libavcodec/interplayvideo.c

   1 /*
   2  * Interplay MVE Video Decoder
   3  * Copyright (C) 2003 the ffmpeg project
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  *
  21  */
  22
  23 /**
  24  * @file interplayvideo.c
  25  * Interplay MVE Video Decoder by Mike Melanson (melanson@pcisys.net)
  26  * For more information about the Interplay MVE format, visit:
  27  *   http://www.pcisys.net/~melanson/codecs/interplay-mve.txt
  28  * This code is written in such a way that the identifiers match up
  29  * with the encoding descriptions in the document.
  30  *
  31  * This decoder presently only supports a PAL8 output colorspace.
  32  *
  33  * An Interplay video frame consists of 2 parts: The decoding map and
  34  * the video data. A demuxer must load these 2 parts together in a single
  35  * buffer before sending it through the stream to this decoder.
  36  */
  37
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41 #include <unistd.h>
  42
  43 #include "avcodec.h"
  44 #include "dsputil.h"
  45
  46 #define PALETTE_COUNT 256
  47
  48 /* debugging support */
  49 #define DEBUG_INTERPLAY 0
  50 #if DEBUG_INTERPLAY
  51 #define debug_interplay(x,...) av_log(NULL, AV_LOG_DEBUG, x, __VA_ARGS__)
  52 #else
  53 static inline void debug_interplay(const char *format, ...) { }
  54 #endif
  55
  56 typedef struct IpvideoContext {
  57
  58     AVCodecContext *avctx;
  59     DSPContext dsp;
  60     AVFrame second_last_frame;
  61     AVFrame last_frame;
  62     AVFrame current_frame;
  63     unsigned char *decoding_map;
  64     int decoding_map_size;
  65
  66     unsigned char *buf;
  67     int size;
  68
  69     unsigned char *stream_ptr;
  70     unsigned char *stream_end;
  71     unsigned char *pixel_ptr;
  72     int line_inc;
  73     int stride;
  74     int upper_motion_limit_offset;
  75
  76 } IpvideoContext;
  77
  78 #define CHECK_STREAM_PTR(n) \
  79   if ((s->stream_ptr + n) > s->stream_end) { \
  80     av_log(s->avctx, AV_LOG_ERROR, "Interplay video warning: stream_ptr out of bounds (%p >= %p)\n", \
  81       s->stream_ptr + n, s->stream_end); \
  82     return -1; \
  83   }
  84
  85 #define COPY_FROM_CURRENT() \
  86     motion_offset = current_offset; \
  87     motion_offset += y * s->stride; \
  88     motion_offset += x; \
  89     if (motion_offset < 0) { \
  90         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset < 0 (%d)\n", motion_offset); \
  91         return -1; \
  92     } else if (motion_offset > s->upper_motion_limit_offset) { \
  93         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset above limit (%d >= %d)\n", \
  94             motion_offset, s->upper_motion_limit_offset); \
  95         return -1; \
  96     } \
  97     s->dsp.put_pixels_tab[0][0](s->pixel_ptr, \
  98         s->current_frame.data[0] + motion_offset, s->stride, 8);
  99
 100 #define COPY_FROM_PREVIOUS() \
 101     motion_offset = current_offset; \
 102     motion_offset += y * s->stride; \
 103     motion_offset += x; \
 104     if (motion_offset < 0) { \
 105         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset < 0 (%d)\n", motion_offset); \
 106         return -1; \
 107     } else if (motion_offset > s->upper_motion_limit_offset) { \
 108         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset above limit (%d >= %d)\n", \
 109             motion_offset, s->upper_motion_limit_offset); \
 110         return -1; \
 111     } \
 112     s->dsp.put_pixels_tab[0][0](s->pixel_ptr, \
 113         s->last_frame.data[0] + motion_offset, s->stride, 8);
 114
 115 #define COPY_FROM_SECOND_LAST() \
 116     motion_offset = current_offset; \
 117     motion_offset += y * s->stride; \
 118     motion_offset += x; \
 119     if (motion_offset < 0) { \
 120         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset < 0 (%d)\n", motion_offset); \
 121         return -1; \
 122     } else if (motion_offset > s->upper_motion_limit_offset) { \
 123         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset above limit (%d >= %d)\n", \
 124             motion_offset, s->upper_motion_limit_offset); \
 125         return -1; \
 126     } \
 127     s->dsp.put_pixels_tab[0][0](s->pixel_ptr, \
 128         s->second_last_frame.data[0] + motion_offset, s->stride, 8);
 129
 130 static int ipvideo_decode_block_opcode_0x0(IpvideoContext *s)
 131 {
 132     int x, y;
 133     int motion_offset;
 134     int current_offset = s->pixel_ptr - s->current_frame.data[0];
 135
 136     /* copy a block from the previous frame */
 137     x = y = 0;
 138     COPY_FROM_PREVIOUS();
 139
 140     /* report success */
 141     return 0;
 142 }
 143
 144 static int ipvideo_decode_block_opcode_0x1(IpvideoContext *s)
 145 {
 146     int x, y;
 147     int motion_offset;
 148     int current_offset = s->pixel_ptr - s->current_frame.data[0];
 149
 150     /* copy block from 2 frames ago */
 151     x = y = 0;
 152     COPY_FROM_SECOND_LAST();
 153
 154     /* report success */
 155     return 0;
 156 }
 157
 158 static int ipvideo_decode_block_opcode_0x2(IpvideoContext *s)
 159 {
 160     unsigned char B;
 161     int x, y;
 162     int motion_offset;
 163     int current_offset = s->pixel_ptr - s->current_frame.data[0];
 164
 165     /* copy block from 2 frames ago using a motion vector; need 1 more byte */
 166     CHECK_STREAM_PTR(1);
 167     B = *s->stream_ptr++;
 168
 169     if (B < 56) {
 170         x = 8 + (B % 7);
 171         y = B / 7;
 172     } else {
 173         x = -14 + ((B - 56) % 29);
 174         y =   8 + ((B - 56) / 29);
 175     }
 176
 177     debug_interplay ("    motion byte = %d, (x, y) = (%d, %d)\n", B, x, y);
 178     COPY_FROM_SECOND_LAST();
 179
 180     /* report success */
 181     return 0;
 182 }
 183
 184 static int ipvideo_decode_block_opcode_0x3(IpvideoContext *s)
 185 {
 186     unsigned char B;
 187     int x, y;
 188     int motion_offset;
 189     int current_offset = s->pixel_ptr - s->current_frame.data[0];
 190
 191     /* copy 8x8 block from current frame from an up/left block */
 192
 193     /* need 1 more byte for motion */
 194     CHECK_STREAM_PTR(1);
 195     B = *s->stream_ptr++;
 196
 197     if (B < 56) {
 198         x = -(8 + (B % 7));
 199         y = -(B / 7);
 200     } else {
 201         x = -(-14 + ((B - 56) % 29));
 202         y = -(  8 + ((B - 56) / 29));
 203     }
 204
 205     debug_interplay ("    motion byte = %d, (x, y) = (%d, %d)\n", B, x, y);
 206     COPY_FROM_CURRENT();
 207
 208     /* report success */
 209     return 0;
 210 }
 211
 212 static int ipvideo_decode_block_opcode_0x4(IpvideoContext *s)
 213 {
 214     int x, y;
 215     unsigned char B, BL, BH;
 216     int motion_offset;
 217     int current_offset = s->pixel_ptr - s->current_frame.data[0];
 218
 219     /* copy a block from the previous frame; need 1 more byte */
 220     CHECK_STREAM_PTR(1);
 221
 222     B = *s->stream_ptr++;
 223     BL = B & 0x0F;
 224     BH = (B >> 4) & 0x0F;
 225     x = -8 + BL;
 226     y = -8 + BH;
 227
 228     debug_interplay ("    motion byte = %d, (x, y) = (%d, %d)\n", B, x, y);
 229     COPY_FROM_PREVIOUS();
 230
 231     /* report success */
 232     return 0;
 233 }
 234
 235 static int ipvideo_decode_block_opcode_0x5(IpvideoContext *s)
 236 {
 237     signed char x, y;
 238     int motion_offset;
 239     int current_offset = s->pixel_ptr - s->current_frame.data[0];
 240
 241     /* copy a block from the previous frame using an expanded range;
 242      * need 2 more bytes */
 243     CHECK_STREAM_PTR(2);
 244
 245     x = *s->stream_ptr++;
 246     y = *s->stream_ptr++;
 247
 248     debug_interplay ("    motion bytes = %d, %d\n", x, y);
 249     COPY_FROM_PREVIOUS();
 250
 251     /* report success */
 252     return 0;
 253 }
 254
 255 static int ipvideo_decode_block_opcode_0x6(IpvideoContext *s)
 256 {
 257     /* mystery opcode? skip multiple blocks? */
 258     av_log(s->avctx, AV_LOG_ERROR, "  Interplay video: Help! Mystery opcode 0x6 seen\n");
 259
 260     /* report success */
 261     return 0;
 262 }
 263
 264 static int ipvideo_decode_block_opcode_0x7(IpvideoContext *s)
 265 {
 266     int x, y;
 267     unsigned char P0, P1;
 268     unsigned char B[8];
 269     unsigned int flags;
 270     int bitmask;
 271
 272     /* 2-color encoding */
 273     CHECK_STREAM_PTR(2);
 274
 275     P0 = *s->stream_ptr++;
 276     P1 = *s->stream_ptr++;
 277
 278     if (P0 <= P1) {
 279
 280         /* need 8 more bytes from the stream */
 281         CHECK_STREAM_PTR(8);
 282         for (y = 0; y < 8; y++)
 283             B[y] = *s->stream_ptr++;
 284
 285         for (y = 0; y < 8; y++) {
 286             flags = B[y];
 287             for (x = 0x01; x <= 0x80; x <<= 1) {
 288                 if (flags & x)
 289                     *s->pixel_ptr++ = P1;
 290                 else
 291                     *s->pixel_ptr++ = P0;
 292             }
 293             s->pixel_ptr += s->line_inc;
 294         }
 295
 296     } else {
 297
 298         /* need 2 more bytes from the stream */
 299         CHECK_STREAM_PTR(2);
 300         B[0] = *s->stream_ptr++;
 301         B[1] = *s->stream_ptr++;
 302
 303         flags = (B[1] << 8) | B[0];
 304         bitmask = 0x0001;
 305         for (y = 0; y < 8; y += 2) {
 306             for (x = 0; x < 8; x += 2, bitmask <<= 1) {
 307                 if (flags & bitmask) {
 308                     *(s->pixel_ptr + x) = P1;
 309                     *(s->pixel_ptr + x + 1) = P1;
 310                     *(s->pixel_ptr + s->stride + x) = P1;
 311                     *(s->pixel_ptr + s->stride + x + 1) = P1;
 312                 } else {
 313                     *(s->pixel_ptr + x) = P0;
 314                     *(s->pixel_ptr + x + 1) = P0;
 315                     *(s->pixel_ptr + s->stride + x) = P0;
 316                     *(s->pixel_ptr + s->stride + x + 1) = P0;
 317                 }
 318             }
 319             s->pixel_ptr += s->stride * 2;
 320         }
 321     }
 322
 323     /* report success */
 324     return 0;
 325 }
 326
 327 static int ipvideo_decode_block_opcode_0x8(IpvideoContext *s)
 328 {
 329     int x, y;
 330     unsigned char P[8];
 331     unsigned char B[8];
 332     unsigned int flags = 0;
 333     unsigned int bitmask = 0;
 334     unsigned char P0 = 0, P1 = 0;
 335     int lower_half = 0;
 336
 337     /* 2-color encoding for each 4x4 quadrant, or 2-color encoding on
 338      * either top and bottom or left and right halves */
 339     CHECK_STREAM_PTR(2);
 340
 341     P[0] = *s->stream_ptr++;
 342     P[1] = *s->stream_ptr++;
 343
 344     if (P[0] <= P[1]) {
 345
 346         /* need 12 more bytes */
 347         CHECK_STREAM_PTR(12);
 348         B[0] = *s->stream_ptr++;  B[1] = *s->stream_ptr++;
 349         P[2] = *s->stream_ptr++;  P[3] = *s->stream_ptr++;
 350         B[2] = *s->stream_ptr++;  B[3] = *s->stream_ptr++;
 351         P[4] = *s->stream_ptr++;  P[5] = *s->stream_ptr++;
 352         B[4] = *s->stream_ptr++;  B[5] = *s->stream_ptr++;
 353         P[6] = *s->stream_ptr++;  P[7] = *s->stream_ptr++;
 354         B[6] = *s->stream_ptr++;  B[7] = *s->stream_ptr++;
 355
 356         for (y = 0; y < 8; y++) {
 357
 358             /* time to reload flags? */
 359             if (y == 0) {
 360                 flags =
 361                     ((B[0] & 0xF0) <<  4) | ((B[4] & 0xF0) <<  8) |
 362                     ((B[0] & 0x0F)      ) | ((B[4] & 0x0F) <<  4) |
 363                     ((B[1] & 0xF0) << 20) | ((B[5] & 0xF0) << 24) |
 364                     ((B[1] & 0x0F) << 16) | ((B[5] & 0x0F) << 20);
 365                 bitmask = 0x00000001;
 366                 lower_half = 0;  /* still on top half */
 367             } else if (y == 4) {
 368                 flags =
 369                     ((B[2] & 0xF0) <<  4) | ((B[6] & 0xF0) <<  8) |
 370                     ((B[2] & 0x0F)      ) | ((B[6] & 0x0F) <<  4) |
 371                     ((B[3] & 0xF0) << 20) | ((B[7] & 0xF0) << 24) |
 372                     ((B[3] & 0x0F) << 16) | ((B[7] & 0x0F) << 20);
 373                 bitmask = 0x00000001;
 374                 lower_half = 2;
 375             }
 376
 377             for (x = 0; x < 8; x++, bitmask <<= 1) {
 378                 /* get the pixel values ready for this quadrant */
 379                 if (x == 0) {
 380                     P0 = P[lower_half + 0];
 381                     P1 = P[lower_half + 1];
 382                 } else if (x == 4) {
 383                     P0 = P[lower_half + 4];
 384                     P1 = P[lower_half + 5];
 385                 }
 386
 387                 if (flags & bitmask)
 388                     *s->pixel_ptr++ = P1;
 389                 else
 390                     *s->pixel_ptr++ = P0;
 391             }
 392             s->pixel_ptr += s->line_inc;
 393         }
 394
 395     } else {
 396
 397         /* need 10 more bytes */
 398         CHECK_STREAM_PTR(10);
 399         B[0] = *s->stream_ptr++;  B[1] = *s->stream_ptr++;
 400         B[2] = *s->stream_ptr++;  B[3] = *s->stream_ptr++;
 401         P[2] = *s->stream_ptr++;  P[3] = *s->stream_ptr++;
 402         B[4] = *s->stream_ptr++;  B[5] = *s->stream_ptr++;
 403         B[6] = *s->stream_ptr++;  B[7] = *s->stream_ptr++;
 404
 405         if (P[2] <= P[3]) {
 406
 407             /* vertical split; left & right halves are 2-color encoded */
 408
 409             for (y = 0; y < 8; y++) {
 410
 411                 /* time to reload flags? */
 412                 if (y == 0) {
 413                     flags =
 414                         ((B[0] & 0xF0) <<  4) | ((B[4] & 0xF0) <<  8) |
 415                         ((B[0] & 0x0F)      ) | ((B[4] & 0x0F) <<  4) |
 416                         ((B[1] & 0xF0) << 20) | ((B[5] & 0xF0) << 24) |
 417                         ((B[1] & 0x0F) << 16) | ((B[5] & 0x0F) << 20);
 418                     bitmask = 0x00000001;
 419                 } else if (y == 4) {
 420                     flags =
 421                         ((B[2] & 0xF0) <<  4) | ((B[6] & 0xF0) <<  8) |
 422                         ((B[2] & 0x0F)      ) | ((B[6] & 0x0F) <<  4) |
 423                         ((B[3] & 0xF0) << 20) | ((B[7] & 0xF0) << 24) |
 424                         ((B[3] & 0x0F) << 16) | ((B[7] & 0x0F) << 20);
 425                     bitmask = 0x00000001;
 426                 }
 427
 428                 for (x = 0; x < 8; x++, bitmask <<= 1) {
 429                     /* get the pixel values ready for this half */
 430                     if (x == 0) {
 431                         P0 = P[0];
 432                         P1 = P[1];
 433                     } else if (x == 4) {
 434                         P0 = P[2];
 435                         P1 = P[3];
 436                     }
 437
 438                     if (flags & bitmask)
 439                         *s->pixel_ptr++ = P1;
 440                     else
 441                         *s->pixel_ptr++ = P0;
 442                 }
 443                 s->pixel_ptr += s->line_inc;
 444             }
 445
 446         } else {
 447
 448             /* horizontal split; top & bottom halves are 2-color encoded */
 449
 450             for (y = 0; y < 8; y++) {
 451
 452                 flags = B[y];
 453                 if (y == 0) {
 454                     P0 = P[0];
 455                     P1 = P[1];
 456                 } else if (y == 4) {
 457                     P0 = P[2];
 458                     P1 = P[3];
 459                 }
 460
 461                 for (bitmask = 0x01; bitmask <= 0x80; bitmask <<= 1) {
 462
 463                     if (flags & bitmask)
 464                         *s->pixel_ptr++ = P1;
 465                     else
 466                         *s->pixel_ptr++ = P0;
 467                 }
 468                 s->pixel_ptr += s->line_inc;
 469             }
 470         }
 471     }
 472
 473     /* report success */
 474     return 0;
 475 }
 476
 477 static int ipvideo_decode_block_opcode_0x9(IpvideoContext *s)
 478 {
 479     int x, y;
 480     unsigned char P[4];
 481     unsigned char B[4];
 482     unsigned int flags = 0;
 483     int shifter = 0;
 484     unsigned char pix;
 485
 486     /* 4-color encoding */
 487     CHECK_STREAM_PTR(4);
 488
 489     for (y = 0; y < 4; y++)
 490         P[y] = *s->stream_ptr++;
 491
 492     if ((P[0] <= P[1]) && (P[2] <= P[3])) {
 493
 494         /* 1 of 4 colors for each pixel, need 16 more bytes */
 495         CHECK_STREAM_PTR(16);
 496
 497         for (y = 0; y < 8; y++) {
 498             /* get the next set of 8 2-bit flags */
 499             flags = (s->stream_ptr[1] << 8) | s->stream_ptr[0];
 500             s->stream_ptr += 2;
 501             for (x = 0, shifter = 0; x < 8; x++, shifter += 2) {
 502                 *s->pixel_ptr++ = P[(flags >> shifter) & 0x03];
 503             }
 504             s->pixel_ptr += s->line_inc;
 505         }
 506
 507     } else if ((P[0] <= P[1]) && (P[2] > P[3])) {
 508
 509         /* 1 of 4 colors for each 2x2 block, need 4 more bytes */
 510         CHECK_STREAM_PTR(4);
 511
 512         B[0] = *s->stream_ptr++;
 513         B[1] = *s->stream_ptr++;
 514         B[2] = *s->stream_ptr++;
 515         B[3] = *s->stream_ptr++;
 516         flags = (B[3] << 24) | (B[2] << 16) | (B[1] << 8) | B[0];
 517         shifter = 0;
 518
 519         for (y = 0; y < 8; y += 2) {
 520             for (x = 0; x < 8; x += 2, shifter += 2) {
 521                 pix = P[(flags >> shifter) & 0x03];
 522                 *(s->pixel_ptr + x) = pix;
 523                 *(s->pixel_ptr + x + 1) = pix;
 524                 *(s->pixel_ptr + s->stride + x) = pix;
 525                 *(s->pixel_ptr + s->stride + x + 1) = pix;
 526             }
 527             s->pixel_ptr += s->stride * 2;
 528         }
 529
 530     } else if ((P[0] > P[1]) && (P[2] <= P[3])) {
 531
 532         /* 1 of 4 colors for each 2x1 block, need 8 more bytes */
 533         CHECK_STREAM_PTR(8);
 534
 535         for (y = 0; y < 8; y++) {
 536             /* time to reload flags? */
 537             if ((y == 0) || (y == 4)) {
 538                 B[0] = *s->stream_ptr++;
 539                 B[1] = *s->stream_ptr++;
 540                 B[2] = *s->stream_ptr++;
 541                 B[3] = *s->stream_ptr++;
 542                 flags = (B[3] << 24) | (B[2] << 16) | (B[1] << 8) | B[0];
 543                 shifter = 0;
 544             }
 545             for (x = 0; x < 8; x += 2, shifter += 2) {
 546                 pix = P[(flags >> shifter) & 0x03];
 547                 *(s->pixel_ptr + x) = pix;
 548                 *(s->pixel_ptr + x + 1) = pix;
 549             }
 550             s->pixel_ptr += s->stride;
 551         }
 552
 553     } else {
 554
 555         /* 1 of 4 colors for each 1x2 block, need 8 more bytes */
 556         CHECK_STREAM_PTR(8);
 557
 558         for (y = 0; y < 8; y += 2) {
 559             /* time to reload flags? */
 560             if ((y == 0) || (y == 4)) {
 561                 B[0] = *s->stream_ptr++;
 562                 B[1] = *s->stream_ptr++;
 563                 B[2] = *s->stream_ptr++;
 564                 B[3] = *s->stream_ptr++;
 565                 flags = (B[3] << 24) | (B[2] << 16) | (B[1] << 8) | B[0];
 566                 shifter = 0;
 567             }
 568             for (x = 0; x < 8; x++, shifter += 2) {
 569                 pix = P[(flags >> shifter) & 0x03];
 570                 *(s->pixel_ptr + x) = pix;
 571                 *(s->pixel_ptr + s->stride + x) = pix;
 572             }
 573             s->pixel_ptr += s->stride * 2;
 574         }
 575     }
 576
 577     /* report success */
 578     return 0;
 579 }
 580
 581 static int ipvideo_decode_block_opcode_0xA(IpvideoContext *s)
 582 {
 583     int x, y;
 584     unsigned char P[16];
 585     unsigned char B[16];
 586     int flags = 0;
 587     int shifter = 0;
 588     int index;
 589     int split;
 590     int lower_half;
 591
 592     /* 4-color encoding for each 4x4 quadrant, or 4-color encoding on
 593      * either top and bottom or left and right halves */
 594     CHECK_STREAM_PTR(4);
 595
 596     for (y = 0; y < 4; y++)
 597         P[y] = *s->stream_ptr++;
 598
 599     if (P[0] <= P[1]) {
 600
 601         /* 4-color encoding for each quadrant; need 28 more bytes */
 602         CHECK_STREAM_PTR(28);
 603
 604         for (y = 0; y < 4; y++)
 605             B[y] = *s->stream_ptr++;
 606         for (y = 4; y < 16; y += 4) {
 607             for (x = y; x < y + 4; x++)
 608                 P[x] = *s->stream_ptr++;
 609             for (x = y; x < y + 4; x++)
 610                 B[x] = *s->stream_ptr++;
 611         }
 612
 613         for (y = 0; y < 8; y++) {
 614
 615             lower_half = (y >= 4) ? 4 : 0;
 616             flags = (B[y + 8] << 8) | B[y];
 617
 618             for (x = 0, shifter = 0; x < 8; x++, shifter += 2) {
 619                 split = (x >= 4) ? 8 : 0;
 620                 index = split + lower_half + ((flags >> shifter) & 0x03);
 621                 *s->pixel_ptr++ = P[index];
 622             }
 623
 624             s->pixel_ptr += s->line_inc;
 625         }
 626
 627     } else {
 628
 629         /* 4-color encoding for either left and right or top and bottom
 630          * halves; need 20 more bytes */
 631         CHECK_STREAM_PTR(20);
 632
 633         for (y = 0; y < 8; y++)
 634             B[y] = *s->stream_ptr++;
 635         for (y = 4; y < 8; y++)
 636             P[y] = *s->stream_ptr++;
 637         for (y = 8; y < 16; y++)
 638             B[y] = *s->stream_ptr++;
 639
 640         if (P[4] <= P[5]) {
 641
 642             /* block is divided into left and right halves */
 643             for (y = 0; y < 8; y++) {
 644
 645                 flags = (B[y + 8] << 8) | B[y];
 646                 split = 0;
 647
 648                 for (x = 0, shifter = 0; x < 8; x++, shifter += 2) {
 649                     if (x == 4)
 650                         split = 4;
 651                     *s->pixel_ptr++ = P[split + ((flags >> shifter) & 0x03)];
 652                 }
 653
 654                 s->pixel_ptr += s->line_inc;
 655             }
 656
 657         } else {
 658
 659             /* block is divided into top and bottom halves */
 660             split = 0;
 661             for (y = 0; y < 8; y++) {
 662
 663                 flags = (B[y * 2 + 1] << 8) | B[y * 2];
 664                 if (y == 4)
 665                     split = 4;
 666
 667                 for (x = 0, shifter = 0; x < 8; x++, shifter += 2)
 668                     *s->pixel_ptr++ = P[split + ((flags >> shifter) & 0x03)];
 669
 670                 s->pixel_ptr += s->line_inc;
 671             }
 672         }
 673     }
 674
 675     /* report success */
 676     return 0;
 677 }
 678
 679 static int ipvideo_decode_block_opcode_0xB(IpvideoContext *s)
 680 {
 681     int x, y;
 682
 683     /* 64-color encoding (each pixel in block is a different color) */
 684     CHECK_STREAM_PTR(64);
 685
 686     for (y = 0; y < 8; y++) {
 687         for (x = 0; x < 8; x++) {
 688             *s->pixel_ptr++ = *s->stream_ptr++;
 689         }
 690         s->pixel_ptr += s->line_inc;
 691     }
 692
 693     /* report success */
 694     return 0;
 695 }
 696
 697 static int ipvideo_decode_block_opcode_0xC(IpvideoContext *s)
 698 {
 699     int x, y;
 700     unsigned char pix;
 701
 702     /* 16-color block encoding: each 2x2 block is a different color */
 703     CHECK_STREAM_PTR(16);
 704
 705     for (y = 0; y < 8; y += 2) {
 706         for (x = 0; x < 8; x += 2) {
 707             pix = *s->stream_ptr++;
 708             *(s->pixel_ptr + x) = pix;
 709             *(s->pixel_ptr + x + 1) = pix;
 710             *(s->pixel_ptr + s->stride + x) = pix;
 711             *(s->pixel_ptr + s->stride + x + 1) = pix;
 712         }
 713         s->pixel_ptr += s->stride * 2;
 714     }
 715
 716     /* report success */
 717     return 0;
 718 }
 719
 720 static int ipvideo_decode_block_opcode_0xD(IpvideoContext *s)
 721 {
 722     int x, y;
 723     unsigned char P[4];
 724     unsigned char index = 0;
 725
 726     /* 4-color block encoding: each 4x4 block is a different color */
 727     CHECK_STREAM_PTR(4);
 728
 729     for (y = 0; y < 4; y++)
 730         P[y] = *s->stream_ptr++;
 731
 732     for (y = 0; y < 8; y++) {
 733         if (y < 4)
 734             index = 0;
 735         else
 736             index = 2;
 737
 738         for (x = 0; x < 8; x++) {
 739             if (x == 4)
 740                 index++;
 741             *s->pixel_ptr++ = P[index];
 742         }
 743         s->pixel_ptr += s->line_inc;
 744     }
 745
 746     /* report success */
 747     return 0;
 748 }
 749
 750 static int ipvideo_decode_block_opcode_0xE(IpvideoContext *s)
 751 {
 752     int x, y;
 753     unsigned char pix;
 754
 755     /* 1-color encoding: the whole block is 1 solid color */
 756     CHECK_STREAM_PTR(1);
 757     pix = *s->stream_ptr++;
 758
 759     for (y = 0; y < 8; y++) {
 760         for (x = 0; x < 8; x++) {
 761             *s->pixel_ptr++ = pix;
 762         }
 763         s->pixel_ptr += s->line_inc;
 764     }
 765
 766     /* report success */
 767     return 0;
 768 }
 769
 770 static int ipvideo_decode_block_opcode_0xF(IpvideoContext *s)
 771 {
 772     int x, y;
 773     unsigned char sample0, sample1;
 774
 775     /* dithered encoding */
 776     CHECK_STREAM_PTR(2);
 777     sample0 = *s->stream_ptr++;
 778     sample1 = *s->stream_ptr++;
 779
 780     for (y = 0; y < 8; y++) {
 781         for (x = 0; x < 8; x += 2) {
 782             if (y & 1) {
 783                 *s->pixel_ptr++ = sample1;
 784                 *s->pixel_ptr++ = sample0;
 785             } else {
 786                 *s->pixel_ptr++ = sample0;
 787                 *s->pixel_ptr++ = sample1;
 788             }
 789         }
 790         s->pixel_ptr += s->line_inc;
 791     }
 792
 793     /* report success */
 794     return 0;
 795 }
 796
 797 static int (*ipvideo_decode_block[16])(IpvideoContext *s);
 798
 799 static void ipvideo_decode_opcodes(IpvideoContext *s)
 800 {
 801     int x, y;
 802     int index = 0;
 803     unsigned char opcode;
 804     int ret;
 805     int code_counts[16];
 806     static int frame = 0;
 807
 808     debug_interplay("------------------ frame %d\n", frame);
 809     frame++;
 810
 811     for (x = 0; x < 16; x++)
 812         code_counts[x] = 0;
 813
 814     /* this is PAL8, so make the palette available */
 815     memcpy(s->current_frame.data[1], s->avctx->palctrl->palette, PALETTE_COUNT * 4);
 816
 817     s->stride = s->current_frame.linesize[0];
 818     s->stream_ptr = s->buf + 14;  /* data starts 14 bytes in */
 819     s->stream_end = s->buf + s->size;
 820     s->line_inc = s->stride - 8;
 821     s->upper_motion_limit_offset = (s->avctx->height - 8) * s->stride
 822         + s->avctx->width - 8;
 823     s->dsp = s->dsp;
 824
 825     for (y = 0; y < (s->stride * s->avctx->height); y += s->stride * 8) {
 826         for (x = y; x < y + s->avctx->width; x += 8) {
 827             /* bottom nibble first, then top nibble (which makes it
 828              * hard to use a GetBitcontext) */
 829             if (index & 1)
 830                 opcode = s->decoding_map[index >> 1] >> 4;
 831             else
 832                 opcode = s->decoding_map[index >> 1] & 0xF;
 833             index++;
 834
 835             debug_interplay("  block @ (%3d, %3d): encoding 0x%X, data ptr @ %p\n",
 836                 x - y, y / s->stride, opcode, s->stream_ptr);
 837             code_counts[opcode]++;
 838
 839             s->pixel_ptr = s->current_frame.data[0] + x;
 840             ret = ipvideo_decode_block[opcode](s);
 841             if (ret != 0) {
 842                 av_log(s->avctx, AV_LOG_ERROR, " Interplay video: decode problem on frame %d, @ block (%d, %d)\n",
 843                     frame, x - y, y / s->stride);
 844                 return;
 845             }
 846         }
 847     }
 848     if ((s->stream_ptr != s->stream_end) &&
 849         (s->stream_ptr + 1 != s->stream_end)) {
 850         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: decode finished with %td bytes left over\n",
 851             s->stream_end - s->stream_ptr);
 852     }
 853 }
 854
 855 static int ipvideo_decode_init(AVCodecContext *avctx)
 856 {
 857     IpvideoContext *s = avctx->priv_data;
 858
 859     s->avctx = avctx;
 860
 861     if (s->avctx->palctrl == NULL) {
 862         av_log(avctx, AV_LOG_ERROR, " Interplay video: palette expected.\n");
 863         return -1;
 864     }
 865
 866     avctx->pix_fmt = PIX_FMT_PAL8;
 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 };