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
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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)
146 av_init_packet(&pkt);
150 get_audio_frame(samples, audio_input_frame_size, c->channels);
152 pkt.size= avcodec_encode_audio(c, audio_outbuf, audio_outbuf_size, samples);
154 pkt.pts= c->coded_frame->pts;
155 pkt.flags |= PKT_FLAG_KEY;
156 pkt.stream_index= st->index;
157 pkt.data= audio_outbuf;
159 /* write the compressed frame in the media file */
160 if (av_write_frame(oc, &pkt) != 0) {
161 fprintf(stderr, "Error while writing audio frame\n");
166 void close_audio(AVFormatContext *oc, AVStream *st)
168 avcodec_close(&st->codec);
171 av_free(audio_outbuf);
174 /**************************************************************/
177 AVFrame *picture, *tmp_picture;
178 uint8_t *video_outbuf;
179 int frame_count, video_outbuf_size;
181 /* add a video output stream */
182 AVStream *add_video_stream(AVFormatContext *oc, int codec_id)
187 st = av_new_stream(oc, 0);
189 fprintf(stderr, "Could not alloc stream\n");
194 c->codec_id = codec_id;
195 c->codec_type = CODEC_TYPE_VIDEO;
197 /* put sample parameters */
198 c->bit_rate = 400000;
199 /* resolution must be a multiple of two */
202 /* frames per second */
203 c->frame_rate = STREAM_FRAME_RATE;
204 c->frame_rate_base = 1;
205 c->gop_size = 12; /* emit one intra frame every twelve frames at most */
206 if (c->codec_id == CODEC_ID_MPEG2VIDEO) {
207 /* just for testing, we also add B frames */
210 if (c->codec_id == CODEC_ID_MPEG1VIDEO){
211 /* needed to avoid using macroblocks in which some coeffs overflow
212 this doesnt happen with normal video, it just happens here as the
213 motion of the chroma plane doesnt match the luma plane */
216 // some formats want stream headers to be seperate
217 if(!strcmp(oc->oformat->name, "mp4") || !strcmp(oc->oformat->name, "mov") || !strcmp(oc->oformat->name, "3gp"))
218 c->flags |= CODEC_FLAG_GLOBAL_HEADER;
223 AVFrame *alloc_picture(int pix_fmt, int width, int height)
226 uint8_t *picture_buf;
229 picture = avcodec_alloc_frame();
232 size = avpicture_get_size(pix_fmt, width, height);
233 picture_buf = malloc(size);
238 avpicture_fill((AVPicture *)picture, picture_buf,
239 pix_fmt, width, height);
243 void open_video(AVFormatContext *oc, AVStream *st)
250 /* find the video encoder */
251 codec = avcodec_find_encoder(c->codec_id);
253 fprintf(stderr, "codec not found\n");
258 if (avcodec_open(c, codec) < 0) {
259 fprintf(stderr, "could not open codec\n");
264 if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) {
265 /* allocate output buffer */
266 /* XXX: API change will be done */
267 video_outbuf_size = 200000;
268 video_outbuf = malloc(video_outbuf_size);
271 /* allocate the encoded raw picture */
272 picture = alloc_picture(c->pix_fmt, c->width, c->height);
274 fprintf(stderr, "Could not allocate picture\n");
278 /* if the output format is not YUV420P, then a temporary YUV420P
279 picture is needed too. It is then converted to the required
282 if (c->pix_fmt != PIX_FMT_YUV420P) {
283 tmp_picture = alloc_picture(PIX_FMT_YUV420P, c->width, c->height);
285 fprintf(stderr, "Could not allocate temporary picture\n");
291 /* prepare a dummy image */
292 void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height)
299 for(y=0;y<height;y++) {
300 for(x=0;x<width;x++) {
301 pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
306 for(y=0;y<height/2;y++) {
307 for(x=0;x<width/2;x++) {
308 pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
309 pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
314 void write_video_frame(AVFormatContext *oc, AVStream *st)
318 AVFrame *picture_ptr;
322 if (frame_count >= STREAM_NB_FRAMES) {
323 /* no more frame to compress. The codec has a latency of a few
324 frames if using B frames, so we get the last frames by
325 passing a NULL picture */
328 if (c->pix_fmt != PIX_FMT_YUV420P) {
329 /* as we only generate a YUV420P picture, we must convert it
330 to the codec pixel format if needed */
331 fill_yuv_image(tmp_picture, frame_count, c->width, c->height);
332 img_convert((AVPicture *)picture, c->pix_fmt,
333 (AVPicture *)tmp_picture, PIX_FMT_YUV420P,
334 c->width, c->height);
336 fill_yuv_image(picture, frame_count, c->width, c->height);
338 picture_ptr = picture;
342 if (oc->oformat->flags & AVFMT_RAWPICTURE) {
343 /* raw video case. The API will change slightly in the near
346 av_init_packet(&pkt);
348 pkt.flags |= PKT_FLAG_KEY;
349 pkt.stream_index= st->index;
350 pkt.data= (uint8_t *)picture_ptr;
351 pkt.size= sizeof(AVPicture);
353 ret = av_write_frame(oc, &pkt);
355 /* encode the image */
356 out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture_ptr);
357 /* if zero size, it means the image was buffered */
360 av_init_packet(&pkt);
362 pkt.pts= c->coded_frame->pts;
363 if(c->coded_frame->key_frame)
364 pkt.flags |= PKT_FLAG_KEY;
365 pkt.stream_index= st->index;
366 pkt.data= video_outbuf;
369 /* write the compressed frame in the media file */
370 ret = av_write_frame(oc, &pkt);
376 fprintf(stderr, "Error while writing video frame\n");
382 void close_video(AVFormatContext *oc, AVStream *st)
384 avcodec_close(&st->codec);
385 av_free(picture->data[0]);
388 av_free(tmp_picture->data[0]);
389 av_free(tmp_picture);
391 av_free(video_outbuf);
394 /**************************************************************/
395 /* media file output */
397 int main(int argc, char **argv)
399 const char *filename;
402 AVStream *audio_st, *video_st;
403 double audio_pts, video_pts;
406 /* initialize libavcodec, and register all codecs and formats */
410 printf("usage: %s output_file\n"
411 "API example program to output a media file with libavformat.\n"
412 "The output format is automatically guessed according to the file extension.\n"
413 "Raw images can also be output by using '%%d' in the filename\n"
420 /* auto detect the output format from the name. default is
422 fmt = guess_format(NULL, filename, NULL);
424 printf("Could not deduce output format from file extension: using MPEG.\n");
425 fmt = guess_format("mpeg", NULL, NULL);
428 fprintf(stderr, "Could not find suitable output format\n");
432 /* allocate the output media context */
433 oc = av_alloc_format_context();
435 fprintf(stderr, "Memory error\n");
439 snprintf(oc->filename, sizeof(oc->filename), "%s", filename);
441 /* add the audio and video streams using the default format codecs
442 and initialize the codecs */
445 if (fmt->video_codec != CODEC_ID_NONE) {
446 video_st = add_video_stream(oc, fmt->video_codec);
448 if (fmt->audio_codec != CODEC_ID_NONE) {
449 audio_st = add_audio_stream(oc, fmt->audio_codec);
452 /* set the output parameters (must be done even if no
454 if (av_set_parameters(oc, NULL) < 0) {
455 fprintf(stderr, "Invalid output format parameters\n");
459 dump_format(oc, 0, filename, 1);
461 /* now that all the parameters are set, we can open the audio and
462 video codecs and allocate the necessary encode buffers */
464 open_video(oc, video_st);
466 open_audio(oc, audio_st);
468 /* open the output file, if needed */
469 if (!(fmt->flags & AVFMT_NOFILE)) {
470 if (url_fopen(&oc->pb, filename, URL_WRONLY) < 0) {
471 fprintf(stderr, "Could not open '%s'\n", filename);
476 /* write the stream header, if any */
480 /* compute current audio and video time */
482 audio_pts = (double)audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den;
487 video_pts = (double)video_st->pts.val * video_st->time_base.num / video_st->time_base.den;
491 if ((!audio_st || audio_pts >= STREAM_DURATION) &&
492 (!video_st || video_pts >= STREAM_DURATION))
495 /* write interleaved audio and video frames */
496 if (!video_st || (video_st && audio_st && audio_pts < video_pts)) {
497 write_audio_frame(oc, audio_st);
499 write_video_frame(oc, video_st);
503 /* close each codec */
505 close_video(oc, video_st);
507 close_audio(oc, audio_st);
509 /* write the trailer, if any */
510 av_write_trailer(oc);
512 /* free the streams */
513 for(i = 0; i < oc->nb_streams; i++) {
514 av_freep(&oc->streams[i]);
517 if (!(fmt->flags & AVFMT_NOFILE)) {
518 /* close the output file */
522 /* free the stream */