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  * @file libavcodec/interplayvideo.c
  24  * Interplay MVE Video Decoder by Mike Melanson (melanson@pcisys.net)
  25  * For more information about the Interplay MVE format, visit:
  26  *   http://www.pcisys.net/~melanson/codecs/interplay-mve.txt
  27  * This code is written in such a way that the identifiers match up
  28  * with the encoding descriptions in the document.
  29  *
  30  * This decoder presently only supports a PAL8 output colorspace.
  31  *
  32  * An Interplay video frame consists of 2 parts: The decoding map and
  33  * the video data. A demuxer must load these 2 parts together in a single
  34  * buffer before sending it through the stream to this decoder.
  35  */
  36
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <unistd.h>
  41
  42 #include "avcodec.h"
  43 #include "bytestream.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     const unsigned char *decoding_map;
  64     int decoding_map_size;
  65
  66     const unsigned char *buf;
  67     int size;
  68
  69     const unsigned char *stream_ptr;
  70     const 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[1][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[1][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[1][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
 301         flags = bytestream_get_le16(&s->stream_ptr);
 302         bitmask = 0x0001;
 303         for (y = 0; y < 8; y += 2) {
 304             for (x = 0; x < 8; x += 2, bitmask <<= 1) {
 305                 if (flags & bitmask) {
 306                     *(s->pixel_ptr + x) = P1;
 307                     *(s->pixel_ptr + x + 1) = P1;
 308                     *(s->pixel_ptr + s->stride + x) = P1;
 309                     *(s->pixel_ptr + s->stride + x + 1) = P1;
 310                 } else {
 311                     *(s->pixel_ptr + x) = P0;
 312                     *(s->pixel_ptr + x + 1) = P0;
 313                     *(s->pixel_ptr + s->stride + x) = P0;
 314                     *(s->pixel_ptr + s->stride + x + 1) = P0;
 315                 }
 316             }
 317             s->pixel_ptr += s->stride * 2;
 318         }
 319     }
 320
 321     /* report success */
 322     return 0;
 323 }
 324
 325 static int ipvideo_decode_block_opcode_0x8(IpvideoContext *s)
 326 {
 327     int x, y;
 328     unsigned char P[8];
 329     unsigned char B[8];
 330     unsigned int flags = 0;
 331     unsigned int bitmask = 0;
 332     unsigned char P0 = 0, P1 = 0;
 333     int lower_half = 0;
 334
 335     /* 2-color encoding for each 4x4 quadrant, or 2-color encoding on
 336      * either top and bottom or left and right halves */
 337     CHECK_STREAM_PTR(2);
 338
 339     P[0] = *s->stream_ptr++;
 340     P[1] = *s->stream_ptr++;
 341
 342     if (P[0] <= P[1]) {
 343
 344         /* need 12 more bytes */
 345         CHECK_STREAM_PTR(12);
 346         B[0] = *s->stream_ptr++;  B[1] = *s->stream_ptr++;
 347         P[2] = *s->stream_ptr++;  P[3] = *s->stream_ptr++;
 348         B[2] = *s->stream_ptr++;  B[3] = *s->stream_ptr++;
 349         P[4] = *s->stream_ptr++;  P[5] = *s->stream_ptr++;
 350         B[4] = *s->stream_ptr++;  B[5] = *s->stream_ptr++;
 351         P[6] = *s->stream_ptr++;  P[7] = *s->stream_ptr++;
 352         B[6] = *s->stream_ptr++;  B[7] = *s->stream_ptr++;
 353
 354         for (y = 0; y < 8; y++) {
 355
 356             /* time to reload flags? */
 357             if (y == 0) {
 358                 flags =
 359                     ((B[0] & 0xF0) <<  4) | ((B[4] & 0xF0) <<  8) |
 360                     ((B[0] & 0x0F)      ) | ((B[4] & 0x0F) <<  4) |
 361                     ((B[1] & 0xF0) << 20) | ((B[5] & 0xF0) << 24) |
 362                     ((B[1] & 0x0F) << 16) | ((B[5] & 0x0F) << 20);
 363                 bitmask = 0x00000001;
 364                 lower_half = 0;  /* still on top half */
 365             } else if (y == 4) {
 366                 flags =
 367                     ((B[2] & 0xF0) <<  4) | ((B[6] & 0xF0) <<  8) |
 368                     ((B[2] & 0x0F)      ) | ((B[6] & 0x0F) <<  4) |
 369                     ((B[3] & 0xF0) << 20) | ((B[7] & 0xF0) << 24) |
 370                     ((B[3] & 0x0F) << 16) | ((B[7] & 0x0F) << 20);
 371                 bitmask = 0x00000001;
 372                 lower_half = 2;
 373             }
 374
 375             for (x = 0; x < 8; x++, bitmask <<= 1) {
 376                 /* get the pixel values ready for this quadrant */
 377                 if (x == 0) {
 378                     P0 = P[lower_half + 0];
 379                     P1 = P[lower_half + 1];
 380                 } else if (x == 4) {
 381                     P0 = P[lower_half + 4];
 382                     P1 = P[lower_half + 5];
 383                 }
 384
 385                 if (flags & bitmask)
 386                     *s->pixel_ptr++ = P1;
 387                 else
 388                     *s->pixel_ptr++ = P0;
 389             }
 390             s->pixel_ptr += s->line_inc;
 391         }
 392
 393     } else {
 394
 395         /* need 10 more bytes */
 396         CHECK_STREAM_PTR(10);
 397         B[0] = *s->stream_ptr++;  B[1] = *s->stream_ptr++;
 398         B[2] = *s->stream_ptr++;  B[3] = *s->stream_ptr++;
 399         P[2] = *s->stream_ptr++;  P[3] = *s->stream_ptr++;
 400         B[4] = *s->stream_ptr++;  B[5] = *s->stream_ptr++;
 401         B[6] = *s->stream_ptr++;  B[7] = *s->stream_ptr++;
 402
 403         if (P[2] <= P[3]) {
 404
 405             /* vertical split; left & right halves are 2-color encoded */
 406
 407             for (y = 0; y < 8; y++) {
 408
 409                 /* time to reload flags? */
 410                 if (y == 0) {
 411                     flags =
 412                         ((B[0] & 0xF0) <<  4) | ((B[4] & 0xF0) <<  8) |
 413                         ((B[0] & 0x0F)      ) | ((B[4] & 0x0F) <<  4) |
 414                         ((B[1] & 0xF0) << 20) | ((B[5] & 0xF0) << 24) |
 415                         ((B[1] & 0x0F) << 16) | ((B[5] & 0x0F) << 20);
 416                     bitmask = 0x00000001;
 417                 } else if (y == 4) {
 418                     flags =
 419                         ((B[2] & 0xF0) <<  4) | ((B[6] & 0xF0) <<  8) |
 420                         ((B[2] & 0x0F)      ) | ((B[6] & 0x0F) <<  4) |
 421                         ((B[3] & 0xF0) << 20) | ((B[7] & 0xF0) << 24) |
 422                         ((B[3] & 0x0F) << 16) | ((B[7] & 0x0F) << 20);
 423                     bitmask = 0x00000001;
 424                 }
 425
 426                 for (x = 0; x < 8; x++, bitmask <<= 1) {
 427                     /* get the pixel values ready for this half */
 428                     if (x == 0) {
 429                         P0 = P[0];
 430                         P1 = P[1];
 431                     } else if (x == 4) {
 432                         P0 = P[2];
 433                         P1 = P[3];
 434                     }
 435
 436                     if (flags & bitmask)
 437                         *s->pixel_ptr++ = P1;
 438                     else
 439                         *s->pixel_ptr++ = P0;
 440                 }
 441                 s->pixel_ptr += s->line_inc;
 442             }
 443
 444         } else {
 445
 446             /* horizontal split; top & bottom halves are 2-color encoded */
 447
 448             for (y = 0; y < 8; y++) {
 449
 450                 flags = B[y];
 451                 if (y == 0) {
 452                     P0 = P[0];
 453                     P1 = P[1];
 454                 } else if (y == 4) {
 455                     P0 = P[2];
 456                     P1 = P[3];
 457                 }
 458
 459                 for (bitmask = 0x01; bitmask <= 0x80; bitmask <<= 1) {
 460
 461                     if (flags & bitmask)
 462                         *s->pixel_ptr++ = P1;
 463                     else
 464                         *s->pixel_ptr++ = P0;
 465                 }
 466                 s->pixel_ptr += s->line_inc;
 467             }
 468         }
 469     }
 470
 471     /* report success */
 472     return 0;
 473 }
 474
 475 static int ipvideo_decode_block_opcode_0x9(IpvideoContext *s)
 476 {
 477     int x, y;
 478     unsigned char P[4];
 479     unsigned int flags = 0;
 480     int shifter = 0;
 481     unsigned char pix;
 482
 483     /* 4-color encoding */
 484     CHECK_STREAM_PTR(4);
 485
 486     for (y = 0; y < 4; y++)
 487         P[y] = *s->stream_ptr++;
 488
 489     if ((P[0] <= P[1]) && (P[2] <= P[3])) {
 490
 491         /* 1 of 4 colors for each pixel, need 16 more bytes */
 492         CHECK_STREAM_PTR(16);
 493
 494         for (y = 0; y < 8; y++) {
 495             /* get the next set of 8 2-bit flags */
 496             flags = bytestream_get_le16(&s->stream_ptr);
 497             for (x = 0, shifter = 0; x < 8; x++, shifter += 2) {
 498                 *s->pixel_ptr++ = P[(flags >> shifter) & 0x03];
 499             }
 500             s->pixel_ptr += s->line_inc;
 501         }
 502
 503     } else if ((P[0] <= P[1]) && (P[2] > P[3])) {
 504
 505         /* 1 of 4 colors for each 2x2 block, need 4 more bytes */
 506         CHECK_STREAM_PTR(4);
 507
 508         flags = bytestream_get_le32(&s->stream_ptr);
 509         shifter = 0;
 510
 511         for (y = 0; y < 8; y += 2) {
 512             for (x = 0; x < 8; x += 2, shifter += 2) {
 513                 pix = P[(flags >> shifter) & 0x03];
 514                 *(s->pixel_ptr + x) = pix;
 515                 *(s->pixel_ptr + x + 1) = pix;
 516                 *(s->pixel_ptr + s->stride + x) = pix;
 517                 *(s->pixel_ptr + s->stride + x + 1) = pix;
 518             }
 519             s->pixel_ptr += s->stride * 2;
 520         }
 521
 522     } else if ((P[0] > P[1]) && (P[2] <= P[3])) {
 523
 524         /* 1 of 4 colors for each 2x1 block, need 8 more bytes */
 525         CHECK_STREAM_PTR(8);
 526
 527         for (y = 0; y < 8; y++) {
 528             /* time to reload flags? */
 529             if ((y == 0) || (y == 4)) {
 530                 flags = bytestream_get_le32(&s->stream_ptr);
 531                 shifter = 0;
 532             }
 533             for (x = 0; x < 8; x += 2, shifter += 2) {
 534                 pix = P[(flags >> shifter) & 0x03];
 535                 *(s->pixel_ptr + x) = pix;
 536                 *(s->pixel_ptr + x + 1) = pix;
 537             }
 538             s->pixel_ptr += s->stride;
 539         }
 540
 541     } else {
 542
 543         /* 1 of 4 colors for each 1x2 block, need 8 more bytes */
 544         CHECK_STREAM_PTR(8);
 545
 546         for (y = 0; y < 8; y += 2) {
 547             /* time to reload flags? */
 548             if ((y == 0) || (y == 4)) {
 549                 flags = bytestream_get_le32(&s->stream_ptr);
 550                 shifter = 0;
 551             }
 552             for (x = 0; x < 8; x++, shifter += 2) {
 553                 pix = P[(flags >> shifter) & 0x03];
 554                 *(s->pixel_ptr + x) = pix;
 555                 *(s->pixel_ptr + s->stride + x) = pix;
 556             }
 557             s->pixel_ptr += s->stride * 2;
 558         }
 559     }
 560
 561     /* report success */
 562     return 0;
 563 }
 564
 565 static int ipvideo_decode_block_opcode_0xA(IpvideoContext *s)
 566 {
 567     int x, y;
 568     unsigned char P[16];
 569     unsigned char B[16];
 570     int flags = 0;
 571     int shifter = 0;
 572     int index;
 573     int split;
 574     int lower_half;
 575
 576     /* 4-color encoding for each 4x4 quadrant, or 4-color encoding on
 577      * either top and bottom or left and right halves */
 578     CHECK_STREAM_PTR(4);
 579
 580     for (y = 0; y < 4; y++)
 581         P[y] = *s->stream_ptr++;
 582
 583     if (P[0] <= P[1]) {
 584
 585         /* 4-color encoding for each quadrant; need 28 more bytes */
 586         CHECK_STREAM_PTR(28);
 587
 588         for (y = 0; y < 4; y++)
 589             B[y] = *s->stream_ptr++;
 590         for (y = 4; y < 16; y += 4) {
 591             for (x = y; x < y + 4; x++)
 592                 P[x] = *s->stream_ptr++;
 593             for (x = y; x < y + 4; x++)
 594                 B[x] = *s->stream_ptr++;
 595         }
 596
 597         for (y = 0; y < 8; y++) {
 598
 599             lower_half = (y >= 4) ? 4 : 0;
 600             flags = (B[y + 8] << 8) | B[y];
 601
 602             for (x = 0, shifter = 0; x < 8; x++, shifter += 2) {
 603                 split = (x >= 4) ? 8 : 0;
 604                 index = split + lower_half + ((flags >> shifter) & 0x03);
 605                 *s->pixel_ptr++ = P[index];
 606             }
 607
 608             s->pixel_ptr += s->line_inc;
 609         }
 610
 611     } else {
 612
 613         /* 4-color encoding for either left and right or top and bottom
 614          * halves; need 20 more bytes */
 615         CHECK_STREAM_PTR(20);
 616
 617         for (y = 0; y < 8; y++)
 618             B[y] = *s->stream_ptr++;
 619         for (y = 4; y < 8; y++)
 620             P[y] = *s->stream_ptr++;
 621         for (y = 8; y < 16; y++)
 622             B[y] = *s->stream_ptr++;
 623
 624         if (P[4] <= P[5]) {
 625
 626             /* block is divided into left and right halves */
 627             for (y = 0; y < 8; y++) {
 628
 629                 flags = (B[y + 8] << 8) | B[y];
 630                 split = 0;
 631
 632                 for (x = 0, shifter = 0; x < 8; x++, shifter += 2) {
 633                     if (x == 4)
 634                         split = 4;
 635                     *s->pixel_ptr++ = P[split + ((flags >> shifter) & 0x03)];
 636                 }
 637
 638                 s->pixel_ptr += s->line_inc;
 639             }
 640
 641         } else {
 642
 643             /* block is divided into top and bottom halves */
 644             split = 0;
 645             for (y = 0; y < 8; y++) {
 646
 647                 flags = (B[y * 2 + 1] << 8) | B[y * 2];
 648                 if (y == 4)
 649                     split = 4;
 650
 651                 for (x = 0, shifter = 0; x < 8; x++, shifter += 2)
 652                     *s->pixel_ptr++ = P[split + ((flags >> shifter) & 0x03)];
 653
 654                 s->pixel_ptr += s->line_inc;
 655             }
 656         }
 657     }
 658
 659     /* report success */
 660     return 0;
 661 }
 662
 663 static int ipvideo_decode_block_opcode_0xB(IpvideoContext *s)
 664 {
 665     int x, y;
 666
 667     /* 64-color encoding (each pixel in block is a different color) */
 668     CHECK_STREAM_PTR(64);
 669
 670     for (y = 0; y < 8; y++) {
 671         for (x = 0; x < 8; x++) {
 672             *s->pixel_ptr++ = *s->stream_ptr++;
 673         }
 674         s->pixel_ptr += s->line_inc;
 675     }
 676
 677     /* report success */
 678     return 0;
 679 }
 680
 681 static int ipvideo_decode_block_opcode_0xC(IpvideoContext *s)
 682 {
 683     int x, y;
 684     unsigned char pix;
 685
 686     /* 16-color block encoding: each 2x2 block is a different color */
 687     CHECK_STREAM_PTR(16);
 688
 689     for (y = 0; y < 8; y += 2) {
 690         for (x = 0; x < 8; x += 2) {
 691             pix = *s->stream_ptr++;
 692             *(s->pixel_ptr + x) = pix;
 693             *(s->pixel_ptr + x + 1) = pix;
 694             *(s->pixel_ptr + s->stride + x) = pix;
 695             *(s->pixel_ptr + s->stride + x + 1) = pix;
 696         }
 697         s->pixel_ptr += s->stride * 2;
 698     }
 699
 700     /* report success */
 701     return 0;
 702 }
 703
 704 static int ipvideo_decode_block_opcode_0xD(IpvideoContext *s)
 705 {
 706     int x, y;
 707     unsigned char P[4];
 708     unsigned char index = 0;
 709
 710     /* 4-color block encoding: each 4x4 block is a different color */
 711     CHECK_STREAM_PTR(4);
 712
 713     for (y = 0; y < 4; y++)
 714         P[y] = *s->stream_ptr++;
 715
 716     for (y = 0; y < 8; y++) {
 717         if (y < 4)
 718             index = 0;
 719         else
 720             index = 2;
 721
 722         for (x = 0; x < 8; x++) {
 723             if (x == 4)
 724                 index++;
 725             *s->pixel_ptr++ = P[index];
 726         }
 727         s->pixel_ptr += s->line_inc;
 728     }
 729
 730     /* report success */
 731     return 0;
 732 }
 733
 734 static int ipvideo_decode_block_opcode_0xE(IpvideoContext *s)
 735 {
 736     int x, y;
 737     unsigned char pix;
 738
 739     /* 1-color encoding: the whole block is 1 solid color */
 740     CHECK_STREAM_PTR(1);
 741     pix = *s->stream_ptr++;
 742
 743     for (y = 0; y < 8; y++) {
 744         for (x = 0; x < 8; x++) {
 745             *s->pixel_ptr++ = pix;
 746         }
 747         s->pixel_ptr += s->line_inc;
 748     }
 749
 750     /* report success */
 751     return 0;
 752 }
 753
 754 static int ipvideo_decode_block_opcode_0xF(IpvideoContext *s)
 755 {
 756     int x, y;
 757     unsigned char sample0, sample1;
 758
 759     /* dithered encoding */
 760     CHECK_STREAM_PTR(2);
 761     sample0 = *s->stream_ptr++;
 762     sample1 = *s->stream_ptr++;
 763
 764     for (y = 0; y < 8; y++) {
 765         for (x = 0; x < 8; x += 2) {
 766             if (y & 1) {
 767                 *s->pixel_ptr++ = sample1;
 768                 *s->pixel_ptr++ = sample0;
 769             } else {
 770                 *s->pixel_ptr++ = sample0;
 771                 *s->pixel_ptr++ = sample1;
 772             }
 773         }
 774         s->pixel_ptr += s->line_inc;
 775     }
 776
 777     /* report success */
 778     return 0;
 779 }
 780
 781 static int (*ipvideo_decode_block[16])(IpvideoContext *s);
 782
 783 static void ipvideo_decode_opcodes(IpvideoContext *s)
 784 {
 785     int x, y;
 786     int index = 0;
 787     unsigned char opcode;
 788     int ret;
 789     int code_counts[16];
 790     static int frame = 0;
 791
 792     debug_interplay("------------------ frame %d\n", frame);
 793     frame++;
 794
 795     for (x = 0; x < 16; x++)
 796         code_counts[x] = 0;
 797
 798     /* this is PAL8, so make the palette available */
 799     memcpy(s->current_frame.data[1], s->avctx->palctrl->palette, PALETTE_COUNT * 4);
 800
 801     s->stride = s->current_frame.linesize[0];
 802     s->stream_ptr = s->buf + 14;  /* data starts 14 bytes in */
 803     s->stream_end = s->buf + s->size;
 804     s->line_inc = s->stride - 8;
 805     s->upper_motion_limit_offset = (s->avctx->height - 8) * s->stride
 806         + s->avctx->width - 8;
 807
 808     for (y = 0; y < (s->stride * s->avctx->height); y += s->stride * 8) {
 809         for (x = y; x < y + s->avctx->width; x += 8) {
 810             /* bottom nibble first, then top nibble (which makes it
 811              * hard to use a GetBitcontext) */
 812             if (index & 1)
 813                 opcode = s->decoding_map[index >> 1] >> 4;
 814             else
 815                 opcode = s->decoding_map[index >> 1] & 0xF;
 816             index++;
 817
 818             debug_interplay("  block @ (%3d, %3d): encoding 0x%X, data ptr @ %p\n",
 819                 x - y, y / s->stride, opcode, s->stream_ptr);
 820             code_counts[opcode]++;
 821
 822             s->pixel_ptr = s->current_frame.data[0] + x;
 823             ret = ipvideo_decode_block[opcode](s);
 824             if (ret != 0) {
 825                 av_log(s->avctx, AV_LOG_ERROR, " Interplay video: decode problem on frame %d, @ block (%d, %d)\n",
 826                     frame, x - y, y / s->stride);
 827                 return;
 828             }
 829         }
 830     }
 831     if ((s->stream_ptr != s->stream_end) &&
 832         (s->stream_ptr + 1 != s->stream_end)) {
 833         av_log(s->avctx, AV_LOG_ERROR, " Interplay video: decode finished with %td bytes left over\n",
 834             s->stream_end - s->stream_ptr);
 835     }
 836 }
 837
 838 static av_cold int ipvideo_decode_init(AVCodecContext *avctx)
 839 {
 840     IpvideoContext *s = avctx->priv_data;
 841
 842     s->avctx = avctx;
 843
 844     if (s->avctx->palctrl == NULL) {
 845         av_log(avctx, AV_LOG_ERROR, " Interplay video: palette expected.\n");
 846         return -1;
 847     }
 848
 849     avctx->pix_fmt = PIX_FMT_PAL8;
 850     dsputil_init(&s->dsp, avctx);
 851
 852     /* decoding map contains 4 bits of information per 8x8 block */
 853     s->decoding_map_size = avctx->width * avctx->height / (8 * 8 * 2);
 854
 855     /* assign block decode functions */
 856     ipvideo_decode_block[0x0] = ipvideo_decode_block_opcode_0x0;
 857     ipvideo_decode_block[0x1] = ipvideo_decode_block_opcode_0x1;
 858     ipvideo_decode_block[0x2] = ipvideo_decode_block_opcode_0x2;
 859     ipvideo_decode_block[0x3] = ipvideo_decode_block_opcode_0x3;
 860     ipvideo_decode_block[0x4] = ipvideo_decode_block_opcode_0x4;
 861     ipvideo_decode_block[0x5] = ipvideo_decode_block_opcode_0x5;
 862     ipvideo_decode_block[0x6] = ipvideo_decode_block_opcode_0x6;
 863     ipvideo_decode_block[0x7] = ipvideo_decode_block_opcode_0x7;
 864     ipvideo_decode_block[0x8] = ipvideo_decode_block_opcode_0x8;
 865     ipvideo_decode_block[0x9] = ipvideo_decode_block_opcode_0x9;
 866     ipvideo_decode_block[0xA] = ipvideo_decode_block_opcode_0xA;
 867     ipvideo_decode_block[0xB] = ipvideo_decode_block_opcode_0xB;
 868     ipvideo_decode_block[0xC] = ipvideo_decode_block_opcode_0xC;
 869     ipvideo_decode_block[0xD] = ipvideo_decode_block_opcode_0xD;
 870     ipvideo_decode_block[0xE] = ipvideo_decode_block_opcode_0xE;
 871     ipvideo_decode_block[0xF] = ipvideo_decode_block_opcode_0xF;
 872
 873     s->current_frame.data[0] = s->last_frame.data[0] =
 874     s->second_last_frame.data[0] = NULL;
 875
 876     return 0;
 877 }
 878
 879 static int ipvideo_decode_frame(AVCodecContext *avctx,
 880                                 void *data, int *data_size,
 881                                 const uint8_t *buf, int buf_size)
 882 {
 883     IpvideoContext *s = avctx->priv_data;
 884     AVPaletteControl *palette_control = avctx->palctrl;
 885
 886     /* compressed buffer needs to be large enough to at least hold an entire
 887      * decoding map */
 888     if (buf_size < s->decoding_map_size)
 889         return buf_size;
 890
 891     s->decoding_map = buf;
 892     s->buf = buf + s->decoding_map_size;
 893     s->size = buf_size - s->decoding_map_size;
 894
 895     s->current_frame.reference = 3;
 896     if (avctx->get_buffer(avctx, &s->current_frame)) {
 897         av_log(avctx, AV_LOG_ERROR, "  Interplay Video: get_buffer() failed\n");
 898         return -1;
 899     }
 900
 901     ipvideo_decode_opcodes(s);
 902
 903     if (palette_control->palette_changed) {
 904         palette_control->palette_changed = 0;
 905         s->current_frame.palette_has_changed = 1;
 906     }
 907
 908     *data_size = sizeof(AVFrame);
 909     *(AVFrame*)data = s->current_frame;
 910
 911     /* shuffle frames */
 912     if (s->second_last_frame.data[0])
 913         avctx->release_buffer(avctx, &s->second_last_frame);
 914     s->second_last_frame = s->last_frame;
 915     s->last_frame = s->current_frame;
 916     s->current_frame.data[0] = NULL;  /* catch any access attempts */
 917
 918     /* report that the buffer was completely consumed */
 919     return buf_size;
 920 }
 921
 922 static av_cold int ipvideo_decode_end(AVCodecContext *avctx)
 923 {
 924     IpvideoContext *s = avctx->priv_data;
 925
 926     /* release the last frame */
 927     if (s->last_frame.data[0])
 928         avctx->release_buffer(avctx, &s->last_frame);
 929     if (s->second_last_frame.data[0])
 930         avctx->release_buffer(avctx, &s->second_last_frame);
 931
 932     return 0;
 933 }
 934
 935 AVCodec interplay_video_decoder = {
 936     "interplayvideo",
 937     CODEC_TYPE_VIDEO,
 938     CODEC_ID_INTERPLAY_VIDEO,
 939     sizeof(IpvideoContext),
 940     ipvideo_decode_init,
 941     NULL,
 942     ipvideo_decode_end,
 943     ipvideo_decode_frame,
 944     CODEC_CAP_DR1,
 945     .long_name = NULL_IF_CONFIG_SMALL("Interplay MVE video"),
 946 };