libavcodec/xan.c

   1 /*
   2  * Wing Commander/Xan Video Decoder
   3  * Copyright (C) 2003 the ffmpeg project
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  *
  19  */
  20
  21 /**
  22  * @file xan.c
  23  * Xan video decoder for Wing Commander III & IV computer games
  24  * by Mario Brito (mbrito@student.dei.uc.pt)
  25  * and Mike Melanson (melanson@pcisys.net)
  26  *
  27  * The xan_wc3 decoder outputs the following colorspaces natively:
  28  *   PAL8 (default), RGB555, RGB565, RGB24, BGR24, RGBA32, YUV444P
  29  */
  30
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <unistd.h>
  35
  36 #include "common.h"
  37 #include "avcodec.h"
  38 #include "dsputil.h"
  39
  40 #define PALETTE_COUNT 256
  41 #define PALETTE_CONTROL_SIZE ((256 * 3) + 1)
  42
  43 typedef struct XanContext {
  44
  45     AVCodecContext *avctx;
  46     DSPContext dsp;
  47     AVFrame last_frame;
  48     AVFrame current_frame;
  49
  50     unsigned char *buf;
  51     int size;
  52
  53     unsigned char palette[PALETTE_COUNT * 4];
  54
  55     /* scratch space */
  56     unsigned char *buffer1;
  57     unsigned char *buffer2;
  58
  59 } XanContext;
  60
  61 #define BE_16(x)  ((((uint8_t*)(x))[0] << 8) | ((uint8_t*)(x))[1])
  62 #define LE_16(x)  ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0])
  63 #define LE_32(x)  ((((uint8_t*)(x))[3] << 24) | \
  64                    (((uint8_t*)(x))[2] << 16) | \
  65                    (((uint8_t*)(x))[1] << 8) | \
  66                     ((uint8_t*)(x))[0])
  67
  68 /* RGB -> YUV conversion stuff */
  69 #define SCALEFACTOR 65536
  70 #define CENTERSAMPLE 128
  71
  72 #define COMPUTE_Y(r, g, b) \
  73   (unsigned char) \
  74   ((y_r_table[r] + y_g_table[g] + y_b_table[b]) / SCALEFACTOR)
  75 #define COMPUTE_U(r, g, b) \
  76   (unsigned char) \
  77   ((u_r_table[r] + u_g_table[g] + u_b_table[b]) / SCALEFACTOR + CENTERSAMPLE)
  78 #define COMPUTE_V(r, g, b) \
  79   (unsigned char) \
  80   ((v_r_table[r] + v_g_table[g] + v_b_table[b]) / SCALEFACTOR + CENTERSAMPLE)
  81
  82 #define Y_R (SCALEFACTOR *  0.29900)
  83 #define Y_G (SCALEFACTOR *  0.58700)
  84 #define Y_B (SCALEFACTOR *  0.11400)
  85
  86 #define U_R (SCALEFACTOR * -0.16874)
  87 #define U_G (SCALEFACTOR * -0.33126)
  88 #define U_B (SCALEFACTOR *  0.50000)
  89
  90 #define V_R (SCALEFACTOR *  0.50000)
  91 #define V_G (SCALEFACTOR * -0.41869)
  92 #define V_B (SCALEFACTOR * -0.08131)
  93
  94 /*
  95  * Precalculate all of the YUV tables since it requires fewer than
  96  * 10 kilobytes to store them.
  97  */
  98 static int y_r_table[256];
  99 static int y_g_table[256];
 100 static int y_b_table[256];
 101
 102 static int u_r_table[256];
 103 static int u_g_table[256];
 104 static int u_b_table[256];
 105
 106 static int v_r_table[256];
 107 static int v_g_table[256];
 108 static int v_b_table[256];
 109
 110 static int xan_decode_init(AVCodecContext *avctx)
 111 {
 112     XanContext *s = avctx->priv_data;
 113     int i;
 114
 115     s->avctx = avctx;
 116
 117     if ((avctx->codec->id == CODEC_ID_XAN_WC3) &&
 118         (s->avctx->palctrl == NULL)) {
 119         printf (" WC3 Xan video: palette expected.\n");
 120         return -1;
 121     }
 122
 123     avctx->pix_fmt = PIX_FMT_PAL8;
 124     avctx->has_b_frames = 0;
 125     dsputil_init(&s->dsp, avctx);
 126
 127     /* initialize the RGB -> YUV tables */
 128     for (i = 0; i < 256; i++) {
 129         y_r_table[i] = Y_R * i;
 130         y_g_table[i] = Y_G * i;
 131         y_b_table[i] = Y_B * i;
 132
 133         u_r_table[i] = U_R * i;
 134         u_g_table[i] = U_G * i;
 135         u_b_table[i] = U_B * i;
 136
 137         v_r_table[i] = V_R * i;
 138         v_g_table[i] = V_G * i;
 139         v_b_table[i] = V_B * i;
 140     }
 141
 142     s->buffer1 = av_malloc(avctx->width * avctx->height);
 143     s->buffer2 = av_malloc(avctx->width * avctx->height);
 144     if (!s->buffer1 || !s->buffer2)
 145         return -1;
 146
 147     return 0;
 148 }
 149
 150 /* This function is used in lieu of memcpy(). This decoder can not use
 151  * memcpy because the memory locations often overlap and
 152  * memcpy doesn't like that; it's not uncommon, for example, for
 153  * dest = src+1, to turn byte A into  pattern AAAAAAAA.
 154  * This was originally repz movsb in Intel x86 ASM. */
 155 static inline void bytecopy(unsigned char *dest, unsigned char *src, int count)
 156 {
 157     int i;
 158
 159     for (i = 0; i < count; i++)
 160         dest[i] = src[i];
 161 }
 162
 163 static int xan_huffman_decode(unsigned char *dest, unsigned char *src)
 164 {
 165     unsigned char byte = *src++;
 166     unsigned char ival = byte + 0x16;
 167     unsigned char * ptr = src + byte*2;
 168     unsigned char val = ival;
 169     int counter = 0;
 170
 171     unsigned char bits = *ptr++;
 172
 173     while ( val != 0x16 ) {
 174         if ( (1 << counter) & bits )
 175             val = src[byte + val - 0x17];
 176         else
 177             val = src[val - 0x17];
 178
 179         if ( val < 0x16 ) {
 180             *dest++ = val;
 181             val = ival;
 182         }
 183
 184         if (counter++ == 7) {
 185             counter = 0;
 186             bits = *ptr++;
 187         }
 188     }
 189
 190     return 0;
 191 }
 192
 193 static void xan_unpack(unsigned char *dest, unsigned char *src)
 194 {
 195     unsigned char opcode;
 196     int size;
 197     int offset;
 198     int byte1, byte2, byte3;
 199
 200     for (;;) {
 201         opcode = *src++;
 202
 203         if ( (opcode & 0x80) == 0 ) {
 204
 205             offset = *src++;
 206
 207             size = opcode & 3;
 208             bytecopy(dest, src, size);  dest += size;  src += size;
 209
 210             size = ((opcode & 0x1c) >> 2) + 3;
 211             bytecopy (dest, dest - (((opcode & 0x60) << 3) + offset + 1), size);
 212             dest += size;
 213
 214         } else if ( (opcode & 0x40) == 0 ) {
 215
 216             byte1 = *src++;
 217             byte2 = *src++;
 218
 219             size = byte1 >> 6;
 220             bytecopy (dest, src, size);  dest += size;  src += size;
 221
 222             size = (opcode & 0x3f) + 4;
 223             bytecopy (dest, dest - (((byte1 & 0x3f) << 8) + byte2 + 1), size);
 224             dest += size;
 225
 226         } else if ( (opcode & 0x20) == 0 ) {
 227
 228             byte1 = *src++;
 229             byte2 = *src++;
 230             byte3 = *src++;
 231
 232             size = opcode & 3;
 233             bytecopy (dest, src, size);  dest += size;  src += size;
 234
 235             size = byte3 + 5 + ((opcode & 0xc) << 6);
 236             bytecopy (dest,
 237                 dest - ((((opcode & 0x10) >> 4) << 0x10) + 1 + (byte1 << 8) + byte2),
 238                 size);
 239             dest += size;
 240         } else {
 241             size = ((opcode & 0x1f) << 2) + 4;
 242
 243             if (size > 0x70)
 244                 break;
 245
 246             bytecopy (dest, src, size);  dest += size;  src += size;
 247         }
 248     }
 249
 250     size = opcode & 3;
 251     bytecopy(dest, src, size);  dest += size;  src += size;
 252 }
 253
 254 static void inline xan_wc3_build_palette(XanContext *s,
 255     unsigned int *palette_data)
 256 {
 257     int i;
 258     unsigned char r, g, b;
 259     unsigned short *palette16;
 260     unsigned int *palette32;
 261     unsigned int pal_elem;
 262
 263     /* transform the palette passed through the palette control structure
 264      * into the necessary internal format depending on colorspace */
 265
 266     switch (s->avctx->pix_fmt) {
 267
 268     case PIX_FMT_RGB555:
 269         palette16 = (unsigned short *)s->palette;
 270         for (i = 0; i < PALETTE_COUNT; i++) {
 271             pal_elem = palette_data[i];
 272             r = (pal_elem >> 16) & 0xff;
 273             g = (pal_elem >> 8) & 0xff;
 274             b = pal_elem & 0xff;
 275             palette16[i] =
 276                 ((r >> 3) << 10) |
 277                 ((g >> 3) <<  5) |
 278                 ((b >> 3) <<  0);
 279         }
 280         break;
 281
 282     case PIX_FMT_RGB565:
 283         palette16 = (unsigned short *)s->palette;
 284         for (i = 0; i < PALETTE_COUNT; i++) {
 285             pal_elem = palette_data[i];
 286             r = (pal_elem >> 16) & 0xff;
 287             g = (pal_elem >> 8) & 0xff;
 288             b = pal_elem & 0xff;
 289             palette16[i] =
 290                 ((r >> 3) << 11) |
 291                 ((g >> 2) <<  5) |
 292                 ((b >> 3) <<  0);
 293         }
 294         break;
 295
 296     case PIX_FMT_RGB24:
 297         for (i = 0; i < PALETTE_COUNT; i++) {
 298             pal_elem = palette_data[i];
 299             r = (pal_elem >> 16) & 0xff;
 300             g = (pal_elem >> 8) & 0xff;
 301             b = pal_elem & 0xff;
 302             s->palette[i * 4 + 0] = r;
 303             s->palette[i * 4 + 1] = g;
 304             s->palette[i * 4 + 2] = b;
 305         }
 306         break;
 307
 308     case PIX_FMT_BGR24:
 309         for (i = 0; i < PALETTE_COUNT; i++) {
 310             pal_elem = palette_data[i];
 311             r = (pal_elem >> 16) & 0xff;
 312             g = (pal_elem >> 8) & 0xff;
 313             b = pal_elem & 0xff;
 314             s->palette[i * 4 + 0] = b;
 315             s->palette[i * 4 + 1] = g;
 316             s->palette[i * 4 + 2] = r;
 317         }
 318         break;
 319
 320     case PIX_FMT_PAL8:
 321     case PIX_FMT_RGBA32:
 322         palette32 = (unsigned int *)s->palette;
 323         memcpy (palette32, palette_data, PALETTE_COUNT * sizeof(unsigned int));
 324         break;
 325
 326     case PIX_FMT_YUV444P:
 327         for (i = 0; i < PALETTE_COUNT; i++) {
 328             pal_elem = palette_data[i];
 329             r = (pal_elem >> 16) & 0xff;
 330             g = (pal_elem >> 8) & 0xff;
 331             b = pal_elem & 0xff;
 332             s->palette[i * 4 + 0] = COMPUTE_Y(r, g, b);
 333             s->palette[i * 4 + 1] = COMPUTE_U(r, g, b);
 334             s->palette[i * 4 + 2] = COMPUTE_V(r, g, b);
 335         }
 336         break;
 337
 338     default:
 339         printf (" Xan WC3: Unhandled colorspace\n");
 340         break;
 341     }
 342 }
 343
 344 /* advance current_x variable; reset accounting variables if current_x
 345  * moves beyond width */
 346 #define ADVANCE_CURRENT_X() \
 347     current_x++; \
 348     if (current_x >= width) { \
 349         index += line_inc; \
 350         current_x = 0; \
 351     }
 352
 353 static void inline xan_wc3_output_pixel_run(XanContext *s,
 354     unsigned char *pixel_buffer, int x, int y, int pixel_count)
 355 {
 356     int stride;
 357     int line_inc;
 358     int index;
 359     int current_x;
 360     int width = s->avctx->width;
 361     unsigned char pix;
 362     unsigned char *palette_plane;
 363     unsigned char *y_plane;
 364     unsigned char *u_plane;
 365     unsigned char *v_plane;
 366     unsigned char *rgb_plane;
 367     unsigned short *rgb16_plane;
 368     unsigned short *palette16;
 369     unsigned int *rgb32_plane;
 370     unsigned int *palette32;
 371
 372     switch (s->avctx->pix_fmt) {
 373
 374     case PIX_FMT_PAL8:
 375         palette_plane = s->current_frame.data[0];
 376         stride = s->current_frame.linesize[0];
 377         line_inc = stride - width;
 378         index = y * stride + x;
 379         current_x = x;
 380         while(pixel_count--) {
 381
 382             /* don't do a memcpy() here; keyframes generally copy an entire
 383              * frame of data and the stride needs to be accounted for */
 384             palette_plane[index++] = *pixel_buffer++;
 385
 386             ADVANCE_CURRENT_X();
 387         }
 388         break;
 389
 390     case PIX_FMT_RGB555:
 391     case PIX_FMT_RGB565:
 392         rgb16_plane = (unsigned short *)s->current_frame.data[0];
 393         palette16 = (unsigned short *)s->palette;
 394         stride = s->current_frame.linesize[0] / 2;
 395         line_inc = stride - width;
 396         index = y * stride + x;
 397         current_x = x;
 398         while(pixel_count--) {
 399
 400             rgb16_plane[index++] = palette16[*pixel_buffer++];
 401
 402             ADVANCE_CURRENT_X();
 403         }
 404         break;
 405
 406     case PIX_FMT_RGB24:
 407     case PIX_FMT_BGR24:
 408         rgb_plane = s->current_frame.data[0];
 409         stride = s->current_frame.linesize[0];
 410         line_inc = stride - width * 3;
 411         index = y * stride + x * 3;
 412         current_x = x;
 413         while(pixel_count--) {
 414             pix = *pixel_buffer++;
 415
 416             rgb_plane[index++] = s->palette[pix * 4 + 0];
 417             rgb_plane[index++] = s->palette[pix * 4 + 1];
 418             rgb_plane[index++] = s->palette[pix * 4 + 2];
 419
 420             ADVANCE_CURRENT_X();
 421         }
 422         break;
 423
 424     case PIX_FMT_RGBA32:
 425         rgb32_plane = (unsigned int *)s->current_frame.data[0];
 426         palette32 = (unsigned int *)s->palette;
 427         stride = s->current_frame.linesize[0] / 4;
 428         line_inc = stride - width;
 429         index = y * stride + x;
 430         current_x = x;
 431         while(pixel_count--) {
 432
 433             rgb32_plane[index++] = palette32[*pixel_buffer++];
 434
 435             ADVANCE_CURRENT_X();
 436         }
 437         break;
 438
 439     case PIX_FMT_YUV444P:
 440         y_plane = s->current_frame.data[0];
 441         u_plane = s->current_frame.data[1];
 442         v_plane = s->current_frame.data[2];
 443         stride = s->current_frame.linesize[0];
 444         line_inc = stride - width;
 445         index = y * stride + x;
 446         current_x = x;
 447         while(pixel_count--) {
 448             pix = *pixel_buffer++;
 449
 450             y_plane[index] = s->palette[pix * 4 + 0];
 451             u_plane[index] = s->palette[pix * 4 + 1];
 452             v_plane[index] = s->palette[pix * 4 + 2];
 453
 454             index++;
 455             ADVANCE_CURRENT_X();
 456         }
 457         break;
 458
 459     default:
 460         printf (" Xan WC3: Unhandled colorspace\n");
 461         break;
 462     }
 463 }
 464
 465 #define ADVANCE_CURFRAME_X() \
 466     curframe_x++; \
 467     if (curframe_x >= width) { \
 468         curframe_index += line_inc; \
 469         curframe_x = 0; \
 470     }
 471
 472 #define ADVANCE_PREVFRAME_X() \
 473     prevframe_x++; \
 474     if (prevframe_x >= width) { \
 475         prevframe_index += line_inc; \
 476         prevframe_x = 0; \
 477     }
 478
 479 static void inline xan_wc3_copy_pixel_run(XanContext *s,
 480     int x, int y, int pixel_count, int motion_x, int motion_y)
 481 {
 482     int stride;
 483     int line_inc;
 484     int curframe_index, prevframe_index;
 485     int curframe_x, prevframe_x;
 486     int width = s->avctx->width;
 487     unsigned char *palette_plane, *prev_palette_plane;
 488     unsigned char *y_plane, *u_plane, *v_plane;
 489     unsigned char *prev_y_plane, *prev_u_plane, *prev_v_plane;
 490     unsigned char *rgb_plane, *prev_rgb_plane;
 491     unsigned short *rgb16_plane, *prev_rgb16_plane;
 492     unsigned int *rgb32_plane, *prev_rgb32_plane;
 493
 494     switch (s->avctx->pix_fmt) {
 495
 496     case PIX_FMT_PAL8:
 497         palette_plane = s->current_frame.data[0];
 498         prev_palette_plane = s->last_frame.data[0];
 499         stride = s->current_frame.linesize[0];
 500         line_inc = stride - width;
 501         curframe_index = y * stride + x;
 502         curframe_x = x;
 503         prevframe_index = (y + motion_y) * stride + x + motion_x;
 504         prevframe_x = x + motion_x;
 505         while(pixel_count--) {
 506
 507             palette_plane[curframe_index++] =
 508                 prev_palette_plane[prevframe_index++];
 509
 510             ADVANCE_CURFRAME_X();
 511             ADVANCE_PREVFRAME_X();
 512         }
 513         break;
 514
 515     case PIX_FMT_RGB555:
 516     case PIX_FMT_RGB565:
 517         rgb16_plane = (unsigned short *)s->current_frame.data[0];
 518         prev_rgb16_plane = (unsigned short *)s->last_frame.data[0];
 519         stride = s->current_frame.linesize[0] / 2;
 520         line_inc = stride - width;
 521         curframe_index = y * stride + x;
 522         curframe_x = x;
 523         prevframe_index = (y + motion_y) * stride + x + motion_x;
 524         prevframe_x = x + motion_x;
 525         while(pixel_count--) {
 526
 527             rgb16_plane[curframe_index++] =
 528                 prev_rgb16_plane[prevframe_index++];
 529
 530             ADVANCE_CURFRAME_X();
 531             ADVANCE_PREVFRAME_X();
 532         }
 533         break;
 534
 535     case PIX_FMT_RGB24:
 536     case PIX_FMT_BGR24:
 537         rgb_plane = s->current_frame.data[0];
 538         prev_rgb_plane = s->last_frame.data[0];
 539         stride = s->current_frame.linesize[0];
 540         line_inc = stride - width * 3;
 541         curframe_index = y * stride + x * 3;
 542         curframe_x = x;
 543         prevframe_index = (y + motion_y) * stride +
 544             (3 * (x + motion_x));
 545         prevframe_x = x + motion_x;
 546         while(pixel_count--) {
 547
 548             rgb_plane[curframe_index++] = prev_rgb_plane[prevframe_index++];
 549             rgb_plane[curframe_index++] = prev_rgb_plane[prevframe_index++];
 550             rgb_plane[curframe_index++] = prev_rgb_plane[prevframe_index++];
 551
 552             ADVANCE_CURFRAME_X();
 553             ADVANCE_PREVFRAME_X();
 554         }
 555         break;
 556
 557     case PIX_FMT_RGBA32:
 558         rgb32_plane = (unsigned int *)s->current_frame.data[0];
 559         prev_rgb32_plane = (unsigned int *)s->last_frame.data[0];
 560         stride = s->current_frame.linesize[0] / 4;
 561         line_inc = stride - width;
 562         curframe_index = y * stride + x;
 563         curframe_x = x;
 564         prevframe_index = (y + motion_y) * stride + x + motion_x;
 565         prevframe_x = x + motion_x;
 566         while(pixel_count--) {
 567
 568             rgb32_plane[curframe_index++] =
 569                 prev_rgb32_plane[prevframe_index++];
 570
 571             ADVANCE_CURFRAME_X();
 572             ADVANCE_PREVFRAME_X();
 573         }
 574         break;
 575
 576     case PIX_FMT_YUV444P:
 577         y_plane = s->current_frame.data[0];
 578         u_plane = s->current_frame.data[1];
 579         v_plane = s->current_frame.data[2];
 580         prev_y_plane = s->last_frame.data[0];
 581         prev_u_plane = s->last_frame.data[1];
 582         prev_v_plane = s->last_frame.data[2];
 583         stride = s->current_frame.linesize[0];
 584         line_inc = stride - width;
 585         curframe_index = y * stride + x;
 586         curframe_x = x;
 587         prevframe_index = (y + motion_y) * stride + x + motion_x;
 588         prevframe_x = x + motion_x;
 589         while(pixel_count--) {
 590
 591             y_plane[curframe_index] = prev_y_plane[prevframe_index];
 592             u_plane[curframe_index] = prev_u_plane[prevframe_index];
 593             v_plane[curframe_index] = prev_v_plane[prevframe_index];
 594
 595             curframe_index++;
 596             ADVANCE_CURFRAME_X();
 597             prevframe_index++;
 598             ADVANCE_PREVFRAME_X();
 599         }
 600         break;
 601
 602     default:
 603         printf (" Xan WC3: Unhandled colorspace\n");
 604         break;
 605     }
 606 }
 607
 608 static void xan_wc3_decode_frame(XanContext *s) {
 609
 610     int width = s->avctx->width;
 611     int height = s->avctx->height;
 612     int total_pixels = width * height;
 613     unsigned char opcode;
 614     unsigned char flag = 0;
 615     int size = 0;
 616     int motion_x, motion_y;
 617     int x, y;
 618
 619     unsigned char *opcode_buffer = s->buffer1;
 620     unsigned char *imagedata_buffer = s->buffer2;
 621
 622     /* pointers to segments inside the compressed chunk */
 623     unsigned char *huffman_segment;
 624     unsigned char *size_segment;
 625     unsigned char *vector_segment;
 626     unsigned char *imagedata_segment;
 627
 628     huffman_segment =   s->buf + LE_16(&s->buf[0]);
 629     size_segment =      s->buf + LE_16(&s->buf[2]);
 630     vector_segment =    s->buf + LE_16(&s->buf[4]);
 631     imagedata_segment = s->buf + LE_16(&s->buf[6]);
 632
 633     xan_huffman_decode(opcode_buffer, huffman_segment);
 634
 635     if (imagedata_segment[0] == 2)
 636         xan_unpack(imagedata_buffer, &imagedata_segment[1]);
 637     else
 638         imagedata_buffer = &imagedata_segment[1];
 639
 640     /* use the decoded data segments to build the frame */
 641     x = y = 0;
 642     while (total_pixels) {
 643
 644         opcode = *opcode_buffer++;
 645         size = 0;
 646
 647         switch (opcode) {
 648
 649         case 0:
 650             flag ^= 1;
 651             continue;
 652
 653         case 1:
 654         case 2:
 655         case 3:
 656         case 4:
 657         case 5:
 658         case 6:
 659         case 7:
 660         case 8:
 661             size = opcode;
 662             break;
 663
 664         case 12:
 665         case 13:
 666         case 14:
 667         case 15:
 668         case 16:
 669         case 17:
 670         case 18:
 671             size += (opcode - 10);
 672             break;
 673
 674         case 9:
 675         case 19:
 676             size = *size_segment++;
 677             break;
 678
 679         case 10:
 680         case 20:
 681             size = BE_16(&size_segment[0]);
 682             size_segment += 2;
 683             break;
 684
 685         case 11:
 686         case 21:
 687             size = (size_segment[0] << 16) | (size_segment[1] << 8) |
 688                 size_segment[2];
 689             size_segment += 3;
 690             break;
 691         }
 692
 693         if (opcode < 12) {
 694             flag ^= 1;
 695             if (flag) {
 696                 /* run of (size) pixels is unchanged from last frame */
 697                 xan_wc3_copy_pixel_run(s, x, y, size, 0, 0);
 698             } else {
 699                 /* output a run of pixels from imagedata_buffer */
 700                 xan_wc3_output_pixel_run(s, imagedata_buffer, x, y, size);
 701                 imagedata_buffer += size;
 702             }
 703         } else {
 704             /* run-based motion compensation from last frame */
 705             motion_x = (*vector_segment >> 4) & 0xF;
 706             motion_y = *vector_segment & 0xF;
 707             vector_segment++;
 708
 709             /* sign extension */
 710             if (motion_x & 0x8)
 711                 motion_x |= 0xFFFFFFF0;
 712             if (motion_y & 0x8)
 713                 motion_y |= 0xFFFFFFF0;
 714
 715             /* copy a run of pixels from the previous frame */
 716             xan_wc3_copy_pixel_run(s, x, y, size, motion_x, motion_y);
 717
 718             flag = 0;
 719         }
 720
 721         /* coordinate accounting */
 722         total_pixels -= size;
 723         while (size) {
 724             if (x + size >= width) {
 725                 y++;
 726                 size -= (width - x);
 727                 x = 0;
 728             } else {
 729                 x += size;
 730                 size = 0;
 731             }
 732         }
 733     }
 734
 735     /* for PAL8, make the palette available on the way out */
 736     if (s->avctx->pix_fmt == PIX_FMT_PAL8) {
 737         memcpy(s->current_frame.data[1], s->palette, PALETTE_COUNT * 4);
 738         s->current_frame.palette_has_changed = 1;
 739         s->avctx->palctrl->palette_changed = 0;
 740     }
 741 }
 742
 743 static void xan_wc4_decode_frame(XanContext *s) {
 744 }
 745
 746 static int xan_decode_frame(AVCodecContext *avctx,
 747                             void *data, int *data_size,
 748                             uint8_t *buf, int buf_size)
 749 {
 750     XanContext *s = avctx->priv_data;
 751     AVPaletteControl *palette_control = avctx->palctrl;
 752     int keyframe = 0;
 753
 754     if (palette_control->palette_changed) {
 755         /* load the new palette and reset the palette control */
 756         xan_wc3_build_palette(s, palette_control->palette);
 757         /* If pal8 we clear flag when we copy palette */
 758         if (s->avctx->pix_fmt != PIX_FMT_PAL8)
 759             palette_control->palette_changed = 0;
 760         keyframe = 1;
 761     }
 762
 763     if (avctx->get_buffer(avctx, &s->current_frame)) {
 764         printf ("  Xan Video: get_buffer() failed\n");
 765         return -1;
 766     }
 767     s->current_frame.reference = 3;
 768
 769     s->buf = buf;
 770     s->size = buf_size;
 771
 772     if (avctx->codec->id == CODEC_ID_XAN_WC3)
 773         xan_wc3_decode_frame(s);
 774     else if (avctx->codec->id == CODEC_ID_XAN_WC4)
 775         xan_wc4_decode_frame(s);
 776
 777     /* release the last frame if it is allocated */
 778     if (s->last_frame.data[0])
 779         avctx->release_buffer(avctx, &s->last_frame);
 780
 781     /* shuffle frames */
 782     s->last_frame = s->current_frame;
 783
 784     *data_size = sizeof(AVFrame);
 785     *(AVFrame*)data = s->current_frame;
 786
 787     /* always report that the buffer was completely consumed */
 788     return buf_size;
 789 }
 790
 791 static int xan_decode_end(AVCodecContext *avctx)
 792 {
 793     XanContext *s = avctx->priv_data;
 794
 795     /* release the last frame */
 796     avctx->release_buffer(avctx, &s->last_frame);
 797
 798     av_free(s->buffer1);
 799     av_free(s->buffer2);
 800
 801     return 0;
 802 }
 803
 804 AVCodec xan_wc3_decoder = {
 805     "xan_wc3",
 806     CODEC_TYPE_VIDEO,
 807     CODEC_ID_XAN_WC3,
 808     sizeof(XanContext),
 809     xan_decode_init,
 810     NULL,
 811     xan_decode_end,
 812     xan_decode_frame,
 813     CODEC_CAP_DR1,
 814 };
 815
 816 /*
 817 AVCodec xan_wc4_decoder = {
 818     "xan_wc4",
 819     CODEC_TYPE_VIDEO,
 820     CODEC_ID_XAN_WC4,
 821     sizeof(XanContext),
 822     xan_decode_init,
 823     NULL,
 824     xan_decode_end,
 825     xan_decode_frame,
 826     CODEC_CAP_DR1,
 827 };
 828 */