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 <string.h>
  28 #include <math.h>
  29
  30 #ifndef M_PI
  31 #define M_PI 3.14159265358979323846
  32 #endif
  33
  34 #include "libavformat/avformat.h"
  35 #include "libswscale/swscale.h"
  36
  37 #undef exit
  38
  39 /* 5 seconds stream duration */
  40 #define STREAM_DURATION   5.0
  41 #define STREAM_FRAME_RATE 25 /* 25 images/s */
  42 #define STREAM_NB_FRAMES  ((int)(STREAM_DURATION * STREAM_FRAME_RATE))
  43 #define STREAM_PIX_FMT PIX_FMT_YUV420P /* default pix_fmt */
  44
  45 static int sws_flags = SWS_BICUBIC;
  46
  47 /**************************************************************/
  48 /* audio output */
  49
  50 float t, tincr, tincr2;
  51 int16_t *samples;
  52 uint8_t *audio_outbuf;
  53 int audio_outbuf_size;
  54 int audio_input_frame_size;
  55
  56 /*
  57  * add an audio output stream
  58  */
  59 static AVStream *add_audio_stream(AVFormatContext *oc, int codec_id)
  60 {
  61     AVCodecContext *c;
  62     AVStream *st;
  63
  64     st = av_new_stream(oc, 1);
  65     if (!st) {
  66         fprintf(stderr, "Could not alloc stream\n");
  67         exit(1);
  68     }
  69
  70     c = st->codec;
  71     c->codec_id = codec_id;
  72     c->codec_type = CODEC_TYPE_AUDIO;
  73
  74     /* put sample parameters */
  75     c->bit_rate = 64000;
  76     c->sample_rate = 44100;
  77     c->channels = 2;
  78     return st;
  79 }
  80
  81 static void open_audio(AVFormatContext *oc, AVStream *st)
  82 {
  83     AVCodecContext *c;
  84     AVCodec *codec;
  85
  86     c = st->codec;
  87
  88     /* find the audio encoder */
  89     codec = avcodec_find_encoder(c->codec_id);
  90     if (!codec) {
  91         fprintf(stderr, "codec not found\n");
  92         exit(1);
  93     }
  94
  95     /* open it */
  96     if (avcodec_open(c, codec) < 0) {
  97         fprintf(stderr, "could not open codec\n");
  98         exit(1);
  99     }
 100
 101     /* init signal generator */
 102     t = 0;
 103     tincr = 2 * M_PI * 110.0 / c->sample_rate;
 104     /* increment frequency by 110 Hz per second */
 105     tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
 106
 107     audio_outbuf_size = 10000;
 108     audio_outbuf = av_malloc(audio_outbuf_size);
 109
 110     /* ugly hack for PCM codecs (will be removed ASAP with new PCM
 111        support to compute the input frame size in samples */
 112     if (c->frame_size <= 1) {
 113         audio_input_frame_size = audio_outbuf_size / c->channels;
 114         switch(st->codec->codec_id) {
 115         case CODEC_ID_PCM_S16LE:
 116         case CODEC_ID_PCM_S16BE:
 117         case CODEC_ID_PCM_U16LE:
 118         case CODEC_ID_PCM_U16BE:
 119             audio_input_frame_size >>= 1;
 120             break;
 121         default:
 122             break;
 123         }
 124     } else {
 125         audio_input_frame_size = c->frame_size;
 126     }
 127     samples = av_malloc(audio_input_frame_size * 2 * c->channels);
 128 }
 129
 130 /* prepare a 16 bit dummy audio frame of 'frame_size' samples and
 131    'nb_channels' channels */
 132 static void get_audio_frame(int16_t *samples, int frame_size, int nb_channels)
 133 {
 134     int j, i, v;
 135     int16_t *q;
 136
 137     q = samples;
 138     for(j=0;j<frame_size;j++) {
 139         v = (int)(sin(t) * 10000);
 140         for(i = 0; i < nb_channels; i++)
 141             *q++ = v;
 142         t += tincr;
 143         tincr += tincr2;
 144     }
 145 }
 146
 147 static void write_audio_frame(AVFormatContext *oc, AVStream *st)
 148 {
 149     AVCodecContext *c;
 150     AVPacket pkt;
 151     av_init_packet(&pkt);
 152
 153     c = st->codec;
 154
 155     get_audio_frame(samples, audio_input_frame_size, c->channels);
 156
 157     pkt.size= avcodec_encode_audio(c, audio_outbuf, audio_outbuf_size, samples);
 158
 159     if (c->coded_frame->pts != AV_NOPTS_VALUE)
 160         pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
 161     pkt.flags |= PKT_FLAG_KEY;
 162     pkt.stream_index= st->index;
 163     pkt.data= audio_outbuf;
 164
 165     /* write the compressed frame in the media file */
 166     if (av_interleaved_write_frame(oc, &pkt) != 0) {
 167         fprintf(stderr, "Error while writing audio frame\n");
 168         exit(1);
 169     }
 170 }
 171
 172 static void close_audio(AVFormatContext *oc, AVStream *st)
 173 {
 174     avcodec_close(st->codec);
 175
 176     av_free(samples);
 177     av_free(audio_outbuf);
 178 }
 179
 180 /**************************************************************/
 181 /* video output */
 182
 183 AVFrame *picture, *tmp_picture;
 184 uint8_t *video_outbuf;
 185 int frame_count, video_outbuf_size;
 186
 187 /* add a video output stream */
 188 static AVStream *add_video_stream(AVFormatContext *oc, int codec_id)
 189 {
 190     AVCodecContext *c;
 191     AVStream *st;
 192
 193     st = av_new_stream(oc, 0);
 194     if (!st) {
 195         fprintf(stderr, "Could not alloc stream\n");
 196         exit(1);
 197     }
 198
 199     c = st->codec;
 200     c->codec_id = codec_id;
 201     c->codec_type = CODEC_TYPE_VIDEO;
 202
 203     /* put sample parameters */
 204     c->bit_rate = 400000;
 205     /* resolution must be a multiple of two */
 206     c->width = 352;
 207     c->height = 288;
 208     /* time base: this is the fundamental unit of time (in seconds) in terms
 209        of which frame timestamps are represented. for fixed-fps content,
 210        timebase should be 1/framerate and timestamp increments should be
 211        identically 1. */
 212     c->time_base.den = STREAM_FRAME_RATE;
 213     c->time_base.num = 1;
 214     c->gop_size = 12; /* emit one intra frame every twelve frames at most */
 215     c->pix_fmt = STREAM_PIX_FMT;
 216     if (c->codec_id == CODEC_ID_MPEG2VIDEO) {
 217         /* just for testing, we also add B frames */
 218         c->max_b_frames = 2;
 219     }
 220     if (c->codec_id == CODEC_ID_MPEG1VIDEO){
 221         /* Needed to avoid using macroblocks in which some coeffs overflow.
 222            This does not happen with normal video, it just happens here as
 223            the motion of the chroma plane does not match the luma plane. */
 224         c->mb_decision=2;
 225     }
 226     // some formats want stream headers to be separate
 227     if(oc->oformat->flags & AVFMT_GLOBALHEADER)
 228         c->flags |= CODEC_FLAG_GLOBAL_HEADER;
 229
 230     return st;
 231 }
 232
 233 static AVFrame *alloc_picture(int pix_fmt, int width, int height)
 234 {
 235     AVFrame *picture;
 236     uint8_t *picture_buf;
 237     int size;
 238
 239     picture = avcodec_alloc_frame();
 240     if (!picture)
 241         return NULL;
 242     size = avpicture_get_size(pix_fmt, width, height);
 243     picture_buf = av_malloc(size);
 244     if (!picture_buf) {
 245         av_free(picture);
 246         return NULL;
 247     }
 248     avpicture_fill((AVPicture *)picture, picture_buf,
 249                    pix_fmt, width, height);
 250     return picture;
 251 }
 252
 253 static void open_video(AVFormatContext *oc, AVStream *st)
 254 {
 255     AVCodec *codec;
 256     AVCodecContext *c;
 257
 258     c = st->codec;
 259
 260     /* find the video encoder */
 261     codec = avcodec_find_encoder(c->codec_id);
 262     if (!codec) {
 263         fprintf(stderr, "codec not found\n");
 264         exit(1);
 265     }
 266
 267     /* open the codec */
 268     if (avcodec_open(c, codec) < 0) {
 269         fprintf(stderr, "could not open codec\n");
 270         exit(1);
 271     }
 272
 273     video_outbuf = NULL;
 274     if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) {
 275         /* allocate output buffer */
 276         /* XXX: API change will be done */
 277         /* buffers passed into lav* can be allocated any way you prefer,
 278            as long as they're aligned enough for the architecture, and
 279            they're freed appropriately (such as using av_free for buffers
 280            allocated with av_malloc) */
 281         video_outbuf_size = 200000;
 282         video_outbuf = av_malloc(video_outbuf_size);
 283     }
 284
 285     /* allocate the encoded raw picture */
 286     picture = alloc_picture(c->pix_fmt, c->width, c->height);
 287     if (!picture) {
 288         fprintf(stderr, "Could not allocate picture\n");
 289         exit(1);
 290     }
 291
 292     /* if the output format is not YUV420P, then a temporary YUV420P
 293        picture is needed too. It is then converted to the required
 294        output format */
 295     tmp_picture = NULL;
 296     if (c->pix_fmt != PIX_FMT_YUV420P) {
 297         tmp_picture = alloc_picture(PIX_FMT_YUV420P, c->width, c->height);
 298         if (!tmp_picture) {
 299             fprintf(stderr, "Could not allocate temporary picture\n");
 300             exit(1);
 301         }
 302     }
 303 }
 304
 305 /* prepare a dummy image */
 306 static void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height)
 307 {
 308     int x, y, i;
 309
 310     i = frame_index;
 311
 312     /* Y */
 313     for(y=0;y<height;y++) {
 314         for(x=0;x<width;x++) {
 315             pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
 316         }
 317     }
 318
 319     /* Cb and Cr */
 320     for(y=0;y<height/2;y++) {
 321         for(x=0;x<width/2;x++) {
 322             pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
 323             pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
 324         }
 325     }
 326 }
 327
 328 static void write_video_frame(AVFormatContext *oc, AVStream *st)
 329 {
 330     int out_size, ret;
 331     AVCodecContext *c;
 332     static struct SwsContext *img_convert_ctx;
 333
 334     c = st->codec;
 335
 336     if (frame_count >= STREAM_NB_FRAMES) {
 337         /* no more frame to compress. The codec has a latency of a few
 338            frames if using B frames, so we get the last frames by
 339            passing the same picture again */
 340     } else {
 341         if (c->pix_fmt != PIX_FMT_YUV420P) {
 342             /* as we only generate a YUV420P picture, we must convert it
 343                to the codec pixel format if needed */
 344             if (img_convert_ctx == NULL) {
 345                 img_convert_ctx = sws_getContext(c->width, c->height,
 346                                                  PIX_FMT_YUV420P,
 347                                                  c->width, c->height,
 348                                                  c->pix_fmt,
 349                                                  sws_flags, NULL, NULL, NULL);
 350                 if (img_convert_ctx == NULL) {
 351                     fprintf(stderr, "Cannot initialize the conversion context\n");
 352                     exit(1);
 353                 }
 354             }
 355             fill_yuv_image(tmp_picture, frame_count, c->width, c->height);
 356             sws_scale(img_convert_ctx, tmp_picture->data, tmp_picture->linesize,
 357                       0, c->height, picture->data, picture->linesize);
 358         } else {
 359             fill_yuv_image(picture, frame_count, c->width, c->height);
 360         }
 361     }
 362
 363
 364     if (oc->oformat->flags & AVFMT_RAWPICTURE) {
 365         /* raw video case. The API will change slightly in the near
 366            futur for that */
 367         AVPacket pkt;
 368         av_init_packet(&pkt);
 369
 370         pkt.flags |= PKT_FLAG_KEY;
 371         pkt.stream_index= st->index;
 372         pkt.data= (uint8_t *)picture;
 373         pkt.size= sizeof(AVPicture);
 374
 375         ret = av_interleaved_write_frame(oc, &pkt);
 376     } else {
 377         /* encode the image */
 378         out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture);
 379         /* if zero size, it means the image was buffered */
 380         if (out_size > 0) {
 381             AVPacket pkt;
 382             av_init_packet(&pkt);
 383
 384             if (c->coded_frame->pts != AV_NOPTS_VALUE)
 385                 pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
 386             if(c->coded_frame->key_frame)
 387                 pkt.flags |= PKT_FLAG_KEY;
 388             pkt.stream_index= st->index;
 389             pkt.data= video_outbuf;
 390             pkt.size= out_size;
 391
 392             /* write the compressed frame in the media file */
 393             ret = av_interleaved_write_frame(oc, &pkt);
 394         } else {
 395             ret = 0;
 396         }
 397     }
 398     if (ret != 0) {
 399         fprintf(stderr, "Error while writing video frame\n");
 400         exit(1);
 401     }
 402     frame_count++;
 403 }
 404
 405 static void close_video(AVFormatContext *oc, AVStream *st)
 406 {
 407     avcodec_close(st->codec);
 408     av_free(picture->data[0]);
 409     av_free(picture);
 410     if (tmp_picture) {
 411         av_free(tmp_picture->data[0]);
 412         av_free(tmp_picture);
 413     }
 414     av_free(video_outbuf);
 415 }
 416
 417 /**************************************************************/
 418 /* media file output */
 419
 420 int main(int argc, char **argv)
 421 {
 422     const char *filename;
 423     AVOutputFormat *fmt;
 424     AVFormatContext *oc;
 425     AVStream *audio_st, *video_st;
 426     double audio_pts, video_pts;
 427     int i;
 428
 429     /* initialize libavcodec, and register all codecs and formats */
 430     av_register_all();
 431
 432     if (argc != 2) {
 433         printf("usage: %s output_file\n"
 434                "API example program to output a media file with libavformat.\n"
 435                "The output format is automatically guessed according to the file extension.\n"
 436                "Raw images can also be output by using '%%d' in the filename\n"
 437                "\n", argv[0]);
 438         exit(1);
 439     }
 440
 441     filename = argv[1];
 442
 443     /* auto detect the output format from the name. default is
 444        mpeg. */
 445     fmt = guess_format(NULL, filename, NULL);
 446     if (!fmt) {
 447         printf("Could not deduce output format from file extension: using MPEG.\n");
 448         fmt = guess_format("mpeg", NULL, NULL);
 449     }
 450     if (!fmt) {
 451         fprintf(stderr, "Could not find suitable output format\n");
 452         exit(1);
 453     }
 454
 455     /* allocate the output media context */
 456     oc = avformat_alloc_context();
 457     if (!oc) {
 458         fprintf(stderr, "Memory error\n");
 459         exit(1);
 460     }
 461     oc->oformat = fmt;
 462     snprintf(oc->filename, sizeof(oc->filename), "%s", filename);
 463
 464     /* add the audio and video streams using the default format codecs
 465        and initialize the codecs */
 466     video_st = NULL;
 467     audio_st = NULL;
 468     if (fmt->video_codec != CODEC_ID_NONE) {
 469         video_st = add_video_stream(oc, fmt->video_codec);
 470     }
 471     if (fmt->audio_codec != CODEC_ID_NONE) {
 472         audio_st = add_audio_stream(oc, fmt->audio_codec);
 473     }
 474
 475     /* set the output parameters (must be done even if no
 476        parameters). */
 477     if (av_set_parameters(oc, NULL) < 0) {
 478         fprintf(stderr, "Invalid output format parameters\n");
 479         exit(1);
 480     }
 481
 482     dump_format(oc, 0, filename, 1);
 483
 484     /* now that all the parameters are set, we can open the audio and
 485        video codecs and allocate the necessary encode buffers */
 486     if (video_st)
 487         open_video(oc, video_st);
 488     if (audio_st)
 489         open_audio(oc, audio_st);
 490
 491     /* open the output file, if needed */
 492     if (!(fmt->flags & AVFMT_NOFILE)) {
 493         if (url_fopen(&oc->pb, filename, URL_WRONLY) < 0) {
 494             fprintf(stderr, "Could not open '%s'\n", filename);
 495             exit(1);
 496         }
 497     }
 498
 499     /* write the stream header, if any */
 500     av_write_header(oc);
 501
 502     for(;;) {
 503         /* compute current audio and video time */
 504         if (audio_st)
 505             audio_pts = (double)audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den;
 506         else
 507             audio_pts = 0.0;
 508
 509         if (video_st)
 510             video_pts = (double)video_st->pts.val * video_st->time_base.num / video_st->time_base.den;
 511         else
 512             video_pts = 0.0;
 513
 514         if ((!audio_st || audio_pts >= STREAM_DURATION) &&
 515             (!video_st || video_pts >= STREAM_DURATION))
 516             break;
 517
 518         /* write interleaved audio and video frames */
 519         if (!video_st || (video_st && audio_st && audio_pts < video_pts)) {
 520             write_audio_frame(oc, audio_st);
 521         } else {
 522             write_video_frame(oc, video_st);
 523         }
 524     }
 525
 526     /* write the trailer, if any.  the trailer must be written
 527      * before you close the CodecContexts open when you wrote the
 528      * header; otherwise write_trailer may try to use memory that
 529      * was freed on av_codec_close() */
 530     av_write_trailer(oc);
 531
 532     /* close each codec */
 533     if (video_st)
 534         close_video(oc, video_st);
 535     if (audio_st)
 536         close_audio(oc, audio_st);
 537
 538     /* free the streams */
 539     for(i = 0; i < oc->nb_streams; i++) {
 540         av_freep(&oc->streams[i]->codec);
 541         av_freep(&oc->streams[i]);
 542     }
 543
 544     if (!(fmt->flags & AVFMT_NOFILE)) {
 545         /* close the output file */
 546         url_fclose(oc->pb);
 547     }
 548
 549     /* free the stream */
 550     av_free(oc);
 551
 552     return 0;
 553 }