodec *codec,
247  OutputStream *ost, AVDictionary *opt_arg)
248 {
249  AVCodecContext *c;
250  int nb_samples;
251  int ret;
252  AVDictionary *opt = NULL;
253 
254  c = ost->enc;
255 
256  /* open it */
257  av_dict_copy(&opt, opt_arg, 0);
258  ret = avcodec_open2(c, codec, &opt);
259  av_dict_free(&opt);
260  if (ret < 0) {
261  fprintf(stderr, "Could not open audio codec: %s\n", av_err2str(ret));
262  exit(1);
263  }
264 
265  /* init signal generator */
266  ost->t = 0;
267  ost->tincr = 2 * M_PI * 110.0 / c->sample_rate;
268  /* increment frequency by 110 Hz per second */
269  ost->tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
270 
271  if (c->codec->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE)
272  nb_samples = 10000;
273  else
274  nb_samples = c->frame_size;
275 
276  ost->frame = alloc_audio_frame(c->sample_fmt, c->channel_layout,
277  c->sample_rate, nb_samples);
278  ost->tmp_frame = alloc_audio_frame(AV_SAMPLE_FMT_S16, c->channel_layout,
279  c->sample_rate, nb_samples);
280 
281  /* copy the stream parameters to the muxer */
283  if (ret < 0) {
284  fprintf(stderr, "Could not copy the stream parameters\n");
285  exit(1);
286  }
287 
288  /* create resampler context */
289  ost->swr_ctx = swr_alloc();
290  if (!ost->swr_ctx) {
291  fprintf(stderr, "Could not allocate resampler context\n");
292  exit(1);
293  }
294 
295  /* set options */
296  av_opt_set_int (ost->swr_ctx, "in_channel_count", c->channels, 0);
297  av_opt_set_int (ost->swr_ctx, "in_sample_rate", c->sample_rate, 0);
298  av_opt_set_sample_fmt(ost->swr_ctx, "in_sample_fmt", AV_SAMPLE_FMT_S16, 0);
299  av_opt_set_int (ost->swr_ctx, "out_channel_count", c->channels, 0);
300  av_opt_set_int (ost->swr_ctx, "out_sample_rate", c->sample_rate, 0);
301  av_opt_set_sample_fmt(ost->swr_ctx, "out_sample_fmt", c->sample_fmt, 0);
302 
303  /* initialize the resampling context */
304  if ((ret = swr_init(ost->swr_ctx)) < 0) {
305  fprintf(stderr, "Failed to initialize the resampling context\n");
306  exit(1);
307  }
308 }
309 
310 /* Prepare a 16 bit dummy audio frame of 'frame_size' samples and
311  * 'nb_channels' channels. */
313 {
315  int j, i, v;
316  int16_t *q = (int16_t*)frame->data[0];
317 
318  /* check if we want to generate more frames */
320  STREAM_DURATION, (AVRational){ 1, 1 }) > 0)
321  return NULL;
322 
323  for (j = 0; j <frame->nb_samples; j++) {
324  v = (int)(sin(ost->t) * 10000);
325  for (i = 0; i < ost->enc->channels; i++)
326  *q++ = v;
327  ost->t += ost->tincr;
328  ost->tincr += ost->tincr2;
329  }
330 
331  frame->pts = ost->next_pts;
332  ost->next_pts += frame->nb_samples;
333 
334  return frame;
335 }
336 
337 /*
338  * encode one audio frame and send it to the muxer
339  * return 1 when encoding is finished, 0 otherwise
340  */
342 {
343  AVCodecContext *c;
344  AVFrame *frame;
345  int ret;
346  int dst_nb_samples;
347 
348  c = ost->enc;
349 
351 
352  if (frame) {
353  /* convert samples from native format to destination codec format, using the resampler */
354  /* compute destination number of samples */
355  dst_nb_samples = av_rescale_rnd(swr_get_delay(ost->swr_ctx, c->sample_rate) + frame->nb_samples,
356  c->sample_rate, c->sample_rate, AV_ROUND_UP);
357  av_assert0(dst_nb_samples == frame->nb_samples);
358 
359  /* when we pass a frame to the encoder, it may keep a reference to it
360  * internally;
361  * make sure we do not overwrite it here
362  */
364  if (ret < 0)
365  exit(1);
366 
367  /* convert to destination format */
369  ost->frame->data, dst_nb_samples,
370  (const uint8_t **)frame->data, frame->nb_samples);
371  if (ret < 0) {
372  fprintf(stderr, "Error while converting\n");
373  exit(1);
374  }
375  frame = ost->frame;
376 
377  frame->pts = av_rescale_q(ost->samples_count, (AVRational){1, c->sample_rate}, c->time_base);
378  ost->samples_count += dst_nb_samples;
379  }
380 
381  return write_frame(oc, c, ost->st, frame);
382 }
383 
384 /**************************************************************/
385 /* video output */
386 
388 {
389  AVFrame *picture;
390  int ret;
391 
392  picture = av_frame_alloc();
393  if (!picture)
394  return NULL;
395 
396  picture->format = pix_fmt;
397  picture->width = width;
398  picture->height = height;
399 
400  /* allocate the buffers for the frame data */
401  ret = av_frame_get_buffer(picture, 0);
402  if (ret < 0) {
403  fprintf(stderr, "Could not allocate frame data.\n");
404  exit(1);
405  }
406 
407  return picture;
408 }
409 
410 static void open_video(AVFormatContext *oc, const AVCodec *codec,
411  OutputStream *ost, AVDictionary *opt_arg)
412 {
413  int ret;
414  AVCodecContext *c = ost->enc;
415  AVDictionary *opt = NULL;
416 
417  av_dict_copy(&opt, opt_arg, 0);
418 
419  /* open the codec */
420  ret = avcodec_open2(c, codec, &opt);
421  av_dict_free(&opt);
422  if (ret < 0) {
423  fprintf(stderr, "Could not open video codec: %s\n", av_err2str(ret));
424  exit(1);
425  }
426 
427  /* allocate and init a re-usable frame */
428  ost->frame = alloc_picture(c->pix_fmt, c->width, c->height);
429  if (!ost->frame) {
430  fprintf(stderr, "Could not allocate video frame\n");
431  exit(1);
432  }
433 
434  /* If the output format is not YUV420P, then a temporary YUV420P
435  * picture is needed too. It is then converted to the required
436  * output format. */
437  ost->tmp_frame = NULL;
438  if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
439  ost->tmp_frame = alloc_picture(AV_PIX_FMT_YUV420P, c->width, c->height);
440  if (!ost->tmp_frame) {
441  fprintf(stderr, "Could not allocate temporary picture\n");
442  exit(1);
443  }
444  }
445 
446  /* copy the stream parameters to the muxer */
448  if (ret < 0) {
449  fprintf(stderr, "Could not copy the stream parameters\n");
450  exit(1);
451  }
452 }
453 
454 /* Prepare a dummy image. */
455 static void fill_yuv_image(AVFrame *pict, int frame_index,
456  int width, int height)
457 {
458  int x, y, i;
459 
460  i = frame_index;
461 
462  /* Y */
463  for (y = 0; y < height; y++)
464  for (x = 0; x < width; x++)
465  pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
466 
467  /* Cb and Cr */
468  for (y = 0; y < height / 2; y++) {
469  for (x = 0; x < width / 2; x++) {
470  pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
471  pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
472  }
473  }
474 }
475 
477 {
478  AVCodecContext *c = ost->enc;
479 
480  /* check if we want to generate more frames */
481  if (av_compare_ts(ost->next_pts, c->time_base,
482  STREAM_DURATION, (AVRational){ 1, 1 }) > 0)
483  return NULL;
484 
485  /* when we pass a frame to the encoder, it may keep a reference to it
486  * internally; make sure we do not overwrite it here */
487  if (av_frame_make_writable(ost->frame) < 0)
488  exit(1);
489 
490  if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
491  /* as we only generate a YUV420P picture, we must convert it
492  * to the codec pixel format if needed */
493  if (!ost->sws_ctx) {
494  ost->sws_ctx = sws_getContext(c->width, c->height,
496  c->width, c->height,
497  c->pix_fmt,
499  if (!ost->sws_ctx) {
500  fprintf(stderr,
501  "Could not initialize the conversion context\n");
502  exit(1);
503  }
504  }
505  fill_yuv_image(ost->tmp_frame, ost->next_pts, c->width, c->height);
506  sws_scale(ost->sws_ctx, (const uint8_t * const *) ost->tmp_frame->data,
507  ost->tmp_frame->linesize, 0, c->height, ost->frame->data,
508  ost->frame->linesize);
509  } else {
510  fill_yuv_image(ost->frame, ost->next_pts, c->width, c->height);
511  }
512 
513  ost->frame->pts = ost->next_pts++;
514 
515  return ost->frame;
516 }
517 
518 /*
519  * encode one video frame and send it to the muxer
520  * return 1 when encoding is finished, 0 otherwise
521  */
523 {
524  return write_frame(oc, ost->enc, ost->st, get_video_frame(ost));
525 }
526 
528 {
533  swr_free(&ost->swr_ctx);
534 }
535 
536 /**************************************************************/
537 /* media file output */
538 
539 int main(int argc, char **argv)
540 {
541  OutputStream video_st = { 0 }, audio_st = { 0 };
542  const AVOutputFormat *fmt;
543  const char *filename;
544  AVFormatContext *oc;
545  const AVCodec *audio_codec, *video_codec;
546  int ret;
547  int have_video = 0, have_audio = 0;
548  int encode_video = 0, encode_audio = 0;
549  AVDictionary *opt = NULL;
550  int i;
551 
552  if (argc < 2) {
553  printf("usage: %s output_file\n"
554  "API example program to output a media file with libavformat.\n"
555  "This program generates a synthetic audio and video stream, encodes and\n"
556  "muxes them into a file named output_file.\n"
557  "The output format is automatically guessed according to the file extension.\n"
558  "Raw images can also be output by using '%%d' in the filename.\n"
559  "\n", argv[0]);
560  return 1;
561  }
562 
563  filename = argv[1];
564  for (i = 2; i+1 < argc; i+=2) {
565  if (!strcmp(argv[i], "-flags") || !strcmp(argv[i], "-fflags"))
566  av_dict_set(&opt, argv[i]+1, argv[i+1], 0);
567  }
568 
569  /* allocate the output media context */
570  avformat_alloc_output_context2(&oc, NULL, NULL, filename);
571  if (!oc) {
572  printf("Could not deduce output format from file extension: using MPEG.\n");
573  avformat_alloc_output_context2(&oc, NULL, "mpeg", filename);
574  }
575  if (!oc)
576  return 1;
577 
578  fmt = oc->oformat;
579 
580  /* Add the audio and video streams using the default format codecs
581  * and initialize the codecs. */
582  if (fmt->video_codec != AV_CODEC_ID_NONE) {
583  add_stream(&video_st, oc, &video_codec, fmt->video_codec);
584  have_video = 1;
585  encode_video = 1;
586  }
587  if (fmt->audio_codec != AV_CODEC_ID_NONE) {
588  add_stream(&audio_st, oc, &audio_codec, fmt->audio_codec);
589  have_audio = 1;
590  encode_audio = 1;
591  }
592 
593  /* Now that all the parameters are set, we can open the audio and
594  * video codecs and allocate the necessary encode buffers. */
595  if (have_video)
596  open_video(oc, video_codec, &video_st, opt);
597 
598  if (have_audio)
599  open_audio(oc, audio_codec, &audio_st, opt);
600 
601  av_dump_format(oc, 0, filename, 1);
602 
603  /* open the output file, if needed */
604  if (!(fmt->flags & AVFMT_NOFILE)) {
605  ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE);
606  if (ret < 0) {
607  fprintf(stderr, "Could not open '%s': %s\n", filename,
608  av_err2str(ret));
609  return 1;
610  }
611  }
612 
613  /* Write the stream header, if any. */
614  ret = avformat_write_header(oc, &opt);
615  if (ret < 0) {
616  fprintf(stderr, "Error occurred when opening output file: %s\n",
617  av_err2str(ret));
618  return 1;
619  }
620 
621  while (encode_video || encode_audio) {
622  /* select the stream to encode */
623  if (encode_video &&
624  (!encode_audio || av_compare_ts(video_st.next_pts, video_st.enc->time_base,
625  audio_st.next_pts, audio_st.enc->time_base) <= 0)) {
626  encode_video = !write_video_frame(oc, &video_st);
627  } else {
628  encode_audio = !write_audio_frame(oc, &audio_st);
629  }
630  }
631 
632  /* Write the trailer, if any. The trailer must be written before you
633  * close the CodecContexts open when you wrote the header; otherwise
634  * av_write_trailer() may try to use memory that was freed on
635  * av_codec_close(). */
636  av_write_trailer(oc);
637 
638  /* Close each codec. */
639  if (have_video)
640  close_stream(oc, &video_st);
641  if (have_audio)
642  close_stream(oc, &audio_st);
643 
644  if (!(fmt->flags & AVFMT_NOFILE))
645  /* Close the output file. */
646  avio_closep(&oc->pb);
647 
648  /* free the stream */
650 
651  return 0;
652 }
av_packet_unref
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:404
AVCodec
AVCodec.
Definition: codec.h:197
AV_SAMPLE_FMT_FLTP
@ AV_SAMPLE_FMT_FLTP
float, planar
Definition: samplefmt.h:69
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
avcodec_receive_packet
int avcodec_receive_packet(AVCodecContext *avctx, AVPacket *avpkt)
Read encoded data from the encoder.
Definition: encode.c:392
OutputStream::tincr
float tincr
Definition: muxing.c:65
OutputStream::samples_count
int samples_count
Definition: muxing.c:60
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
opt.h
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4375
OutputStream::enc
AVCodecContext * enc
Definition: muxing.c:56
av_compare_ts
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.
Definition: mathematics.c:146
alloc_picture
static AVFrame * alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
Definition: muxing.c:387
av_frame_get_buffer
int av_frame_get_buffer(AVFrame *frame, int align)
Allocate new buffer(s) for audio or video data.
Definition: frame.c:246
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
avcodec_parameters_from_context
int avcodec_parameters_from_context(AVCodecParameters *par, const AVCodecContext *codec)
Fill the parameters struct based on the values from the supplied codec context.
Definition: codec_par.c:90
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:112
avcodec_find_encoder
const AVCodec * avcodec_find_encoder(enum AVCodecID id)
Find a registered encoder with a matching codec ID.
Definition: allcodecs.c:910
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
av_frame_make_writable
int av_frame_make_writable(AVFrame *frame)
Ensure that the frame data is writable, avoiding data copy if possible.
Definition: frame.c:490
AVFormatContext::streams
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1175
AVFrame::pts
int64_t pts
Presentation timestamp in time_base units (time when frame should be shown to user).
Definition: frame.h:396
AVFrame::width
int width
Definition: frame.h:361
fill_yuv_image
static void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height)
Definition: muxing.c:455
open_audio
static void open_audio(AVFormatContext *oc, const AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
Definition: muxing.c:246
write_frame
static int write_frame(AVFormatContext *fmt_ctx, AVCodecContext *c, AVStream *st, AVFrame *frame)
Definition: muxing.c:82
AVPacket::duration
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:391
mathematics.h
sws_scale
int attribute_align_arg sws_scale(struct SwsContext *c, const uint8_t *const srcSlice[], const int srcStride[], int srcSliceY, int srcSliceH, uint8_t *const dst[], const int dstStride[])
swscale wrapper, so we don't need to export the SwsContext.
Definition: swscale.c:863
AVDictionary
Definition: dict.c:30
sample_rate
sample_rate
Definition: ffmpeg_filter.c:156
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:317
AV_CODEC_FLAG_GLOBAL_HEADER
#define AV_CODEC_FLAG_GLOBAL_HEADER
Place global headers in extradata instead of every keyframe.
Definition: avcodec.h:264
get_video_frame
static AVFrame * get_video_frame(OutputStream *ost)
Definition: muxing.c:476
STREAM_PIX_FMT
#define STREAM_PIX_FMT
Definition: muxing.c:49
OutputStream::next_pts
int64_t next_pts
Definition: muxing.c:59
write_audio_frame
static int write_audio_frame(AVFormatContext *oc, OutputStream *ost)
Definition: muxing.c:341
OutputStream::tmp_frame
AVFrame * tmp_frame
Definition: muxing.c:63
AV_ROUND_UP
@ AV_ROUND_UP
Round toward +infinity.
Definition: mathematics.h:83
AV_CH_LAYOUT_STEREO
#define AV_CH_LAYOUT_STEREO
Definition: channel_layout.h:91
open_video
static void open_video(AVFormatContext *oc, const AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
Definition: muxing.c:410
swr_get_delay
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.
Definition: swresample.c:867
main
int main(int argc, char **argv)
Definition: muxing.c:539
av_frame_alloc
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:99
avassert.h
pkt
AVPacket * pkt
Definition: movenc.c:59
OutputStream::swr_ctx
struct SwrContext * swr_ctx
Definition: muxing.c:68
av_dump_format
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,...
Definition: dump.c:620
swr_init
av_cold int swr_init(struct SwrContext *s)
Initialize context after user parameters have been set.
Definition: swresample.c:152
alloc_audio_frame
static AVFrame * alloc_audio_frame(enum AVSampleFormat sample_fmt, uint64_t channel_layout, int sample_rate, int nb_samples)
Definition: muxing.c:218
get_audio_frame
static AVFrame * get_audio_frame(OutputStream *ost)
Definition: muxing.c:312
avcodec_alloc_context3
AVCodecContext * avcodec_alloc_context3(const AVCodec *codec)
Allocate an AVCodecContext and set its fields to default values.
Definition: options.c:141
width
#define width
OutputStream::frame
AVFrame * frame
Definition: muxing.c:62
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
STREAM_DURATION
#define STREAM_DURATION
Definition: muxing.c:47
swr_alloc
av_cold struct SwrContext * swr_alloc(void)
Allocate SwrContext.
Definition: options.c:150
AVOutputFormat::audio_codec
enum AVCodecID audio_codec
default audio codec
Definition: avformat.h:506
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
AVIO_FLAG_WRITE
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:656
swr_convert
int attribute_align_arg swr_convert(struct SwrContext *s, uint8_t *out_arg[SWR_CH_MAX], int out_count, const uint8_t *in_arg[SWR_CH_MAX], int in_count)
Definition: swresample.c:714
av_rescale_q
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
Rescale a 64-bit integer by 2 rational numbers.
Definition: mathematics.c:141
pix_fmt
static enum AVPixelFormat pix_fmt
Definition: demuxing_decoding.c:41
log_packet
static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt)
Definition: muxing.c:71
codec_id
enum AVCodecID codec_id
Definition: vaapi_decode.c:369
AV_PIX_FMT_YUV420P
@ AV_PIX_FMT_YUV420P
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:66
SwrContext
The libswresample context.
Definition: swresample_internal.h:95
avformat_write_header
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.
Definition: mux.c:469
if
if(ret)
Definition: filter_design.txt:179
AVFormatContext
Format I/O context.
Definition: avformat.h:1107
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:994
AVStream::time_base
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented.
Definition: avformat.h:870
NULL
#define NULL
Definition: coverity.c:32
fmt_ctx
static AVFormatContext * fmt_ctx
Definition: demuxing_decoding.c:38
avcodec_free_context
void avcodec_free_context(AVCodecContext **avctx)
Free the codec context and everything associated with it and write NULL to the provided pointer.
Definition: options.c:156
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
AVFormatContext::pb
AVIOContext * pb
I/O context.
Definition: avformat.h:1149
AV_CODEC_CAP_VARIABLE_FRAME_SIZE
#define AV_CODEC_CAP_VARIABLE_FRAME_SIZE
Audio encoder supports receiving a different number of samples in each call.
Definition: codec.h:129
avcodec_open2
int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options)
Initialize the AVCodecContext to use the given AVCodec.
Definition: avcodec.c:137
OutputStream::sws_ctx
struct SwsContext * sws_ctx
Definition: muxing.c:67
audio_st
AVStream * audio_st
Definition: movenc.c:60
swresample.h
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
av_get_channel_layout_nb_channels
int av_get_channel_layout_nb_channels(uint64_t channel_layout)
Return the number of channels in the channel layout.
Definition: channel_layout.c:226
av_opt_set_int
int av_opt_set_int(void *obj, const char *name, int64_t val, int search_flags)
Definition: opt.c:586
AV_CODEC_ID_MPEG1VIDEO
@ AV_CODEC_ID_MPEG1VIDEO
Definition: codec_id.h:51
AVCodecID
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: codec_id.h:47
for
for(j=16;j >0;--j)
Definition: h264pred_template.c:469
AVFormatContext::nb_streams
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1163
AVOutputFormat::flags
int flags
can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS,...
Definition: avformat.h:515
AVCodecContext::time_base
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented.
Definition: avcodec.h:502
av_rescale_rnd
int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding rnd)
Rescale a 64-bit integer with specified rounding.
Definition: mathematics.c:57
av_ts2timestr
#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
SCALE_FLAGS
#define SCALE_FLAGS
Definition: muxing.c:51
sws_getContext
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.
Definition: utils.c:1913
av_err2str
#define av_err2str(errnum)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: error.h:121
video_st
AVStream * video_st
Definition: movenc.c:60
swr_free
av_cold void swr_free(SwrContext **ss)
Free the given SwrContext and set the pointer to NULL.
Definition: swresample.c:137
AVFMT_NOFILE
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:463
printf
printf("static const uint8_t my_array[100] = {\n")
AVFrame::format
int format
format of the frame, -1 if unknown or unset Values correspond to enum AVPixelFormat for video frames,...
Definition: frame.h:376
AVPacket::dts
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed.
Definition: packet.h:372
height
#define height
OutputStream::t
float t
Definition: muxing.c:65
av_dict_free
void av_dict_free(AVDictionary **pm)
Free all the memory allocated for an AVDictionary struct and all keys and values.
Definition: dict.c:203
av_packet_rescale_ts
void av_packet_rescale_ts(AVPacket *pkt, AVRational src_tb, AVRational dst_tb)
Convert valid timing fields (timestamps / durations) in a packet from one timebase to another.
Definition: avpacket.c:507
M_PI
#define M_PI
Definition: mathematics.h:52
AVCodecContext::channels
int channels
number of audio channels
Definition: avcodec.h:989
avcodec_get_name
const char * avcodec_get_name(enum AVCodecID id)
Get the name of a codec.
Definition: utils.c:448
avio_closep
int avio_closep(AVIOContext **s)
Close the resource accessed by the AVIOContext *s, free it and set the pointer pointing to it to NULL...
Definition: aviobuf.c:1175
av_write_trailer
int av_write_trailer(AVFormatContext *s)
Write the stream trailer to an output media file and free the file private data.
Definition: mux.c:1237
i
int i
Definition: input.c:406
AVFMT_GLOBALHEADER
#define AVFMT_GLOBALHEADER
Format wants global header.
Definition: avformat.h:466
AV_CODEC_ID_NONE
@ AV_CODEC_ID_NONE
Definition: codec_id.h:48
AVOutputFormat
Definition: avformat.h:495
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:366
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
AV_SAMPLE_FMT_S16
@ AV_SAMPLE_FMT_S16
signed 16 bits
Definition: samplefmt.h:61
avcodec_send_frame
int avcodec_send_frame(AVCodecContext *avctx, const AVFrame *frame)
Supply a raw video or audio frame to the encoder.
Definition: encode.c:361
avcodec.h
AVStream::id
int id
Format-specific stream ID.
Definition: avformat.h:854
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:847
OutputStream::tincr2
float tincr2
Definition: muxing.c:65
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
AVFormatContext::oformat
const struct AVOutputFormat * oformat
The output container format.
Definition: avformat.h:1126
avformat.h
ost
OutputStream * ost
Definition: ffmpeg_filter.c:163
AVCodecContext
main external API structure.
Definition: avcodec.h:379
AVFrame::height
int height
Definition: frame.h:361
AVStream::index
int index
stream index in AVFormatContext
Definition: avformat.h:848
channel_layout.h
sws_freeContext
void sws_freeContext(struct SwsContext *swsContext)
Free the swscaler context swsContext.
Definition: utils.c:2244
avformat_free_context
void avformat_free_context(AVFormatContext *s)
Free an AVFormatContext and all its streams.
Definition: utils.c:4302
AVOutputFormat::video_codec
enum AVCodecID video_codec
default video codec
Definition: avformat.h:507
avio_open
int avio_open(AVIOContext **s, const char *url, int flags)
Create and initialize a AVIOContext for accessing the resource indicated by url.
Definition: aviobuf.c:1120
AVPacket::stream_index
int stream_index
Definition: packet.h:375
close_stream
static void close_stream(AVFormatContext *oc, OutputStream *ost)
Definition: muxing.c:527
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVPacket
This structure stores compressed data.
Definition: packet.h:350
STREAM_FRAME_RATE
#define STREAM_FRAME_RATE
Definition: muxing.c:48
av_interleaved_write_frame
int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
Write a packet to an output media file ensuring correct interleaving.
Definition: mux.c:1222
av_dict_set
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Definition: dict.c:70
av_dict_copy
int av_dict_copy(AVDictionary **dst, const AVDictionary *src, int flags)
Copy entries from one AVDictionary struct into another.
Definition: dict.c:217
add_stream
static void add_stream(OutputStream *ost, AVFormatContext *oc, const AVCodec **codec, enum AVCodecID codec_id)
Definition: muxing.c:124
write_video_frame
static int write_video_frame(AVFormatContext *oc, OutputStream *ost)
Definition: muxing.c:522
timestamp.h
OutputStream
Definition: muxing.c:54
OutputStream::st
AVStream * st
Definition: muxing.c:55
AVFrame::linesize
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:334
av_ts2str
#define av_ts2str(ts)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: timestamp.h:54
avformat_alloc_output_context2
int avformat_alloc_output_context2(AVFormatContext **ctx, const AVOutputFormat *oformat, const char *format_name, const char *filename)
Allocate an AVFormatContext for an output format.
Definition: mux.c:137
int
int
Definition: ffmpeg_filter.c:156
SwsContext
Definition: swscale_internal.h:283
av_opt_set_sample_fmt
int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags)
Definition: opt.c:704
AV_CODEC_ID_MPEG2VIDEO
@ AV_CODEC_ID_MPEG2VIDEO
preferred ID for MPEG-1/2 video decoding
Definition: codec_id.h:52
swscale.h