2 * Libavformat API example: Output a media file in any supported
3 * libavformat format. The default codecs are used.
5 * Copyright (c) 2003 Fabrice Bellard
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31 #define M_PI 3.1415926535897931
36 /* 5 seconds stream duration */
37 #define STREAM_DURATION 5.0
38 #define STREAM_FRAME_RATE 25 /* 25 images/s */
39 #define STREAM_NB_FRAMES ((int)(STREAM_DURATION * STREAM_FRAME_RATE))
41 /**************************************************************/
44 float t, tincr, tincr2;
46 uint8_t *audio_outbuf;
47 int audio_outbuf_size;
48 int audio_input_frame_size;
51 * add an audio output stream
53 AVStream *add_audio_stream(AVFormatContext *oc, int codec_id)
58 st = av_new_stream(oc, 1);
60 fprintf(stderr, "Could not alloc stream\n");
65 c->codec_id = codec_id;
66 c->codec_type = CODEC_TYPE_AUDIO;
68 /* put sample parameters */
70 c->sample_rate = 44100;
75 void open_audio(AVFormatContext *oc, AVStream *st)
82 /* find the audio encoder */
83 codec = avcodec_find_encoder(c->codec_id);
85 fprintf(stderr, "codec not found\n");
90 if (avcodec_open(c, codec) < 0) {
91 fprintf(stderr, "could not open codec\n");
95 /* init signal generator */
97 tincr = 2 * M_PI * 110.0 / c->sample_rate;
98 /* increment frequency by 110 Hz per second */
99 tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
101 audio_outbuf_size = 10000;
102 audio_outbuf = malloc(audio_outbuf_size);
104 /* ugly hack for PCM codecs (will be removed ASAP with new PCM
105 support to compute the input frame size in samples */
106 if (c->frame_size <= 1) {
107 audio_input_frame_size = audio_outbuf_size / c->channels;
108 switch(st->codec.codec_id) {
109 case CODEC_ID_PCM_S16LE:
110 case CODEC_ID_PCM_S16BE:
111 case CODEC_ID_PCM_U16LE:
112 case CODEC_ID_PCM_U16BE:
113 audio_input_frame_size >>= 1;
119 audio_input_frame_size = c->frame_size;
121 samples = malloc(audio_input_frame_size * 2 * c->channels);
124 /* prepare a 16 bit dummy audio frame of 'frame_size' samples and
125 'nb_channels' channels */
126 void get_audio_frame(int16_t *samples, int frame_size, int nb_channels)
132 for(j=0;j<frame_size;j++) {
133 v = (int)(sin(t) * 10000);
134 for(i = 0; i < nb_channels; i++)
141 void write_audio_frame(AVFormatContext *oc, AVStream *st)
149 get_audio_frame(samples, audio_input_frame_size, c->channels);
151 out_size = avcodec_encode_audio(c, audio_outbuf, audio_outbuf_size, samples);
153 /* write the compressed frame in the media file */
154 if (av_write_frame(oc, st->index, audio_outbuf, out_size) != 0) {
155 fprintf(stderr, "Error while writing audio frame\n");
160 void close_audio(AVFormatContext *oc, AVStream *st)
162 avcodec_close(&st->codec);
165 av_free(audio_outbuf);
168 /**************************************************************/
171 AVFrame *picture, *tmp_picture;
172 uint8_t *video_outbuf;
173 int frame_count, video_outbuf_size;
175 /* add a video output stream */
176 AVStream *add_video_stream(AVFormatContext *oc, int codec_id)
181 st = av_new_stream(oc, 0);
183 fprintf(stderr, "Could not alloc stream\n");
188 c->codec_id = codec_id;
189 c->codec_type = CODEC_TYPE_VIDEO;
191 /* put sample parameters */
192 c->bit_rate = 400000;
193 /* resolution must be a multiple of two */
196 /* frames per second */
197 c->frame_rate = STREAM_FRAME_RATE;
198 c->frame_rate_base = 1;
199 c->gop_size = 12; /* emit one intra frame every twelve frames at most */
200 if (c->codec_id == CODEC_ID_MPEG1VIDEO ||
201 c->codec_id == CODEC_ID_MPEG2VIDEO) {
202 /* just for testing, we also add B frames */
205 // some formats want stream headers to be seperate
206 if(!strcmp(oc->oformat->name, "mp4") || !strcmp(oc->oformat->name, "mov") || !strcmp(oc->oformat->name, "3gp"))
207 c->flags |= CODEC_FLAG_GLOBAL_HEADER;
212 AVFrame *alloc_picture(int pix_fmt, int width, int height)
215 uint8_t *picture_buf;
218 picture = avcodec_alloc_frame();
221 size = avpicture_get_size(pix_fmt, width, height);
222 picture_buf = malloc(size);
227 avpicture_fill((AVPicture *)picture, picture_buf,
228 pix_fmt, width, height);
232 void open_video(AVFormatContext *oc, AVStream *st)
239 /* find the video encoder */
240 codec = avcodec_find_encoder(c->codec_id);
242 fprintf(stderr, "codec not found\n");
247 if (avcodec_open(c, codec) < 0) {
248 fprintf(stderr, "could not open codec\n");
253 if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) {
254 /* allocate output buffer */
255 /* XXX: API change will be done */
256 video_outbuf_size = 200000;
257 video_outbuf = malloc(video_outbuf_size);
260 /* allocate the encoded raw picture */
261 picture = alloc_picture(c->pix_fmt, c->width, c->height);
263 fprintf(stderr, "Could not allocate picture\n");
267 /* if the output format is not YUV420P, then a temporary YUV420P
268 picture is needed too. It is then converted to the required
271 if (c->pix_fmt != PIX_FMT_YUV420P) {
272 tmp_picture = alloc_picture(PIX_FMT_YUV420P, c->width, c->height);
274 fprintf(stderr, "Could not allocate temporary picture\n");
280 /* prepare a dummy image */
281 void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height)
288 for(y=0;y<height;y++) {
289 for(x=0;x<width;x++) {
290 pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
295 for(y=0;y<height/2;y++) {
296 for(x=0;x<width/2;x++) {
297 pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
298 pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
303 void write_video_frame(AVFormatContext *oc, AVStream *st)
307 AVFrame *picture_ptr;
311 if (frame_count >= STREAM_NB_FRAMES) {
312 /* no more frame to compress. The codec has a latency of a few
313 frames if using B frames, so we get the last frames by
314 passing a NULL picture */
317 if (c->pix_fmt != PIX_FMT_YUV420P) {
318 /* as we only generate a YUV420P picture, we must convert it
319 to the codec pixel format if needed */
320 fill_yuv_image(tmp_picture, frame_count, c->width, c->height);
321 img_convert((AVPicture *)picture, c->pix_fmt,
322 (AVPicture *)tmp_picture, PIX_FMT_YUV420P,
323 c->width, c->height);
325 fill_yuv_image(picture, frame_count, c->width, c->height);
327 picture_ptr = picture;
331 if (oc->oformat->flags & AVFMT_RAWPICTURE) {
332 /* raw video case. The API will change slightly in the near
334 ret = av_write_frame(oc, st->index,
335 (uint8_t *)picture_ptr, sizeof(AVPicture));
337 /* encode the image */
338 out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture_ptr);
339 /* if zero size, it means the image was buffered */
341 /* write the compressed frame in the media file */
342 /* XXX: in case of B frames, the pts is not yet valid */
343 ret = av_write_frame(oc, st->index, video_outbuf, out_size);
349 fprintf(stderr, "Error while writing video frame\n");
355 void close_video(AVFormatContext *oc, AVStream *st)
357 avcodec_close(&st->codec);
358 av_free(picture->data[0]);
361 av_free(tmp_picture->data[0]);
362 av_free(tmp_picture);
364 av_free(video_outbuf);
367 /**************************************************************/
368 /* media file output */
370 int main(int argc, char **argv)
372 const char *filename;
375 AVStream *audio_st, *video_st;
376 double audio_pts, video_pts;
379 /* initialize libavcodec, and register all codecs and formats */
383 printf("usage: %s output_file\n"
384 "API example program to output a media file with libavformat.\n"
385 "The output format is automatically guessed according to the file extension.\n"
386 "Raw images can also be output by using '%%d' in the filename\n"
393 /* auto detect the output format from the name. default is
395 fmt = guess_format(NULL, filename, NULL);
397 printf("Could not deduce output format from file extension: using MPEG.\n");
398 fmt = guess_format("mpeg", NULL, NULL);
401 fprintf(stderr, "Could not find suitable output format\n");
405 /* allocate the output media context */
406 oc = av_mallocz(sizeof(AVFormatContext));
408 fprintf(stderr, "Memory error\n");
412 snprintf(oc->filename, sizeof(oc->filename), "%s", filename);
414 /* add the audio and video streams using the default format codecs
415 and initialize the codecs */
418 if (fmt->video_codec != CODEC_ID_NONE) {
419 video_st = add_video_stream(oc, fmt->video_codec);
421 if (fmt->audio_codec != CODEC_ID_NONE) {
422 audio_st = add_audio_stream(oc, fmt->audio_codec);
425 /* set the output parameters (must be done even if no
427 if (av_set_parameters(oc, NULL) < 0) {
428 fprintf(stderr, "Invalid output format parameters\n");
432 dump_format(oc, 0, filename, 1);
434 /* now that all the parameters are set, we can open the audio and
435 video codecs and allocate the necessary encode buffers */
437 open_video(oc, video_st);
439 open_audio(oc, audio_st);
441 /* open the output file, if needed */
442 if (!(fmt->flags & AVFMT_NOFILE)) {
443 if (url_fopen(&oc->pb, filename, URL_WRONLY) < 0) {
444 fprintf(stderr, "Could not open '%s'\n", filename);
449 /* write the stream header, if any */
453 /* compute current audio and video time */
455 audio_pts = (double)audio_st->pts.val * oc->pts_num / oc->pts_den;
460 video_pts = (double)video_st->pts.val * oc->pts_num / oc->pts_den;
464 if ((!audio_st || audio_pts >= STREAM_DURATION) &&
465 (!video_st || video_pts >= STREAM_DURATION))
468 /* write interleaved audio and video frames */
469 if (!video_st || (video_st && audio_st && audio_pts < video_pts)) {
470 write_audio_frame(oc, audio_st);
472 write_video_frame(oc, video_st);
476 /* close each codec */
478 close_video(oc, video_st);
480 close_audio(oc, audio_st);
482 /* write the trailer, if any */
483 av_write_trailer(oc);
485 /* free the streams */
486 for(i = 0; i < oc->nb_streams; i++) {
487 av_freep(&oc->streams[i]);
490 if (!(fmt->flags & AVFMT_NOFILE)) {
491 /* close the output file */
495 /* free the stream */