extern/ffmpeg/libavcodec/apiexample.c

   1 /**
   2  * @file apiexample.c
   3  * avcodec API use example.
   4  *
   5  * Note that this library only handles codecs (mpeg, mpeg4, etc...),
   6  * not file formats (avi, vob, etc...). See library 'libavformat' for the
   7  * format handling
   8  */
   9
  10 #include <stdlib.h>
  11 #include <stdio.h>
  12 #include <string.h>
  13 #include <math.h>
  14
  15 #ifdef HAVE_AV_CONFIG_H
  16 #undef HAVE_AV_CONFIG_H
  17 #endif
  18
  19 #include "avcodec.h"
  20
  21 #define INBUF_SIZE 4096
  22
  23 /*
  24  * Audio encoding example
  25  */
  26 void audio_encode_example(const char *filename)
  27 {
  28     AVCodec *codec;
  29     AVCodecContext *c= NULL;
  30     int frame_size, i, j, out_size, outbuf_size;
  31     FILE *f;
  32     short *samples;
  33     float t, tincr;
  34     uint8_t *outbuf;
  35
  36     printf("Audio encoding\n");
  37
  38     /* find the MP2 encoder */
  39     codec = avcodec_find_encoder(CODEC_ID_MP2);
  40     if (!codec) {
  41         fprintf(stderr, "codec not found\n");
  42         exit(1);
  43     }
  44
  45     c= avcodec_alloc_context();
  46
  47     /* put sample parameters */
  48     c->bit_rate = 64000;
  49     c->sample_rate = 44100;
  50     c->channels = 2;
  51
  52     /* open it */
  53     if (avcodec_open(c, codec) < 0) {
  54         fprintf(stderr, "could not open codec\n");
  55         exit(1);
  56     }
  57
  58     /* the codec gives us the frame size, in samples */
  59     frame_size = c->frame_size;
  60     samples = malloc(frame_size * 2 * c->channels);
  61     outbuf_size = 10000;
  62     outbuf = malloc(outbuf_size);
  63
  64     f = fopen(filename, "wb");
  65     if (!f) {
  66         fprintf(stderr, "could not open %s\n", filename);
  67         exit(1);
  68     }
  69
  70     /* encode a single tone sound */
  71     t = 0;
  72     tincr = 2 * M_PI * 440.0 / c->sample_rate;
  73     for(i=0;i<200;i++) {
  74         for(j=0;j<frame_size;j++) {
  75             samples[2*j] = (int)(sin(t) * 10000);
  76             samples[2*j+1] = samples[2*j];
  77             t += tincr;
  78         }
  79         /* encode the samples */
  80         out_size = avcodec_encode_audio(c, outbuf, outbuf_size, samples);
  81         fwrite(outbuf, 1, out_size, f);
  82     }
  83     fclose(f);
  84     free(outbuf);
  85     free(samples);
  86
  87     avcodec_close(c);
  88     av_free(c);
  89 }
  90
  91 /*
  92  * Audio decoding.
  93  */
  94 void audio_decode_example(const char *outfilename, const char *filename)
  95 {
  96     AVCodec *codec;
  97     AVCodecContext *c= NULL;
  98     int out_size, size, len;
  99     FILE *f, *outfile;
 100     uint8_t *outbuf;
 101     uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE], *inbuf_ptr;
 102
 103     printf("Audio decoding\n");
 104
 105     /* set end of buffer to 0 (this ensures that no overreading happens for damaged mpeg streams) */
 106     memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE);
 107
 108     /* find the mpeg audio decoder */
 109     codec = avcodec_find_decoder(CODEC_ID_MP2);
 110     if (!codec) {
 111         fprintf(stderr, "codec not found\n");
 112         exit(1);
 113     }
 114
 115     c= avcodec_alloc_context();
 116
 117     /* open it */
 118     if (avcodec_open(c, codec) < 0) {
 119         fprintf(stderr, "could not open codec\n");
 120         exit(1);
 121     }
 122
 123     outbuf = malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE);
 124
 125     f = fopen(filename, "rb");
 126     if (!f) {
 127         fprintf(stderr, "could not open %s\n", filename);
 128         exit(1);
 129     }
 130     outfile = fopen(outfilename, "wb");
 131     if (!outfile) {
 132         av_free(c);
 133         exit(1);
 134     }
 135
 136     /* decode until eof */
 137     inbuf_ptr = inbuf;
 138     for(;;) {
 139         size = fread(inbuf, 1, INBUF_SIZE, f);
 140         if (size == 0)
 141             break;
 142
 143         inbuf_ptr = inbuf;
 144         while (size > 0) {
 145             len = avcodec_decode_audio(c, (short *)outbuf, &out_size,
 146                                        inbuf_ptr, size);
 147             if (len < 0) {
 148                 fprintf(stderr, "Error while decoding\n");
 149                 exit(1);
 150             }
 151             if (out_size > 0) {
 152                 /* if a frame has been decoded, output it */
 153                 fwrite(outbuf, 1, out_size, outfile);
 154             }
 155             size -= len;
 156             inbuf_ptr += len;
 157         }
 158     }
 159
 160     fclose(outfile);
 161     fclose(f);
 162     free(outbuf);
 163
 164     avcodec_close(c);
 165     av_free(c);
 166 }
 167
 168 /*
 169  * Video encoding example
 170  */
 171 void video_encode_example(const char *filename)
 172 {
 173     AVCodec *codec;
 174     AVCodecContext *c= NULL;
 175     int i, out_size, size, x, y, outbuf_size;
 176     FILE *f;
 177     AVFrame *picture;
 178     uint8_t *outbuf, *picture_buf;
 179
 180     printf("Video encoding\n");
 181
 182     /* find the mpeg1 video encoder */
 183     codec = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO);
 184     if (!codec) {
 185         fprintf(stderr, "codec not found\n");
 186         exit(1);
 187     }
 188
 189     c= avcodec_alloc_context();
 190     picture= avcodec_alloc_frame();
 191
 192     /* put sample parameters */
 193     c->bit_rate = 400000;
 194     /* resolution must be a multiple of two */
 195     c->width = 352;
 196     c->height = 288;
 197     /* frames per second */
 198     c->time_base= (AVRational){1,25};
 199     c->gop_size = 10; /* emit one intra frame every ten frames */
 200     c->max_b_frames=1;
 201     c->pix_fmt = PIX_FMT_YUV420P;
 202
 203     /* open it */
 204     if (avcodec_open(c, codec) < 0) {
 205         fprintf(stderr, "could not open codec\n");
 206         exit(1);
 207     }
 208
 209     /* the codec gives us the frame size, in samples */
 210
 211     f = fopen(filename, "wb");
 212     if (!f) {
 213         fprintf(stderr, "could not open %s\n", filename);
 214         exit(1);
 215     }
 216
 217     /* alloc image and output buffer */
 218     outbuf_size = 100000;
 219     outbuf = malloc(outbuf_size);
 220     size = c->width * c->height;
 221     picture_buf = malloc((size * 3) / 2); /* size for YUV 420 */
 222
 223     picture->data[0] = picture_buf;
 224     picture->data[1] = picture->data[0] + size;
 225     picture->data[2] = picture->data[1] + size / 4;
 226     picture->linesize[0] = c->width;
 227     picture->linesize[1] = c->width / 2;
 228     picture->linesize[2] = c->width / 2;
 229
 230     /* encode 1 second of video */
 231     for(i=0;i<25;i++) {
 232         fflush(stdout);
 233         /* prepare a dummy image */
 234         /* Y */
 235         for(y=0;y<c->height;y++) {
 236             for(x=0;x<c->width;x++) {
 237                 picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
 238             }
 239         }
 240
 241         /* Cb and Cr */
 242         for(y=0;y<c->height/2;y++) {
 243             for(x=0;x<c->width/2;x++) {
 244                 picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
 245                 picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
 246             }
 247         }
 248
 249         /* encode the image */
 250         out_size = avcodec_encode_video(c, outbuf, outbuf_size, picture);
 251         printf("encoding frame %3d (size=%5d)\n", i, out_size);
 252         fwrite(outbuf, 1, out_size, f);
 253     }
 254
 255     /* get the delayed frames */
 256     for(; out_size; i++) {
 257         fflush(stdout);
 258
 259         out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
 260         printf("write frame %3d (size=%5d)\n", i, out_size);
 261         fwrite(outbuf, 1, out_size, f);
 262     }
 263
 264     /* add sequence end code to have a real mpeg file */
 265     outbuf[0] = 0x00;
 266     outbuf[1] = 0x00;
 267     outbuf[2] = 0x01;
 268     outbuf[3] = 0xb7;
 269     fwrite(outbuf, 1, 4, f);
 270     fclose(f);
 271     free(picture_buf);
 272     free(outbuf);
 273
 274     avcodec_close(c);
 275     av_free(c);
 276     av_free(picture);
 277     printf("\n");
 278 }
 279
 280 /*
 281  * Video decoding example
 282  */
 283
 284 void pgm_save(unsigned char *buf,int wrap, int xsize,int ysize,char *filename)
 285 {
 286     FILE *f;
 287     int i;
 288
 289     f=fopen(filename,"w");
 290     fprintf(f,"P5\n%d %d\n%d\n",xsize,ysize,255);
 291     for(i=0;i<ysize;i++)
 292         fwrite(buf + i * wrap,1,xsize,f);
 293     fclose(f);
 294 }
 295
 296 void video_decode_example(const char *outfilename, const char *filename)
 297 {
 298     AVCodec *codec;
 299     AVCodecContext *c= NULL;
 300     int frame, size, got_picture, len;
 301     FILE *f;
 302     AVFrame *picture;
 303     uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE], *inbuf_ptr;
 304     char buf[1024];
 305
 306     /* set end of buffer to 0 (this ensures that no overreading happens for damaged mpeg streams) */
 307     memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE);
 308
 309     printf("Video decoding\n");
 310
 311     /* find the mpeg1 video decoder */
 312     codec = avcodec_find_decoder(CODEC_ID_MPEG1VIDEO);
 313     if (!codec) {
 314         fprintf(stderr, "codec not found\n");
 315         exit(1);
 316     }
 317
 318     c= avcodec_alloc_context();
 319     picture= avcodec_alloc_frame();
 320
 321     if(codec->capabilities&CODEC_CAP_TRUNCATED)
 322         c->flags|= CODEC_FLAG_TRUNCATED; /* we dont send complete frames */
 323
 324     /* for some codecs, such as msmpeg4 and mpeg4, width and height
 325        MUST be initialized there because these info are not available
 326        in the bitstream */
 327
 328     /* open it */
 329     if (avcodec_open(c, codec) < 0) {
 330         fprintf(stderr, "could not open codec\n");
 331         exit(1);
 332     }
 333
 334     /* the codec gives us the frame size, in samples */
 335
 336     f = fopen(filename, "rb");
 337     if (!f) {
 338         fprintf(stderr, "could not open %s\n", filename);
 339         exit(1);
 340     }
 341
 342     frame = 0;
 343     for(;;) {
 344         size = fread(inbuf, 1, INBUF_SIZE, f);
 345         if (size == 0)
 346             break;
 347
 348         /* NOTE1: some codecs are stream based (mpegvideo, mpegaudio)
 349            and this is the only method to use them because you cannot
 350            know the compressed data size before analysing it.
 351
 352            BUT some other codecs (msmpeg4, mpeg4) are inherently frame
 353            based, so you must call them with all the data for one
 354            frame exactly. You must also initialize 'width' and
 355            'height' before initializing them. */
 356
 357         /* NOTE2: some codecs allow the raw parameters (frame size,
 358            sample rate) to be changed at any frame. We handle this, so
 359            you should also take care of it */
 360
 361         /* here, we use a stream based decoder (mpeg1video), so we
 362            feed decoder and see if it could decode a frame */
 363         inbuf_ptr = inbuf;
 364         while (size > 0) {
 365             len = avcodec_decode_video(c, picture, &got_picture,
 366                                        inbuf_ptr, size);
 367             if (len < 0) {
 368                 fprintf(stderr, "Error while decoding frame %d\n", frame);
 369                 exit(1);
 370             }
 371             if (got_picture) {
 372                 printf("saving frame %3d\n", frame);
 373                 fflush(stdout);
 374
 375                 /* the picture is allocated by the decoder. no need to
 376                    free it */
 377                 snprintf(buf, sizeof(buf), outfilename, frame);
 378                 pgm_save(picture->data[0], picture->linesize[0],
 379                          c->width, c->height, buf);
 380                 frame++;
 381             }
 382             size -= len;
 383             inbuf_ptr += len;
 384         }
 385     }
 386
 387     /* some codecs, such as MPEG, transmit the I and P frame with a
 388        latency of one frame. You must do the following to have a
 389        chance to get the last frame of the video */
 390     len = avcodec_decode_video(c, picture, &got_picture,
 391                                NULL, 0);
 392     if (got_picture) {
 393         printf("saving last frame %3d\n", frame);
 394         fflush(stdout);
 395
 396         /* the picture is allocated by the decoder. no need to
 397            free it */
 398         snprintf(buf, sizeof(buf), outfilename, frame);
 399         pgm_save(picture->data[0], picture->linesize[0],
 400                  c->width, c->height, buf);
 401         frame++;
 402     }
 403
 404     fclose(f);
 405
 406     avcodec_close(c);
 407     av_free(c);
 408     av_free(picture);
 409     printf("\n");
 410 }
 411
 412 int main(int argc, char **argv)
 413 {
 414     const char *filename;
 415
 416     /* must be called before using avcodec lib */
 417     avcodec_init();
 418
 419     /* register all the codecs (you can also register only the codec
 420        you wish to have smaller code */
 421     avcodec_register_all();
 422
 423     if (argc <= 1) {
 424         audio_encode_example("/tmp/test.mp2");
 425         audio_decode_example("/tmp/test.sw", "/tmp/test.mp2");
 426
 427         video_encode_example("/tmp/test.mpg");
 428         filename = "/tmp/test.mpg";
 429     } else {
 430         filename = argv[1];
 431     }
 432
 433     //    audio_decode_example("/tmp/test.sw", filename);
 434     video_decode_example("/tmp/test%d.pgm", filename);
 435
 436     return 0;
 437 }