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 "avformat.h"
  35 #include "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     pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
 160     pkt.flags |= PKT_FLAG_KEY;
 161     pkt.stream_index= st->index;
 162     pkt.data= audio_outbuf;
 163
 164     /* write the compressed frame in the media file */
 165     if (av_write_frame(oc, &pkt) != 0) {
 166         fprintf(stderr, "Error while writing audio frame\n");
 167         exit(1);
 168     }
 169 }
 170
 171 static void close_audio(AVFormatContext *oc, AVStream *st)
 172 {
 173     avcodec_close(st->codec);
 174
 175     av_free(samples);
 176     av_free(audio_outbuf);
 177 }
 178
 179 /**************************************************************/
 180 /* video output */
 181
 182 AVFrame *picture, *tmp_picture;
 183 uint8_t *video_outbuf;
 184 int frame_count, video_outbuf_size;
 185
 186 /* add a video output stream */
 187 static AVStream *add_video_stream(AVFormatContext *oc, int codec_id)
 188 {
 189     AVCodecContext *c;
 190     AVStream *st;
 191
 192     st = av_new_stream(oc, 0);
 193     if (!st) {
 194         fprintf(stderr, "Could not alloc stream\n");
 195         exit(1);
 196     }
 197
 198     c = st->codec;
 199     c->codec_id = codec_id;
 200     c->codec_type = CODEC_TYPE_VIDEO;
 201
 202     /* put sample parameters */
 203     c->bit_rate = 400000;
 204     /* resolution must be a multiple of two */
 205     c->width = 352;
 206     c->height = 288;
 207     /* time base: this is the fundamental unit of time (in seconds) in terms
 208        of which frame timestamps are represented. for fixed-fps content,
 209        timebase should be 1/framerate and timestamp increments should be
 210        identically 1. */
 211     c->time_base.den = STREAM_FRAME_RATE;
 212     c->time_base.num = 1;
 213     c->gop_size = 12; /* emit one intra frame every twelve frames at most */
 214     c->pix_fmt = STREAM_PIX_FMT;
 215     if (c->codec_id == CODEC_ID_MPEG2VIDEO) {
 216         /* just for testing, we also add B frames */
 217         c->max_b_frames = 2;
 218     }
 219     if (c->codec_id == CODEC_ID_MPEG1VIDEO){
 220         /* Needed to avoid using macroblocks in which some coeffs overflow.
 221            This does not happen with normal video, it just happens here as
 222            the motion of the chroma plane does not match the luma plane. */
 223         c->mb_decision=2;
 224     }
 225     // some formats want stream headers to be separate
 226     if(!strcmp(oc->oformat->name, "mp4") || !strcmp(oc->oformat->name, "mov") || !strcmp(oc->oformat->name, "3gp"))
 227         c->flags |= CODEC_FLAG_GLOBAL_HEADER;
 228
 229     return st;
 230 }
 231
 232 static AVFrame *alloc_picture(int pix_fmt, int width, int height)
 233 {
 234     AVFrame *picture;
 235     uint8_t *picture_buf;
 236     int size;
 237
 238     picture = avcodec_alloc_frame();
 239     if (!picture)
 240         return NULL;
 241     size = avpicture_get_size(pix_fmt, width, height);
 242     picture_buf = av_malloc(size);
 243     if (!picture_buf) {
 244         av_free(picture);
 245         return NULL;
 246     }
 247     avpicture_fill((AVPicture *)picture, picture_buf,
 248                    pix_fmt, width, height);
 249     return picture;
 250 }
 251
 252 static void open_video(AVFormatContext *oc, AVStream *st)
 253 {
 254     AVCodec *codec;
 255     AVCodecContext *c;
 256
 257     c = st->codec;
 258
 259     /* find the video encoder */
 260     codec = avcodec_find_encoder(c->codec_id);
 261     if (!codec) {
 262         fprintf(stderr, "codec not found\n");
 263         exit(1);
 264     }
 265
 266     /* open the codec */
 267     if (avcodec_open(c, codec) < 0) {
 268         fprintf(stderr, "could not open codec\n");
 269         exit(1);
 270     }
 271
 272     video_outbuf = NULL;
 273     if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) {
 274         /* allocate output buffer */
 275         /* XXX: API change will be done */
 276         /* buffers passed into lav* can be allocated any way you prefer,
 277            as long as they're aligned enough for the architecture, and
 278            they're freed appropriately (such as using av_free for buffers
 279            allocated with av_malloc) */
 280         video_outbuf_size = 200000;
 281         video_outbuf = av_malloc(video_outbuf_size);
 282     }
 283
 284     /* allocate the encoded raw picture */
 285     picture = alloc_picture(c->pix_fmt, c->width, c->height);
 286     if (!picture) {
 287         fprintf(stderr, "Could not allocate picture\n");
 288         exit(1);
 289     }
 290
 291     /* if the output format is not YUV420P, then a temporary YUV420P
 292        picture is needed too. It is then converted to the required
 293        output format */
 294     tmp_picture = NULL;
 295     if (c->pix_fmt != PIX_FMT_YUV420P) {
 296         tmp_picture = alloc_picture(PIX_FMT_YUV420P, c->width, c->height);
 297         if (!tmp_picture) {
 298             fprintf(stderr, "Could not allocate temporary picture\n");
 299             exit(1);
 300         }
 301     }
 302 }
 303
 304 /* prepare a dummy image */
 305 static void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height)
 306 {
 307     int x, y, i;
 308
 309     i = frame_index;
 310
 311     /* Y */
 312     for(y=0;y<height;y++) {
 313         for(x=0;x<width;x++) {
 314             pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
 315         }
 316     }
 317
 318     /* Cb and Cr */
 319     for(y=0;y<height/2;y++) {
 320         for(x=0;x<width/2;x++) {
 321             pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
 322             pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
 323         }
 324     }
 325 }
 326
 327 static void write_video_frame(AVFormatContext *oc, AVStream *st)
 328 {
 329     int out_size, ret;
 330     AVCodecContext *c;
 331     static struct SwsContext *img_convert_ctx;
 332
 333     c = st->codec;
 334
 335     if (frame_count >= STREAM_NB_FRAMES) {
 336         /* no more frame to compress. The codec has a latency of a few
 337            frames if using B frames, so we get the last frames by
 338            passing the same picture again */
 339     } else {
 340         if (c->pix_fmt != PIX_FMT_YUV420P) {
 341             /* as we only generate a YUV420P picture, we must convert it
 342                to the codec pixel format if needed */
 343             if (img_convert_ctx == NULL) {
 344                 img_convert_ctx = sws_getContext(c->width, c->height,
 345                                                  PIX_FMT_YUV420P,
 346                                                  c->width, c->height,
 347                                                  c->pix_fmt,
 348                                                  sws_flags, NULL, NULL, NULL);
 349                 if (img_convert_ctx == NULL) {
 350                     fprintf(stderr, "Cannot initialize the conversion context\n");
 351                     exit(1);
 352                 }
 353             }
 354             fill_yuv_image(tmp_picture, frame_count, c->width, c->height);
 355             sws_scale(img_convert_ctx, tmp_picture->data, tmp_picture->linesize,
 356                       0, c->height, picture->data, picture->linesize);
 357         } else {
 358             fill_yuv_image(picture, frame_count, c->width, c->height);
 359         }
 360     }
 361
 362
 363     if (oc->oformat->flags & AVFMT_RAWPICTURE) {
 364         /* raw video case. The API will change slightly in the near
 365            futur for that */
 366         AVPacket pkt;
 367         av_init_packet(&pkt);
 368
 369         pkt.flags |= PKT_FLAG_KEY;
 370         pkt.stream_index= st->index;
 371         pkt.data= (uint8_t *)picture;
 372         pkt.size= sizeof(AVPicture);
 373
 374         ret = av_write_frame(oc, &pkt);
 375     } else {
 376         /* encode the image */
 377         out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture);
 378         /* if zero size, it means the image was buffered */
 379         if (out_size > 0) {
 380             AVPacket pkt;
 381             av_init_packet(&pkt);
 382
 383             pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
 384             if(c->coded_frame->key_frame)
 385                 pkt.flags |= PKT_FLAG_KEY;
 386             pkt.stream_index= st->index;
 387             pkt.data= video_outbuf;
 388             pkt.size= out_size;
 389
 390             /* write the compressed frame in the media file */
 391             ret = av_write_frame(oc, &pkt);
 392         } else {
 393             ret = 0;
 394         }
 395     }
 396     if (ret != 0) {
 397         fprintf(stderr, "Error while writing video frame\n");
 398         exit(1);
 399     }
 400     frame_count++;
 401 }
 402
 403 static void close_video(AVFormatContext *oc, AVStream *st)
 404 {
 405     avcodec_close(st->codec);
 406     av_free(picture->data[0]);
 407     av_free(picture);
 408     if (tmp_picture) {
 409         av_free(tmp_picture->data[0]);
 410         av_free(tmp_picture);
 411     }
 412     av_free(video_outbuf);
 413 }
 414
 415 /**************************************************************/
 416 /* media file output */
 417
 418 int main(int argc, char **argv)
 419 {
 420     const char *filename;
 421     AVOutputFormat *fmt;
 422     AVFormatContext *oc;
 423     AVStream *audio_st, *video_st;
 424     double audio_pts, video_pts;
 425     int i;
 426
 427     /* initialize libavcodec, and register all codecs and formats */
 428     av_register_all();
 429
 430     if (argc != 2) {
 431         printf("usage: %s output_file\n"
 432                "API example program to output a media file with libavformat.\n"
 433                "The output format is automatically guessed according to the file extension.\n"
 434                "Raw images can also be output by using '%%d' in the filename\n"
 435                "\n", argv[0]);
 436         exit(1);
 437     }
 438
 439     filename = argv[1];
 440
 441     /* auto detect the output format from the name. default is
 442        mpeg. */
 443     fmt = guess_format(NULL, filename, NULL);
 444     if (!fmt) {
 445         printf("Could not deduce output format from file extension: using MPEG.\n");
 446         fmt = guess_format("mpeg", NULL, NULL);
 447     }
 448     if (!fmt) {
 449         fprintf(stderr, "Could not find suitable output format\n");
 450         exit(1);
 451     }
 452
 453     /* allocate the output media context */
 454     oc = av_alloc_format_context();
 455     if (!oc) {
 456         fprintf(stderr, "Memory error\n");
 457         exit(1);
 458     }
 459     oc->oformat = fmt;
 460     snprintf(oc->filename, sizeof(oc->filename), "%s", filename);
 461
 462     /* add the audio and video streams using the default format codecs
 463        and initialize the codecs */
 464     video_st = NULL;
 465     audio_st = NULL;
 466     if (fmt->video_codec != CODEC_ID_NONE) {
 467         video_st = add_video_stream(oc, fmt->video_codec);
 468     }
 469     if (fmt->audio_codec != CODEC_ID_NONE) {
 470         audio_st = add_audio_stream(oc, fmt->audio_codec);
 471     }
 472
 473     /* set the output parameters (must be done even if no
 474        parameters). */
 475     if (av_set_parameters(oc, NULL) < 0) {
 476         fprintf(stderr, "Invalid output format parameters\n");
 477         exit(1);
 478     }
 479
 480     dump_format(oc, 0, filename, 1);
 481
 482     /* now that all the parameters are set, we can open the audio and
 483        video codecs and allocate the necessary encode buffers */
 484     if (video_st)
 485         open_video(oc, video_st);
 486     if (audio_st)
 487         open_audio(oc, audio_st);
 488
 489     /* open the output file, if needed */
 490     if (!(fmt->flags & AVFMT_NOFILE)) {
 491         if (url_fopen(&oc->pb, filename, URL_WRONLY) < 0) {
 492             fprintf(stderr, "Could not open '%s'\n", filename);
 493             exit(1);
 494         }
 495     }
 496
 497     /* write the stream header, if any */
 498     av_write_header(oc);
 499
 500     for(;;) {
 501         /* compute current audio and video time */
 502         if (audio_st)
 503             audio_pts = (double)audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den;
 504         else
 505             audio_pts = 0.0;
 506
 507         if (video_st)
 508             video_pts = (double)video_st->pts.val * video_st->time_base.num / video_st->time_base.den;
 509         else
 510             video_pts = 0.0;
 511
 512         if ((!audio_st || audio_pts >= STREAM_DURATION) &&
 513             (!video_st || video_pts >= STREAM_DURATION))
 514             break;
 515
 516         /* write interleaved audio and video frames */
 517         if (!video_st || (video_st && audio_st && audio_pts < video_pts)) {
 518             write_audio_frame(oc, audio_st);
 519         } else {
 520             write_video_frame(oc, video_st);
 521         }
 522     }
 523
 524     /* close each codec */
 525     if (video_st)
 526         close_video(oc, video_st);
 527     if (audio_st)
 528         close_audio(oc, audio_st);
 529
 530     /* write the trailer, if any */
 531     av_write_trailer(oc);
 532
 533     /* free the streams */
 534     for(i = 0; i < oc->nb_streams; i++) {
 535         av_freep(&oc->streams[i]->codec);
 536         av_freep(&oc->streams[i]);
 537     }
 538
 539     if (!(fmt->flags & AVFMT_NOFILE)) {
 540         /* close the output file */
 541         url_fclose(oc->pb);
 542     }
 543
 544     /* free the stream */
 545     av_free(oc);
 546
 547     return 0;
 548 }