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 libavcodec/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 "libavutil/intreadwrite.h"
  37 #include "avcodec.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     AVFrame frame;
  49
  50     const unsigned char *buf;
  51     int size;
  52
  53     /* SMC color tables */
  54     unsigned char color_pairs[COLORS_PER_TABLE * CPAIR];
  55     unsigned char color_quads[COLORS_PER_TABLE * CQUAD];
  56     unsigned char color_octets[COLORS_PER_TABLE * COCTET];
  57
  58 } SmcContext;
  59
  60 #define GET_BLOCK_COUNT() \
  61   (opcode & 0x10) ? (1 + s->buf[stream_ptr++]) : 1 + (opcode & 0x0F);
  62
  63 #define ADVANCE_BLOCK() \
  64 { \
  65     pixel_ptr += 4; \
  66     if (pixel_ptr >= width) \
  67     { \
  68         pixel_ptr = 0; \
  69         row_ptr += stride * 4; \
  70     } \
  71     total_blocks--; \
  72     if (total_blocks < 0) \
  73     { \
  74         av_log(s->avctx, AV_LOG_INFO, "warning: block counter just went negative (this should not happen)\n"); \
  75         return; \
  76     } \
  77 }
  78
  79 static void smc_decode_stream(SmcContext *s)
  80 {
  81     int width = s->avctx->width;
  82     int height = s->avctx->height;
  83     int stride = s->frame.linesize[0];
  84     int i;
  85     int stream_ptr = 0;
  86     int chunk_size;
  87     unsigned char opcode;
  88     int n_blocks;
  89     unsigned int color_flags;
  90     unsigned int color_flags_a;
  91     unsigned int color_flags_b;
  92     unsigned int flag_mask;
  93
  94     unsigned char *pixels = s->frame.data[0];
  95
  96     int image_size = height * s->frame.linesize[0];
  97     int row_ptr = 0;
  98     int pixel_ptr = 0;
  99     int pixel_x, pixel_y;
 100     int row_inc = stride - 4;
 101     int block_ptr;
 102     int prev_block_ptr;
 103     int prev_block_ptr1, prev_block_ptr2;
 104     int prev_block_flag;
 105     int total_blocks;
 106     int color_table_index;  /* indexes to color pair, quad, or octet tables */
 107     int pixel;
 108
 109     int color_pair_index = 0;
 110     int color_quad_index = 0;
 111     int color_octet_index = 0;
 112
 113     /* make the palette available */
 114     memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
 115     if (s->avctx->palctrl->palette_changed) {
 116         s->frame.palette_has_changed = 1;
 117         s->avctx->palctrl->palette_changed = 0;
 118     }
 119
 120     chunk_size = AV_RB32(&s->buf[stream_ptr]) & 0x00FFFFFF;
 121     stream_ptr += 4;
 122     if (chunk_size != s->size)
 123         av_log(s->avctx, AV_LOG_INFO, "warning: MOV chunk size != encoded chunk size (%d != %d); using MOV chunk size\n",
 124             chunk_size, s->size);
 125
 126     chunk_size = s->size;
 127     total_blocks = ((s->avctx->width + 3) / 4) * ((s->avctx->height + 3) / 4);
 128
 129     /* traverse through the blocks */
 130     while (total_blocks) {
 131         /* sanity checks */
 132         /* make sure stream ptr hasn't gone out of bounds */
 133         if (stream_ptr > chunk_size) {
 134             av_log(s->avctx, AV_LOG_INFO, "SMC decoder just went out of bounds (stream ptr = %d, chunk size = %d)\n",
 135                 stream_ptr, chunk_size);
 136             return;
 137         }
 138         /* make sure the row pointer hasn't gone wild */
 139         if (row_ptr >= image_size) {
 140             av_log(s->avctx, AV_LOG_INFO, "SMC decoder just went out of bounds (row ptr = %d, height = %d)\n",
 141                 row_ptr, image_size);
 142             return;
 143         }
 144
 145         opcode = s->buf[stream_ptr++];
 146         switch (opcode & 0xF0) {
 147         /* skip n blocks */
 148         case 0x00:
 149         case 0x10:
 150             n_blocks = GET_BLOCK_COUNT();
 151             while (n_blocks--) {
 152                 ADVANCE_BLOCK();
 153             }
 154             break;
 155
 156         /* repeat last block n times */
 157         case 0x20:
 158         case 0x30:
 159             n_blocks = GET_BLOCK_COUNT();
 160
 161             /* sanity check */
 162             if ((row_ptr == 0) && (pixel_ptr == 0)) {
 163                 av_log(s->avctx, AV_LOG_INFO, "encountered repeat block opcode (%02X) but no blocks rendered yet\n",
 164                     opcode & 0xF0);
 165                 break;
 166             }
 167
 168             /* figure out where the previous block started */
 169             if (pixel_ptr == 0)
 170                 prev_block_ptr1 =
 171                     (row_ptr - s->avctx->width * 4) + s->avctx->width - 4;
 172             else
 173                 prev_block_ptr1 = row_ptr + pixel_ptr - 4;
 174
 175             while (n_blocks--) {
 176                 block_ptr = row_ptr + pixel_ptr;
 177                 prev_block_ptr = prev_block_ptr1;
 178                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 179                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 180                         pixels[block_ptr++] = pixels[prev_block_ptr++];
 181                     }
 182                     block_ptr += row_inc;
 183                     prev_block_ptr += row_inc;
 184                 }
 185                 ADVANCE_BLOCK();
 186             }
 187             break;
 188
 189         /* repeat previous pair of blocks n times */
 190         case 0x40:
 191         case 0x50:
 192             n_blocks = GET_BLOCK_COUNT();
 193             n_blocks *= 2;
 194
 195             /* sanity check */
 196             if ((row_ptr == 0) && (pixel_ptr < 2 * 4)) {
 197                 av_log(s->avctx, AV_LOG_INFO, "encountered repeat block opcode (%02X) but not enough blocks rendered yet\n",
 198                     opcode & 0xF0);
 199                 break;
 200             }
 201
 202             /* figure out where the previous 2 blocks started */
 203             if (pixel_ptr == 0)
 204                 prev_block_ptr1 = (row_ptr - s->avctx->width * 4) +
 205                     s->avctx->width - 4 * 2;
 206             else if (pixel_ptr == 4)
 207                 prev_block_ptr1 = (row_ptr - s->avctx->width * 4) + row_inc;
 208             else
 209                 prev_block_ptr1 = row_ptr + pixel_ptr - 4 * 2;
 210
 211             if (pixel_ptr == 0)
 212                 prev_block_ptr2 = (row_ptr - s->avctx->width * 4) + row_inc;
 213             else
 214                 prev_block_ptr2 = row_ptr + pixel_ptr - 4;
 215
 216             prev_block_flag = 0;
 217             while (n_blocks--) {
 218                 block_ptr = row_ptr + pixel_ptr;
 219                 if (prev_block_flag)
 220                     prev_block_ptr = prev_block_ptr2;
 221                 else
 222                     prev_block_ptr = prev_block_ptr1;
 223                 prev_block_flag = !prev_block_flag;
 224
 225                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 226                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 227                         pixels[block_ptr++] = pixels[prev_block_ptr++];
 228                     }
 229                     block_ptr += row_inc;
 230                     prev_block_ptr += row_inc;
 231                 }
 232                 ADVANCE_BLOCK();
 233             }
 234             break;
 235
 236         /* 1-color block encoding */
 237         case 0x60:
 238         case 0x70:
 239             n_blocks = GET_BLOCK_COUNT();
 240             pixel = s->buf[stream_ptr++];
 241
 242             while (n_blocks--) {
 243                 block_ptr = row_ptr + pixel_ptr;
 244                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 245                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 246                         pixels[block_ptr++] = pixel;
 247                     }
 248                     block_ptr += row_inc;
 249                 }
 250                 ADVANCE_BLOCK();
 251             }
 252             break;
 253
 254         /* 2-color block encoding */
 255         case 0x80:
 256         case 0x90:
 257             n_blocks = (opcode & 0x0F) + 1;
 258
 259             /* figure out which color pair to use to paint the 2-color block */
 260             if ((opcode & 0xF0) == 0x80) {
 261                 /* fetch the next 2 colors from bytestream and store in next
 262                  * available entry in the color pair table */
 263                 for (i = 0; i < CPAIR; i++) {
 264                     pixel = s->buf[stream_ptr++];
 265                     color_table_index = CPAIR * color_pair_index + i;
 266                     s->color_pairs[color_table_index] = pixel;
 267                 }
 268                 /* this is the base index to use for this block */
 269                 color_table_index = CPAIR * color_pair_index;
 270                 color_pair_index++;
 271                 /* wraparound */
 272                 if (color_pair_index == COLORS_PER_TABLE)
 273                     color_pair_index = 0;
 274             } else
 275                 color_table_index = CPAIR * s->buf[stream_ptr++];
 276
 277             while (n_blocks--) {
 278                 color_flags = AV_RB16(&s->buf[stream_ptr]);
 279                 stream_ptr += 2;
 280                 flag_mask = 0x8000;
 281                 block_ptr = row_ptr + pixel_ptr;
 282                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 283                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 284                         if (color_flags & flag_mask)
 285                             pixel = color_table_index + 1;
 286                         else
 287                             pixel = color_table_index;
 288                         flag_mask >>= 1;
 289                         pixels[block_ptr++] = s->color_pairs[pixel];
 290                     }
 291                     block_ptr += row_inc;
 292                 }
 293                 ADVANCE_BLOCK();
 294             }
 295             break;
 296
 297         /* 4-color block encoding */
 298         case 0xA0:
 299         case 0xB0:
 300             n_blocks = (opcode & 0x0F) + 1;
 301
 302             /* figure out which color quad to use to paint the 4-color block */
 303             if ((opcode & 0xF0) == 0xA0) {
 304                 /* fetch the next 4 colors from bytestream and store in next
 305                  * available entry in the color quad table */
 306                 for (i = 0; i < CQUAD; i++) {
 307                     pixel = s->buf[stream_ptr++];
 308                     color_table_index = CQUAD * color_quad_index + i;
 309                     s->color_quads[color_table_index] = pixel;
 310                 }
 311                 /* this is the base index to use for this block */
 312                 color_table_index = CQUAD * color_quad_index;
 313                 color_quad_index++;
 314                 /* wraparound */
 315                 if (color_quad_index == COLORS_PER_TABLE)
 316                     color_quad_index = 0;
 317             } else
 318                 color_table_index = CQUAD * s->buf[stream_ptr++];
 319
 320             while (n_blocks--) {
 321                 color_flags = AV_RB32(&s->buf[stream_ptr]);
 322                 stream_ptr += 4;
 323                 /* flag mask actually acts as a bit shift count here */
 324                 flag_mask = 30;
 325                 block_ptr = row_ptr + pixel_ptr;
 326                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 327                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 328                         pixel = color_table_index +
 329                             ((color_flags >> flag_mask) & 0x03);
 330                         flag_mask -= 2;
 331                         pixels[block_ptr++] = s->color_quads[pixel];
 332                     }
 333                     block_ptr += row_inc;
 334                 }
 335                 ADVANCE_BLOCK();
 336             }
 337             break;
 338
 339         /* 8-color block encoding */
 340         case 0xC0:
 341         case 0xD0:
 342             n_blocks = (opcode & 0x0F) + 1;
 343
 344             /* figure out which color octet to use to paint the 8-color block */
 345             if ((opcode & 0xF0) == 0xC0) {
 346                 /* fetch the next 8 colors from bytestream and store in next
 347                  * available entry in the color octet table */
 348                 for (i = 0; i < COCTET; i++) {
 349                     pixel = s->buf[stream_ptr++];
 350                     color_table_index = COCTET * color_octet_index + i;
 351                     s->color_octets[color_table_index] = pixel;
 352                 }
 353                 /* this is the base index to use for this block */
 354                 color_table_index = COCTET * color_octet_index;
 355                 color_octet_index++;
 356                 /* wraparound */
 357                 if (color_octet_index == COLORS_PER_TABLE)
 358                     color_octet_index = 0;
 359             } else
 360                 color_table_index = COCTET * s->buf[stream_ptr++];
 361
 362             while (n_blocks--) {
 363                 /*
 364                   For this input of 6 hex bytes:
 365                     01 23 45 67 89 AB
 366                   Mangle it to this output:
 367                     flags_a = xx012456, flags_b = xx89A37B
 368                 */
 369                 /* build the color flags */
 370                 color_flags_a = color_flags_b = 0;
 371                 color_flags_a =
 372                     (s->buf[stream_ptr + 0] << 16) |
 373                     ((s->buf[stream_ptr + 1] & 0xF0) << 8) |
 374                     ((s->buf[stream_ptr + 2] & 0xF0) << 4) |
 375                     ((s->buf[stream_ptr + 2] & 0x0F) << 4) |
 376                     ((s->buf[stream_ptr + 3] & 0xF0) >> 4);
 377                 color_flags_b =
 378                     (s->buf[stream_ptr + 4] << 16) |
 379                     ((s->buf[stream_ptr + 5] & 0xF0) << 8) |
 380                     ((s->buf[stream_ptr + 1] & 0x0F) << 8) |
 381                     ((s->buf[stream_ptr + 3] & 0x0F) << 4) |
 382                     (s->buf[stream_ptr + 5] & 0x0F);
 383                 stream_ptr += 6;
 384
 385                 color_flags = color_flags_a;
 386                 /* flag mask actually acts as a bit shift count here */
 387                 flag_mask = 21;
 388                 block_ptr = row_ptr + pixel_ptr;
 389                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 390                     /* reload flags at third row (iteration pixel_y == 2) */
 391                     if (pixel_y == 2) {
 392                         color_flags = color_flags_b;
 393                         flag_mask = 21;
 394                     }
 395                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 396                         pixel = color_table_index +
 397                             ((color_flags >> flag_mask) & 0x07);
 398                         flag_mask -= 3;
 399                         pixels[block_ptr++] = s->color_octets[pixel];
 400                     }
 401                     block_ptr += row_inc;
 402                 }
 403                 ADVANCE_BLOCK();
 404             }
 405             break;
 406
 407         /* 16-color block encoding (every pixel is a different color) */
 408         case 0xE0:
 409             n_blocks = (opcode & 0x0F) + 1;
 410
 411             while (n_blocks--) {
 412                 block_ptr = row_ptr + pixel_ptr;
 413                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 414                     for (pixel_x = 0; pixel_x < 4; pixel_x++) {
 415                         pixels[block_ptr++] = s->buf[stream_ptr++];
 416                     }
 417                     block_ptr += row_inc;
 418                 }
 419                 ADVANCE_BLOCK();
 420             }
 421             break;
 422
 423         case 0xF0:
 424             av_log(s->avctx, AV_LOG_INFO, "0xF0 opcode seen in SMC chunk (contact the developers)\n");
 425             break;
 426         }
 427     }
 428 }
 429
 430 static av_cold int smc_decode_init(AVCodecContext *avctx)
 431 {
 432     SmcContext *s = avctx->priv_data;
 433
 434     s->avctx = avctx;
 435     avctx->pix_fmt = PIX_FMT_PAL8;
 436
 437     s->frame.data[0] = NULL;
 438
 439     return 0;
 440 }
 441
 442 static int smc_decode_frame(AVCodecContext *avctx,
 443                              void *data, int *data_size,
 444                              AVPacket *avpkt)
 445 {
 446     const uint8_t *buf = avpkt->data;
 447     int buf_size = avpkt->size;
 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 av_cold 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     .long_name = NULL_IF_CONFIG_SMALL("QuickTime Graphics (SMC)"),
 491 };