libavcodec/smc.c

   1 /*
   2  * Quicktime Graphics (SMC) 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 smc.c
  24  * QT SMC Video Decoder by Mike Melanson (melanson@pcisys.net)
  25  * For more information about the SMC format, visit:
  26  *   http://www.pcisys.net/~melanson/codecs/
  27  *
  28  * The SMC decoder outputs PAL8 colorspace data.
  29  */
  30
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <unistd.h>
  35
  36 #include "avcodec.h"
  37 #include "dsputil.h"
  38
  39 #define CPAIR 2
  40 #define CQUAD 4
  41 #define COCTET 8
  42
  43 #define COLORS_PER_TABLE 256
  44
  45 typedef struct SmcContext {
  46
  47     AVCodecContext *avctx;
  48     DSPContext dsp;
  49     AVFrame frame;
  50
  51     const unsigned char *buf;
  52     int size;
  53
  54     /* SMC color tables */
  55     unsigned char color_pairs[COLORS_PER_TABLE * CPAIR];
  56     unsigned char color_quads[COLORS_PER_TABLE * CQUAD];
  57     unsigned char color_octets[COLORS_PER_TABLE * COCTET];
  58
  59 } SmcContext;
  60
  61 #define GET_BLOCK_COUNT() \
  62   (opcode & 0x10) ? (1 + s->buf[stream_ptr++]) : 1 + (opcode & 0x0F);
  63
  64 #define ADVANCE_BLOCK() \
  65 { \
  66     pixel_ptr += 4; \
  67     if (pixel_ptr >= width) \
  68     { \
  69         pixel_ptr = 0; \
  70         row_ptr += stride * 4; \
  71     } \
  72     total_blocks--; \
  73     if (total_blocks < 0) \
  74     { \
  75         av_log(s->avctx, AV_LOG_INFO, "warning: block counter just went negative (this should not happen)\n"); \
  76         return; \
  77     } \
  78 }
  79
  80 static void smc_decode_stream(SmcContext *s)
  81 {
  82     int width = s->avctx->width;
  83     int height = s->avctx->height;
  84     int stride = s->frame.linesize[0];
  85     int i;
  86     int stream_ptr = 0;
  87     int chunk_size;
  88     unsigned char opcode;
  89     int n_blocks;
  90     unsigned int color_flags;
  91     unsigned int color_flags_a;
  92     unsigned int color_flags_b;
  93     unsigned int flag_mask;
  94
  95     unsigned char *pixels = s->frame.data[0];
  96
  97     int image_size = height * s->frame.linesize[0];
  98     int row_ptr = 0;
  99     int pixel_ptr = 0;
 100     int pixel_x, pixel_y;
 101     int row_inc = stride - 4;
 102     int block_ptr;
 103     int prev_block_ptr;
 104     int prev_block_ptr1, prev_block_ptr2;
 105     int prev_block_flag;
 106     int total_blocks;
 107     int color_table_index;  /* indexes to color pair, quad, or octet tables */
 108     int pixel;
 109
 110     int color_pair_index = 0;
 111     int color_quad_index = 0;
 112     int color_octet_index = 0;
 113
 114     /* make the palette available */
 115     memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
 116     if (s->avctx->palctrl->palette_changed) {
 117         s->frame.palette_has_changed = 1;
 118         s->avctx->palctrl->palette_changed = 0;
 119     }
 120
 121     chunk_size = AV_RB32(&s->buf[stream_ptr]) & 0x00FFFFFF;
 122     stream_ptr += 4;
 123     if (chunk_size != s->size)
 124         av_log(s->avctx, AV_LOG_INFO, "warning: MOV chunk size != encoded chunk size (%d != %d); using MOV chunk size\n",
 125             chunk_size, s->size);
 126
 127     chunk_size = s->size;
 128     total_blocks = ((s->avctx->width + 3) / 4) * ((s->avctx->height + 3) / 4);
 129
 130     /* traverse through the blocks */
 131     while (total_blocks) {
 132         /* sanity checks */
 133         /* make sure stream ptr hasn't gone out of bounds */
 134         if (stream_ptr > chunk_size) {
 135             av_log(s->avctx, AV_LOG_INFO, "SMC decoder just went out of bounds (stream ptr = %d, chunk size = %d)\n",
 136                 stream_ptr, chunk_size);
 137             return;
 138         }
 139         /* make sure the row pointer hasn't gone wild */
 140         if (row_ptr >= image_size) {
 141             av_log(s->avctx, AV_LOG_INFO, "SMC decoder just went out of bounds (row ptr = %d, height = %d)\n",
 142                 row_ptr, image_size);
 143             return;
 144         }
 145
 146         opcode = s->buf[stream_ptr++];
 147         switch (opcode & 0xF0) {
 148         /* skip n blocks */
 149         case 0x00:
 150         case 0x10:
 151             n_blocks = GET_BLOCK_COUNT();
 152             while (n_blocks--) {
 153                 ADVANCE_BLOCK();
 154             }
 155             break;
 156
 157         /* repeat last block n times */
 158         case 0x20:
 159         case 0x30:
 160             n_blocks = GET_BLOCK_COUNT();
 161
 162             /* sanity check */
 163             if ((row_ptr == 0) && (pixel_ptr == 0)) {
 164                 av_log(s->avctx, AV_LOG_INFO, "encountered repeat block opcode (%02X) but no blocks rendered yet\n",
 165                     opcode & 0xF0);
 166                 break;
 167             }
 168
 169             /* figure out where the previous block started */
 170             if (pixel_ptr == 0)
 171                 prev_block_ptr1 =
 172                     (row_ptr - s->avctx->width * 4) + s->avctx->width - 4;
 173             else
 174                 prev_block_ptr1 = row_ptr + pixel_ptr - 4;
 175
 176             while (n_blocks--) {
 177                 block_ptr = row_ptr + pixel_ptr;
 178                 prev_block_ptr = prev_block_ptr1;
 179                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 180                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 181                         pixels[block_ptr++] = pixels[prev_block_ptr++];
 182                     }
 183                     block_ptr += row_inc;
 184                     prev_block_ptr += row_inc;
 185                 }
 186                 ADVANCE_BLOCK();
 187             }
 188             break;
 189
 190         /* repeat previous pair of blocks n times */
 191         case 0x40:
 192         case 0x50:
 193             n_blocks = GET_BLOCK_COUNT();
 194             n_blocks *= 2;
 195
 196             /* sanity check */
 197             if ((row_ptr == 0) && (pixel_ptr < 2 * 4)) {
 198                 av_log(s->avctx, AV_LOG_INFO, "encountered repeat block opcode (%02X) but not enough blocks rendered yet\n",
 199                     opcode & 0xF0);
 200                 break;
 201             }
 202
 203             /* figure out where the previous 2 blocks started */
 204             if (pixel_ptr == 0)
 205                 prev_block_ptr1 = (row_ptr - s->avctx->width * 4) +
 206                     s->avctx->width - 4 * 2;
 207             else if (pixel_ptr == 4)
 208                 prev_block_ptr1 = (row_ptr - s->avctx->width * 4) + row_inc;
 209             else
 210                 prev_block_ptr1 = row_ptr + pixel_ptr - 4 * 2;
 211
 212             if (pixel_ptr == 0)
 213                 prev_block_ptr2 = (row_ptr - s->avctx->width * 4) + row_inc;
 214             else
 215                 prev_block_ptr2 = row_ptr + pixel_ptr - 4;
 216
 217             prev_block_flag = 0;
 218             while (n_blocks--) {
 219                 block_ptr = row_ptr + pixel_ptr;
 220                 if (prev_block_flag)
 221                     prev_block_ptr = prev_block_ptr2;
 222                 else
 223                     prev_block_ptr = prev_block_ptr1;
 224                 prev_block_flag = !prev_block_flag;
 225
 226                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 227                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 228                         pixels[block_ptr++] = pixels[prev_block_ptr++];
 229                     }
 230                     block_ptr += row_inc;
 231                     prev_block_ptr += row_inc;
 232                 }
 233                 ADVANCE_BLOCK();
 234             }
 235             break;
 236
 237         /* 1-color block encoding */
 238         case 0x60:
 239         case 0x70:
 240             n_blocks = GET_BLOCK_COUNT();
 241             pixel = s->buf[stream_ptr++];
 242
 243             while (n_blocks--) {
 244                 block_ptr = row_ptr + pixel_ptr;
 245                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 246                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 247                         pixels[block_ptr++] = pixel;
 248                     }
 249                     block_ptr += row_inc;
 250                 }
 251                 ADVANCE_BLOCK();
 252             }
 253             break;
 254
 255         /* 2-color block encoding */
 256         case 0x80:
 257         case 0x90:
 258             n_blocks = (opcode & 0x0F) + 1;
 259
 260             /* figure out which color pair to use to paint the 2-color block */
 261             if ((opcode & 0xF0) == 0x80) {
 262                 /* fetch the next 2 colors from bytestream and store in next
 263                  * available entry in the color pair table */
 264                 for (i = 0; i < CPAIR; i++) {
 265                     pixel = s->buf[stream_ptr++];
 266                     color_table_index = CPAIR * color_pair_index + i;
 267                     s->color_pairs[color_table_index] = pixel;
 268                 }
 269                 /* this is the base index to use for this block */
 270                 color_table_index = CPAIR * color_pair_index;
 271                 color_pair_index++;
 272                 /* wraparound */
 273                 if (color_pair_index == COLORS_PER_TABLE)
 274                     color_pair_index = 0;
 275             } else
 276                 color_table_index = CPAIR * s->buf[stream_ptr++];
 277
 278             while (n_blocks--) {
 279                 color_flags = AV_RB16(&s->buf[stream_ptr]);
 280                 stream_ptr += 2;
 281                 flag_mask = 0x8000;
 282                 block_ptr = row_ptr + pixel_ptr;
 283                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 284                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 285                         if (color_flags & flag_mask)
 286                             pixel = color_table_index + 1;
 287                         else
 288                             pixel = color_table_index;
 289                         flag_mask >>= 1;
 290                         pixels[block_ptr++] = s->color_pairs[pixel];
 291                     }
 292                     block_ptr += row_inc;
 293                 }
 294                 ADVANCE_BLOCK();
 295             }
 296             break;
 297
 298         /* 4-color block encoding */
 299         case 0xA0:
 300         case 0xB0:
 301             n_blocks = (opcode & 0x0F) + 1;
 302
 303             /* figure out which color quad to use to paint the 4-color block */
 304             if ((opcode & 0xF0) == 0xA0) {
 305                 /* fetch the next 4 colors from bytestream and store in next
 306                  * available entry in the color quad table */
 307                 for (i = 0; i < CQUAD; i++) {
 308                     pixel = s->buf[stream_ptr++];
 309                     color_table_index = CQUAD * color_quad_index + i;
 310                     s->color_quads[color_table_index] = pixel;
 311                 }
 312                 /* this is the base index to use for this block */
 313                 color_table_index = CQUAD * color_quad_index;
 314                 color_quad_index++;
 315                 /* wraparound */
 316                 if (color_quad_index == COLORS_PER_TABLE)
 317                     color_quad_index = 0;
 318             } else
 319                 color_table_index = CQUAD * s->buf[stream_ptr++];
 320
 321             while (n_blocks--) {
 322                 color_flags = AV_RB32(&s->buf[stream_ptr]);
 323                 stream_ptr += 4;
 324                 /* flag mask actually acts as a bit shift count here */
 325                 flag_mask = 30;
 326                 block_ptr = row_ptr + pixel_ptr;
 327                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 328                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 329                         pixel = color_table_index +
 330                             ((color_flags >> flag_mask) & 0x03);
 331                         flag_mask -= 2;
 332                         pixels[block_ptr++] = s->color_quads[pixel];
 333                     }
 334                     block_ptr += row_inc;
 335                 }
 336                 ADVANCE_BLOCK();
 337             }
 338             break;
 339
 340         /* 8-color block encoding */
 341         case 0xC0:
 342         case 0xD0:
 343             n_blocks = (opcode & 0x0F) + 1;
 344
 345             /* figure out which color octet to use to paint the 8-color block */
 346             if ((opcode & 0xF0) == 0xC0) {
 347                 /* fetch the next 8 colors from bytestream and store in next
 348                  * available entry in the color octet table */
 349                 for (i = 0; i < COCTET; i++) {
 350                     pixel = s->buf[stream_ptr++];
 351                     color_table_index = COCTET * color_octet_index + i;
 352                     s->color_octets[color_table_index] = pixel;
 353                 }
 354                 /* this is the base index to use for this block */
 355                 color_table_index = COCTET * color_octet_index;
 356                 color_octet_index++;
 357                 /* wraparound */
 358                 if (color_octet_index == COLORS_PER_TABLE)
 359                     color_octet_index = 0;
 360             } else
 361                 color_table_index = COCTET * s->buf[stream_ptr++];
 362
 363             while (n_blocks--) {
 364                 /*
 365                   For this input of 6 hex bytes:
 366                     01 23 45 67 89 AB
 367                   Mangle it to this output:
 368                     flags_a = xx012456, flags_b = xx89A37B
 369                 */
 370                 /* build the color flags */
 371                 color_flags_a = color_flags_b = 0;
 372                 color_flags_a =
 373                     (s->buf[stream_ptr + 0] << 16) |
 374                     ((s->buf[stream_ptr + 1] & 0xF0) << 8) |
 375                     ((s->buf[stream_ptr + 2] & 0xF0) << 4) |
 376                     ((s->buf[stream_ptr + 2] & 0x0F) << 4) |
 377                     ((s->buf[stream_ptr + 3] & 0xF0) >> 4);
 378                 color_flags_b =
 379                     (s->buf[stream_ptr + 4] << 16) |
 380                     ((s->buf[stream_ptr + 5] & 0xF0) << 8) |
 381                     ((s->buf[stream_ptr + 1] & 0x0F) << 8) |
 382                     ((s->buf[stream_ptr + 3] & 0x0F) << 4) |
 383                     (s->buf[stream_ptr + 5] & 0x0F);
 384                 stream_ptr += 6;
 385
 386                 color_flags = color_flags_a;
 387                 /* flag mask actually acts as a bit shift count here */
 388                 flag_mask = 21;
 389                 block_ptr = row_ptr + pixel_ptr;
 390                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 391                     /* reload flags at third row (iteration pixel_y == 2) */
 392                     if (pixel_y == 2) {
 393                         color_flags = color_flags_b;
 394                         flag_mask = 21;
 395                     }
 396                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 397                         pixel = color_table_index +
 398                             ((color_flags >> flag_mask) & 0x07);
 399                         flag_mask -= 3;
 400                         pixels[block_ptr++] = s->color_octets[pixel];
 401                     }
 402                     block_ptr += row_inc;
 403                 }
 404                 ADVANCE_BLOCK();
 405             }
 406             break;
 407
 408         /* 16-color block encoding (every pixel is a different color) */
 409         case 0xE0:
 410             n_blocks = (opcode & 0x0F) + 1;
 411
 412             while (n_blocks--) {
 413                 block_ptr = row_ptr + pixel_ptr;
 414                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 415                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 416                         pixels[block_ptr++] = s->buf[stream_ptr++];
 417                     }
 418                     block_ptr += row_inc;
 419                 }
 420                 ADVANCE_BLOCK();
 421             }
 422             break;
 423
 424         case 0xF0:
 425             av_log(s->avctx, AV_LOG_INFO, "0xF0 opcode seen in SMC chunk (contact the developers)\n");
 426             break;
 427         }
 428     }
 429 }
 430
 431 static int smc_decode_init(AVCodecContext *avctx)
 432 {
 433     SmcContext *s = avctx->priv_data;
 434
 435     s->avctx = avctx;
 436     avctx->pix_fmt = PIX_FMT_PAL8;
 437     dsputil_init(&s->dsp, avctx);
 438
 439     s->frame.data[0] = NULL;
 440
 441     return 0;
 442 }
 443
 444 static int smc_decode_frame(AVCodecContext *avctx,
 445                              void *data, int *data_size,
 446                              const uint8_t *buf, int buf_size)
 447 {
 448     SmcContext *s = avctx->priv_data;
 449
 450     s->buf = buf;
 451     s->size = buf_size;
 452
 453     s->frame.reference = 1;
 454     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE |
 455                             FF_BUFFER_HINTS_REUSABLE | FF_BUFFER_HINTS_READABLE;
 456     if (avctx->reget_buffer(avctx, &s->frame)) {
 457         av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
 458         return -1;
 459     }
 460
 461     smc_decode_stream(s);
 462
 463     *data_size = sizeof(AVFrame);
 464     *(AVFrame*)data = s->frame;
 465
 466     /* always report that the buffer was completely consumed */
 467     return buf_size;
 468 }
 469
 470 static int smc_decode_end(AVCodecContext *avctx)
 471 {
 472     SmcContext *s = avctx->priv_data;
 473
 474     if (s->frame.data[0])
 475         avctx->release_buffer(avctx, &s->frame);
 476
 477     return 0;
 478 }
 479
 480 AVCodec smc_decoder = {
 481     "smc",
 482     CODEC_TYPE_VIDEO,
 483     CODEC_ID_SMC,
 484     sizeof(SmcContext),
 485     smc_decode_init,
 486     NULL,
 487     smc_decode_end,
 488     smc_decode_frame,
 489     CODEC_CAP_DR1,
 490 };