output_example.c

   1 /*
   2  * Libavformat API example: Output a media file in any supported
   3  * libavformat format. The default codecs are used.
   4  *
   5  * Copyright (c) 2003 Fabrice Bellard
   6  *
   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:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  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
  23  * THE SOFTWARE.
  24  */
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <math.h>
  28
  29 #include "avformat.h"
  30
  31 /* 5 seconds stream duration */
  32 #define STREAM_DURATION 5.0
  33
  34
  35 /**************************************************************/
  36 /* audio output */
  37
  38 float t, tincr;
  39 int16_t *samples;
  40 uint8_t *audio_outbuf;
  41 int audio_outbuf_size;
  42 int audio_input_frame_size;
  43
  44 /*
  45  * add an audio output stream
  46  */
  47 AVStream *add_audio_stream(AVFormatContext *oc, int codec_id)
  48 {
  49     AVCodec *codec;
  50     AVCodecContext *c;
  51     AVStream *st;
  52
  53     st = av_new_stream(oc, 1);
  54     if (!st) {
  55         fprintf(stderr, "Could not alloc stream\n");
  56         exit(1);
  57     }
  58
  59     /* find the MP2 encoder */
  60     codec = avcodec_find_encoder(codec_id);
  61     if (!codec) {
  62         fprintf(stderr, "codec not found\n");
  63         exit(1);
  64     }
  65     c = &st->codec;
  66
  67     avcodec_get_context_defaults(c);
  68
  69     c->codec_type = CODEC_TYPE_AUDIO;
  70
  71     /* put sample parameters */
  72     c->bit_rate = 64000;
  73     c->sample_rate = 44100;
  74     c->channels = 2;
  75
  76     /* open it */
  77     if (avcodec_open(c, codec) < 0) {
  78         fprintf(stderr, "could not open codec\n");
  79         exit(1);
  80     }
  81
  82     /* init signal generator */
  83     t = 0;
  84     tincr = 2 * M_PI * 440.0 / c->sample_rate;
  85
  86     audio_outbuf_size = 10000;
  87     audio_outbuf = malloc(audio_outbuf_size);
  88
  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;
  99             break;
 100         default:
 101             break;
 102         }
 103     } else {
 104         audio_input_frame_size = c->frame_size;
 105     }
 106     samples = malloc(audio_input_frame_size * 2 * c->channels);
 107
 108     return st;
 109 }
 110
 111 void write_audio_frame(AVFormatContext *oc, AVStream *st)
 112 {
 113     int j, out_size;
 114     AVCodecContext *c;
 115
 116
 117     c = &st->codec;
 118
 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];
 122         t += tincr;
 123     }
 124
 125     out_size = avcodec_encode_audio(c, audio_outbuf, audio_outbuf_size, samples);
 126
 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");
 130         exit(1);
 131     }
 132 }
 133
 134 /**************************************************************/
 135 /* video output */
 136
 137 AVFrame *picture;
 138 uint8_t *video_outbuf;
 139 int frame_count, video_outbuf_size;
 140
 141 /* add a video output stream */
 142 AVStream *add_video_stream(AVFormatContext *oc, int codec_id)
 143 {
 144     AVCodec *codec;
 145     AVCodecContext *c;
 146     AVStream *st;
 147     uint8_t *picture_buf;
 148     int size;
 149
 150     st = av_new_stream(oc, 0);
 151     if (!st) {
 152         fprintf(stderr, "Could not alloc stream\n");
 153         exit(1);
 154     }
 155
 156     /* find the mpeg1 video encoder */
 157     codec = avcodec_find_encoder(codec_id);
 158     if (!codec) {
 159         fprintf(stderr, "codec not found\n");
 160         exit(1);
 161     }
 162
 163     c = &st->codec;
 164
 165     avcodec_get_context_defaults(c);
 166
 167     c->codec_type = CODEC_TYPE_VIDEO;
 168
 169     /* put sample parameters */
 170     c->bit_rate = 400000;
 171     /* resolution must be a multiple of two */
 172     c->width = 352;
 173     c->height = 288;
 174     /* frames per second */
 175     c->frame_rate = 25;
 176     c->frame_rate_base= 1;
 177     c->gop_size = 12; /* emit one intra frame every twelve frames */
 178
 179     /* open it */
 180     if (avcodec_open(c, codec) < 0) {
 181         fprintf(stderr, "could not open codec\n");
 182         exit(1);
 183     }
 184
 185     /* alloc various buffers */
 186     picture= avcodec_alloc_frame();
 187     video_outbuf_size = 100000;
 188     video_outbuf = malloc(video_outbuf_size);
 189
 190     size = c->width * c->height;
 191     picture_buf = malloc((size * 3) / 2); /* size for YUV 420 */
 192
 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;
 199
 200     return st;
 201 }
 202
 203 void write_video_frame(AVFormatContext *oc, AVStream *st)
 204 {
 205     int x, y, i, out_size;
 206     AVCodecContext *c;
 207
 208     c = &st->codec;
 209
 210     /* prepare a dummy image */
 211     /* Y */
 212     i = frame_count++;
 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;
 216         }
 217     }
 218
 219     /* Cb and Cr */
 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;
 224         }
 225     }
 226
 227     /* encode the image */
 228     out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture);
 229
 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");
 233         exit(1);
 234     }
 235 }
 236
 237 /**************************************************************/
 238 /* media file output */
 239
 240 int main(int argc, char **argv)
 241 {
 242     const char *filename;
 243     AVOutputFormat *fmt;
 244     AVFormatContext *oc;
 245     AVStream *st, *audio_st, *video_st;
 246     int i;
 247     double audio_pts, video_pts;
 248
 249     /* initialize libavcodec, and register all codecs and formats */
 250     av_register_all();
 251
 252     if (argc != 2) {
 253         printf("usage: %s output_file\n"
 254                "API example program for to output media file with libavformat\n"
 255                "\n", argv[0]);
 256         exit(1);
 257     }
 258
 259     filename = argv[1];
 260
 261     /* auto detect the output format from the name. default is
 262        mpeg. */
 263     fmt = guess_format(NULL, filename, NULL);
 264     if (!fmt) {
 265         printf("Could not deduce output format from file extension: using MPEG.\n");
 266         fmt = guess_format("mpeg", NULL, NULL);
 267     }
 268     if (!fmt) {
 269         fprintf(stderr, "Could not find suitable output format\n");
 270         exit(1);
 271     }
 272
 273     /* allocate the output media context */
 274     oc = av_mallocz(sizeof(AVFormatContext));
 275     if (!oc) {
 276         fprintf(stderr, "Memory error\n");
 277         exit(1);
 278     }
 279     oc->oformat = fmt;
 280
 281     /* add the audio and video streams using the default format codecs
 282        and initialize the codecs */
 283     video_st = NULL;
 284     audio_st = NULL;
 285     if (fmt->video_codec != CODEC_ID_NONE) {
 286         video_st = add_video_stream(oc, fmt->video_codec);
 287     }
 288     if (fmt->audio_codec != CODEC_ID_NONE) {
 289         audio_st = add_audio_stream(oc, fmt->audio_codec);
 290     }
 291
 292     dump_format(oc, 0, filename, 1);
 293
 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);
 298             exit(1);
 299         }
 300     }
 301
 302     /* set the output parameters (must be done even if no parameters) */
 303     av_set_parameters(oc, NULL);
 304
 305     /* write the stream header, if any */
 306     av_write_header(oc);
 307
 308     for(;;) {
 309         /* compute current audio and video time */
 310         if (audio_st)
 311             audio_pts = (double)audio_st->pts.val * oc->pts_num / oc->pts_den;
 312         else
 313             audio_pts = 0.0;
 314
 315         if (video_st)
 316             video_pts = (double)video_st->pts.val * oc->pts_num / oc->pts_den;
 317         else
 318             video_pts = 0.0;
 319
 320         if ((!audio_st || audio_pts >= STREAM_DURATION) &&
 321             (!video_st || video_pts >= STREAM_DURATION))
 322             break;
 323
 324         /* write interleaved audio and video frames */
 325         if (!video_st || (video_st && audio_pts < video_pts)) {
 326             write_audio_frame(oc, audio_st);
 327         } else {
 328             write_video_frame(oc, video_st);
 329         }
 330     }
 331
 332     /* close each codec */
 333     for(i = 0;i < oc->nb_streams; i++) {
 334         st = oc->streams[i];
 335         avcodec_close(&st->codec);
 336     }
 337
 338     /* write the trailer, if any */
 339     av_write_trailer(oc);
 340
 341     if (!(fmt->flags & AVFMT_NOFILE)) {
 342         /* close the output file */
 343         url_fclose(&oc->pb);
 344     }
 345
 346     /* free the stream */
 347     av_free(oc);
 348
 349     return 0;
 350 }