libmpdemux/mpeg_hdr.c

   1
   2 // based on libmpeg2/header.c by Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
   3
   4 #include <inttypes.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8
   9 #include "config.h"
  10 #include "mpeg_hdr.h"
  11
  12 #include "mp_msg.h"
  13
  14 static float frameratecode2framerate[16] = {
  15   0,
  16   // Official mpeg1/2 framerates: (1-8)
  17   24000.0/1001, 24,25,
  18   30000.0/1001, 30,50,
  19   60000.0/1001, 60,
  20   // Xing's 15fps: (9)
  21   15,
  22   // libmpeg3's "Unofficial economy rates": (10-13)
  23   5,10,12,15,
  24   // some invalid ones: (14-15)
  25   0,0
  26 };
  27
  28
  29 int mp_header_process_sequence_header (mp_mpeg_header_t * picture, unsigned char * buffer)
  30 {
  31     int width, height;
  32
  33     if ((buffer[6] & 0x20) != 0x20){
  34         fprintf(stderr, "missing marker bit!\n");
  35         return 1;       /* missing marker_bit */
  36     }
  37
  38     height = (buffer[0] << 16) | (buffer[1] << 8) | buffer[2];
  39
  40     picture->display_picture_width = (height >> 12);
  41     picture->display_picture_height = (height & 0xfff);
  42
  43     width = ((height >> 12) + 15) & ~15;
  44     height = ((height & 0xfff) + 15) & ~15;
  45
  46     picture->aspect_ratio_information = buffer[3] >> 4;
  47     picture->frame_rate_code = buffer[3] & 15;
  48     picture->fps=frameratecode2framerate[picture->frame_rate_code];
  49     picture->bitrate = (buffer[4]<<10)|(buffer[5]<<2)|(buffer[6]>>6);
  50     picture->mpeg1 = 1;
  51     picture->picture_structure = 3; //FRAME_PICTURE;
  52     picture->display_time=100;
  53     return 0;
  54 }
  55
  56 static int header_process_sequence_extension (mp_mpeg_header_t * picture,
  57                                               unsigned char * buffer)
  58 {
  59     /* check chroma format, size extensions, marker bit */
  60
  61     if ( ((buffer[1] & 0x06) == 0x00) ||
  62          ((buffer[1] & 0x01) != 0x00) || (buffer[2] & 0xe0) ||
  63          ((buffer[3] & 0x01) != 0x01) )
  64         return 1;
  65
  66     picture->progressive_sequence = (buffer[1] >> 3) & 1;
  67     picture->mpeg1 = 0;
  68     return 0;
  69 }
  70
  71 static int header_process_picture_coding_extension (mp_mpeg_header_t * picture, unsigned char * buffer)
  72 {
  73     picture->picture_structure = buffer[2] & 3;
  74     picture->top_field_first = buffer[3] >> 7;
  75     picture->repeat_first_field = (buffer[3] >> 1) & 1;
  76     picture->progressive_frame = buffer[4] >> 7;
  77
  78     // repeat_first implementation by A'rpi/ESP-team, based on libmpeg3:
  79     picture->display_time=100;
  80     if(picture->repeat_first_field){
  81         if(picture->progressive_sequence){
  82             if(picture->top_field_first)
  83                 picture->display_time+=200;
  84             else
  85                 picture->display_time+=100;
  86         } else
  87         if(picture->progressive_frame){
  88                 picture->display_time+=50;
  89         }
  90     }
  91     //temopral hack. We calc time on every field, so if we have 2 fields
  92     // interlaced we'll end with double time for 1 frame
  93     if( picture->picture_structure!=3 ) picture->display_time/=2;
  94     return 0;
  95 }
  96
  97 int mp_header_process_extension (mp_mpeg_header_t * picture, unsigned char * buffer)
  98 {
  99     switch (buffer[0] & 0xf0) {
 100     case 0x10:  /* sequence extension */
 101         return header_process_sequence_extension (picture, buffer);
 102     case 0x80:  /* picture coding extension */
 103         return header_process_picture_coding_extension (picture, buffer);
 104     }
 105     return 0;
 106 }
 107
 108 float mpeg12_aspect_info(mp_mpeg_header_t *picture)
 109 {
 110     float aspect = 0.0;
 111
 112     switch(picture->aspect_ratio_information) {
 113       case 2:  // PAL/NTSC SVCD/DVD 4:3
 114       case 8:  // PAL VCD 4:3
 115       case 12: // NTSC VCD 4:3
 116         aspect=4.0/3.0;
 117         break;
 118       case 3:  // PAL/NTSC Widescreen SVCD/DVD 16:9
 119       case 6:  // (PAL?)/NTSC Widescreen SVCD 16:9
 120         aspect=16.0/9.0;
 121         break;
 122       case 4:  // according to ISO-138182-2 Table 6.3
 123         aspect=2.21;
 124         break;
 125       case 1:  // VGA 1:1 - do not prescale
 126       case 9: // Movie Type ??? / 640x480
 127         aspect=0.0;
 128         break;
 129       default:
 130         mp_msg(MSGT_DECVIDEO,MSGL_ERR,"Detected unknown aspect_ratio_information in mpeg sequence header.\n"
 131                "Please report the aspect value (%i) along with the movie type (VGA,PAL,NTSC,"
 132                "SECAM) and the movie resolution (720x576,352x240,480x480,...) to the MPlayer"
 133                " developers, so that we can add support for it!\nAssuming 1:1 aspect for now.\n",
 134                picture->aspect_ratio_information);
 135     }
 136
 137     return aspect;
 138 }
 139
 140 //MPEG4 HEADERS
 141 unsigned char mp_getbits(unsigned char *buffer, unsigned int from, unsigned char len)
 142 {
 143     unsigned int n;
 144     unsigned char m, u, l, y;
 145
 146     n = from / 8;
 147     m = from % 8;
 148     u = 8 - m;
 149     l = (len > u ? len - u : 0);
 150
 151     y = (buffer[n] << m);
 152     if(8 > len)
 153         y  >>= (8-len);
 154     if(l)
 155         y |= (buffer[n+1] >> (8-l));
 156
 157     //fprintf(stderr, "GETBITS(%d -> %d): bytes=0x%x 0x%x, n=%d, m=%d, l=%d, u=%d, Y=%d\n",
 158     //  from, (int) len, (int) buffer[n],(int) buffer[n+1], n, (int) m, (int) l, (int) u, (int) y);
 159     return  y;
 160 }
 161
 162 static inline unsigned int mp_getbits16(unsigned char *buffer, unsigned int from, unsigned char len)
 163 {
 164     if(len > 8)
 165         return (mp_getbits(buffer, from, len - 8) << 8) | mp_getbits(buffer, from + len - 8, 8);
 166     else
 167         return mp_getbits(buffer, from, len);
 168 }
 169
 170 #define getbits mp_getbits
 171 #define getbits16 mp_getbits16
 172
 173 static int read_timeinc(mp_mpeg_header_t * picture, unsigned char * buffer, int n)
 174 {
 175     if(picture->timeinc_bits > 8) {
 176       picture->timeinc_unit = getbits(buffer, n, picture->timeinc_bits - 8) << 8;
 177       n += picture->timeinc_bits - 8;
 178       picture->timeinc_unit |= getbits(buffer, n, 8);
 179       n += 8;
 180     } else {
 181       picture->timeinc_unit = getbits(buffer, n, picture->timeinc_bits);
 182       n += picture->timeinc_bits;
 183     }
 184     //fprintf(stderr, "TIMEINC2: %d, bits: %d\n", picture->timeinc_unit, picture->timeinc_bits);
 185     return n;
 186 }
 187
 188 int mp4_header_process_vol(mp_mpeg_header_t * picture, unsigned char * buffer)
 189 {
 190     unsigned int n, aspect=0, aspectw=0, aspecth=0,  x=1, v;
 191
 192     //begins with 0x0000012x
 193     picture->fps = 0;
 194     picture->timeinc_bits = picture->timeinc_resolution = picture->timeinc_unit = 0;
 195     n = 9;
 196     if(getbits(buffer, n, 1))
 197       n += 7;
 198     n++;
 199     aspect=getbits(buffer, n, 4);
 200     n += 4;
 201     if(aspect == 0x0f) {
 202       aspectw = getbits(buffer, n, 8);
 203       n += 8;
 204       aspecth = getbits(buffer, n, 8);
 205       n += 8;
 206     }
 207
 208     if(getbits(buffer, n, 1)) {
 209       n += 4;
 210       if(getbits(buffer, n, 1))
 211         n += 79;
 212       n++;
 213     } else n++;
 214
 215     n+=3;
 216
 217     picture->timeinc_resolution = getbits(buffer, n, 8) << 8;
 218     n += 8;
 219     picture->timeinc_resolution |= getbits(buffer, n, 8);
 220     n += 8;
 221
 222     picture->timeinc_bits = 0;
 223     v = picture->timeinc_resolution - 1;
 224     while(v && (x<16)) {
 225       v>>=1;
 226       picture->timeinc_bits++;
 227     }
 228     picture->timeinc_bits = (picture->timeinc_bits > 1 ? picture->timeinc_bits : 1);
 229
 230     n++; //marker bit
 231
 232     if(getbits(buffer, n, 1)) { //fixed_vop_timeinc
 233       n++;
 234       n = read_timeinc(picture, buffer, n);
 235
 236       if(picture->timeinc_unit)
 237         picture->fps = (float) picture->timeinc_resolution / (float) picture->timeinc_unit;
 238     }
 239
 240     //fprintf(stderr, "ASPECT: %d, PARW=%d, PARH=%d, TIMEINCRESOLUTION: %d, FIXED_TIMEINC: %d (number of bits: %d), FPS: %u\n",
 241     //  aspect, aspectw, aspecth, picture->timeinc_resolution, picture->timeinc_unit, picture->timeinc_bits, picture->fps);
 242
 243     return 0;
 244 }
 245
 246 void mp4_header_process_vop(mp_mpeg_header_t * picture, unsigned char * buffer)
 247 {
 248   int n;
 249   n = 0;
 250   picture->picture_type = getbits(buffer, n, 2);
 251   n += 2;
 252   while(getbits(buffer, n, 1))
 253     n++;
 254   n++;
 255   getbits(buffer, n, 1);
 256   n++;
 257   n = read_timeinc(picture, buffer, n);
 258 }
 259
 260 #define min(a, b) ((a) <= (b) ? (a) : (b))
 261
 262 static unsigned int read_golomb(unsigned char *buffer, unsigned int *init)
 263 {
 264   unsigned int x, v = 0, v2 = 0, m, len = 0, n = *init;
 265
 266   while(getbits(buffer, n++, 1) == 0)
 267     len++;
 268
 269   x = len + n;
 270   while(n < x)
 271   {
 272     m = min(x - n, 8);
 273     v |= getbits(buffer, n, m);
 274     n += m;
 275     if(x - n > 8)
 276       v <<= 8;
 277   }
 278
 279   v2 = 1;
 280   for(n = 0; n < len; n++)
 281     v2 <<= 1;
 282   v2 = (v2 - 1) + v;
 283
 284   //fprintf(stderr, "READ_GOLOMB(%u), V=2^%u + %u-1 = %u\n", *init, len, v, v2);
 285   *init = x;
 286   return v2;
 287 }
 288
 289
 290 static int h264_parse_vui(mp_mpeg_header_t * picture, unsigned char * buf, unsigned int n)
 291 {
 292   unsigned int overscan, vsp_color, chroma, timing, fixed_fps;
 293
 294   if(getbits(buf, n++, 1))
 295   {
 296     picture->aspect_ratio_information = getbits(buf, n, 8);
 297     n += 8;
 298     if(picture->aspect_ratio_information == 255)
 299     {
 300       picture->display_picture_width = (getbits(buf, n, 8) << 8) | getbits(buf, n + 8, 8);
 301       n += 16;
 302
 303       picture->display_picture_height = (getbits(buf, n, 8) << 8) | getbits(buf, n + 8, 8);
 304       n += 16;
 305     }
 306   }
 307
 308   if((overscan=getbits(buf, n++, 1)))
 309     n++;
 310   if((vsp_color=getbits(buf, n++, 1)))
 311   {
 312     n += 4;
 313     if(getbits(buf, n++, 1))
 314       n += 24;
 315   }
 316   if((chroma=getbits(buf, n++, 1)))
 317   {
 318     read_golomb(buf, &n);
 319     read_golomb(buf, &n);
 320   }
 321   if((timing=getbits(buf, n++, 1)))
 322   {
 323     picture->timeinc_unit = (getbits(buf, n, 8) << 24) | (getbits(buf, n+8, 8) << 16) | (getbits(buf, n+16, 8) << 8) | getbits(buf, n+24, 8);
 324     n += 32;
 325
 326     picture->timeinc_resolution = (getbits(buf, n, 8) << 24) | (getbits(buf, n+8, 8) << 16) | (getbits(buf, n+16, 8) << 8) | getbits(buf, n+24, 8);
 327     n += 32;
 328
 329     fixed_fps = getbits(buf, n, 1);
 330
 331     if(picture->timeinc_unit > 0 && picture->timeinc_resolution > 0)
 332       picture->fps = (float) picture->timeinc_resolution / (float) picture->timeinc_unit;
 333     if(fixed_fps)
 334       picture->fps /= 2;
 335   }
 336
 337   //fprintf(stderr, "H264_PARSE_VUI, OVESCAN=%u, VSP_COLOR=%u, CHROMA=%u, TIMING=%u, DISPW=%u, DISPH=%u, TIMERES=%u, TIMEINC=%u, FIXED_FPS=%u\n", overscan, vsp_color, chroma, timing, picture->display_picture_width, picture->display_picture_height,
 338   //    picture->timeinc_resolution, picture->timeinc_unit, picture->timeinc_unit, fixed_fps);
 339
 340   return n;
 341 }
 342
 343 static int mp_unescape03(unsigned char *buf, int len);
 344
 345 int h264_parse_sps(mp_mpeg_header_t * picture, unsigned char * buf, int len)
 346 {
 347   unsigned int n = 0, v, i, mbh;
 348   int frame_mbs_only;
 349
 350   len = mp_unescape03(buf, len);
 351
 352   picture->fps = picture->timeinc_unit = picture->timeinc_resolution = 0;
 353   n = 24;
 354   read_golomb(buf, &n);
 355   if(buf[0] >= 100){
 356     if(read_golomb(buf, &n) == 3)
 357       n++;
 358     read_golomb(buf, &n);
 359     read_golomb(buf, &n);
 360     n++;
 361     if(getbits(buf, n++, 1)){
 362       //FIXME scaling matrix
 363     }
 364   }
 365   read_golomb(buf, &n);
 366   v = read_golomb(buf, &n);
 367   if(v == 0)
 368     read_golomb(buf, &n);
 369   else if(v == 1)
 370   {
 371     getbits(buf, n++, 1);
 372     read_golomb(buf, &n);
 373     read_golomb(buf, &n);
 374     v = read_golomb(buf, &n);
 375     for(i = 0; i < v; i++)
 376       read_golomb(buf, &n);
 377   }
 378   read_golomb(buf, &n);
 379   getbits(buf, n++, 1);
 380   picture->display_picture_width = 16 *(read_golomb(buf, &n)+1);
 381   mbh = read_golomb(buf, &n)+1;
 382   frame_mbs_only = getbits(buf, n++, 1);
 383   picture->display_picture_height = 16 * (2 - frame_mbs_only) * mbh;
 384   if(!frame_mbs_only)
 385     getbits(buf, n++, 1);
 386   getbits(buf, n++, 1);
 387   if(getbits(buf, n++, 1))
 388   {
 389     read_golomb(buf, &n);
 390     read_golomb(buf, &n);
 391     read_golomb(buf, &n);
 392     read_golomb(buf, &n);
 393   }
 394   if(getbits(buf, n++, 1))
 395     n = h264_parse_vui(picture, buf, n);
 396
 397   return n;
 398 }
 399
 400 static int mp_unescape03(unsigned char *buf, int len)
 401 {
 402   unsigned char *dest;
 403   int i, j, skip;
 404
 405   dest = malloc(len);
 406   if(! dest)
 407     return 0;
 408
 409   j = i = skip = 0;
 410   while(i <= len-3)
 411   {
 412     if(buf[i] == 0 && buf[i+1] == 0 && buf[i+2] == 3)
 413     {
 414       dest[j] = dest[j+1] = 0;
 415       j += 2;
 416       i += 3;
 417       skip++;
 418     }
 419     else
 420     {
 421       dest[j] = buf[i];
 422       j++;
 423       i++;
 424     }
 425   }
 426   dest[j] = buf[len-2];
 427   dest[j+1] = buf[len-1];
 428   len -= skip;
 429   memcpy(buf, dest, len);
 430   free(dest);
 431
 432   return len;
 433 }
 434
 435 int mp_vc1_decode_sequence_header(mp_mpeg_header_t * picture, unsigned char * buf, int len)
 436 {
 437   int n, x;
 438
 439   len = mp_unescape03(buf, len);
 440
 441   picture->display_picture_width = picture->display_picture_height = 0;
 442   picture->fps = 0;
 443   n = 0;
 444   x = getbits(buf, n, 2);
 445   n += 2;
 446   if(x != 3) //not advanced profile
 447     return 0;
 448
 449   getbits16(buf, n, 14);
 450   n += 14;
 451   picture->display_picture_width = getbits16(buf, n, 12) * 2 + 2;
 452   n += 12;
 453   picture->display_picture_height = getbits16(buf, n, 12) * 2 + 2;
 454   n += 12;
 455   getbits(buf, n, 6);
 456   n += 6;
 457   x = getbits(buf, n, 1);
 458   n += 1;
 459   if(x) //display info
 460   {
 461     getbits16(buf, n, 14);
 462     n += 14;
 463     getbits16(buf, n, 14);
 464     n += 14;
 465     if(getbits(buf, n++, 1)) //aspect ratio
 466     {
 467       x = getbits(buf, n, 4);
 468       n += 4;
 469       if(x == 15)
 470       {
 471         getbits16(buf, n, 16);
 472         n += 16;
 473       }
 474     }
 475
 476     if(getbits(buf, n++, 1)) //framerates
 477     {
 478       int frexp=0, frnum=0, frden=0;
 479
 480       if(getbits(buf, n++, 1))
 481       {
 482         frexp = getbits16(buf, n, 16);
 483         n += 16;
 484         picture->fps = (double) (frexp+1) / 32.0;
 485       }
 486       else
 487       {
 488         float frates[] = {0, 24000, 25000, 30000, 50000, 60000, 48000, 72000, 0};
 489         float frdivs[] = {0, 1000, 1001, 0};
 490
 491         frnum = getbits(buf, n, 8);
 492         n += 8;
 493         frden = getbits(buf, n, 4);
 494         n += 4;
 495         if((frden == 1 || frden == 2) && (frnum < 8))
 496             picture->fps = frates[frnum] / frdivs[frden];
 497       }
 498     }
 499   }
 500
 501   //free(dest);
 502   return 1;
 503 }