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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8 * of this software and associated documentation files (the "Software"), to deal
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31 /* 5 seconds stream duration */
32 #define STREAM_DURATION 5.0
35 /**************************************************************/
40 uint8_t *audio_outbuf;
41 int audio_outbuf_size;
42 int audio_input_frame_size;
45 * add an audio output stream
47 AVStream *add_audio_stream(AVFormatContext *oc, int codec_id)
53 st = av_new_stream(oc, 1);
55 fprintf(stderr, "Could not alloc stream\n");
59 /* find the MP2 encoder */
60 codec = avcodec_find_encoder(codec_id);
62 fprintf(stderr, "codec not found\n");
67 avcodec_get_context_defaults(c);
69 c->codec_type = CODEC_TYPE_AUDIO;
71 /* put sample parameters */
73 c->sample_rate = 44100;
77 if (avcodec_open(c, codec) < 0) {
78 fprintf(stderr, "could not open codec\n");
82 /* init signal generator */
84 tincr = 2 * M_PI * 440.0 / c->sample_rate;
86 audio_outbuf_size = 10000;
87 audio_outbuf = malloc(audio_outbuf_size);
89 /* ugly hack for PCM codecs (will be removed ASAP with new PCM
90 support to compute the input frame size in samples */
91 if (c->frame_size <= 1) {
92 audio_input_frame_size = audio_outbuf_size / c->channels;
93 switch(st->codec.codec_id) {
94 case CODEC_ID_PCM_S16LE:
95 case CODEC_ID_PCM_S16BE:
96 case CODEC_ID_PCM_U16LE:
97 case CODEC_ID_PCM_U16BE:
98 audio_input_frame_size >>= 1;
104 audio_input_frame_size = c->frame_size;
106 samples = malloc(audio_input_frame_size * 2 * c->channels);
111 void write_audio_frame(AVFormatContext *oc, AVStream *st)
119 for(j=0;j<audio_input_frame_size;j++) {
120 samples[2*j] = (int)(sin(t) * 10000);
121 samples[2*j+1] = samples[2*j];
125 out_size = avcodec_encode_audio(c, audio_outbuf, audio_outbuf_size, samples);
127 /* write the compressed frame in the media file */
128 if (av_write_frame(oc, st->index, audio_outbuf, out_size) != 0) {
129 fprintf(stderr, "Error while writing audio frame\n");
134 /**************************************************************/
138 uint8_t *video_outbuf;
139 int frame_count, video_outbuf_size;
141 /* add a video output stream */
142 AVStream *add_video_stream(AVFormatContext *oc, int codec_id)
147 uint8_t *picture_buf;
150 st = av_new_stream(oc, 0);
152 fprintf(stderr, "Could not alloc stream\n");
156 /* find the mpeg1 video encoder */
157 codec = avcodec_find_encoder(codec_id);
159 fprintf(stderr, "codec not found\n");
165 avcodec_get_context_defaults(c);
167 c->codec_type = CODEC_TYPE_VIDEO;
169 /* put sample parameters */
170 c->bit_rate = 400000;
171 /* resolution must be a multiple of two */
174 /* frames per second */
176 c->frame_rate_base= 1;
177 c->gop_size = 12; /* emit one intra frame every twelve frames */
180 if (avcodec_open(c, codec) < 0) {
181 fprintf(stderr, "could not open codec\n");
185 /* alloc various buffers */
186 picture= avcodec_alloc_frame();
187 video_outbuf_size = 100000;
188 video_outbuf = malloc(video_outbuf_size);
190 size = c->width * c->height;
191 picture_buf = malloc((size * 3) / 2); /* size for YUV 420 */
193 picture->data[0] = picture_buf;
194 picture->data[1] = picture->data[0] + size;
195 picture->data[2] = picture->data[1] + size / 4;
196 picture->linesize[0] = c->width;
197 picture->linesize[1] = c->width / 2;
198 picture->linesize[2] = c->width / 2;
203 void write_video_frame(AVFormatContext *oc, AVStream *st)
205 int x, y, i, out_size;
210 /* prepare a dummy image */
213 for(y=0;y<c->height;y++) {
214 for(x=0;x<c->width;x++) {
215 picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
220 for(y=0;y<c->height/2;y++) {
221 for(x=0;x<c->width/2;x++) {
222 picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
223 picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
227 /* encode the image */
228 out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture);
230 /* write the compressed frame in the media file */
231 if (av_write_frame(oc, st->index, video_outbuf, out_size) != 0) {
232 fprintf(stderr, "Error while writing video frame\n");
237 /**************************************************************/
238 /* media file output */
240 int main(int argc, char **argv)
242 const char *filename;
245 AVStream *st, *audio_st, *video_st;
247 double audio_pts, video_pts;
249 /* initialize libavcodec, and register all codecs and formats */
253 printf("usage: %s output_file\n"
254 "API example program for to output media file with libavformat\n"
261 /* auto detect the output format from the name. default is
263 fmt = guess_format(NULL, filename, NULL);
265 printf("Could not deduce output format from file extension: using MPEG.\n");
266 fmt = guess_format("mpeg", NULL, NULL);
269 fprintf(stderr, "Could not find suitable output format\n");
273 /* allocate the output media context */
274 oc = av_mallocz(sizeof(AVFormatContext));
276 fprintf(stderr, "Memory error\n");
281 /* add the audio and video streams using the default format codecs
282 and initialize the codecs */
285 if (fmt->video_codec != CODEC_ID_NONE) {
286 video_st = add_video_stream(oc, fmt->video_codec);
288 if (fmt->audio_codec != CODEC_ID_NONE) {
289 audio_st = add_audio_stream(oc, fmt->audio_codec);
292 dump_format(oc, 0, filename, 1);
294 /* open the output file, if needed */
295 if (!(fmt->flags & AVFMT_NOFILE)) {
296 if (url_fopen(&oc->pb, filename, URL_WRONLY) < 0) {
297 fprintf(stderr, "Could not open '%s'\n", filename);
302 /* set the output parameters (must be done even if no parameters) */
303 av_set_parameters(oc, NULL);
305 /* write the stream header, if any */
309 /* compute current audio and video time */
311 audio_pts = (double)audio_st->pts.val * oc->pts_num / oc->pts_den;
316 video_pts = (double)video_st->pts.val * oc->pts_num / oc->pts_den;
320 if ((!audio_st || audio_pts >= STREAM_DURATION) &&
321 (!video_st || video_pts >= STREAM_DURATION))
324 /* write interleaved audio and video frames */
325 if (!video_st || (video_st && audio_pts < video_pts)) {
326 write_audio_frame(oc, audio_st);
328 write_video_frame(oc, video_st);
332 /* close each codec */
333 for(i = 0;i < oc->nb_streams; i++) {
335 avcodec_close(&st->codec);
338 /* write the trailer, if any */
339 av_write_trailer(oc);
341 if (!(fmt->flags & AVFMT_NOFILE)) {
342 /* close the output file */
346 /* free the stream */