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 <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 
64  float t, tincr, tincr2;
65 
68 } OutputStream;
69 
70 static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt)
71 {
73 
74  printf("pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
75  av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
76  av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
78  pkt->stream_index);
79 }
80 
82  AVStream *st, AVFrame *frame)
83 {
84  int ret;
85 
86  // send the frame to the encoder
88  if (ret < 0) {
89  fprintf(stderr, "Error sending a frame to the encoder: %s\n",
90  av_err2str(ret));
91  exit(1);
92  }
93 
94  while (ret >= 0) {
95  AVPacket pkt = { 0 };
96 
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. */
113  if (ret < 0) {
114  fprintf(stderr, "Error while writing output packet: %s\n", av_err2str(ret));
115  exit(1);
116  }
117  }
118 
119  return ret == AVERROR_EOF ? 1 : 0;
120 }
121 
122 /* Add an output stream. */
124  const AVCodec **codec,
125  enum AVCodecID codec_id)
126 {
127  AVCodecContext *c;
128  int i;
129 
130  /* find the encoder */
131  *codec = avcodec_find_encoder(codec_id);
132  if (!(*codec)) {
133  fprintf(stderr, "Could not find encoder for '%s'\n",
135  exit(1);
136  }
137 
138  ost->st = avformat_new_stream(oc, NULL);
139  if (!ost->st) {
140  fprintf(stderr, "Could not allocate stream\n");
141  exit(1);
142  }
143  ost->st->id = oc->nb_streams-1;
144  c = avcodec_alloc_context3(*codec);
145  if (!c) {
146  fprintf(stderr, "Could not alloc an encoding context\n");
147  exit(1);
148  }
149  ost->enc = c;
150 
151  switch ((*codec)->type) {
152  case AVMEDIA_TYPE_AUDIO:
153  c->sample_fmt = (*codec)->sample_fmts ?
154  (*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;
155  c->bit_rate = 64000;
156  c->sample_rate = 44100;
157  if ((*codec)->supported_samplerates) {
158  c->sample_rate = (*codec)->supported_samplerates[0];
159  for (i = 0; (*codec)->supported_samplerates[i]; i++) {
160  if ((*codec)->supported_samplerates[i] == 44100)
161  c->sample_rate = 44100;
162  }
163  }
164  c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
165  c->channel_layout = AV_CH_LAYOUT_STEREO;
166  if ((*codec)->channel_layouts) {
167  c->channel_layout = (*codec)->channel_layouts[0];
168  for (i = 0; (*codec)->channel_layouts[i]; i++) {
169  if ((*codec)->channel_layouts[i] == AV_CH_LAYOUT_STEREO)
170  c->channel_layout = AV_CH_LAYOUT_STEREO;
171  }
172  }
173  c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
174  ost->st->time_base = (AVRational){ 1, c->sample_rate };
175  break;
176 
177  case AVMEDIA_TYPE_VIDEO:
178  c->codec_id = codec_id;
179 
180  c->bit_rate = 400000;
181  /* Resolution must be a multiple of two. */
182  c->width = 352;
183  c->height = 288;
184  /* timebase: This is the fundamental unit of time (in seconds) in terms
185  * of which frame timestamps are represented. For fixed-fps content,
186  * timebase should be 1/framerate and timestamp increments should be
187  * identical to 1. */
189  c->time_base = ost->st->time_base;
190 
191  c->gop_size = 12; /* emit one intra frame every twelve frames at most */
192  c->pix_fmt = STREAM_PIX_FMT;
193  if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
194  /* just for testing, we also add B-frames */
195  c->max_b_frames = 2;
196  }
197  if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
198  /* Needed to avoid using macroblocks in which some coeffs overflow.
199  * This does not happen with normal video, it just happens here as
200  * the motion of the chroma plane does not match the luma plane. */
201  c->mb_decision = 2;
202  }
203  break;
204 
205  default:
206  break;
207  }
208 
209  /* Some formats want stream headers to be separate. */
210  if (oc->oformat->flags & AVFMT_GLOBALHEADER)
211  c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
212 }
213 
214 /**************************************************************/
215 /* audio output */
216 
217 static AVFrame *alloc_audio_frame(enum AVSampleFormat sample_fmt,
218  uint64_t channel_layout,
219  int sample_rate, int nb_samples)
220 {
222  int ret;
223 
224  if (!frame) {
225  fprintf(stderr, "Error allocating an audio frame\n");
226  exit(1);
227  }
228 
229  frame->format = sample_fmt;
230  frame->channel_layout = channel_layout;
231  frame->sample_rate = sample_rate;
232  frame->nb_samples = nb_samples;
233 
234  if (nb_samples) {
236  if (ret < 0) {
237  fprintf(stderr, "Error allocating an audio buffer\n");
238  exit(1);
239  }
240  }
241 
242  return frame;
243 }
244 
245 static void open_audio(AVFormatContext *oc, const AVCodec *codec,
246  OutputStream *ost, AVDictionary *opt_arg)
247 {
248  AVCodecContext *c;
249  int nb_samples;
250  int ret;
251  AVDictionary *opt = NULL;
252 
253  c = ost->enc;
254 
255  /* open it */
256  av_dict_copy(&opt, opt_arg, 0);
257  ret = avcodec_open2(c, codec, &opt);
258  av_dict_free(&opt);
259  if (ret < 0) {
260  fprintf(stderr, "Could not open audio codec: %s\n", av_err2str(ret));
261  exit(1);
262  }
263 
264  /* init signal generator */
265  ost->t = 0;
266  ost->tincr = 2 * M_PI * 110.0 / c->sample_rate;
267  /* increment frequency by 110 Hz per second */
268  ost->tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
269 
270  if (c->codec->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE)
271  nb_samples = 10000;
272  else
273  nb_samples = c->frame_size;
274 
275  ost->frame = alloc_audio_frame(c->sample_fmt, c->channel_layout,
276  c->sample_rate, nb_samples);
277  ost->tmp_frame = alloc_audio_frame(AV_SAMPLE_FMT_S16, c->channel_layout,
278  c->sample_rate, nb_samples);
279 
280  /* copy the stream parameters to the muxer */
282  if (ret < 0) {
283  fprintf(stderr, "Could not copy the stream parameters\n");
284  exit(1);
285  }
286 
287  /* create resampler context */
288  ost->swr_ctx = swr_alloc();
289  if (!ost->swr_ctx) {
290  fprintf(stderr, "Could not allocate resampler context\n");
291  exit(1);
292  }
293 
294  /* set options */
295  av_opt_set_int (ost->swr_ctx, "in_channel_count", c->channels, 0);
296  av_opt_set_int (ost->swr_ctx, "in_sample_rate", c->sample_rate, 0);
297  av_opt_set_sample_fmt(ost->swr_ctx, "in_sample_fmt", AV_SAMPLE_FMT_S16, 0);
298  av_opt_set_int (ost->swr_ctx, "out_channel_count", c->channels, 0);
299  av_opt_set_int (ost->swr_ctx, "out_sample_rate", c->sample_rate, 0);
300  av_opt_set_sample_fmt(ost->swr_ctx, "out_sample_fmt", c->sample_fmt, 0);
301 
302  /* initialize the resampling context */
303  if ((ret = swr_init(ost->swr_ctx)) < 0) {
304  fprintf(stderr, "Failed to initialize the resampling context\n");
305  exit(1);
306  }
307 }
308 
309 /* Prepare a 16 bit dummy audio frame of 'frame_size' samples and
310  * 'nb_channels' channels. */
312 {
314  int j, i, v;
315  int16_t *q = (int16_t*)frame->data[0];
316 
317  /* check if we want to generate more frames */
319  STREAM_DURATION, (AVRational){ 1, 1 }) > 0)
320  return NULL;
321 
322  for (j = 0; j <frame->nb_samples; j++) {
323  v = (int)(sin(ost->t) * 10000);
324  for (i = 0; i < ost->enc->channels; i++)
325  *q++ = v;
326  ost->t += ost->tincr;
327  ost->tincr += ost->tincr2;
328  }
329 
330  frame->pts = ost->next_pts;
331  ost->next_pts += frame->nb_samples;
332 
333  return frame;
334 }
335 
336 /*
337  * encode one audio frame and send it to the muxer
338  * return 1 when encoding is finished, 0 otherwise
339  */
341 {
342  AVCodecContext *c;
343  AVFrame *frame;
344  int ret;
345  int dst_nb_samples;
346 
347  c = ost->enc;
348 
350 
351  if (frame) {
352  /* convert samples from native format to destination codec format, using the resampler */
353  /* compute destination number of samples */
354  dst_nb_samples = av_rescale_rnd(swr_get_delay(ost->swr_ctx, c->sample_rate) + frame->nb_samples,
355  c->sample_rate, c->sample_rate, AV_ROUND_UP);
356  av_assert0(dst_nb_samples == frame->nb_samples);
357 
358  /* when we pass a frame to the encoder, it may keep a reference to it
359  * internally;
360  * make sure we do not overwrite it here
361  */
363  if (ret < 0)
364  exit(1);
365 
366  /* convert to destination format */
368  ost->frame->data, dst_nb_samples,
369  (const uint8_t **)frame->data, frame->nb_samples);
370  if (ret < 0) {
371  fprintf(stderr, "Error while converting\n");
372  exit(1);
373  }
374  frame = ost->frame;
375 
376  frame->pts = av_rescale_q(ost->samples_count, (AVRational){1, c->sample_rate}, c->time_base);
377  ost->samples_count += dst_nb_samples;
378  }
379 
380  return write_frame(oc, c, ost->st, frame);
381 }
382 
383 /**************************************************************/
384 /* video output */
385 
387 {
388  AVFrame *picture;
389  int ret;
390 
391  picture = av_frame_alloc();
392  if (!picture)
393  return NULL;
394 
395  picture->format = pix_fmt;
396  picture->width = width;
397  picture->height = height;
398 
399  /* allocate the buffers for the frame data */
400  ret = av_frame_get_buffer(picture, 0);
401  if (ret < 0) {
402  fprintf(stderr, "Could not allocate frame data.\n");
403  exit(1);
404  }
405 
406  return picture;
407 }
408 
409 static void open_video(AVFormatContext *oc, const AVCodec *codec,
410  OutputStream *ost, AVDictionary *opt_arg)
411 {
412  int ret;
413  AVCodecContext *c = ost->enc;
414  AVDictionary *opt = NULL;
415 
416  av_dict_copy(&opt, opt_arg, 0);
417 
418  /* open the codec */
419  ret = avcodec_open2(c, codec, &opt);
420  av_dict_free(&opt);
421  if (ret < 0) {
422  fprintf(stderr, "Could not open video codec: %s\n", av_err2str(ret));
423  exit(1);
424  }
425 
426  /* allocate and init a re-usable frame */
427  ost->frame = alloc_picture(c->pix_fmt, c->width, c->height);
428  if (!ost->frame) {
429  fprintf(stderr, "Could not allocate video frame\n");
430  exit(1);
431  }
432 
433  /* If the output format is not YUV420P, then a temporary YUV420P
434  * picture is needed too. It is then converted to the required
435  * output format. */
436  ost->tmp_frame = NULL;
437  if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
438  ost->tmp_frame = alloc_picture(AV_PIX_FMT_YUV420P, c->width, c->height);
439  if (!ost->tmp_frame) {
440  fprintf(stderr, "Could not allocate temporary picture\n");
441  exit(1);
442  }
443  }
444 
445  /* copy the stream parameters to the muxer */
447  if (ret < 0) {
448  fprintf(stderr, "Could not copy the stream parameters\n");
449  exit(1);
450  }
451 }
452 
453 /* Prepare a dummy image. */
454 static void fill_yuv_image(AVFrame *pict, int frame_index,
455  int width, int height)
456 {
457  int x, y, i;
458 
459  i = frame_index;
460 
461  /* Y */
462  for (y = 0; y < height; y++)
463  for (x = 0; x < width; x++)
464  pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
465 
466  /* Cb and Cr */
467  for (y = 0; y < height / 2; y++) {
468  for (x = 0; x < width / 2; x++) {
469  pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
470  pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
471  }
472  }
473 }
474 
476 {
477  AVCodecContext *c = ost->enc;
478 
479  /* check if we want to generate more frames */
480  if (av_compare_ts(ost->next_pts, c->time_base,
481  STREAM_DURATION, (AVRational){ 1, 1 }) > 0)
482  return NULL;
483 
484  /* when we pass a frame to the encoder, it may keep a reference to it
485  * internally; make sure we do not overwrite it here */
486  if (av_frame_make_writable(ost->frame) < 0)
487  exit(1);
488 
489  if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
490  /* as we only generate a YUV420P picture, we must convert it
491  * to the codec pixel format if needed */
492  if (!ost->sws_ctx) {
493  ost->sws_ctx = sws_getContext(c->width, c->height,
495  c->width, c->height,
496  c->pix_fmt,
498  if (!ost->sws_ctx) {
499  fprintf(stderr,
500  "Could not initialize the conversion context\n");
501  exit(1);
502  }
503  }
504  fill_yuv_image(ost->tmp_frame, ost->next_pts, c->width, c->height);
505  sws_scale(ost->sws_ctx, (const uint8_t * const *) ost->tmp_frame->data,
506  ost->tmp_frame->linesize, 0, c->height, ost->frame->data,
507  ost->frame->linesize);
508  } else {
509  fill_yuv_image(ost->frame, ost->next_pts, c->width, c->height);
510  }
511 
512  ost->frame->pts = ost->next_pts++;
513 
514  return ost->frame;
515 }
516 
517 /*
518  * encode one video frame and send it to the muxer
519  * return 1 when encoding is finished, 0 otherwise
520  */
522 {
523  return write_frame(oc, ost->enc, ost->st, get_video_frame(ost));
524 }
525 
527 {
532  swr_free(&ost->swr_ctx);
533 }
534 
535 /**************************************************************/
536 /* media file output */
537 
538 int main(int argc, char **argv)
539 {
540  OutputStream video_st = { 0 }, audio_st = { 0 };
541  const AVOutputFormat *fmt;
542  const char *filename;
543  AVFormatContext *oc;
544  const AVCodec *audio_codec, *video_codec;
545  int ret;
546  int have_video = 0, have_audio = 0;
547  int encode_video = 0, encode_audio = 0;
548  AVDictionary *opt = NULL;
549  int i;
550 
551  if (argc < 2) {
552  printf("usage: %s output_file\n"
553  "API example program to output a media file with libavformat.\n"
554  "This program generates a synthetic audio and video stream, encodes and\n"
555  "muxes them into a file named output_file.\n"
556  "The output format is automatically guessed according to the file extension.\n"
557  "Raw images can also be output by using '%%d' in the filename.\n"
558  "\n", argv[0]);
559  return 1;
560  }
561 
562  filename = argv[1];
563  for (i = 2; i+1 < argc; i+=2) {
564  if (!strcmp(argv[i], "-flags") || !strcmp(argv[i], "-fflags"))
565  av_dict_set(&opt, argv[i]+1, argv[i+1], 0);
566  }
567 
568  /* allocate the output media context */
569  avformat_alloc_output_context2(&oc, NULL, NULL, filename);
570  if (!oc) {
571  printf("Could not deduce output format from file extension: using MPEG.\n");
572  avformat_alloc_output_context2(&oc, NULL, "mpeg", filename);
573  }
574  if (!oc)
575  return 1;
576 
577  fmt = oc->oformat;
578 
579  /* Add the audio and video streams using the default format codecs
580  * and initialize the codecs. */
581  if (fmt->video_codec != AV_CODEC_ID_NONE) {
582  add_stream(&video_st, oc, &video_codec, fmt->video_codec);
583  have_video = 1;
584  encode_video = 1;
585  }
586  if (fmt->audio_codec != AV_CODEC_ID_NONE) {
587  add_stream(&audio_st, oc, &audio_codec, fmt->audio_codec);
588  have_audio = 1;
589  encode_audio = 1;
590  }
591 
592  /* Now that all the parameters are set, we can open the audio and
593  * video codecs and allocate the necessary encode buffers. */
594  if (have_video)
595  open_video(oc, video_codec, &video_st, opt);
596 
597  if (have_audio)
598  open_audio(oc, audio_codec, &audio_st, opt);
599 
600  av_dump_format(oc, 0, filename, 1);
601 
602  /* open the output file, if needed */
603  if (!(fmt->flags & AVFMT_NOFILE)) {
604  ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE);
605  if (ret < 0) {
606  fprintf(stderr, "Could not open '%s': %s\n", filename,
607  av_err2str(ret));
608  return 1;
609  }
610  }
611 
612  /* Write the stream header, if any. */
613  ret = avformat_write_header(oc, &opt);
614  if (ret < 0) {
615  fprintf(stderr, "Error occurred when opening output file: %s\n",
616  av_err2str(ret));
617  return 1;
618  }
619 
620  while (encode_video || encode_audio) {
621  /* select the stream to encode */
622  if (encode_video &&
623  (!encode_audio || av_compare_ts(video_st.next_pts, video_st.enc->time_base,
624  audio_st.next_pts, audio_st.enc->time_base) <= 0)) {
625  encode_video = !write_video_frame(oc, &video_st);
626  } else {
627  encode_audio = !write_audio_frame(oc, &audio_st);
628  }
629  }
630 
631  /* Write the trailer, if any. The trailer must be written before you
632  * close the CodecContexts open when you wrote the header; otherwise
633  * av_write_trailer() may try to use memory that was freed on
634  * av_codec_close(). */
635  av_write_trailer(oc);
636 
637  /* Close each codec. */
638  if (have_video)
639  close_stream(oc, &video_st);
640  if (have_audio)
641  close_stream(oc, &audio_st);
642 
643  if (!(fmt->flags & AVFMT_NOFILE))
644  /* Close the output file. */
645  avio_closep(&oc->pb);
646 
647  /* free the stream */
649 
650  return 0;
651 }
av_packet_unref
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:403
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:395
OutputStream::tincr
float tincr
Definition: muxing.c:64
OutputStream::samples_count
int samples_count
Definition: muxing.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
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4372
OutputStream::enc
AVCodecContext * enc
Definition: muxing.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
alloc_picture
static AVFrame * alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
Definition: muxing.c:386
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:245
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:55
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:111
avcodec_find_encoder
const AVCodec * avcodec_find_encoder(enum AVCodecID id)
Find a registered encoder with a matching codec ID.
Definition: allcodecs.c:906
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:489
AVFormatContext::streams
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1174
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:454
open_audio
static void open_audio(AVFormatContext *oc, const AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
Definition: muxing.c:245
write_frame
static int write_frame(AVFormatContext *fmt_ctx, AVCodecContext *c, AVStream *st, AVFrame *frame)
Definition: muxing.c:81
AVPacket::duration
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:383
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:745
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:306
get_video_frame
static AVFrame * get_video_frame(OutputStream *ost)
Definition: muxing.c:475
STREAM_PIX_FMT
#define STREAM_PIX_FMT
Definition: muxing.c:48
OutputStream::next_pts
int64_t next_pts
Definition: muxing.c:58
write_audio_frame
static int write_audio_frame(AVFormatContext *oc, OutputStream *ost)
Definition: muxing.c:340
OutputStream::tmp_frame
AVFrame * tmp_frame
Definition: muxing.c:62
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:409
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:538
av_frame_alloc
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:98
avassert.h
pkt
AVPacket * pkt
Definition: movenc.c:59
OutputStream::swr_ctx
struct SwrContext * swr_ctx
Definition: muxing.c:67
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:217
get_audio_frame
static AVFrame * get_audio_frame(OutputStream *ost)
Definition: muxing.c:311
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:61
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
STREAM_DURATION
#define STREAM_DURATION
Definition: muxing.c:46
swr_alloc
av_cold struct SwrContext * swr_alloc(void)
Allocate SwrContext.
Definition: options.c:149
AVOutputFormat::audio_codec
enum AVCodecID audio_codec
default audio codec
Definition: avformat.h:501
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:675
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:142
pix_fmt
static enum AVPixelFormat pix_fmt
Definition: demuxing_decoding.c:40
log_packet
static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt)
Definition: muxing.c:70
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:468
if
if(ret)
Definition: filter_design.txt:179
AVFormatContext
Format I/O context.
Definition: avformat.h:1106
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:979
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:855
NULL
#define NULL
Definition: coverity.c:32
fmt_ctx
static AVFormatContext * fmt_ctx
Definition: demuxing_decoding.c:37
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:1148
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:135
OutputStream::sws_ctx
struct SwsContext * sws_ctx
Definition: muxing.c:66
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:50
AVCodecID
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: codec_id.h:46
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:1162
AVOutputFormat::flags
int flags
can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS,...
Definition: avformat.h:510
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:624
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:58
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:50
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:1910
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:119
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:458
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:364
height
#define height
OutputStream::t
float t
Definition: muxing.c:64
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:506
M_PI
#define M_PI
Definition: mathematics.h:52
AVCodecContext::channels
int channels
number of audio channels
Definition: avcodec.h:1099
avcodec_get_name
const char * avcodec_get_name(enum AVCodecID id)
Get the name of a codec.
Definition: utils.c:446
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:1236
i
int i
Definition: input.c:407
AVFMT_GLOBALHEADER
#define AVFMT_GLOBALHEADER
Format wants global header.
Definition: avformat.h:461
AV_CODEC_ID_NONE
@ AV_CODEC_ID_NONE
Definition: codec_id.h:47
AVOutputFormat
Definition: avformat.h:490
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:358
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:364
AVStream::id
int id
Format-specific stream ID.
Definition: avformat.h:839
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:832
OutputStream::tincr2
float tincr2
Definition: muxing.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:1125
avformat.h
ost
OutputStream * ost
Definition: ffmpeg_filter.c:163
AVCodecContext
main external API structure.
Definition: avcodec.h:501
AVFrame::height
int height
Definition: frame.h:361
AVStream::index
int index
stream index in AVFormatContext
Definition: avformat.h:833
channel_layout.h
sws_freeContext
void sws_freeContext(struct SwsContext *swsContext)
Free the swscaler context swsContext.
Definition: utils.c:2241
avformat_free_context
void avformat_free_context(AVFormatContext *s)
Free an AVFormatContext and all its streams.
Definition: utils.c:4299
AVOutputFormat::video_codec
enum AVCodecID video_codec
default video codec
Definition: avformat.h:502
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:367
close_stream
static void close_stream(AVFormatContext *oc, OutputStream *ost)
Definition: muxing.c:526
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVPacket
This structure stores compressed data.
Definition: packet.h:342
STREAM_FRAME_RATE
#define STREAM_FRAME_RATE
Definition: muxing.c:47
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:1221
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:123
write_video_frame
static int write_video_frame(AVFormatContext *oc, OutputStream *ost)
Definition: muxing.c:521
timestamp.h
OutputStream
Definition: muxing.c:53
OutputStream::st
AVStream * st
Definition: muxing.c:54
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:136
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:51
swscale.h