extern/ffmpeg/libavcodec/xan.c

   1 /*
   2  * Wing Commander/Xan Video Decoder
   3  * Copyright (C) 2003 the ffmpeg project
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18  *
  19  */
  20
  21 /**
  22  * @file xan.c
  23  * Xan video decoder for Wing Commander III computer game
  24  * by Mario Brito (mbrito@student.dei.uc.pt)
  25  * and Mike Melanson (melanson@pcisys.net)
  26  *
  27  * The xan_wc3 decoder outputs PAL8 data.
  28  */
  29
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <unistd.h>
  34
  35 #include "common.h"
  36 #include "avcodec.h"
  37
  38 typedef struct XanContext {
  39
  40     AVCodecContext *avctx;
  41     AVFrame last_frame;
  42     AVFrame current_frame;
  43
  44     unsigned char *buf;
  45     int size;
  46
  47     /* scratch space */
  48     unsigned char *buffer1;
  49     int buffer1_size;
  50     unsigned char *buffer2;
  51     int buffer2_size;
  52
  53     int frame_size;
  54
  55 } XanContext;
  56
  57 static int xan_decode_init(AVCodecContext *avctx)
  58 {
  59     XanContext *s = avctx->priv_data;
  60
  61     s->avctx = avctx;
  62     s->frame_size = 0;
  63
  64     if ((avctx->codec->id == CODEC_ID_XAN_WC3) &&
  65         (s->avctx->palctrl == NULL)) {
  66         av_log(avctx, AV_LOG_ERROR, " WC3 Xan video: palette expected.\n");
  67         return -1;
  68     }
  69
  70     avctx->pix_fmt = PIX_FMT_PAL8;
  71     avctx->has_b_frames = 0;
  72
  73     if(avcodec_check_dimensions(avctx, avctx->width, avctx->height))
  74         return -1;
  75
  76     s->buffer1_size = avctx->width * avctx->height;
  77     s->buffer1 = av_malloc(s->buffer1_size);
  78     s->buffer2_size = avctx->width * avctx->height;
  79     s->buffer2 = av_malloc(s->buffer2_size);
  80     if (!s->buffer1 || !s->buffer2)
  81         return -1;
  82
  83     return 0;
  84 }
  85
  86 /* This function is used in lieu of memcpy(). This decoder can not use
  87  * memcpy because the memory locations often overlap and
  88  * memcpy doesn't like that; it's not uncommon, for example, for
  89  * dest = src+1, to turn byte A into  pattern AAAAAAAA.
  90  * This was originally repz movsb in Intel x86 ASM. */
  91 static inline void bytecopy(unsigned char *dest, unsigned char *src, int count)
  92 {
  93     int i;
  94
  95     for (i = 0; i < count; i++)
  96         dest[i] = src[i];
  97 }
  98
  99 static int xan_huffman_decode(unsigned char *dest, unsigned char *src,
 100     int dest_len)
 101 {
 102     unsigned char byte = *src++;
 103     unsigned char ival = byte + 0x16;
 104     unsigned char * ptr = src + byte*2;
 105     unsigned char val = ival;
 106     int counter = 0;
 107     unsigned char *dest_end = dest + dest_len;
 108
 109     unsigned char bits = *ptr++;
 110
 111     while ( val != 0x16 ) {
 112         if ( (1 << counter) & bits )
 113             val = src[byte + val - 0x17];
 114         else
 115             val = src[val - 0x17];
 116
 117         if ( val < 0x16 ) {
 118             if (dest + 1 > dest_end)
 119                 return 0;
 120             *dest++ = val;
 121             val = ival;
 122         }
 123
 124         if (counter++ == 7) {
 125             counter = 0;
 126             bits = *ptr++;
 127         }
 128     }
 129
 130     return 0;
 131 }
 132
 133 static void xan_unpack(unsigned char *dest, unsigned char *src, int dest_len)
 134 {
 135     unsigned char opcode;
 136     int size;
 137     int offset;
 138     int byte1, byte2, byte3;
 139     unsigned char *dest_end = dest + dest_len;
 140
 141     for (;;) {
 142         opcode = *src++;
 143
 144         if ( (opcode & 0x80) == 0 ) {
 145
 146             offset = *src++;
 147
 148             size = opcode & 3;
 149             if (dest + size > dest_end)
 150                 return;
 151             bytecopy(dest, src, size);  dest += size;  src += size;
 152
 153             size = ((opcode & 0x1c) >> 2) + 3;
 154             if (dest + size > dest_end)
 155                 return;
 156             bytecopy (dest, dest - (((opcode & 0x60) << 3) + offset + 1), size);
 157             dest += size;
 158
 159         } else if ( (opcode & 0x40) == 0 ) {
 160
 161             byte1 = *src++;
 162             byte2 = *src++;
 163
 164             size = byte1 >> 6;
 165             if (dest + size > dest_end)
 166                 return;
 167             bytecopy (dest, src, size);  dest += size;  src += size;
 168
 169             size = (opcode & 0x3f) + 4;
 170             if (dest + size > dest_end)
 171                 return;
 172             bytecopy (dest, dest - (((byte1 & 0x3f) << 8) + byte2 + 1), size);
 173             dest += size;
 174
 175         } else if ( (opcode & 0x20) == 0 ) {
 176
 177             byte1 = *src++;
 178             byte2 = *src++;
 179             byte3 = *src++;
 180
 181             size = opcode & 3;
 182             if (dest + size > dest_end)
 183                 return;
 184             bytecopy (dest, src, size);  dest += size;  src += size;
 185
 186             size = byte3 + 5 + ((opcode & 0xc) << 6);
 187             if (dest + size > dest_end)
 188                 return;
 189             bytecopy (dest,
 190                 dest - ((((opcode & 0x10) >> 4) << 0x10) + 1 + (byte1 << 8) + byte2),
 191                 size);
 192             dest += size;
 193         } else {
 194             size = ((opcode & 0x1f) << 2) + 4;
 195
 196             if (size > 0x70)
 197                 break;
 198
 199             if (dest + size > dest_end)
 200                 return;
 201             bytecopy (dest, src, size);  dest += size;  src += size;
 202         }
 203     }
 204
 205     size = opcode & 3;
 206     bytecopy(dest, src, size);  dest += size;  src += size;
 207 }
 208
 209 static void inline xan_wc3_output_pixel_run(XanContext *s,
 210     unsigned char *pixel_buffer, int x, int y, int pixel_count)
 211 {
 212     int stride;
 213     int line_inc;
 214     int index;
 215     int current_x;
 216     int width = s->avctx->width;
 217     unsigned char *palette_plane;
 218
 219     palette_plane = s->current_frame.data[0];
 220     stride = s->current_frame.linesize[0];
 221     line_inc = stride - width;
 222     index = y * stride + x;
 223     current_x = x;
 224     while((pixel_count--) && (index < s->frame_size)) {
 225
 226         /* don't do a memcpy() here; keyframes generally copy an entire
 227          * frame of data and the stride needs to be accounted for */
 228         palette_plane[index++] = *pixel_buffer++;
 229
 230         current_x++;
 231         if (current_x >= width) {
 232             index += line_inc;
 233             current_x = 0;
 234         }
 235     }
 236 }
 237
 238 static void inline xan_wc3_copy_pixel_run(XanContext *s,
 239     int x, int y, int pixel_count, int motion_x, int motion_y)
 240 {
 241     int stride;
 242     int line_inc;
 243     int curframe_index, prevframe_index;
 244     int curframe_x, prevframe_x;
 245     int width = s->avctx->width;
 246     unsigned char *palette_plane, *prev_palette_plane;
 247
 248     palette_plane = s->current_frame.data[0];
 249     prev_palette_plane = s->last_frame.data[0];
 250     stride = s->current_frame.linesize[0];
 251     line_inc = stride - width;
 252     curframe_index = y * stride + x;
 253     curframe_x = x;
 254     prevframe_index = (y + motion_y) * stride + x + motion_x;
 255     prevframe_x = x + motion_x;
 256     while((pixel_count--) && (curframe_index < s->frame_size)) {
 257
 258         palette_plane[curframe_index++] =
 259             prev_palette_plane[prevframe_index++];
 260
 261         curframe_x++;
 262         if (curframe_x >= width) {
 263             curframe_index += line_inc;
 264             curframe_x = 0;
 265         }
 266
 267         prevframe_x++;
 268         if (prevframe_x >= width) {
 269             prevframe_index += line_inc;
 270             prevframe_x = 0;
 271         }
 272     }
 273 }
 274
 275 static void xan_wc3_decode_frame(XanContext *s) {
 276
 277     int width = s->avctx->width;
 278     int height = s->avctx->height;
 279     int total_pixels = width * height;
 280     unsigned char opcode;
 281     unsigned char flag = 0;
 282     int size = 0;
 283     int motion_x, motion_y;
 284     int x, y;
 285
 286     unsigned char *opcode_buffer = s->buffer1;
 287     int opcode_buffer_size = s->buffer1_size;
 288     unsigned char *imagedata_buffer = s->buffer2;
 289     int imagedata_buffer_size = s->buffer2_size;
 290
 291     /* pointers to segments inside the compressed chunk */
 292     unsigned char *huffman_segment;
 293     unsigned char *size_segment;
 294     unsigned char *vector_segment;
 295     unsigned char *imagedata_segment;
 296
 297     huffman_segment =   s->buf + LE_16(&s->buf[0]);
 298     size_segment =      s->buf + LE_16(&s->buf[2]);
 299     vector_segment =    s->buf + LE_16(&s->buf[4]);
 300     imagedata_segment = s->buf + LE_16(&s->buf[6]);
 301
 302     xan_huffman_decode(opcode_buffer, huffman_segment, opcode_buffer_size);
 303
 304     if (imagedata_segment[0] == 2)
 305         xan_unpack(imagedata_buffer, &imagedata_segment[1],
 306             imagedata_buffer_size);
 307     else
 308         imagedata_buffer = &imagedata_segment[1];
 309
 310     /* use the decoded data segments to build the frame */
 311     x = y = 0;
 312     while (total_pixels) {
 313
 314         opcode = *opcode_buffer++;
 315         size = 0;
 316
 317         switch (opcode) {
 318
 319         case 0:
 320             flag ^= 1;
 321             continue;
 322
 323         case 1:
 324         case 2:
 325         case 3:
 326         case 4:
 327         case 5:
 328         case 6:
 329         case 7:
 330         case 8:
 331             size = opcode;
 332             break;
 333
 334         case 12:
 335         case 13:
 336         case 14:
 337         case 15:
 338         case 16:
 339         case 17:
 340         case 18:
 341             size += (opcode - 10);
 342             break;
 343
 344         case 9:
 345         case 19:
 346             size = *size_segment++;
 347             break;
 348
 349         case 10:
 350         case 20:
 351             size = BE_16(&size_segment[0]);
 352             size_segment += 2;
 353             break;
 354
 355         case 11:
 356         case 21:
 357             size = (size_segment[0] << 16) | (size_segment[1] << 8) |
 358                 size_segment[2];
 359             size_segment += 3;
 360             break;
 361         }
 362
 363         if (opcode < 12) {
 364             flag ^= 1;
 365             if (flag) {
 366                 /* run of (size) pixels is unchanged from last frame */
 367                 xan_wc3_copy_pixel_run(s, x, y, size, 0, 0);
 368             } else {
 369                 /* output a run of pixels from imagedata_buffer */
 370                 xan_wc3_output_pixel_run(s, imagedata_buffer, x, y, size);
 371                 imagedata_buffer += size;
 372             }
 373         } else {
 374             /* run-based motion compensation from last frame */
 375             motion_x = (*vector_segment >> 4) & 0xF;
 376             motion_y = *vector_segment & 0xF;
 377             vector_segment++;
 378
 379             /* sign extension */
 380             if (motion_x & 0x8)
 381                 motion_x |= 0xFFFFFFF0;
 382             if (motion_y & 0x8)
 383                 motion_y |= 0xFFFFFFF0;
 384
 385             /* copy a run of pixels from the previous frame */
 386             xan_wc3_copy_pixel_run(s, x, y, size, motion_x, motion_y);
 387
 388             flag = 0;
 389         }
 390
 391         /* coordinate accounting */
 392         total_pixels -= size;
 393         while (size) {
 394             if (x + size >= width) {
 395                 y++;
 396                 size -= (width - x);
 397                 x = 0;
 398             } else {
 399                 x += size;
 400                 size = 0;
 401             }
 402         }
 403     }
 404 }
 405
 406 static void xan_wc4_decode_frame(XanContext *s) {
 407 }
 408
 409 static int xan_decode_frame(AVCodecContext *avctx,
 410                             void *data, int *data_size,
 411                             uint8_t *buf, int buf_size)
 412 {
 413     XanContext *s = avctx->priv_data;
 414     AVPaletteControl *palette_control = avctx->palctrl;
 415
 416     if (avctx->get_buffer(avctx, &s->current_frame)) {
 417         av_log(s->avctx, AV_LOG_ERROR, "  Xan Video: get_buffer() failed\n");
 418         return -1;
 419     }
 420     s->current_frame.reference = 3;
 421
 422     if (!s->frame_size)
 423         s->frame_size = s->current_frame.linesize[0] * s->avctx->height;
 424
 425     palette_control->palette_changed = 0;
 426     memcpy(s->current_frame.data[1], palette_control->palette,
 427         AVPALETTE_SIZE);
 428     s->current_frame.palette_has_changed = 1;
 429
 430     s->buf = buf;
 431     s->size = buf_size;
 432
 433     if (avctx->codec->id == CODEC_ID_XAN_WC3)
 434         xan_wc3_decode_frame(s);
 435     else if (avctx->codec->id == CODEC_ID_XAN_WC4)
 436         xan_wc4_decode_frame(s);
 437
 438     /* release the last frame if it is allocated */
 439     if (s->last_frame.data[0])
 440         avctx->release_buffer(avctx, &s->last_frame);
 441
 442     /* shuffle frames */
 443     s->last_frame = s->current_frame;
 444
 445     *data_size = sizeof(AVFrame);
 446     *(AVFrame*)data = s->current_frame;
 447
 448     /* always report that the buffer was completely consumed */
 449     return buf_size;
 450 }
 451
 452 static int xan_decode_end(AVCodecContext *avctx)
 453 {
 454     XanContext *s = avctx->priv_data;
 455
 456     /* release the last frame */
 457     if (s->last_frame.data[0])
 458         avctx->release_buffer(avctx, &s->last_frame);
 459
 460     av_free(s->buffer1);
 461     av_free(s->buffer2);
 462
 463     return 0;
 464 }
 465
 466 AVCodec xan_wc3_decoder = {
 467     "xan_wc3",
 468     CODEC_TYPE_VIDEO,
 469     CODEC_ID_XAN_WC3,
 470     sizeof(XanContext),
 471     xan_decode_init,
 472     NULL,
 473     xan_decode_end,
 474     xan_decode_frame,
 475     CODEC_CAP_DR1,
 476 };
 477
 478 /*
 479 AVCodec xan_wc4_decoder = {
 480     "xan_wc4",
 481     CODEC_TYPE_VIDEO,
 482     CODEC_ID_XAN_WC4,
 483     sizeof(XanContext),
 484     xan_decode_init,
 485     NULL,
 486     xan_decode_end,
 487     xan_decode_frame,
 488     CODEC_CAP_DR1,
 489 };
 490 */