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 */
60 
63 
65 
66  float t, tincr, tincr2;
67 
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
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) {
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 */
106  av_packet_rescale_ts(pkt, c->time_base, st->time_base);
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",
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)
210  c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
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 
266  if (c->codec->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE)
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);
273  ost->tmp_frame = alloc_audio_frame(AV_SAMPLE_FMT_S16, &c->ch_layout,
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 = swr_get_delay(ost->swr_ctx, c->sample_rate) + frame->nb_samples;
351  av_assert0(dst_nb_samples == frame->nb_samples);
352 
353  /* when we pass a frame to the encoder, it may keep a reference to it
354  * internally;
355  * make sure we do not overwrite it here
356  */
357  ret = av_frame_make_writable(ost->frame);
358  if (ret < 0)
359  exit(1);
360 
361  /* convert to destination format */
362  ret = swr_convert(ost->swr_ctx,
363  ost->frame->data, dst_nb_samples,
364  (const uint8_t **)frame->data, frame->nb_samples);
365  if (ret < 0) {
366  fprintf(stderr, "Error while converting\n");
367  exit(1);
368  }
369  frame = ost->frame;
370 
371  frame->pts = av_rescale_q(ost->samples_count, (AVRational){1, c->sample_rate}, c->time_base);
372  ost->samples_count += dst_nb_samples;
373  }
374 
375  return write_frame(oc, c, ost->st, frame, ost->tmp_pkt);
376 }
377 
378 /**************************************************************/
379 /* video output */
380 
382 {
383  AVFrame *frame;
384  int ret;
385 
386  frame = av_frame_alloc();
387  if (!frame)
388  return NULL;
389 
390  frame->format = pix_fmt;
391  frame->width = width;
392  frame->height = height;
393 
394  /* allocate the buffers for the frame data */
396  if (ret < 0) {
397  fprintf(stderr, "Could not allocate frame data.\n");
398  exit(1);
399  }
400 
401  return frame;
402 }
403 
404 static void open_video(AVFormatContext *oc, const AVCodec *codec,
405  OutputStream *ost, AVDictionary *opt_arg)
406 {
407  int ret;
408  AVCodecContext *c = ost->enc;
409  AVDictionary *opt = NULL;
410 
411  av_dict_copy(&opt, opt_arg, 0);
412 
413  /* open the codec */
414  ret = avcodec_open2(c, codec, &opt);
415  av_dict_free(&opt);
416  if (ret < 0) {
417  fprintf(stderr, "Could not open video codec: %s\n", av_err2str(ret));
418  exit(1);
419  }
420 
421  /* allocate and init a re-usable frame */
422  ost->frame = alloc_frame(c->pix_fmt, c->width, c->height);
423  if (!ost->frame) {
424  fprintf(stderr, "Could not allocate video frame\n");
425  exit(1);
426  }
427 
428  /* If the output format is not YUV420P, then a temporary YUV420P
429  * picture is needed too. It is then converted to the required
430  * output format. */
431  ost->tmp_frame = NULL;
432  if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
433  ost->tmp_frame = alloc_frame(AV_PIX_FMT_YUV420P, c->width, c->height);
434  if (!ost->tmp_frame) {
435  fprintf(stderr, "Could not allocate temporary video frame\n");
436  exit(1);
437  }
438  }
439 
440  /* copy the stream parameters to the muxer */
442  if (ret < 0) {
443  fprintf(stderr, "Could not copy the stream parameters\n");
444  exit(1);
445  }
446 }
447 
448 /* Prepare a dummy image. */
449 static void fill_yuv_image(AVFrame *pict, int frame_index,
450  int width, int height)
451 {
452  int x, y, i;
453 
454  i = frame_index;
455 
456  /* Y */
457  for (y = 0; y < height; y++)
458  for (x = 0; x < width; x++)
459  pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
460 
461  /* Cb and Cr */
462  for (y = 0; y < height / 2; y++) {
463  for (x = 0; x < width / 2; x++) {
464  pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
465  pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
466  }
467  }
468 }
469 
471 {
472  AVCodecContext *c = ost->enc;
473 
474  /* check if we want to generate more frames */
475  if (av_compare_ts(ost->next_pts, c->time_base,
476  STREAM_DURATION, (AVRational){ 1, 1 }) > 0)
477  return NULL;
478 
479  /* when we pass a frame to the encoder, it may keep a reference to it
480  * internally; make sure we do not overwrite it here */
481  if (av_frame_make_writable(ost->frame) < 0)
482  exit(1);
483 
484  if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
485  /* as we only generate a YUV420P picture, we must convert it
486  * to the codec pixel format if needed */
487  if (!ost->sws_ctx) {
488  ost->sws_ctx = sws_getContext(c->width, c->height,
490  c->width, c->height,
491  c->pix_fmt,
493  if (!ost->sws_ctx) {
494  fprintf(stderr,
495  "Could not initialize the conversion context\n");
496  exit(1);
497  }
498  }
499  fill_yuv_image(ost->tmp_frame, ost->next_pts, c->width, c->height);
500  sws_scale(ost->sws_ctx, (const uint8_t * const *) ost->tmp_frame->data,
501  ost->tmp_frame->linesize, 0, c->height, ost->frame->data,
502  ost->frame->linesize);
503  } else {
504  fill_yuv_image(ost->frame, ost->next_pts, c->width, c->height);
505  }
506 
507  ost->frame->pts = ost->next_pts++;
508 
509  return ost->frame;
510 }
511 
512 /*
513  * encode one video frame and send it to the muxer
514  * return 1 when encoding is finished, 0 otherwise
515  */
517 {
518  return write_frame(oc, ost->enc, ost->st, get_video_frame(ost), ost->tmp_pkt);
519 }
520 
522 {
523  avcodec_free_context(&ost->enc);
524  av_frame_free(&ost->frame);
525  av_frame_free(&ost->tmp_frame);
526  av_packet_free(&ost->tmp_pkt);
527  sws_freeContext(ost->sws_ctx);
528  swr_free(&ost->swr_ctx);
529 }
530 
531 /**************************************************************/
532 /* media file output */
533 
534 int main(int argc, char **argv)
535 {
536  OutputStream video_st = { 0 }, audio_st = { 0 };
537  const AVOutputFormat *fmt;
538  const char *filename;
539  AVFormatContext *oc;
540  const AVCodec *audio_codec, *video_codec;
541  int ret;
542  int have_video = 0, have_audio = 0;
543  int encode_video = 0, encode_audio = 0;
544  AVDictionary *opt = NULL;
545  int i;
546 
547  if (argc < 2) {
548  printf("usage: %s output_file\n"
549  "API example program to output a media file with libavformat.\n"
550  "This program generates a synthetic audio and video stream, encodes and\n"
551  "muxes them into a file named output_file.\n"
552  "The output format is automatically guessed according to the file extension.\n"
553  "Raw images can also be output by using '%%d' in the filename.\n"
554  "\n", argv[0]);
555  return 1;
556  }
557 
558  filename = argv[1];
559  for (i = 2; i+1 < argc; i+=2) {
560  if (!strcmp(argv[i], "-flags") || !strcmp(argv[i], "-fflags"))
561  av_dict_set(&opt, argv[i]+1, argv[i+1], 0);
562  }
563 
564  /* allocate the output media context */
565  avformat_alloc_output_context2(&oc, NULL, NULL, filename);
566  if (!oc) {
567  printf("Could not deduce output format from file extension: using MPEG.\n");
568  avformat_alloc_output_context2(&oc, NULL, "mpeg", filename);
569  }
570  if (!oc)
571  return 1;
572 
573  fmt = oc->oformat;
574 
575  /* Add the audio and video streams using the default format codecs
576  * and initialize the codecs. */
577  if (fmt->video_codec != AV_CODEC_ID_NONE) {
578  add_stream(&video_st, oc, &video_codec, fmt->video_codec);
579  have_video = 1;
580  encode_video = 1;
581  }
582  if (fmt->audio_codec != AV_CODEC_ID_NONE) {
583  add_stream(&audio_st, oc, &audio_codec, fmt->audio_codec);
584  have_audio = 1;
585  encode_audio = 1;
586  }
587 
588  /* Now that all the parameters are set, we can open the audio and
589  * video codecs and allocate the necessary encode buffers. */
590  if (have_video)
591  open_video(oc, video_codec, &video_st, opt);
592 
593  if (have_audio)
594  open_audio(oc, audio_codec, &audio_st, opt);
595 
596  av_dump_format(oc, 0, filename, 1);
597 
598  /* open the output file, if needed */
599  if (!(fmt->flags & AVFMT_NOFILE)) {
600  ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE);
601  if (ret < 0) {
602  fprintf(stderr, "Could not open '%s': %s\n", filename,
603  av_err2str(ret));
604  return 1;
605  }
606  }
607 
608  /* Write the stream header, if any. */
609  ret = avformat_write_header(oc, &opt);
610  if (ret < 0) {
611  fprintf(stderr, "Error occurred when opening output file: %s\n",
612  av_err2str(ret));
613  return 1;
614  }
615 
616  while (encode_video || encode_audio) {
617  /* select the stream to encode */
618  if (encode_video &&
619  (!encode_audio || av_compare_ts(video_st.next_pts, video_st.enc->time_base,
620  audio_st.next_pts, audio_st.enc->time_base) <= 0)) {
621  encode_video = !write_video_frame(oc, &video_st);
622  } else {
623  encode_audio = !write_audio_frame(oc, &audio_st);
624  }
625  }
626 
627  av_write_trailer(oc);
628 
629  /* Close each codec. */
630  if (have_video)
631  close_stream(oc, &video_st);
632  if (have_audio)
633  close_stream(oc, &audio_st);
634 
635  if (!(fmt->flags & AVFMT_NOFILE))
636  /* Close the output file. */
637  avio_closep(&oc->pb);
638 
639  /* free the stream */
641 
642  return 0;
643 }
AVCodec
AVCodec.
Definition: codec.h:187
AV_SAMPLE_FMT_FLTP
@ AV_SAMPLE_FMT_FLTP
float, planar
Definition: samplefmt.h:66
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:71
avcodec_receive_packet
int avcodec_receive_packet(AVCodecContext *avctx, AVPacket *avpkt)
Read encoded data from the encoder.
Definition: encode.c:541
OutputStream::tincr
float tincr
Definition: mux.c:66
OutputStream::samples_count
int samples_count
Definition: mux.c:59
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
OutputStream::enc
AVCodecContext * enc
Definition: mux.c:55
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:147
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:304
AV_CHANNEL_LAYOUT_STEREO
#define AV_CHANNEL_LAYOUT_STEREO
Definition: channel_layout.h:393
avformat_alloc_output_context2
int avformat_alloc_output_context2(AVFormatContext **avctx, const AVOutputFormat *oformat, const char *format, const char *filename)
Allocate an AVFormatContext for an output format.
Definition: mux.c:95
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const struct AVCodec *c)
Add a new stream to a media file.
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
alloc_audio_frame
static AVFrame * alloc_audio_frame(enum AVSampleFormat sample_fmt, const AVChannelLayout *channel_layout, int sample_rate, int nb_samples)
Definition: mux.c:216
int64_t
long long int64_t
Definition: coverity.c:34
write_frame
static int write_frame(AVFormatContext *fmt_ctx, AVCodecContext *c, AVStream *st, AVFrame *frame, AVPacket *pkt)
Definition: mux.c:83
sws_freeContext
void sws_freeContext(SwsContext *swsContext)
Free the swscaler context swsContext.
Definition: utils.c:2447
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:162
avcodec_find_encoder
const AVCodec * avcodec_find_encoder(enum AVCodecID id)
Find a registered encoder with a matching codec ID.
Definition: allcodecs.c:1007
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:389
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:678
AVFormatContext::streams
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1368
avio_open
int avio_open(AVIOContext **s, const char *filename, int flags)
Create and initialize a AVIOContext for accessing the resource indicated by url.
Definition: avio.c:497
AVPacket::duration
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:557
mathematics.h
AVDictionary
Definition: dict.c:34
ost
static AVStream * ost
Definition: vaapi_transcode.c:42
av_packet_free
void av_packet_free(AVPacket **pkt)
Free the packet, if the packet is reference counted, it will be unreferenced first.
Definition: packet.c:74
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:410
AV_CODEC_FLAG_GLOBAL_HEADER
#define AV_CODEC_FLAG_GLOBAL_HEADER
Place global headers in extradata instead of every keyframe.
Definition: avcodec.h:338
OutputStream::next_pts
int64_t next_pts
Definition: mux.c:58
OutputStream::tmp_frame
AVFrame * tmp_frame
Definition: mux.c:62
swr_convert
int attribute_align_arg swr_convert(struct SwrContext *s, uint8_t *const *out_arg, int out_count, const uint8_t *const *in_arg, int in_count)
Convert audio.
Definition: swresample.c:719
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:874
open_audio
static void open_audio(AVFormatContext *oc, const AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
Definition: mux.c:241
av_frame_alloc
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:150
avassert.h
pkt
AVPacket * pkt
Definition: movenc.c:60
OutputStream::swr_ctx
struct SwrContext * swr_ctx
Definition: mux.c:69
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:837
swr_init
av_cold int swr_init(struct SwrContext *s)
Initialize context after user parameters have been set.
Definition: swresample.c:140
avcodec_alloc_context3
AVCodecContext * avcodec_alloc_context3(const AVCodec *codec)
Allocate an AVCodecContext and set its fields to default values.
Definition: options.c:149
get_audio_frame
static AVFrame * get_audio_frame(OutputStream *ost)
Definition: mux.c:307
pix_fmt
static enum AVPixelFormat pix_fmt
Definition: demux_decode.c:41
OutputStream::frame
AVFrame * frame
Definition: mux.c:61
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
swr_alloc
av_cold struct SwrContext * swr_alloc(void)
Allocate SwrContext.
Definition: options.c:148
AVOutputFormat::audio_codec
enum AVCodecID audio_codec
default audio codec
Definition: avformat.h:520
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:40
AVIO_FLAG_WRITE
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:618
open_video
static void open_video(AVFormatContext *oc, const AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
Definition: mux.c:404
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:142
codec_id
enum AVCodecID codec_id
Definition: vaapi_decode.c:410
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:73
SwrContext
The libswresample context.
Definition: swresample_internal.h:95
avformat_write_header
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:488
if
if(ret)
Definition: filter_design.txt:179
AVFormatContext
Format I/O context.
Definition: avformat.h:1300
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:771
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:787
NULL
#define NULL
Definition: coverity.c:32
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:164
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
get_video_frame
static AVFrame * get_video_frame(OutputStream *ost)
Definition: mux.c:470
AVFormatContext::pb
AVIOContext * pb
I/O context.
Definition: avformat.h:1342
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:128
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:143
log_packet
static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt)
Definition: mux.c:72
OutputStream::sws_ctx
struct SwsContext * sws_ctx
Definition: mux.c:68
audio_st
AVStream * audio_st
Definition: movenc.c:61
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_opt_set_int
int av_opt_set_int(void *obj, const char *name, int64_t val, int search_flags)
Definition: opt.c:880
AV_CODEC_ID_MPEG1VIDEO
@ AV_CODEC_ID_MPEG1VIDEO
Definition: codec_id.h:53
AVCodecID
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: codec_id.h:49
AVFormatContext::nb_streams
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1356
AVOutputFormat::flags
int flags
can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS,...
Definition: avformat.h:529
fmt_ctx
static AVFormatContext * fmt_ctx
Definition: decode_filter_audio.c:46
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:83
STREAM_FRAME_RATE
#define STREAM_FRAME_RATE
Definition: mux.c:47
height
#define height
Definition: dsp.h:85
AVChannelLayout
An AVChannelLayout holds information about the channel layout of audio data.
Definition: channel_layout.h:317
av_opt_set_chlayout
int av_opt_set_chlayout(void *obj, const char *name, const AVChannelLayout *channel_layout, int search_flags)
Definition: opt.c:1000
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:122
for
for(k=2;k<=8;++k)
Definition: h264pred_template.c:425
SCALE_FLAGS
#define SCALE_FLAGS
Definition: mux.c:50
alloc_frame
static AVFrame * alloc_frame(enum AVPixelFormat pix_fmt, int width, int height)
Definition: mux.c:381
video_st
AVStream * video_st
Definition: movenc.c:61
main
int main(int argc, char **argv)
Definition: mux.c:534
swr_free
av_cold void swr_free(SwrContext **ss)
Free the given SwrContext and set the pointer to NULL.
Definition: swresample.c:121
AVFMT_NOFILE
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:468
printf
printf("static const uint8_t my_array[100] = {\n")
AVPacket::dts
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed.
Definition: packet.h:538
OutputStream::t
float t
Definition: mux.c:66
av_packet_alloc
AVPacket * av_packet_alloc(void)
Allocate an AVPacket and set its fields to default values.
Definition: packet.c:63
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:223
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: packet.c:533
STREAM_DURATION
#define STREAM_DURATION
Definition: mux.c:46
M_PI
#define M_PI
Definition: mathematics.h:67
avcodec_get_name
const char * avcodec_get_name(enum AVCodecID id)
Get the name of a codec.
Definition: utils.c:409
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:1298
AVFMT_GLOBALHEADER
#define AVFMT_GLOBALHEADER
Format wants global header.
Definition: avformat.h:478
AV_CODEC_ID_NONE
@ AV_CODEC_ID_NONE
Definition: codec_id.h:50
AVOutputFormat
Definition: avformat.h:509
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:532
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:55
AV_SAMPLE_FMT_S16
@ AV_SAMPLE_FMT_S16
signed 16 bits
Definition: samplefmt.h:58
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:508
avcodec.h
AVStream::id
int id
Format-specific stream ID.
Definition: avformat.h:760
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:748
OutputStream::tincr2
float tincr2
Definition: mux.c:66
OutputStream::tmp_pkt
AVPacket * tmp_pkt
Definition: mux.c:64
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:1319
sws_getContext
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:2116
avformat.h
STREAM_PIX_FMT
#define STREAM_PIX_FMT
Definition: mux.c:48
write_audio_frame
static int write_audio_frame(AVFormatContext *oc, OutputStream *ost)
Definition: mux.c:336
AVCodecContext
main external API structure.
Definition: avcodec.h:451
AVStream::index
int index
stream index in AVFormatContext
Definition: avformat.h:754
write_video_frame
static int write_video_frame(AVFormatContext *oc, OutputStream *ost)
Definition: mux.c:516
channel_layout.h
sws_scale
int attribute_align_arg sws_scale(SwsContext *sws, 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:1427
close_stream
static void close_stream(AVFormatContext *oc, OutputStream *ost)
Definition: mux.c:521
avformat_free_context
void avformat_free_context(AVFormatContext *s)
Free an AVFormatContext and all its streams.
Definition: avformat.c:149
AVOutputFormat::video_codec
enum AVCodecID video_codec
default video codec
Definition: avformat.h:521
fill_yuv_image
static void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height)
Definition: mux.c:449
AVPacket::stream_index
int stream_index
Definition: packet.h:541
av_channel_layout_copy
int av_channel_layout_copy(AVChannelLayout *dst, const AVChannelLayout *src)
Make a copy of a channel layout.
Definition: channel_layout.c:447
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
avcodec_parameters_from_context
int avcodec_parameters_from_context(struct AVCodecParameters *par, const AVCodecContext *codec)
Fill the parameters struct based on the values from the supplied codec context.
Definition: codec_par.c:137
AVPacket
This structure stores compressed data.
Definition: packet.h:516
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: avio.c:649
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:1283
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:88
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:237
timestamp.h
OutputStream
Definition: mux.c:53
OutputStream::st
AVStream * st
Definition: mux.c:54
AVFrame::linesize
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:434
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
width
#define width
Definition: dsp.h:85
SwsContext
Main external API structure.
Definition: swscale.h:174
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:979
AV_CODEC_ID_MPEG2VIDEO
@ AV_CODEC_ID_MPEG2VIDEO
preferred ID for MPEG-1/2 video decoding
Definition: codec_id.h:54
add_stream
static void add_stream(OutputStream *ost, AVFormatContext *oc, const AVCodec **codec, enum AVCodecID codec_id)
Definition: mux.c:125
swscale.h