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 /* 5 seconds stream duration */
  38 #define STREAM_DURATION   5.0
  39 #define STREAM_FRAME_RATE 25 /* 25 images/s */
  40 #define STREAM_NB_FRAMES  ((int)(STREAM_DURATION * STREAM_FRAME_RATE))
  41 #define STREAM_PIX_FMT PIX_FMT_YUV420P /* default pix_fmt */
  42
  43 static int sws_flags = SWS_BICUBIC;
  44
  45 /**************************************************************/
  46 /* audio output */
  47
  48 float t, tincr, tincr2;
  49 int16_t *samples;
  50 uint8_t *audio_outbuf;
  51 int audio_outbuf_size;
  52 int audio_input_frame_size;
  53
  54 /*
  55  * add an audio output stream
  56  */
  57 static AVStream *add_audio_stream(AVFormatContext *oc, int codec_id)
  58 {
  59     AVCodecContext *c;
  60     AVStream *st;
  61
  62     st = av_new_stream(oc, 1);
  63     if (!st) {
  64         fprintf(stderr, "Could not alloc stream\n");
  65         exit(1);
  66     }
  67
  68     c = st->codec;
  69     c->codec_id = codec_id;
  70     c->codec_type = CODEC_TYPE_AUDIO;
  71
  72     /* put sample parameters */
  73     c->bit_rate = 64000;
  74     c->sample_rate = 44100;
  75     c->channels = 2;
  76     return st;
  77 }
  78
  79 static void open_audio(AVFormatContext *oc, AVStream *st)
  80 {
  81     AVCodecContext *c;
  82     AVCodec *codec;
  83
  84     c = st->codec;
  85
  86     /* find the audio encoder */
  87     codec = avcodec_find_encoder(c->codec_id);
  88     if (!codec) {
  89         fprintf(stderr, "codec not found\n");
  90         exit(1);
  91     }
  92
  93     /* open it */
  94     if (avcodec_open(c, codec) < 0) {
  95         fprintf(stderr, "could not open codec\n");
  96         exit(1);
  97     }
  98
  99     /* init signal generator */
 100     t = 0;
 101     tincr = 2 * M_PI * 110.0 / c->sample_rate;
 102     /* increment frequency by 110 Hz per second */
 103     tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
 104
 105     audio_outbuf_size = 10000;
 106     audio_outbuf = av_malloc(audio_outbuf_size);
 107
 108     /* ugly hack for PCM codecs (will be removed ASAP with new PCM
 109        support to compute the input frame size in samples */
 110     if (c->frame_size <= 1) {
 111         audio_input_frame_size = audio_outbuf_size / c->channels;
 112         switch(st->codec->codec_id) {
 113         case CODEC_ID_PCM_S16LE:
 114         case CODEC_ID_PCM_S16BE:
 115         case CODEC_ID_PCM_U16LE:
 116         case CODEC_ID_PCM_U16BE:
 117             audio_input_frame_size >>= 1;
 118             break;
 119         default:
 120             break;
 121         }
 122     } else {
 123         audio_input_frame_size = c->frame_size;
 124     }
 125     samples = av_malloc(audio_input_frame_size * 2 * c->channels);
 126 }
 127
 128 /* prepare a 16 bit dummy audio frame of 'frame_size' samples and
 129    'nb_channels' channels */
 130 static void get_audio_frame(int16_t *samples, int frame_size, int nb_channels)
 131 {
 132     int j, i, v;
 133     int16_t *q;
 134
 135     q = samples;
 136     for(j=0;j<frame_size;j++) {
 137         v = (int)(sin(t) * 10000);
 138         for(i = 0; i < nb_channels; i++)
 139             *q++ = v;
 140         t += tincr;
 141         tincr += tincr2;
 142     }
 143 }
 144
 145 static void write_audio_frame(AVFormatContext *oc, AVStream *st)
 146 {
 147     AVCodecContext *c;
 148     AVPacket pkt;
 149     av_init_packet(&pkt);
 150
 151     c = st->codec;
 152
 153     get_audio_frame(samples, audio_input_frame_size, c->channels);
 154
 155     pkt.size= avcodec_encode_audio(c, audio_outbuf, audio_outbuf_size, samples);
 156
 157     pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
 158     pkt.flags |= PKT_FLAG_KEY;
 159     pkt.stream_index= st->index;
 160     pkt.data= audio_outbuf;
 161
 162     /* write the compressed frame in the media file */
 163     if (av_write_frame(oc, &pkt) != 0) {
 164         fprintf(stderr, "Error while writing audio frame\n");
 165         exit(1);
 166     }
 167 }
 168
 169 static void close_audio(AVFormatContext *oc, AVStream *st)
 170 {
 171     avcodec_close(st->codec);
 172
 173     av_free(samples);
 174     av_free(audio_outbuf);
 175 }
 176
 177 /**************************************************************/
 178 /* video output */
 179
 180 AVFrame *picture, *tmp_picture;
 181 uint8_t *video_outbuf;
 182 int frame_count, video_outbuf_size;
 183
 184 /* add a video output stream */
 185 static AVStream *add_video_stream(AVFormatContext *oc, int codec_id)
 186 {
 187     AVCodecContext *c;
 188     AVStream *st;
 189
 190     st = av_new_stream(oc, 0);
 191     if (!st) {
 192         fprintf(stderr, "Could not alloc stream\n");
 193         exit(1);
 194     }
 195
 196     c = st->codec;
 197     c->codec_id = codec_id;
 198     c->codec_type = CODEC_TYPE_VIDEO;
 199
 200     /* put sample parameters */
 201     c->bit_rate = 400000;
 202     /* resolution must be a multiple of two */
 203     c->width = 352;
 204     c->height = 288;
 205     /* time base: this is the fundamental unit of time (in seconds) in terms
 206        of which frame timestamps are represented. for fixed-fps content,
 207        timebase should be 1/framerate and timestamp increments should be
 208        identically 1. */
 209     c->time_base.den = STREAM_FRAME_RATE;
 210     c->time_base.num = 1;
 211     c->gop_size = 12; /* emit one intra frame every twelve frames at most */
 212     c->pix_fmt = STREAM_PIX_FMT;
 213     if (c->codec_id == CODEC_ID_MPEG2VIDEO) {
 214         /* just for testing, we also add B frames */
 215         c->max_b_frames = 2;
 216     }
 217     if (c->codec_id == CODEC_ID_MPEG1VIDEO){
 218         /* needed to avoid using macroblocks in which some coeffs overflow
 219            this doesnt happen with normal video, it just happens here as the
 220            motion of the chroma plane doesnt match the luma plane */
 221         c->mb_decision=2;
 222     }
 223     // some formats want stream headers to be separate
 224     if(!strcmp(oc->oformat->name, "mp4") || !strcmp(oc->oformat->name, "mov") || !strcmp(oc->oformat->name, "3gp"))
 225         c->flags |= CODEC_FLAG_GLOBAL_HEADER;
 226
 227     return st;
 228 }
 229
 230 static AVFrame *alloc_picture(int pix_fmt, int width, int height)
 231 {
 232     AVFrame *picture;
 233     uint8_t *picture_buf;
 234     int size;
 235
 236     picture = avcodec_alloc_frame();
 237     if (!picture)
 238         return NULL;
 239     size = avpicture_get_size(pix_fmt, width, height);
 240     picture_buf = av_malloc(size);
 241     if (!picture_buf) {
 242         av_free(picture);
 243         return NULL;
 244     }
 245     avpicture_fill((AVPicture *)picture, picture_buf,
 246                    pix_fmt, width, height);
 247     return picture;
 248 }
 249
 250 static void open_video(AVFormatContext *oc, AVStream *st)
 251 {
 252     AVCodec *codec;
 253     AVCodecContext *c;
 254
 255     c = st->codec;
 256
 257     /* find the video encoder */
 258     codec = avcodec_find_encoder(c->codec_id);
 259     if (!codec) {
 260         fprintf(stderr, "codec not found\n");
 261         exit(1);
 262     }
 263
 264     /* open the codec */
 265     if (avcodec_open(c, codec) < 0) {
 266         fprintf(stderr, "could not open codec\n");
 267         exit(1);
 268     }
 269
 270     video_outbuf = NULL;
 271     if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) {
 272         /* allocate output buffer */
 273         /* XXX: API change will be done */
 274         /* buffers passed into lav* can be allocated any way you prefer,
 275            as long as they're aligned enough for the architecture, and
 276            they're freed appropriately (such as using av_free for buffers
 277            allocated with av_malloc) */
 278         video_outbuf_size = 200000;
 279         video_outbuf = av_malloc(video_outbuf_size);
 280     }
 281
 282     /* allocate the encoded raw picture */
 283     picture = alloc_picture(c->pix_fmt, c->width, c->height);
 284     if (!picture) {
 285         fprintf(stderr, "Could not allocate picture\n");
 286         exit(1);
 287     }
 288
 289     /* if the output format is not YUV420P, then a temporary YUV420P
 290        picture is needed too. It is then converted to the required
 291        output format */
 292     tmp_picture = NULL;
 293     if (c->pix_fmt != PIX_FMT_YUV420P) {
 294         tmp_picture = alloc_picture(PIX_FMT_YUV420P, c->width, c->height);
 295         if (!tmp_picture) {
 296             fprintf(stderr, "Could not allocate temporary picture\n");
 297             exit(1);
 298         }
 299     }
 300 }
 301
 302 /* prepare a dummy image */
 303 static void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height)
 304 {
 305     int x, y, i;
 306
 307     i = frame_index;
 308
 309     /* Y */
 310     for(y=0;y<height;y++) {
 311         for(x=0;x<width;x++) {
 312             pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
 313         }
 314     }
 315
 316     /* Cb and Cr */
 317     for(y=0;y<height/2;y++) {
 318         for(x=0;x<width/2;x++) {
 319             pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
 320             pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
 321         }
 322     }
 323 }
 324
 325 static void write_video_frame(AVFormatContext *oc, AVStream *st)
 326 {
 327     int out_size, ret;
 328     AVCodecContext *c;
 329     static struct SwsContext *img_convert_ctx;
 330
 331     c = st->codec;
 332
 333     if (frame_count >= STREAM_NB_FRAMES) {
 334         /* no more frame to compress. The codec has a latency of a few
 335            frames if using B frames, so we get the last frames by
 336            passing the same picture again */
 337     } else {
 338         if (c->pix_fmt != PIX_FMT_YUV420P) {
 339             /* as we only generate a YUV420P picture, we must convert it
 340                to the codec pixel format if needed */
 341             if (img_convert_ctx == NULL) {
 342                 img_convert_ctx = sws_getContext(c->width, c->height,
 343                                                  PIX_FMT_YUV420P,
 344                                                  c->width, c->height,
 345                                                  c->pix_fmt,
 346                                                  sws_flags, NULL, NULL, NULL);
 347                 if (img_convert_ctx == NULL) {
 348                     fprintf(stderr, "Cannot initialize the conversion context\n");
 349                     exit(1);
 350                 }
 351             }
 352             fill_yuv_image(tmp_picture, frame_count, c->width, c->height);
 353             sws_scale(img_convert_ctx, tmp_picture->data, tmp_picture->linesize,
 354                       0, c->height, picture->data, picture->linesize);
 355         } else {
 356             fill_yuv_image(picture, frame_count, c->width, c->height);
 357         }
 358     }
 359
 360
 361     if (oc->oformat->flags & AVFMT_RAWPICTURE) {
 362         /* raw video case. The API will change slightly in the near
 363            futur for that */
 364         AVPacket pkt;
 365         av_init_packet(&pkt);
 366
 367         pkt.flags |= PKT_FLAG_KEY;
 368         pkt.stream_index= st->index;
 369         pkt.data= (uint8_t *)picture;
 370         pkt.size= sizeof(AVPicture);
 371
 372         ret = av_write_frame(oc, &pkt);
 373     } else {
 374         /* encode the image */
 375         out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture);
 376         /* if zero size, it means the image was buffered */
 377         if (out_size > 0) {
 378             AVPacket pkt;
 379             av_init_packet(&pkt);
 380
 381             pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
 382             if(c->coded_frame->key_frame)
 383                 pkt.flags |= PKT_FLAG_KEY;
 384             pkt.stream_index= st->index;
 385             pkt.data= video_outbuf;
 386             pkt.size= out_size;
 387
 388             /* write the compressed frame in the media file */
 389             ret = av_write_frame(oc, &pkt);
 390         } else {
 391             ret = 0;
 392         }
 393     }
 394     if (ret != 0) {
 395         fprintf(stderr, "Error while writing video frame\n");
 396         exit(1);
 397     }
 398     frame_count++;
 399 }
 400
 401 static void close_video(AVFormatContext *oc, AVStream *st)
 402 {
 403     avcodec_close(st->codec);
 404     av_free(picture->data[0]);
 405     av_free(picture);
 406     if (tmp_picture) {
 407         av_free(tmp_picture->data[0]);
 408         av_free(tmp_picture);
 409     }
 410     av_free(video_outbuf);
 411 }
 412
 413 /**************************************************************/
 414 /* media file output */
 415
 416 int main(int argc, char **argv)
 417 {
 418     const char *filename;
 419     AVOutputFormat *fmt;
 420     AVFormatContext *oc;
 421     AVStream *audio_st, *video_st;
 422     double audio_pts, video_pts;
 423     int i;
 424
 425     /* initialize libavcodec, and register all codecs and formats */
 426     av_register_all();
 427
 428     if (argc != 2) {
 429         printf("usage: %s output_file\n"
 430                "API example program to output a media file with libavformat.\n"
 431                "The output format is automatically guessed according to the file extension.\n"
 432                "Raw images can also be output by using '%%d' in the filename\n"
 433                "\n", argv[0]);
 434         exit(1);
 435     }
 436
 437     filename = argv[1];
 438
 439     /* auto detect the output format from the name. default is
 440        mpeg. */
 441     fmt = guess_format(NULL, filename, NULL);
 442     if (!fmt) {
 443         printf("Could not deduce output format from file extension: using MPEG.\n");
 444         fmt = guess_format("mpeg", NULL, NULL);
 445     }
 446     if (!fmt) {
 447         fprintf(stderr, "Could not find suitable output format\n");
 448         exit(1);
 449     }
 450
 451     /* allocate the output media context */
 452     oc = av_alloc_format_context();
 453     if (!oc) {
 454         fprintf(stderr, "Memory error\n");
 455         exit(1);
 456     }
 457     oc->oformat = fmt;
 458     snprintf(oc->filename, sizeof(oc->filename), "%s", filename);
 459
 460     /* add the audio and video streams using the default format codecs
 461        and initialize the codecs */
 462     video_st = NULL;
 463     audio_st = NULL;
 464     if (fmt->video_codec != CODEC_ID_NONE) {
 465         video_st = add_video_stream(oc, fmt->video_codec);
 466     }
 467     if (fmt->audio_codec != CODEC_ID_NONE) {
 468         audio_st = add_audio_stream(oc, fmt->audio_codec);
 469     }
 470
 471     /* set the output parameters (must be done even if no
 472        parameters). */
 473     if (av_set_parameters(oc, NULL) < 0) {
 474         fprintf(stderr, "Invalid output format parameters\n");
 475         exit(1);
 476     }
 477
 478     dump_format(oc, 0, filename, 1);
 479
 480     /* now that all the parameters are set, we can open the audio and
 481        video codecs and allocate the necessary encode buffers */
 482     if (video_st)
 483         open_video(oc, video_st);
 484     if (audio_st)
 485         open_audio(oc, audio_st);
 486
 487     /* open the output file, if needed */
 488     if (!(fmt->flags & AVFMT_NOFILE)) {
 489         if (url_fopen(&oc->pb, filename, URL_WRONLY) < 0) {
 490             fprintf(stderr, "Could not open '%s'\n", filename);
 491             exit(1);
 492         }
 493     }
 494
 495     /* write the stream header, if any */
 496     av_write_header(oc);
 497
 498     for(;;) {
 499         /* compute current audio and video time */
 500         if (audio_st)
 501             audio_pts = (double)audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den;
 502         else
 503             audio_pts = 0.0;
 504
 505         if (video_st)
 506             video_pts = (double)video_st->pts.val * video_st->time_base.num / video_st->time_base.den;
 507         else
 508             video_pts = 0.0;
 509
 510         if ((!audio_st || audio_pts >= STREAM_DURATION) &&
 511             (!video_st || video_pts >= STREAM_DURATION))
 512             break;
 513
 514         /* write interleaved audio and video frames */
 515         if (!video_st || (video_st && audio_st && audio_pts < video_pts)) {
 516             write_audio_frame(oc, audio_st);
 517         } else {
 518             write_video_frame(oc, video_st);
 519         }
 520     }
 521
 522     /* close each codec */
 523     if (video_st)
 524         close_video(oc, video_st);
 525     if (audio_st)
 526         close_audio(oc, audio_st);
 527
 528     /* write the trailer, if any */
 529     av_write_trailer(oc);
 530
 531     /* free the streams */
 532     for(i = 0; i < oc->nb_streams; i++) {
 533         av_freep(&oc->streams[i]->codec);
 534         av_freep(&oc->streams[i]);
 535     }
 536
 537     if (!(fmt->flags & AVFMT_NOFILE)) {
 538         /* close the output file */
 539         url_fclose(&oc->pb);
 540     }
 541
 542     /* free the stream */
 543     av_free(oc);
 544
 545     return 0;
 546 }