quicktime/ffmpeg/libavcodec/interplayvideo.c

   1 /*
   2  * Interplay MVE 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 interplayvideo.c
  23  * Interplay MVE Video Decoder by Mike Melanson (melanson@pcisys.net)
  24  * For more information about the Interplay MVE format, visit:
  25  *   http://www.pcisys.net/~melanson/codecs/interplay-mve.txt
  26  * This code is written in such a way that the identifiers match up
  27  * with the encoding descriptions in the document.
  28  *
  29  * This decoder presently only supports a PAL8 output colorspace.
  30  *
  31  * An Interplay video frame consists of 2 parts: The decoding map and
  32  * the video data. A demuxer must load these 2 parts together in a single
  33  * buffer before sending it through the stream to this decoder.
  34  */
  35
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include <unistd.h>
  40
  41 #include "common.h"
  42 #include "avcodec.h"
  43 #include "dsputil.h"
  44
  45 #define PALETTE_COUNT 256
  46
  47 /* debugging support */
  48 #define DEBUG_INTERPLAY 0
  49 #if DEBUG_INTERPLAY
  50 #define debug_interplay(x,...) av_log(NULL, AV_LOG_DEBUG, x, __VA_ARGS__)
  51 #else
  52 static inline void debug_interplay(const char *format, ...) { }
  53 #endif
  54
  55 typedef struct IpvideoContext {
  56
  57     AVCodecContext *avctx;
  58     DSPContext dsp;
  59     AVFrame second_last_frame;
  60     AVFrame last_frame;
  61     AVFrame current_frame;
  62     unsigned char *decoding_map;
  63     int decoding_map_size;
  64
  65     unsigned char *buf;
  66     int size;
  67
  68     unsigned char *stream_ptr;
  69     unsigned char *stream_end;
  70     unsigned char *pixel_ptr;
  71     int line_inc;
  72     int stride;
  73     int upper_motion_limit_offset;
  74
  75 } IpvideoContext;
  76
  77 #define CHECK_STREAM_PTR(n) \
  78   if ((s->stream_ptr + n) > s->stream_end) { \
  79     av_log(s->avctx, AV_LOG_ERROR, "Interplay video warning: stream_ptr out of bounds (%p >= %p)\n", \
  80       s->stream_ptr + n, s->stream_end); \
  81     return -1; \
  82   }
  83
  84 #define COPY_FROM_CURRENT() \
  85     motion_offset = current_offset; \
  86     motion_offset += y * s->stride; \
  87     motion_offset += x; \
  88     if (motion_offset < 0) { \
  89         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset < 0 (%d)\n", motion_offset); \
  90         return -1; \
  91     } else if (motion_offset > s->upper_motion_limit_offset) { \
  92         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset above limit (%d >= %d)\n", \
  93             motion_offset, s->upper_motion_limit_offset); \
  94         return -1; \
  95     } \
  96     s->dsp.put_pixels_tab[0][0](s->pixel_ptr, \
  97         s->current_frame.data[0] + motion_offset, s->stride, 8);
  98
  99 #define COPY_FROM_PREVIOUS() \
 100     motion_offset = current_offset; \
 101     motion_offset += y * s->stride; \
 102     motion_offset += x; \
 103     if (motion_offset < 0) { \
 104         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset < 0 (%d)\n", motion_offset); \
 105         return -1; \
 106     } else if (motion_offset > s->upper_motion_limit_offset) { \
 107         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset above limit (%d >= %d)\n", \
 108             motion_offset, s->upper_motion_limit_offset); \
 109         return -1; \
 110     } \
 111     s->dsp.put_pixels_tab[0][0](s->pixel_ptr, \
 112         s->last_frame.data[0] + motion_offset, s->stride, 8);
 113
 114 #define COPY_FROM_SECOND_LAST() \
 115     motion_offset = current_offset; \
 116     motion_offset += y * s->stride; \
 117     motion_offset += x; \
 118     if (motion_offset < 0) { \
 119         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset < 0 (%d)\n", motion_offset); \
 120         return -1; \
 121     } else if (motion_offset > s->upper_motion_limit_offset) { \
 122         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset above limit (%d >= %d)\n", \
 123             motion_offset, s->upper_motion_limit_offset); \
 124         return -1; \
 125     } \
 126     s->dsp.put_pixels_tab[0][0](s->pixel_ptr, \
 127         s->second_last_frame.data[0] + motion_offset, s->stride, 8);
 128
 129 static int ipvideo_decode_block_opcode_0x0(IpvideoContext *s)
 130 {
 131     int x, y;
 132     int motion_offset;
 133     int current_offset = s->pixel_ptr - s->current_frame.data[0];
 134
 135     /* copy a block from the previous frame */
 136     x = y = 0;
 137     COPY_FROM_PREVIOUS();
 138
 139     /* report success */
 140     return 0;
 141 }
 142
 143 static int ipvideo_decode_block_opcode_0x1(IpvideoContext *s)
 144 {
 145     int x, y;
 146     int motion_offset;
 147     int current_offset = s->pixel_ptr - s->current_frame.data[0];
 148
 149     /* copy block from 2 frames ago */
 150     x = y = 0;
 151     COPY_FROM_SECOND_LAST();
 152
 153     /* report success */
 154     return 0;
 155 }
 156
 157 static int ipvideo_decode_block_opcode_0x2(IpvideoContext *s)
 158 {
 159     unsigned char B;
 160     int x, y;
 161     int motion_offset;
 162     int current_offset = s->pixel_ptr - s->current_frame.data[0];
 163
 164     /* copy block from 2 frames ago using a motion vector; need 1 more byte */
 165     CHECK_STREAM_PTR(1);
 166     B = *s->stream_ptr++;
 167
 168     if (B < 56) {
 169         x = 8 + (B % 7);
 170         y = B / 7;
 171     } else {
 172         x = -14 + ((B - 56) % 29);
 173         y =   8 + ((B - 56) / 29);
 174     }
 175
 176     debug_interplay ("    motion byte = %d, (x, y) = (%d, %d)\n", B, x, y);
 177     COPY_FROM_SECOND_LAST();
 178
 179     /* report success */
 180     return 0;
 181 }
 182
 183 static int ipvideo_decode_block_opcode_0x3(IpvideoContext *s)
 184 {
 185     unsigned char B;
 186     int x, y;
 187     int motion_offset;
 188     int current_offset = s->pixel_ptr - s->current_frame.data[0];
 189
 190     /* copy 8x8 block from current frame from an up/left block */
 191
 192     /* need 1 more byte for motion */
 193     CHECK_STREAM_PTR(1);
 194     B = *s->stream_ptr++;
 195
 196     if (B < 56) {
 197         x = -(8 + (B % 7));
 198         y = -(B / 7);
 199     } else {
 200         x = -(-14 + ((B - 56) % 29));
 201         y = -(  8 + ((B - 56) / 29));
 202     }
 203
 204     debug_interplay ("    motion byte = %d, (x, y) = (%d, %d)\n", B, x, y);
 205     COPY_FROM_CURRENT();
 206
 207     /* report success */
 208     return 0;
 209 }
 210
 211 static int ipvideo_decode_block_opcode_0x4(IpvideoContext *s)
 212 {
 213     int x, y;
 214     unsigned char B, BL, BH;
 215     int motion_offset;
 216     int current_offset = s->pixel_ptr - s->current_frame.data[0];
 217
 218     /* copy a block from the previous frame; need 1 more byte */
 219     CHECK_STREAM_PTR(1);
 220
 221     B = *s->stream_ptr++;
 222     BL = B & 0x0F;
 223     BH = (B >> 4) & 0x0F;
 224     x = -8 + BL;
 225     y = -8 + BH;
 226
 227     debug_interplay ("    motion byte = %d, (x, y) = (%d, %d)\n", B, x, y);
 228     COPY_FROM_PREVIOUS();
 229
 230     /* report success */
 231     return 0;
 232 }
 233
 234 static int ipvideo_decode_block_opcode_0x5(IpvideoContext *s)
 235 {
 236     signed char x, y;
 237     int motion_offset;
 238     int current_offset = s->pixel_ptr - s->current_frame.data[0];
 239
 240     /* copy a block from the previous frame using an expanded range;
 241      * need 2 more bytes */
 242     CHECK_STREAM_PTR(2);
 243
 244     x = *s->stream_ptr++;
 245     y = *s->stream_ptr++;
 246
 247     debug_interplay ("    motion bytes = %d, %d\n", x, y);
 248     COPY_FROM_PREVIOUS();
 249
 250     /* report success */
 251     return 0;
 252 }
 253
 254 static int ipvideo_decode_block_opcode_0x6(IpvideoContext *s)
 255 {
 256     /* mystery opcode? skip multiple blocks? */
 257     av_log(s->avctx, AV_LOG_ERROR, "  Interplay video: Help! Mystery opcode 0x6 seen\n");
 258
 259     /* report success */
 260     return 0;
 261 }
 262
 263 static int ipvideo_decode_block_opcode_0x7(IpvideoContext *s)
 264 {
 265     int x, y;
 266     unsigned char P0, P1;
 267     unsigned char B[8];
 268     unsigned int flags;
 269     int bitmask;
 270
 271     /* 2-color encoding */
 272     CHECK_STREAM_PTR(2);
 273
 274     P0 = *s->stream_ptr++;
 275     P1 = *s->stream_ptr++;
 276
 277     if (P0 <= P1) {
 278
 279         /* need 8 more bytes from the stream */
 280         CHECK_STREAM_PTR(8);
 281         for (y = 0; y < 8; y++)
 282             B[y] = *s->stream_ptr++;
 283
 284         for (y = 0; y < 8; y++) {
 285             flags = B[y];
 286             for (x = 0x01; x <= 0x80; x <<= 1) {
 287                 if (flags & x)
 288                     *s->pixel_ptr++ = P1;
 289                 else
 290                     *s->pixel_ptr++ = P0;
 291             }
 292             s->pixel_ptr += s->line_inc;
 293         }
 294
 295     } else {
 296
 297         /* need 2 more bytes from the stream */
 298         CHECK_STREAM_PTR(2);
 299         B[0] = *s->stream_ptr++;
 300         B[1] = *s->stream_ptr++;
 301
 302         flags = (B[1] << 8) | B[0];
 303         bitmask = 0x0001;
 304         for (y = 0; y < 8; y += 2) {
 305             for (x = 0; x < 8; x += 2, bitmask <<= 1) {
 306                 if (flags & bitmask) {
 307                     *(s->pixel_ptr + x) = P1;
 308                     *(s->pixel_ptr + x + 1) = P1;
 309                     *(s->pixel_ptr + s->stride + x) = P1;
 310                     *(s->pixel_ptr + s->stride + x + 1) = P1;
 311                 } else {
 312                     *(s->pixel_ptr + x) = P0;
 313                     *(s->pixel_ptr + x + 1) = P0;
 314                     *(s->pixel_ptr + s->stride + x) = P0;
 315                     *(s->pixel_ptr + s->stride + x + 1) = P0;
 316                 }
 317             }
 318             s->pixel_ptr += s->stride * 2;
 319         }
 320     }
 321
 322     /* report success */
 323     return 0;
 324 }
 325
 326 static int ipvideo_decode_block_opcode_0x8(IpvideoContext *s)
 327 {
 328     int x, y;
 329     unsigned char P[8];
 330     unsigned char B[8];
 331     unsigned int flags = 0;
 332     unsigned int bitmask = 0;
 333     unsigned char P0 = 0, P1 = 0;
 334     int lower_half = 0;
 335
 336     /* 2-color encoding for each 4x4 quadrant, or 2-color encoding on
 337      * either top and bottom or left and right halves */
 338     CHECK_STREAM_PTR(2);
 339
 340     P[0] = *s->stream_ptr++;
 341     P[1] = *s->stream_ptr++;
 342
 343     if (P[0] <= P[1]) {
 344
 345         /* need 12 more bytes */
 346         CHECK_STREAM_PTR(12);
 347         B[0] = *s->stream_ptr++;  B[1] = *s->stream_ptr++;
 348         P[2] = *s->stream_ptr++;  P[3] = *s->stream_ptr++;
 349         B[2] = *s->stream_ptr++;  B[3] = *s->stream_ptr++;
 350         P[4] = *s->stream_ptr++;  P[5] = *s->stream_ptr++;
 351         B[4] = *s->stream_ptr++;  B[5] = *s->stream_ptr++;
 352         P[6] = *s->stream_ptr++;  P[7] = *s->stream_ptr++;
 353         B[6] = *s->stream_ptr++;  B[7] = *s->stream_ptr++;
 354
 355         for (y = 0; y < 8; y++) {
 356
 357             /* time to reload flags? */
 358             if (y == 0) {
 359                 flags =
 360                     ((B[0] & 0xF0) <<  4) | ((B[4] & 0xF0) <<  8) |
 361                     ((B[0] & 0x0F)      ) | ((B[4] & 0x0F) <<  4) |
 362                     ((B[1] & 0xF0) << 20) | ((B[5] & 0xF0) << 24) |
 363                     ((B[1] & 0x0F) << 16) | ((B[5] & 0x0F) << 20);
 364                 bitmask = 0x00000001;
 365                 lower_half = 0;  /* still on top half */
 366             } else if (y == 4) {
 367                 flags =
 368                     ((B[2] & 0xF0) <<  4) | ((B[6] & 0xF0) <<  8) |
 369                     ((B[2] & 0x0F)      ) | ((B[6] & 0x0F) <<  4) |
 370                     ((B[3] & 0xF0) << 20) | ((B[7] & 0xF0) << 24) |
 371                     ((B[3] & 0x0F) << 16) | ((B[7] & 0x0F) << 20);
 372                 bitmask = 0x00000001;
 373                 lower_half = 2;
 374             }
 375
 376             for (x = 0; x < 8; x++, bitmask <<= 1) {
 377                 /* get the pixel values ready for this quadrant */
 378                 if (x == 0) {
 379                     P0 = P[lower_half + 0];
 380                     P1 = P[lower_half + 1];
 381                 } else if (x == 4) {
 382                     P0 = P[lower_half + 4];
 383                     P1 = P[lower_half + 5];
 384                 }
 385
 386                 if (flags & bitmask)
 387                     *s->pixel_ptr++ = P1;
 388                 else
 389                     *s->pixel_ptr++ = P0;
 390             }
 391             s->pixel_ptr += s->line_inc;
 392         }
 393
 394     } else {
 395
 396         /* need 10 more bytes */
 397         CHECK_STREAM_PTR(10);
 398         B[0] = *s->stream_ptr++;  B[1] = *s->stream_ptr++;
 399         B[2] = *s->stream_ptr++;  B[3] = *s->stream_ptr++;
 400         P[2] = *s->stream_ptr++;  P[3] = *s->stream_ptr++;
 401         B[4] = *s->stream_ptr++;  B[5] = *s->stream_ptr++;
 402         B[6] = *s->stream_ptr++;  B[7] = *s->stream_ptr++;
 403
 404         if (P[2] <= P[3]) {
 405
 406             /* vertical split; left & right halves are 2-color encoded */
 407
 408             for (y = 0; y < 8; y++) {
 409
 410                 /* time to reload flags? */
 411                 if (y == 0) {
 412                     flags =
 413                         ((B[0] & 0xF0) <<  4) | ((B[4] & 0xF0) <<  8) |
 414                         ((B[0] & 0x0F)      ) | ((B[4] & 0x0F) <<  4) |
 415                         ((B[1] & 0xF0) << 20) | ((B[5] & 0xF0) << 24) |
 416                         ((B[1] & 0x0F) << 16) | ((B[5] & 0x0F) << 20);
 417                     bitmask = 0x00000001;
 418                 } else if (y == 4) {
 419                     flags =
 420                         ((B[2] & 0xF0) <<  4) | ((B[6] & 0xF0) <<  8) |
 421                         ((B[2] & 0x0F)      ) | ((B[6] & 0x0F) <<  4) |
 422                         ((B[3] & 0xF0) << 20) | ((B[7] & 0xF0) << 24) |
 423                         ((B[3] & 0x0F) << 16) | ((B[7] & 0x0F) << 20);
 424                     bitmask = 0x00000001;
 425                 }
 426
 427                 for (x = 0; x < 8; x++, bitmask <<= 1) {
 428                     /* get the pixel values ready for this half */
 429                     if (x == 0) {
 430                         P0 = P[0];
 431                         P1 = P[1];
 432                     } else if (x == 4) {
 433                         P0 = P[2];
 434                         P1 = P[3];
 435                     }
 436
 437                     if (flags & bitmask)
 438                         *s->pixel_ptr++ = P1;
 439                     else
 440                         *s->pixel_ptr++ = P0;
 441                 }
 442                 s->pixel_ptr += s->line_inc;
 443             }
 444
 445         } else {
 446
 447             /* horizontal split; top & bottom halves are 2-color encoded */
 448
 449             for (y = 0; y < 8; y++) {
 450
 451                 flags = B[y];
 452                 if (y == 0) {
 453                     P0 = P[0];
 454                     P1 = P[1];
 455                 } else if (y == 4) {
 456                     P0 = P[2];
 457                     P1 = P[3];
 458                 }
 459
 460                 for (bitmask = 0x01; bitmask <= 0x80; bitmask <<= 1) {
 461
 462                     if (flags & bitmask)
 463                         *s->pixel_ptr++ = P1;
 464                     else
 465                         *s->pixel_ptr++ = P0;
 466                 }
 467                 s->pixel_ptr += s->line_inc;
 468             }
 469         }
 470     }
 471
 472     /* report success */
 473     return 0;
 474 }
 475
 476 static int ipvideo_decode_block_opcode_0x9(IpvideoContext *s)
 477 {
 478     int x, y;
 479     unsigned char P[4];
 480     unsigned char B[4];
 481     unsigned int flags = 0;
 482     int shifter = 0;
 483     unsigned char pix;
 484
 485     /* 4-color encoding */
 486     CHECK_STREAM_PTR(4);
 487
 488     for (y = 0; y < 4; y++)
 489         P[y] = *s->stream_ptr++;
 490
 491     if ((P[0] <= P[1]) && (P[2] <= P[3])) {
 492
 493         /* 1 of 4 colors for each pixel, need 16 more bytes */
 494         CHECK_STREAM_PTR(16);
 495
 496         for (y = 0; y < 8; y++) {
 497             /* get the next set of 8 2-bit flags */
 498             flags = (s->stream_ptr[1] << 8) | s->stream_ptr[0];
 499             s->stream_ptr += 2;
 500             for (x = 0, shifter = 0; x < 8; x++, shifter += 2) {
 501                 *s->pixel_ptr++ = P[(flags >> shifter) & 0x03];
 502             }
 503             s->pixel_ptr += s->line_inc;
 504         }
 505
 506     } else if ((P[0] <= P[1]) && (P[2] > P[3])) {
 507
 508         /* 1 of 4 colors for each 2x2 block, need 4 more bytes */
 509         CHECK_STREAM_PTR(4);
 510
 511         B[0] = *s->stream_ptr++;
 512         B[1] = *s->stream_ptr++;
 513         B[2] = *s->stream_ptr++;
 514         B[3] = *s->stream_ptr++;
 515         flags = (B[3] << 24) | (B[2] << 16) | (B[1] << 8) | B[0];
 516         shifter = 0;
 517
 518         for (y = 0; y < 8; y += 2) {
 519             for (x = 0; x < 8; x += 2, shifter += 2) {
 520                 pix = P[(flags >> shifter) & 0x03];
 521                 *(s->pixel_ptr + x) = pix;
 522                 *(s->pixel_ptr + x + 1) = pix;
 523                 *(s->pixel_ptr + s->stride + x) = pix;
 524                 *(s->pixel_ptr + s->stride + x + 1) = pix;
 525             }
 526             s->pixel_ptr += s->stride * 2;
 527         }
 528
 529     } else if ((P[0] > P[1]) && (P[2] <= P[3])) {
 530
 531         /* 1 of 4 colors for each 2x1 block, need 8 more bytes */
 532         CHECK_STREAM_PTR(8);
 533
 534         for (y = 0; y < 8; y++) {
 535             /* time to reload flags? */
 536             if ((y == 0) || (y == 4)) {
 537                 B[0] = *s->stream_ptr++;
 538                 B[1] = *s->stream_ptr++;
 539                 B[2] = *s->stream_ptr++;
 540                 B[3] = *s->stream_ptr++;
 541                 flags = (B[3] << 24) | (B[2] << 16) | (B[1] << 8) | B[0];
 542                 shifter = 0;
 543             }
 544             for (x = 0; x < 8; x += 2, shifter += 2) {
 545                 pix = P[(flags >> shifter) & 0x03];
 546                 *(s->pixel_ptr + x) = pix;
 547                 *(s->pixel_ptr + x + 1) = pix;
 548             }
 549             s->pixel_ptr += s->stride;
 550         }
 551
 552     } else {
 553
 554         /* 1 of 4 colors for each 1x2 block, need 8 more bytes */
 555         CHECK_STREAM_PTR(8);
 556
 557         for (y = 0; y < 8; y += 2) {
 558             /* time to reload flags? */
 559             if ((y == 0) || (y == 4)) {
 560                 B[0] = *s->stream_ptr++;
 561                 B[1] = *s->stream_ptr++;
 562                 B[2] = *s->stream_ptr++;
 563                 B[3] = *s->stream_ptr++;
 564                 flags = (B[3] << 24) | (B[2] << 16) | (B[1] << 8) | B[0];
 565                 shifter = 0;
 566             }
 567             for (x = 0; x < 8; x++, shifter += 2) {
 568                 pix = P[(flags >> shifter) & 0x03];
 569                 *(s->pixel_ptr + x) = pix;
 570                 *(s->pixel_ptr + s->stride + x) = pix;
 571             }
 572             s->pixel_ptr += s->stride * 2;
 573         }
 574     }
 575
 576     /* report success */
 577     return 0;
 578 }
 579
 580 static int ipvideo_decode_block_opcode_0xA(IpvideoContext *s)
 581 {
 582     int x, y;
 583     unsigned char P[16];
 584     unsigned char B[16];
 585     int flags = 0;
 586     int shifter = 0;
 587     int index;
 588     int split;
 589     int lower_half;
 590
 591     /* 4-color encoding for each 4x4 quadrant, or 4-color encoding on
 592      * either top and bottom or left and right halves */
 593     CHECK_STREAM_PTR(4);
 594
 595     for (y = 0; y < 4; y++)
 596         P[y] = *s->stream_ptr++;
 597
 598     if (P[0] <= P[1]) {
 599
 600         /* 4-color encoding for each quadrant; need 28 more bytes */
 601         CHECK_STREAM_PTR(28);
 602
 603         for (y = 0; y < 4; y++)
 604             B[y] = *s->stream_ptr++;
 605         for (y = 4; y < 16; y += 4) {
 606             for (x = y; x < y + 4; x++)
 607                 P[x] = *s->stream_ptr++;
 608             for (x = y; x < y + 4; x++)
 609                 B[x] = *s->stream_ptr++;
 610         }
 611
 612         for (y = 0; y < 8; y++) {
 613
 614             lower_half = (y >= 4) ? 4 : 0;
 615             flags = (B[y + 8] << 8) | B[y];
 616
 617             for (x = 0, shifter = 0; x < 8; x++, shifter += 2) {
 618                 split = (x >= 4) ? 8 : 0;
 619                 index = split + lower_half + ((flags >> shifter) & 0x03);
 620                 *s->pixel_ptr++ = P[index];
 621             }
 622
 623             s->pixel_ptr += s->line_inc;
 624         }
 625
 626     } else {
 627
 628         /* 4-color encoding for either left and right or top and bottom
 629          * halves; need 20 more bytes */
 630         CHECK_STREAM_PTR(20);
 631
 632         for (y = 0; y < 8; y++)
 633             B[y] = *s->stream_ptr++;
 634         for (y = 4; y < 8; y++)
 635             P[y] = *s->stream_ptr++;
 636         for (y = 8; y < 16; y++)
 637             B[y] = *s->stream_ptr++;
 638
 639         if (P[4] <= P[5]) {
 640
 641             /* block is divided into left and right halves */
 642             for (y = 0; y < 8; y++) {
 643
 644                 flags = (B[y + 8] << 8) | B[y];
 645                 split = 0;
 646
 647                 for (x = 0, shifter = 0; x < 8; x++, shifter += 2) {
 648                     if (x == 4)
 649                         split = 4;
 650                     *s->pixel_ptr++ = P[split + ((flags >> shifter) & 0x03)];
 651                 }
 652
 653                 s->pixel_ptr += s->line_inc;
 654             }
 655
 656         } else {
 657
 658             /* block is divided into top and bottom halves */
 659             split = 0;
 660             for (y = 0; y < 8; y++) {
 661
 662                 flags = (B[y * 2 + 1] << 8) | B[y * 2];
 663                 if (y == 4)
 664                     split = 4;
 665
 666                 for (x = 0, shifter = 0; x < 8; x++, shifter += 2)
 667                     *s->pixel_ptr++ = P[split + ((flags >> shifter) & 0x03)];
 668
 669                 s->pixel_ptr += s->line_inc;
 670             }
 671         }
 672     }
 673
 674     /* report success */
 675     return 0;
 676 }
 677
 678 static int ipvideo_decode_block_opcode_0xB(IpvideoContext *s)
 679 {
 680     int x, y;
 681
 682     /* 64-color encoding (each pixel in block is a different color) */
 683     CHECK_STREAM_PTR(64);
 684
 685     for (y = 0; y < 8; y++) {
 686         for (x = 0; x < 8; x++) {
 687             *s->pixel_ptr++ = *s->stream_ptr++;
 688         }
 689         s->pixel_ptr += s->line_inc;
 690     }
 691
 692     /* report success */
 693     return 0;
 694 }
 695
 696 static int ipvideo_decode_block_opcode_0xC(IpvideoContext *s)
 697 {
 698     int x, y;
 699     unsigned char pix;
 700
 701     /* 16-color block encoding: each 2x2 block is a different color */
 702     CHECK_STREAM_PTR(16);
 703
 704     for (y = 0; y < 8; y += 2) {
 705         for (x = 0; x < 8; x += 2) {
 706             pix = *s->stream_ptr++;
 707             *(s->pixel_ptr + x) = pix;
 708             *(s->pixel_ptr + x + 1) = pix;
 709             *(s->pixel_ptr + s->stride + x) = pix;
 710             *(s->pixel_ptr + s->stride + x + 1) = pix;
 711         }
 712         s->pixel_ptr += s->stride * 2;
 713     }
 714
 715     /* report success */
 716     return 0;
 717 }
 718
 719 static int ipvideo_decode_block_opcode_0xD(IpvideoContext *s)
 720 {
 721     int x, y;
 722     unsigned char P[4];
 723     unsigned char index = 0;
 724
 725     /* 4-color block encoding: each 4x4 block is a different color */
 726     CHECK_STREAM_PTR(4);
 727
 728     for (y = 0; y < 4; y++)
 729         P[y] = *s->stream_ptr++;
 730
 731     for (y = 0; y < 8; y++) {
 732         if (y < 4)
 733             index = 0;
 734         else
 735             index = 2;
 736
 737         for (x = 0; x < 8; x++) {
 738             if (x == 4)
 739                 index++;
 740             *s->pixel_ptr++ = P[index];
 741         }
 742         s->pixel_ptr += s->line_inc;
 743     }
 744
 745     /* report success */
 746     return 0;
 747 }
 748
 749 static int ipvideo_decode_block_opcode_0xE(IpvideoContext *s)
 750 {
 751     int x, y;
 752     unsigned char pix;
 753
 754     /* 1-color encoding: the whole block is 1 solid color */
 755     CHECK_STREAM_PTR(1);
 756     pix = *s->stream_ptr++;
 757
 758     for (y = 0; y < 8; y++) {
 759         for (x = 0; x < 8; x++) {
 760             *s->pixel_ptr++ = pix;
 761         }
 762         s->pixel_ptr += s->line_inc;
 763     }
 764
 765     /* report success */
 766     return 0;
 767 }
 768
 769 static int ipvideo_decode_block_opcode_0xF(IpvideoContext *s)
 770 {
 771     int x, y;
 772     unsigned char sample0, sample1;
 773
 774     /* dithered encoding */
 775     CHECK_STREAM_PTR(2);
 776     sample0 = *s->stream_ptr++;
 777     sample1 = *s->stream_ptr++;
 778
 779     for (y = 0; y < 8; y++) {
 780         for (x = 0; x < 8; x += 2) {
 781             if (y & 1) {
 782                 *s->pixel_ptr++ = sample1;
 783                 *s->pixel_ptr++ = sample0;
 784             } else {
 785                 *s->pixel_ptr++ = sample0;
 786                 *s->pixel_ptr++ = sample1;
 787             }
 788         }
 789         s->pixel_ptr += s->line_inc;
 790     }
 791
 792     /* report success */
 793     return 0;
 794 }
 795
 796 static int (*ipvideo_decode_block[16])(IpvideoContext *s);
 797
 798 static void ipvideo_decode_opcodes(IpvideoContext *s)
 799 {
 800     int x, y;
 801     int index = 0;
 802     unsigned char opcode;
 803     int ret;
 804     int code_counts[16];
 805     static int frame = 0;
 806
 807     debug_interplay("------------------ frame %d\n", frame);
 808     frame++;
 809
 810     for (x = 0; x < 16; x++)
 811         code_counts[x] = 0;
 812
 813     /* this is PAL8, so make the palette available */
 814     memcpy(s->current_frame.data[1], s->avctx->palctrl->palette, PALETTE_COUNT * 4);
 815
 816     s->stride = s->current_frame.linesize[0];
 817     s->stream_ptr = s->buf + 14;  /* data starts 14 bytes in */
 818     s->stream_end = s->buf + s->size;
 819     s->line_inc = s->stride - 8;
 820     s->upper_motion_limit_offset = (s->avctx->height - 8) * s->stride
 821         + s->avctx->width - 8;
 822     s->dsp = s->dsp;
 823
 824     for (y = 0; y < (s->stride * s->avctx->height); y += s->stride * 8) {
 825         for (x = y; x < y + s->avctx->width; x += 8) {
 826             /* bottom nibble first, then top nibble (which makes it
 827              * hard to use a GetBitcontext) */
 828             if (index & 1)
 829                 opcode = s->decoding_map[index >> 1] >> 4;
 830             else
 831                 opcode = s->decoding_map[index >> 1] & 0xF;
 832             index++;
 833
 834             debug_interplay("  block @ (%3d, %3d): encoding 0x%X, data ptr @ %p\n",
 835                 x - y, y / s->stride, opcode, s->stream_ptr);
 836             code_counts[opcode]++;
 837
 838             s->pixel_ptr = s->current_frame.data[0] + x;
 839             ret = ipvideo_decode_block[opcode](s);
 840             if (ret != 0) {
 841                 av_log(s->avctx, AV_LOG_ERROR, " Interplay video: decode problem on frame %d, @ block (%d, %d)\n",
 842                     frame, x - y, y / s->stride);
 843                 return;
 844             }
 845         }
 846     }
 847     if ((s->stream_ptr != s->stream_end) &&
 848         (s->stream_ptr + 1 != s->stream_end)) {
 849         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: decode finished with %d bytes left over\n",
 850             s->stream_end - s->stream_ptr);
 851     }
 852 }
 853
 854 static int ipvideo_decode_init(AVCodecContext *avctx)
 855 {
 856     IpvideoContext *s = avctx->priv_data;
 857
 858     s->avctx = avctx;
 859
 860     if (s->avctx->palctrl == NULL) {
 861         av_log(avctx, AV_LOG_ERROR, " Interplay video: palette expected.\n");
 862         return -1;
 863     }
 864
 865     avctx->pix_fmt = PIX_FMT_PAL8;
 866     avctx->has_b_frames = 0;
 867     dsputil_init(&s->dsp, avctx);
 868
 869     /* decoding map contains 4 bits of information per 8x8 block */
 870     s->decoding_map_size = avctx->width * avctx->height / (8 * 8 * 2);
 871
 872     /* assign block decode functions */
 873     ipvideo_decode_block[0x0] = ipvideo_decode_block_opcode_0x0;
 874     ipvideo_decode_block[0x1] = ipvideo_decode_block_opcode_0x1;
 875     ipvideo_decode_block[0x2] = ipvideo_decode_block_opcode_0x2;
 876     ipvideo_decode_block[0x3] = ipvideo_decode_block_opcode_0x3;
 877     ipvideo_decode_block[0x4] = ipvideo_decode_block_opcode_0x4;
 878     ipvideo_decode_block[0x5] = ipvideo_decode_block_opcode_0x5;
 879     ipvideo_decode_block[0x6] = ipvideo_decode_block_opcode_0x6;
 880     ipvideo_decode_block[0x7] = ipvideo_decode_block_opcode_0x7;
 881     ipvideo_decode_block[0x8] = ipvideo_decode_block_opcode_0x8;
 882     ipvideo_decode_block[0x9] = ipvideo_decode_block_opcode_0x9;
 883     ipvideo_decode_block[0xA] = ipvideo_decode_block_opcode_0xA;
 884     ipvideo_decode_block[0xB] = ipvideo_decode_block_opcode_0xB;
 885     ipvideo_decode_block[0xC] = ipvideo_decode_block_opcode_0xC;
 886     ipvideo_decode_block[0xD] = ipvideo_decode_block_opcode_0xD;
 887     ipvideo_decode_block[0xE] = ipvideo_decode_block_opcode_0xE;
 888     ipvideo_decode_block[0xF] = ipvideo_decode_block_opcode_0xF;
 889
 890     s->current_frame.data[0] = s->last_frame.data[0] =
 891     s->second_last_frame.data[0] = NULL;
 892
 893     return 0;
 894 }
 895
 896 static int ipvideo_decode_frame(AVCodecContext *avctx,
 897                                 void *data, int *data_size,
 898                                 uint8_t *buf, int buf_size)
 899 {
 900     IpvideoContext *s = avctx->priv_data;
 901     AVPaletteControl *palette_control = avctx->palctrl;
 902
 903     /* compressed buffer needs to be large enough to at least hold an entire
 904      * decoding map */
 905     if (buf_size < s->decoding_map_size)
 906         return buf_size;
 907
 908     s->decoding_map = buf;
 909     s->buf = buf + s->decoding_map_size;
 910     s->size = buf_size - s->decoding_map_size;
 911
 912     s->current_frame.reference = 3;
 913     if (avctx->get_buffer(avctx, &s->current_frame)) {
 914         av_log(avctx, AV_LOG_ERROR, "  Interplay Video: get_buffer() failed\n");
 915         return -1;
 916     }
 917
 918     ipvideo_decode_opcodes(s);
 919
 920     if (palette_control->palette_changed) {
 921         palette_control->palette_changed = 0;
 922         s->current_frame.palette_has_changed = 1;
 923     }
 924
 925     *data_size = sizeof(AVFrame);
 926     *(AVFrame*)data = s->current_frame;
 927
 928     /* shuffle frames */
 929     if (s->second_last_frame.data[0])
 930         avctx->release_buffer(avctx, &s->second_last_frame);
 931     s->second_last_frame = s->last_frame;
 932     s->last_frame = s->current_frame;
 933     s->current_frame.data[0] = NULL;  /* catch any access attempts */
 934
 935     /* report that the buffer was completely consumed */
 936     return buf_size;
 937 }
 938
 939 static int ipvideo_decode_end(AVCodecContext *avctx)
 940 {
 941     IpvideoContext *s = avctx->priv_data;
 942
 943     /* release the last frame */
 944     if (s->last_frame.data[0])
 945         avctx->release_buffer(avctx, &s->last_frame);
 946     if (s->second_last_frame.data[0])
 947         avctx->release_buffer(avctx, &s->second_last_frame);
 948
 949     return 0;
 950 }
 951
 952 AVCodec interplay_video_decoder = {
 953     "interplayvideo",
 954     CODEC_TYPE_VIDEO,
 955     CODEC_ID_INTERPLAY_VIDEO,
 956     sizeof(IpvideoContext),
 957     ipvideo_decode_init,
 958     NULL,
 959     ipvideo_decode_end,
 960     ipvideo_decode_frame,
 961     CODEC_CAP_DR1,
 962 };