dpvsimpledecode.c

   1
   2 #include "quakedef.h"
   3 #include "dpvsimpledecode.h"
   4
   5 #define HZREADERROR_OK 0
   6 #define HZREADERROR_EOF 1
   7 #define HZREADERROR_MALLOCFAILED 2
   8
   9 //#define HZREADBLOCKSIZE 16000
  10 #define HZREADBLOCKSIZE 1048576
  11
  12 typedef struct hz_bitstream_read_s
  13 {
  14         qfile_t *file;
  15         int endoffile;
  16 }
  17 hz_bitstream_read_t;
  18
  19 typedef struct hz_bitstream_readblock_s
  20 {
  21         struct hz_bitstream_readblock_s *next;
  22         unsigned int size;
  23         unsigned char data[HZREADBLOCKSIZE];
  24 }
  25 hz_bitstream_readblock_t;
  26
  27 typedef struct hz_bitstream_readblocks_s
  28 {
  29         hz_bitstream_readblock_t *blocks;
  30         hz_bitstream_readblock_t *current;
  31         unsigned int position;
  32         unsigned int store;
  33         int count;
  34 }
  35 hz_bitstream_readblocks_t;
  36
  37 hz_bitstream_read_t *hz_bitstream_read_open(char *filename)
  38 {
  39         qfile_t *file;
  40         hz_bitstream_read_t *stream;
  41         if ((file = FS_Open (filename, "rb", false, false)))
  42         {
  43                 stream = (hz_bitstream_read_t *)Z_Malloc(sizeof(hz_bitstream_read_t));
  44                 memset(stream, 0, sizeof(*stream));
  45                 stream->file = file;
  46                 return stream;
  47         }
  48         else
  49                 return NULL;
  50 }
  51
  52 void hz_bitstream_read_close(hz_bitstream_read_t *stream)
  53 {
  54         if (stream)
  55         {
  56                 FS_Close(stream->file);
  57                 Z_Free(stream);
  58         }
  59 }
  60
  61 hz_bitstream_readblocks_t *hz_bitstream_read_blocks_new(void)
  62 {
  63         hz_bitstream_readblocks_t *blocks;
  64         blocks = (hz_bitstream_readblocks_t *)Z_Malloc(sizeof(hz_bitstream_readblocks_t));
  65         if (blocks == NULL)
  66                 return NULL;
  67         memset(blocks, 0, sizeof(hz_bitstream_readblocks_t));
  68         return blocks;
  69 }
  70
  71 void hz_bitstream_read_blocks_free(hz_bitstream_readblocks_t *blocks)
  72 {
  73         hz_bitstream_readblock_t *b, *n;
  74         if (blocks == NULL)
  75                 return;
  76         for (b = blocks->blocks;b;b = n)
  77         {
  78                 n = b->next;
  79                 Z_Free(b);
  80         }
  81         Z_Free(blocks);
  82 }
  83
  84 void hz_bitstream_read_flushbits(hz_bitstream_readblocks_t *blocks)
  85 {
  86         blocks->store = 0;
  87         blocks->count = 0;
  88 }
  89
  90 int hz_bitstream_read_blocks_read(hz_bitstream_readblocks_t *blocks, hz_bitstream_read_t *stream, unsigned int size)
  91 {
  92         int s;
  93         hz_bitstream_readblock_t *b, *p;
  94         s = size;
  95         p = NULL;
  96         b = blocks->blocks;
  97         while (s > 0)
  98         {
  99                 if (b == NULL)
 100                 {
 101                         b = (hz_bitstream_readblock_t *)Z_Malloc(sizeof(hz_bitstream_readblock_t));
 102                         if (b == NULL)
 103                                 return HZREADERROR_MALLOCFAILED;
 104                         b->next = NULL;
 105                         b->size = 0;
 106                         if (p != NULL)
 107                                 p->next = b;
 108                         else
 109                                 blocks->blocks = b;
 110                 }
 111                 if (s > HZREADBLOCKSIZE)
 112                         b->size = HZREADBLOCKSIZE;
 113                 else
 114                         b->size = s;
 115                 s -= b->size;
 116                 if (FS_Read(stream->file, b->data, b->size) != (fs_offset_t)b->size)
 117                 {
 118                         stream->endoffile = 1;
 119                         break;
 120                 }
 121                 p = b;
 122                 b = b->next;
 123         }
 124         while (b)
 125         {
 126                 b->size = 0;
 127                 b = b->next;
 128         }
 129         blocks->current = blocks->blocks;
 130         blocks->position = 0;
 131         hz_bitstream_read_flushbits(blocks);
 132         if (stream->endoffile)
 133                 return HZREADERROR_EOF;
 134         return HZREADERROR_OK;
 135 }
 136
 137 unsigned int hz_bitstream_read_blocks_getbyte(hz_bitstream_readblocks_t *blocks)
 138 {
 139         while (blocks->current != NULL && blocks->position >= blocks->current->size)
 140         {
 141                 blocks->position = 0;
 142                 blocks->current = blocks->current->next;
 143         }
 144         if (blocks->current == NULL)
 145                 return 0;
 146         return blocks->current->data[blocks->position++];
 147 }
 148
 149 int hz_bitstream_read_bit(hz_bitstream_readblocks_t *blocks)
 150 {
 151         if (!blocks->count)
 152         {
 153                 blocks->count += 8;
 154                 blocks->store <<= 8;
 155                 blocks->store |= hz_bitstream_read_blocks_getbyte(blocks) & 0xFF;
 156         }
 157         blocks->count--;
 158         return (blocks->store >> blocks->count) & 1;
 159 }
 160
 161 unsigned int hz_bitstream_read_bits(hz_bitstream_readblocks_t *blocks, int size)
 162 {
 163         unsigned int num = 0;
 164         // we can only handle about 24 bits at a time safely
 165         // (there might be up to 7 bits more than we need in the bit store)
 166         if (size > 24)
 167         {
 168                 size -= 8;
 169                 num |= hz_bitstream_read_bits(blocks, 8) << size;
 170         }
 171         while (blocks->count < size)
 172         {
 173                 blocks->count += 8;
 174                 blocks->store <<= 8;
 175                 blocks->store |= hz_bitstream_read_blocks_getbyte(blocks) & 0xFF;
 176         }
 177         blocks->count -= size;
 178         num |= (blocks->store >> blocks->count) & ((1 << size) - 1);
 179         return num;
 180 }
 181
 182 unsigned int hz_bitstream_read_byte(hz_bitstream_readblocks_t *blocks)
 183 {
 184         return hz_bitstream_read_blocks_getbyte(blocks);
 185 }
 186
 187 unsigned int hz_bitstream_read_short(hz_bitstream_readblocks_t *blocks)
 188 {
 189         return (hz_bitstream_read_byte(blocks) << 8)
 190              | (hz_bitstream_read_byte(blocks));
 191 }
 192
 193 unsigned int hz_bitstream_read_int(hz_bitstream_readblocks_t *blocks)
 194 {
 195         return (hz_bitstream_read_byte(blocks) << 24)
 196              | (hz_bitstream_read_byte(blocks) << 16)
 197              | (hz_bitstream_read_byte(blocks) << 8)
 198              | (hz_bitstream_read_byte(blocks));
 199 }
 200
 201 void hz_bitstream_read_bytes(hz_bitstream_readblocks_t *blocks, void *outdata, unsigned int size)
 202 {
 203         unsigned char *out;
 204         out = (unsigned char *)outdata;
 205         while (size--)
 206                 *out++ = hz_bitstream_read_byte(blocks);
 207 }
 208
 209 #define BLOCKSIZE 8
 210
 211 typedef struct dpvsimpledecodestream_s
 212 {
 213         hz_bitstream_read_t *bitstream;
 214         hz_bitstream_readblocks_t *framedatablocks;
 215
 216         int error;
 217
 218         double info_framerate;
 219         unsigned int info_frames;
 220
 221         unsigned int info_imagewidth;
 222         unsigned int info_imageheight;
 223         unsigned int info_imagebpp;
 224         unsigned int info_imageRloss;
 225         unsigned int info_imageRmask;
 226         unsigned int info_imageRshift;
 227         unsigned int info_imageGloss;
 228         unsigned int info_imageGmask;
 229         unsigned int info_imageGshift;
 230         unsigned int info_imageBloss;
 231         unsigned int info_imageBmask;
 232         unsigned int info_imageBshift;
 233         unsigned int info_imagesize;
 234
 235         // current video frame (needed because of delta compression)
 236         int videoframenum;
 237         // current video frame data (needed because of delta compression)
 238         unsigned int *videopixels;
 239
 240         // channel the sound file is being played on
 241         int sndchan;
 242 }
 243 dpvsimpledecodestream_t;
 244
 245 static int dpvsimpledecode_setpixelformat(dpvsimpledecodestream_t *s, unsigned int Rmask, unsigned int Gmask, unsigned int Bmask, unsigned int bytesperpixel)
 246 {
 247         int Rshift, Rbits, Gshift, Gbits, Bshift, Bbits;
 248         if (!Rmask)
 249         {
 250                 s->error = DPVSIMPLEDECODEERROR_INVALIDRMASK;
 251                 return s->error;
 252         }
 253         if (!Gmask)
 254         {
 255                 s->error = DPVSIMPLEDECODEERROR_INVALIDGMASK;
 256                 return s->error;
 257         }
 258         if (!Bmask)
 259         {
 260                 s->error = DPVSIMPLEDECODEERROR_INVALIDBMASK;
 261                 return s->error;
 262         }
 263         if (Rmask & Gmask || Rmask & Bmask || Gmask & Bmask)
 264         {
 265                 s->error = DPVSIMPLEDECODEERROR_COLORMASKSOVERLAP;
 266                 return s->error;
 267         }
 268         switch (bytesperpixel)
 269         {
 270         case 2:
 271                 if ((Rmask | Gmask | Bmask) > 65536)
 272                 {
 273                         s->error = DPVSIMPLEDECODEERROR_COLORMASKSEXCEEDBPP;
 274                         return s->error;
 275                 }
 276                 break;
 277         case 4:
 278                 break;
 279         default:
 280                 s->error = DPVSIMPLEDECODEERROR_UNSUPPORTEDBPP;
 281                 return s->error;
 282                 break;
 283         }
 284         for (Rshift = 0;!(Rmask & 1);Rshift++, Rmask >>= 1);
 285         for (Gshift = 0;!(Gmask & 1);Gshift++, Gmask >>= 1);
 286         for (Bshift = 0;!(Bmask & 1);Bshift++, Bmask >>= 1);
 287         if (((Rmask + 1) & Rmask) != 0)
 288         {
 289                 s->error = DPVSIMPLEDECODEERROR_INVALIDRMASK;
 290                 return s->error;
 291         }
 292         if (((Gmask + 1) & Gmask) != 0)
 293         {
 294                 s->error = DPVSIMPLEDECODEERROR_INVALIDGMASK;
 295                 return s->error;
 296         }
 297         if (((Bmask + 1) & Bmask) != 0)
 298         {
 299                 s->error = DPVSIMPLEDECODEERROR_INVALIDBMASK;
 300                 return s->error;
 301         }
 302         for (Rbits = 0;Rmask & 1;Rbits++, Rmask >>= 1);
 303         for (Gbits = 0;Gmask & 1;Gbits++, Gmask >>= 1);
 304         for (Bbits = 0;Bmask & 1;Bbits++, Bmask >>= 1);
 305         if (Rbits > 8)
 306         {
 307                 Rshift += (Rbits - 8);
 308                 Rbits = 8;
 309         }
 310         if (Gbits > 8)
 311         {
 312                 Gshift += (Gbits - 8);
 313                 Gbits = 8;
 314         }
 315         if (Bbits > 8)
 316         {
 317                 Bshift += (Bbits - 8);
 318                 Bbits = 8;
 319         }
 320         s->info_imagebpp = bytesperpixel;
 321         s->info_imageRloss = 16 + (8 - Rbits);
 322         s->info_imageGloss =  8 + (8 - Gbits);
 323         s->info_imageBloss =  0 + (8 - Bbits);
 324         s->info_imageRmask = (1 << Rbits) - 1;
 325         s->info_imageGmask = (1 << Gbits) - 1;
 326         s->info_imageBmask = (1 << Bbits) - 1;
 327         s->info_imageRshift = Rshift;
 328         s->info_imageGshift = Gshift;
 329         s->info_imageBshift = Bshift;
 330         s->info_imagesize = s->info_imagewidth * s->info_imageheight * s->info_imagebpp;
 331         return s->error;
 332 }
 333
 334 // opening and closing streams
 335
 336 // opens a stream
 337 void *dpvsimpledecode_open(char *filename, char **errorstring)
 338 {
 339         dpvsimpledecodestream_t *s;
 340         char t[8], *wavename;
 341         if (errorstring != NULL)
 342                 *errorstring = NULL;
 343         s = (dpvsimpledecodestream_t *)Z_Malloc(sizeof(dpvsimpledecodestream_t));
 344         if (s != NULL)
 345         {
 346                 s->bitstream = hz_bitstream_read_open(filename);
 347                 if (s->bitstream != NULL)
 348                 {
 349                         // check file identification
 350                         s->framedatablocks = hz_bitstream_read_blocks_new();
 351                         if (s->framedatablocks != NULL)
 352                         {
 353                                 hz_bitstream_read_blocks_read(s->framedatablocks, s->bitstream, 8);
 354                                 hz_bitstream_read_bytes(s->framedatablocks, t, 8);
 355                                 if (!memcmp(t, "DPVideo", 8))
 356                                 {
 357                                         // check version number
 358                                         hz_bitstream_read_blocks_read(s->framedatablocks, s->bitstream, 2);
 359                                         if (hz_bitstream_read_short(s->framedatablocks) == 1)
 360                                         {
 361                                                 hz_bitstream_read_blocks_read(s->framedatablocks, s->bitstream, 12);
 362                                                 s->info_imagewidth = hz_bitstream_read_short(s->framedatablocks);
 363                                                 s->info_imageheight = hz_bitstream_read_short(s->framedatablocks);
 364                                                 s->info_framerate = (double) hz_bitstream_read_int(s->framedatablocks) * (1.0 / 65536.0);
 365
 366                                                 if (s->info_framerate > 0.0)
 367                                                 {
 368                                                         s->videopixels = (unsigned int *)Z_Malloc(s->info_imagewidth * s->info_imageheight * sizeof(*s->videopixels));
 369                                                         if (s->videopixels != NULL)
 370                                                         {
 371                                                                 size_t namelen;
 372
 373                                                                 namelen = strlen(filename) + 10;
 374                                                                 wavename = (char *)Z_Malloc(namelen);
 375                                                                 if (wavename)
 376                                                                 {
 377                                                                         sfx_t* sfx;
 378
 379                                                                         FS_StripExtension(filename, wavename, namelen);
 380                                                                         strlcat(wavename, ".wav", namelen);
 381                                                                         sfx = S_PrecacheSound (wavename, false, false);
 382                                                                         if (sfx != NULL)
 383                                                                                 s->sndchan = S_StartSound (-1, 0, sfx, vec3_origin, 1.0f, 0);
 384                                                                         else
 385                                                                                 s->sndchan = -1;
 386                                                                         Z_Free(wavename);
 387                                                                 }
 388                                                                 // all is well...
 389                                                                 s->videoframenum = -10000;
 390                                                                 return s;
 391                                                         }
 392                                                         else if (errorstring != NULL)
 393                                                                 *errorstring = "unable to allocate video image buffer";
 394                                                 }
 395                                                 else if (errorstring != NULL)
 396                                                         *errorstring = "error in video info chunk";
 397                                         }
 398                                         else if (errorstring != NULL)
 399                                                 *errorstring = "read error";
 400                                 }
 401                                 else if (errorstring != NULL)
 402                                         *errorstring = "not a dpvideo file";
 403                                 hz_bitstream_read_blocks_free(s->framedatablocks);
 404                         }
 405                         else if (errorstring != NULL)
 406                                 *errorstring = "unable to allocate memory for reading buffer";
 407                         hz_bitstream_read_close(s->bitstream);
 408                 }
 409                 else if (errorstring != NULL)
 410                         *errorstring = "unable to open file";
 411                 Z_Free(s);
 412         }
 413         else if (errorstring != NULL)
 414                 *errorstring = "unable to allocate memory for stream info structure";
 415         return NULL;
 416 }
 417
 418 // closes a stream
 419 void dpvsimpledecode_close(void *stream)
 420 {
 421         dpvsimpledecodestream_t *s = (dpvsimpledecodestream_t *)stream;
 422         if (s == NULL)
 423                 return;
 424         if (s->videopixels)
 425                 Z_Free(s->videopixels);
 426         if (s->sndchan != -1)
 427                 S_StopChannel (s->sndchan);
 428         if (s->framedatablocks)
 429                 hz_bitstream_read_blocks_free(s->framedatablocks);
 430         if (s->bitstream)
 431                 hz_bitstream_read_close(s->bitstream);
 432         Z_Free(s);
 433 }
 434
 435 // utilitarian functions
 436
 437 // returns the current error number for the stream, and resets the error
 438 // number to DPVSIMPLEDECODEERROR_NONE
 439 // if the supplied string pointer variable is not NULL, it will be set to the
 440 // error message
 441 int dpvsimpledecode_error(void *stream, char **errorstring)
 442 {
 443         dpvsimpledecodestream_t *s = (dpvsimpledecodestream_t *)stream;
 444         int e;
 445         e = s->error;
 446         s->error = 0;
 447         if (errorstring)
 448         {
 449                 switch (e)
 450                 {
 451                         case DPVSIMPLEDECODEERROR_NONE:
 452                                 *errorstring = "no error";
 453                                 break;
 454                         case DPVSIMPLEDECODEERROR_EOF:
 455                                 *errorstring = "end of file reached (this is not an error)";
 456                                 break;
 457                         case DPVSIMPLEDECODEERROR_READERROR:
 458                                 *errorstring = "read error (corrupt or incomplete file)";
 459                                 break;
 460                         case DPVSIMPLEDECODEERROR_SOUNDBUFFERTOOSMALL:
 461                                 *errorstring = "sound buffer is too small for decoding frame (please allocate it as large as dpvsimpledecode_getneededsoundbufferlength suggests)";
 462                                 break;
 463                         case DPVSIMPLEDECODEERROR_INVALIDRMASK:
 464                                 *errorstring = "invalid red bits mask";
 465                                 break;
 466                         case DPVSIMPLEDECODEERROR_INVALIDGMASK:
 467                                 *errorstring = "invalid green bits mask";
 468                                 break;
 469                         case DPVSIMPLEDECODEERROR_INVALIDBMASK:
 470                                 *errorstring = "invalid blue bits mask";
 471                                 break;
 472                         case DPVSIMPLEDECODEERROR_COLORMASKSOVERLAP:
 473                                 *errorstring = "color bit masks overlap";
 474                                 break;
 475                         case DPVSIMPLEDECODEERROR_COLORMASKSEXCEEDBPP:
 476                                 *errorstring = "color masks too big for specified bytes per pixel";
 477                                 break;
 478                         case DPVSIMPLEDECODEERROR_UNSUPPORTEDBPP:
 479                                 *errorstring = "unsupported bytes per pixel (must be 2 for 16bit, or 4 for 32bit)";
 480                                 break;
 481                         default:
 482                                 *errorstring = "unknown error";
 483                                 break;
 484                 }
 485         }
 486         return e;
 487 }
 488
 489 // returns the width of the image data
 490 unsigned int dpvsimpledecode_getwidth(void *stream)
 491 {
 492         dpvsimpledecodestream_t *s = (dpvsimpledecodestream_t *)stream;
 493         return s->info_imagewidth;
 494 }
 495
 496 // returns the height of the image data
 497 unsigned int dpvsimpledecode_getheight(void *stream)
 498 {
 499         dpvsimpledecodestream_t *s = (dpvsimpledecodestream_t *)stream;
 500         return s->info_imageheight;
 501 }
 502
 503 // returns the framerate of the stream
 504 double dpvsimpledecode_getframerate(void *stream)
 505 {
 506         dpvsimpledecodestream_t *s = (dpvsimpledecodestream_t *)stream;
 507         return s->info_framerate;
 508 }
 509
 510
 511
 512
 513
 514 static int dpvsimpledecode_convertpixels(dpvsimpledecodestream_t *s, void *imagedata, int imagebytesperrow)
 515 {
 516         unsigned int a, x, y, width, height;
 517         unsigned int Rloss, Rmask, Rshift, Gloss, Gmask, Gshift, Bloss, Bmask, Bshift;
 518         unsigned int *in;
 519
 520         width = s->info_imagewidth;
 521         height = s->info_imageheight;
 522
 523         Rloss = s->info_imageRloss;
 524         Rmask = s->info_imageRmask;
 525         Rshift = s->info_imageRshift;
 526         Gloss = s->info_imageGloss;
 527         Gmask = s->info_imageGmask;
 528         Gshift = s->info_imageGshift;
 529         Bloss = s->info_imageBloss;
 530         Bmask = s->info_imageBmask;
 531         Bshift = s->info_imageBshift;
 532
 533         in = s->videopixels;
 534         if (s->info_imagebpp == 4)
 535         {
 536                 unsigned int *outrow;
 537                 for (y = 0;y < height;y++)
 538                 {
 539                         outrow = (unsigned int *)((unsigned char *)imagedata + y * imagebytesperrow);
 540                         for (x = 0;x < width;x++)
 541                         {
 542                                 a = *in++;
 543                                 outrow[x] = (((a >> Rloss) & Rmask) << Rshift) | (((a >> Gloss) & Gmask) << Gshift) | (((a >> Bloss) & Bmask) << Bshift);
 544                         }
 545                 }
 546         }
 547         else
 548         {
 549                 unsigned short *outrow;
 550                 for (y = 0;y < height;y++)
 551                 {
 552                         outrow = (unsigned short *)((unsigned char *)imagedata + y * imagebytesperrow);
 553                         if (Rloss == 19 && Gloss == 10 && Bloss == 3 && Rshift == 11 && Gshift == 5 && Bshift == 0)
 554                         {
 555                                 // optimized
 556                                 for (x = 0;x < width;x++)
 557                                 {
 558                                         a = *in++;
 559                                         outrow[x] = ((a >> 8) & 0xF800) | ((a >> 5) & 0x07E0) | ((a >> 3) & 0x001F);
 560                                 }
 561                         }
 562                         else
 563                         {
 564                                 for (x = 0;x < width;x++)
 565                                 {
 566                                         a = *in++;
 567                                         outrow[x] = (((a >> Rloss) & Rmask) << Rshift) | (((a >> Gloss) & Gmask) << Gshift) | (((a >> Bloss) & Bmask) << Bshift);
 568                                 }
 569                         }
 570                 }
 571         }
 572         return s->error;
 573 }
 574
 575 static int dpvsimpledecode_decompressimage(dpvsimpledecodestream_t *s)
 576 {
 577         int i, a, b, colors, g, x1, y1, bw, bh, width, height, palettebits;
 578         unsigned int palette[256], *outrow, *out;
 579         g = BLOCKSIZE;
 580         width = s->info_imagewidth;
 581         height = s->info_imageheight;
 582         for (y1 = 0;y1 < height;y1 += g)
 583         {
 584                 outrow = s->videopixels + y1 * width;
 585                 bh = g;
 586                 if (y1 + bh > height)
 587                         bh = height - y1;
 588                 for (x1 = 0;x1 < width;x1 += g)
 589                 {
 590                         out = outrow + x1;
 591                         bw = g;
 592                         if (x1 + bw > width)
 593                                 bw = width - x1;
 594                         if (hz_bitstream_read_bit(s->framedatablocks))
 595                         {
 596                                 // updated block
 597                                 palettebits = hz_bitstream_read_bits(s->framedatablocks, 3);
 598                                 colors = 1 << palettebits;
 599                                 for (i = 0;i < colors;i++)
 600                                         palette[i] = hz_bitstream_read_bits(s->framedatablocks, 24);
 601                                 if (palettebits)
 602                                 {
 603                                         for (b = 0;b < bh;b++, out += width)
 604                                                 for (a = 0;a < bw;a++)
 605                                                         out[a] = palette[hz_bitstream_read_bits(s->framedatablocks, palettebits)];
 606                                 }
 607                                 else
 608                                 {
 609                                         for (b = 0;b < bh;b++, out += width)
 610                                                 for (a = 0;a < bw;a++)
 611                                                         out[a] = palette[0];
 612                                 }
 613                         }
 614                 }
 615         }
 616         return s->error;
 617 }
 618
 619 // decodes a video frame to the supplied output pixels
 620 int dpvsimpledecode_video(void *stream, void *imagedata, unsigned int Rmask, unsigned int Gmask, unsigned int Bmask, unsigned int bytesperpixel, int imagebytesperrow)
 621 {
 622         dpvsimpledecodestream_t *s = (dpvsimpledecodestream_t *)stream;
 623         unsigned int framedatasize;
 624         char t[4];
 625         s->error = DPVSIMPLEDECODEERROR_NONE;
 626         if (dpvsimpledecode_setpixelformat(s, Rmask, Gmask, Bmask, bytesperpixel))
 627                 return s->error;
 628
 629         hz_bitstream_read_blocks_read(s->framedatablocks, s->bitstream, 8);
 630         hz_bitstream_read_bytes(s->framedatablocks, t, 4);
 631         if (memcmp(t, "VID0", 4))
 632         {
 633                 if (t[0] == 0)
 634                         return (s->error = DPVSIMPLEDECODEERROR_EOF);
 635                 else
 636                         return (s->error = DPVSIMPLEDECODEERROR_READERROR);
 637         }
 638         framedatasize = hz_bitstream_read_int(s->framedatablocks);
 639         hz_bitstream_read_blocks_read(s->framedatablocks, s->bitstream, framedatasize);
 640         if (dpvsimpledecode_decompressimage(s))
 641                 return s->error;
 642
 643         dpvsimpledecode_convertpixels(s, imagedata, imagebytesperrow);
 644         return s->error;
 645 }