libavcodec/msvideo1.c

   1 /*
   2  * Microsoft Video-1 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  *
  19  */
  20
  21 /**
  22  * @file msvideo1.c
  23  * Microsoft Video-1 Decoder by Mike Melanson (melanson@pcisys.net)
  24  * For more information about the MS Video-1 format, visit:
  25  *   http://www.pcisys.net/~melanson/codecs/
  26  *
  27  * This decoder outputs either PAL8 or RGB555 data, depending on the
  28  * whether a RGB palette was passed through via extradata; if the extradata
  29  * is present, then the data is PAL8; RGB555 otherwise.
  30  */
  31
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include <unistd.h>
  36
  37 #include "common.h"
  38 #include "avcodec.h"
  39 #include "dsputil.h"
  40
  41 #define PALETTE_COUNT 256
  42 #define LE_16(x)  ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0])
  43 #define CHECK_STREAM_PTR(n) \
  44   if ((stream_ptr + n) > s->size ) { \
  45     printf (" MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
  46       stream_ptr + n, s->size); \
  47     return; \
  48   }
  49
  50 #define COPY_PREV_BLOCK() \
  51     pixel_ptr = block_ptr; \
  52     for (pixel_y = 0; pixel_y < 4; pixel_y++) { \
  53         for (pixel_x = 0; pixel_x < 4; pixel_x++, pixel_ptr++) \
  54             pixels[pixel_ptr] = prev_pixels[pixel_ptr]; \
  55         pixel_ptr -= row_dec; \
  56     }
  57
  58 typedef struct Msvideo1Context {
  59
  60     AVCodecContext *avctx;
  61     DSPContext dsp;
  62     AVFrame frame;
  63     AVFrame prev_frame;
  64
  65     unsigned char *buf;
  66     int size;
  67
  68     int mode_8bit;  /* if it's not 8-bit, it's 16-bit */
  69     unsigned char palette[PALETTE_COUNT * 4];
  70
  71 } Msvideo1Context;
  72
  73 static int msvideo1_decode_init(AVCodecContext *avctx)
  74 {
  75     Msvideo1Context *s = (Msvideo1Context *)avctx->priv_data;
  76     int i;
  77     unsigned char r, g, b;
  78     unsigned char *raw_palette;
  79     unsigned int *palette32;
  80
  81     s->avctx = avctx;
  82
  83     /* figure out the colorspace based on the presence of a palette in
  84      * extradata */
  85     if (s->avctx->extradata_size) {
  86         s->mode_8bit = 1;
  87         /* load up the palette */
  88         palette32 = (unsigned int *)s->palette;
  89         raw_palette = (unsigned char *)s->avctx->extradata;
  90         for (i = 0; i < s->avctx->extradata_size / 4; i++) {
  91             b = *raw_palette++;
  92             g = *raw_palette++;
  93             r = *raw_palette++;
  94             raw_palette++;
  95             palette32[i] = (r << 16) | (g << 8) | (b);
  96         }
  97         avctx->pix_fmt = PIX_FMT_PAL8;
  98     } else {
  99         s->mode_8bit = 0;
 100         avctx->pix_fmt = PIX_FMT_RGB555;
 101     }
 102
 103     avctx->has_b_frames = 0;
 104     dsputil_init(&s->dsp, avctx);
 105
 106     s->frame.data[0] = s->prev_frame.data[0] = NULL;
 107
 108     return 0;
 109 }
 110
 111 static void msvideo1_decode_8bit(Msvideo1Context *s)
 112 {
 113     int block_ptr, pixel_ptr;
 114     int total_blocks;
 115     int pixel_x, pixel_y;  /* pixel width and height iterators */
 116     int block_x, block_y;  /* block width and height iterators */
 117     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
 118     int block_inc;
 119     int row_dec;
 120
 121     /* decoding parameters */
 122     int stream_ptr;
 123     unsigned char byte_a, byte_b;
 124     unsigned short flags;
 125     int skip_blocks;
 126     unsigned char colors[8];
 127     unsigned char *pixels = s->frame.data[0];
 128     unsigned char *prev_pixels = s->prev_frame.data[0];
 129     int stride = s->frame.linesize[0];
 130
 131     stream_ptr = 0;
 132     skip_blocks = 0;
 133     blocks_wide = s->avctx->width / 4;
 134     blocks_high = s->avctx->height / 4;
 135     total_blocks = blocks_wide * blocks_high;
 136     block_inc = 4;
 137     row_dec = stride + 4;
 138
 139     for (block_y = blocks_high; block_y > 0; block_y--) {
 140         block_ptr = ((block_y * 4) - 1) * stride;
 141         for (block_x = blocks_wide; block_x > 0; block_x--) {
 142             /* check if this block should be skipped */
 143             if (skip_blocks) {
 144                 COPY_PREV_BLOCK();
 145                 block_ptr += block_inc;
 146                 skip_blocks--;
 147                 total_blocks--;
 148                 continue;
 149             }
 150
 151             pixel_ptr = block_ptr;
 152
 153             /* get the next two bytes in the encoded data stream */
 154             CHECK_STREAM_PTR(2);
 155             byte_a = s->buf[stream_ptr++];
 156             byte_b = s->buf[stream_ptr++];
 157
 158             /* check if the decode is finished */
 159             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
 160                 return;
 161             else if ((byte_b & 0xFC) == 0x84) {
 162                 /* skip code, but don't count the current block */
 163                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
 164                 COPY_PREV_BLOCK();
 165             } else if (byte_b < 0x80) {
 166                 /* 2-color encoding */
 167                 flags = (byte_b << 8) | byte_a;
 168
 169                 CHECK_STREAM_PTR(2);
 170                 colors[0] = s->buf[stream_ptr++];
 171                 colors[1] = s->buf[stream_ptr++];
 172
 173                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 174                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 175                         pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
 176                     pixel_ptr -= row_dec;
 177                 }
 178             } else if (byte_b >= 0x90) {
 179                 /* 8-color encoding */
 180                 flags = (byte_b << 8) | byte_a;
 181
 182                 CHECK_STREAM_PTR(8);
 183                 memcpy(colors, &s->buf[stream_ptr], 8);
 184                 stream_ptr += 8;
 185
 186                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 187                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 188                         pixels[pixel_ptr++] =
 189                             colors[((pixel_y & 0x2) << 1) +
 190                                 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
 191                     pixel_ptr -= row_dec;
 192                 }
 193             } else {
 194                 /* 1-color encoding */
 195                 colors[0] = byte_a;
 196
 197                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 198                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
 199                         pixels[pixel_ptr++] = colors[0];
 200                     pixel_ptr -= row_dec;
 201                 }
 202             }
 203
 204             block_ptr += block_inc;
 205             total_blocks--;
 206         }
 207     }
 208
 209     /* make the palette available on the way out */
 210     if (s->avctx->pix_fmt == PIX_FMT_PAL8)
 211         memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);
 212 }
 213
 214 static void msvideo1_decode_16bit(Msvideo1Context *s)
 215 {
 216     int block_ptr, pixel_ptr;
 217     int total_blocks;
 218     int pixel_x, pixel_y;  /* pixel width and height iterators */
 219     int block_x, block_y;  /* block width and height iterators */
 220     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
 221     int block_inc;
 222     int row_dec;
 223
 224     /* decoding parameters */
 225     int stream_ptr;
 226     unsigned char byte_a, byte_b;
 227     unsigned short flags;
 228     int skip_blocks;
 229     unsigned short colors[8];
 230     unsigned short *pixels = (unsigned short *)s->frame.data[0];
 231     unsigned short *prev_pixels = (unsigned short *)s->prev_frame.data[0];
 232     int stride = s->frame.linesize[0] / 2;
 233
 234     stream_ptr = 0;
 235     skip_blocks = 0;
 236     blocks_wide = s->avctx->width / 4;
 237     blocks_high = s->avctx->height / 4;
 238     total_blocks = blocks_wide * blocks_high;
 239     block_inc = 4;
 240     row_dec = stride + 4;
 241
 242     for (block_y = blocks_high; block_y > 0; block_y--) {
 243         block_ptr = ((block_y * 4) - 1) * stride;
 244         for (block_x = blocks_wide; block_x > 0; block_x--) {
 245             /* check if this block should be skipped */
 246             if (skip_blocks) {
 247                 COPY_PREV_BLOCK();
 248                 block_ptr += block_inc;
 249                 skip_blocks--;
 250                 total_blocks--;
 251                 continue;
 252             }
 253
 254             pixel_ptr = block_ptr;
 255
 256             /* get the next two bytes in the encoded data stream */
 257             CHECK_STREAM_PTR(2);
 258             byte_a = s->buf[stream_ptr++];
 259             byte_b = s->buf[stream_ptr++];
 260
 261             /* check if the decode is finished */
 262             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
 263                 return;
 264             } else if ((byte_b & 0xFC) == 0x84) {
 265                 /* skip code, but don't count the current block */
 266                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
 267                 COPY_PREV_BLOCK();
 268             } else if (byte_b < 0x80) {
 269                 /* 2- or 8-color encoding modes */
 270                 flags = (byte_b << 8) | byte_a;
 271
 272                 CHECK_STREAM_PTR(4);
 273                 colors[0] = LE_16(&s->buf[stream_ptr]);
 274                 stream_ptr += 2;
 275                 colors[1] = LE_16(&s->buf[stream_ptr]);
 276                 stream_ptr += 2;
 277
 278                 if (colors[0] & 0x8000) {
 279                     /* 8-color encoding */
 280                     CHECK_STREAM_PTR(12);
 281                     colors[2] = LE_16(&s->buf[stream_ptr]);
 282                     stream_ptr += 2;
 283                     colors[3] = LE_16(&s->buf[stream_ptr]);
 284                     stream_ptr += 2;
 285                     colors[4] = LE_16(&s->buf[stream_ptr]);
 286                     stream_ptr += 2;
 287                     colors[5] = LE_16(&s->buf[stream_ptr]);
 288                     stream_ptr += 2;
 289                     colors[6] = LE_16(&s->buf[stream_ptr]);
 290                     stream_ptr += 2;
 291                     colors[7] = LE_16(&s->buf[stream_ptr]);
 292                     stream_ptr += 2;
 293
 294                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 295                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 296                             pixels[pixel_ptr++] =
 297                                 colors[((pixel_y & 0x2) << 1) +
 298                                     (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
 299                         pixel_ptr -= row_dec;
 300                     }
 301                 } else {
 302                     /* 2-color encoding */
 303                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 304                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 305                             pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
 306                         pixel_ptr -= row_dec;
 307                     }
 308                 }
 309             } else {
 310                 /* otherwise, it's a 1-color block */
 311                 colors[0] = (byte_b << 8) | byte_a;
 312
 313                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 314                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
 315                         pixels[pixel_ptr++] = colors[0];
 316                     pixel_ptr -= row_dec;
 317                 }
 318             }
 319
 320             block_ptr += block_inc;
 321             total_blocks--;
 322         }
 323     }
 324 }
 325
 326 static int msvideo1_decode_frame(AVCodecContext *avctx,
 327                                 void *data, int *data_size,
 328                                 uint8_t *buf, int buf_size)
 329 {
 330     Msvideo1Context *s = (Msvideo1Context *)avctx->priv_data;
 331
 332     s->buf = buf;
 333     s->size = buf_size;
 334
 335     if (avctx->get_buffer(avctx, &s->frame)) {
 336         printf ("  MS Video-1 Video: get_buffer() failed\n");
 337         return -1;
 338     }
 339
 340     if (s->mode_8bit)
 341         msvideo1_decode_8bit(s);
 342     else
 343         msvideo1_decode_16bit(s);
 344
 345     if (s->prev_frame.data[0])
 346         avctx->release_buffer(avctx, &s->prev_frame);
 347
 348     /* shuffle frames */
 349     s->prev_frame = s->frame;
 350
 351     *data_size = sizeof(AVFrame);
 352     *(AVFrame*)data = s->frame;
 353
 354     /* report that the buffer was completely consumed */
 355     return buf_size;
 356 }
 357
 358 static int msvideo1_decode_end(AVCodecContext *avctx)
 359 {
 360     Msvideo1Context *s = (Msvideo1Context *)avctx->priv_data;
 361
 362     if (s->prev_frame.data[0])
 363         avctx->release_buffer(avctx, &s->prev_frame);
 364
 365     return 0;
 366 }
 367
 368 AVCodec msvideo1_decoder = {
 369     "msvideo1",
 370     CODEC_TYPE_VIDEO,
 371     CODEC_ID_MSVIDEO1,
 372     sizeof(Msvideo1Context),
 373     msvideo1_decode_init,
 374     NULL,
 375     msvideo1_decode_end,
 376     msvideo1_decode_frame,
 377     CODEC_CAP_DR1,
 378 };