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