libavcodec/msvideo1.c

   1 /*
   2  * Microsoft Video-1 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 msvideo1.c
  24  * Microsoft Video-1 Decoder by Mike Melanson (melanson@pcisys.net)
  25  * For more information about the MS Video-1 format, visit:
  26  *   http://www.pcisys.net/~melanson/codecs/
  27  *
  28  * This decoder outputs either PAL8 or RGB555 data, depending on the
  29  * whether a RGB palette was passed through palctrl;
  30  * if it's present, then the data is PAL8; RGB555 otherwise.
  31  */
  32
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <unistd.h>
  37
  38 #include "avcodec.h"
  39
  40 #define PALETTE_COUNT 256
  41 #define CHECK_STREAM_PTR(n) \
  42   if ((stream_ptr + n) > s->size ) { \
  43     av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
  44       stream_ptr + n, s->size); \
  45     return; \
  46   }
  47
  48 typedef struct Msvideo1Context {
  49
  50     AVCodecContext *avctx;
  51     AVFrame frame;
  52
  53     const unsigned char *buf;
  54     int size;
  55
  56     int mode_8bit;  /* if it's not 8-bit, it's 16-bit */
  57
  58 } Msvideo1Context;
  59
  60 static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
  61 {
  62     Msvideo1Context *s = avctx->priv_data;
  63
  64     s->avctx = avctx;
  65
  66     /* figure out the colorspace based on the presence of a palette */
  67     if (s->avctx->palctrl) {
  68         s->mode_8bit = 1;
  69         avctx->pix_fmt = PIX_FMT_PAL8;
  70     } else {
  71         s->mode_8bit = 0;
  72         avctx->pix_fmt = PIX_FMT_RGB555;
  73     }
  74
  75     s->frame.data[0] = NULL;
  76
  77     return 0;
  78 }
  79
  80 static void msvideo1_decode_8bit(Msvideo1Context *s)
  81 {
  82     int block_ptr, pixel_ptr;
  83     int total_blocks;
  84     int pixel_x, pixel_y;  /* pixel width and height iterators */
  85     int block_x, block_y;  /* block width and height iterators */
  86     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
  87     int block_inc;
  88     int row_dec;
  89
  90     /* decoding parameters */
  91     int stream_ptr;
  92     unsigned char byte_a, byte_b;
  93     unsigned short flags;
  94     int skip_blocks;
  95     unsigned char colors[8];
  96     unsigned char *pixels = s->frame.data[0];
  97     int stride = s->frame.linesize[0];
  98
  99     stream_ptr = 0;
 100     skip_blocks = 0;
 101     blocks_wide = s->avctx->width / 4;
 102     blocks_high = s->avctx->height / 4;
 103     total_blocks = blocks_wide * blocks_high;
 104     block_inc = 4;
 105     row_dec = stride + 4;
 106
 107     for (block_y = blocks_high; block_y > 0; block_y--) {
 108         block_ptr = ((block_y * 4) - 1) * stride;
 109         for (block_x = blocks_wide; block_x > 0; block_x--) {
 110             /* check if this block should be skipped */
 111             if (skip_blocks) {
 112                 block_ptr += block_inc;
 113                 skip_blocks--;
 114                 total_blocks--;
 115                 continue;
 116             }
 117
 118             pixel_ptr = block_ptr;
 119
 120             /* get the next two bytes in the encoded data stream */
 121             CHECK_STREAM_PTR(2);
 122             byte_a = s->buf[stream_ptr++];
 123             byte_b = s->buf[stream_ptr++];
 124
 125             /* check if the decode is finished */
 126             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
 127                 return;
 128             else if ((byte_b & 0xFC) == 0x84) {
 129                 /* skip code, but don't count the current block */
 130                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
 131             } else if (byte_b < 0x80) {
 132                 /* 2-color encoding */
 133                 flags = (byte_b << 8) | byte_a;
 134
 135                 CHECK_STREAM_PTR(2);
 136                 colors[0] = s->buf[stream_ptr++];
 137                 colors[1] = s->buf[stream_ptr++];
 138
 139                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 140                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 141                         pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
 142                     pixel_ptr -= row_dec;
 143                 }
 144             } else if (byte_b >= 0x90) {
 145                 /* 8-color encoding */
 146                 flags = (byte_b << 8) | byte_a;
 147
 148                 CHECK_STREAM_PTR(8);
 149                 memcpy(colors, &s->buf[stream_ptr], 8);
 150                 stream_ptr += 8;
 151
 152                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 153                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 154                         pixels[pixel_ptr++] =
 155                             colors[((pixel_y & 0x2) << 1) +
 156                                 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
 157                     pixel_ptr -= row_dec;
 158                 }
 159             } else {
 160                 /* 1-color encoding */
 161                 colors[0] = byte_a;
 162
 163                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 164                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
 165                         pixels[pixel_ptr++] = colors[0];
 166                     pixel_ptr -= row_dec;
 167                 }
 168             }
 169
 170             block_ptr += block_inc;
 171             total_blocks--;
 172         }
 173     }
 174
 175     /* make the palette available on the way out */
 176     if (s->avctx->pix_fmt == PIX_FMT_PAL8) {
 177         memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
 178         if (s->avctx->palctrl->palette_changed) {
 179             s->frame.palette_has_changed = 1;
 180             s->avctx->palctrl->palette_changed = 0;
 181         }
 182     }
 183 }
 184
 185 static void msvideo1_decode_16bit(Msvideo1Context *s)
 186 {
 187     int block_ptr, pixel_ptr;
 188     int total_blocks;
 189     int pixel_x, pixel_y;  /* pixel width and height iterators */
 190     int block_x, block_y;  /* block width and height iterators */
 191     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
 192     int block_inc;
 193     int row_dec;
 194
 195     /* decoding parameters */
 196     int stream_ptr;
 197     unsigned char byte_a, byte_b;
 198     unsigned short flags;
 199     int skip_blocks;
 200     unsigned short colors[8];
 201     unsigned short *pixels = (unsigned short *)s->frame.data[0];
 202     int stride = s->frame.linesize[0] / 2;
 203
 204     stream_ptr = 0;
 205     skip_blocks = 0;
 206     blocks_wide = s->avctx->width / 4;
 207     blocks_high = s->avctx->height / 4;
 208     total_blocks = blocks_wide * blocks_high;
 209     block_inc = 4;
 210     row_dec = stride + 4;
 211
 212     for (block_y = blocks_high; block_y > 0; block_y--) {
 213         block_ptr = ((block_y * 4) - 1) * stride;
 214         for (block_x = blocks_wide; block_x > 0; block_x--) {
 215             /* check if this block should be skipped */
 216             if (skip_blocks) {
 217                 block_ptr += block_inc;
 218                 skip_blocks--;
 219                 total_blocks--;
 220                 continue;
 221             }
 222
 223             pixel_ptr = block_ptr;
 224
 225             /* get the next two bytes in the encoded data stream */
 226             CHECK_STREAM_PTR(2);
 227             byte_a = s->buf[stream_ptr++];
 228             byte_b = s->buf[stream_ptr++];
 229
 230             /* check if the decode is finished */
 231             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
 232                 return;
 233             } else if ((byte_b & 0xFC) == 0x84) {
 234                 /* skip code, but don't count the current block */
 235                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
 236             } else if (byte_b < 0x80) {
 237                 /* 2- or 8-color encoding modes */
 238                 flags = (byte_b << 8) | byte_a;
 239
 240                 CHECK_STREAM_PTR(4);
 241                 colors[0] = AV_RL16(&s->buf[stream_ptr]);
 242                 stream_ptr += 2;
 243                 colors[1] = AV_RL16(&s->buf[stream_ptr]);
 244                 stream_ptr += 2;
 245
 246                 if (colors[0] & 0x8000) {
 247                     /* 8-color encoding */
 248                     CHECK_STREAM_PTR(12);
 249                     colors[2] = AV_RL16(&s->buf[stream_ptr]);
 250                     stream_ptr += 2;
 251                     colors[3] = AV_RL16(&s->buf[stream_ptr]);
 252                     stream_ptr += 2;
 253                     colors[4] = AV_RL16(&s->buf[stream_ptr]);
 254                     stream_ptr += 2;
 255                     colors[5] = AV_RL16(&s->buf[stream_ptr]);
 256                     stream_ptr += 2;
 257                     colors[6] = AV_RL16(&s->buf[stream_ptr]);
 258                     stream_ptr += 2;
 259                     colors[7] = AV_RL16(&s->buf[stream_ptr]);
 260                     stream_ptr += 2;
 261
 262                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 263                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 264                             pixels[pixel_ptr++] =
 265                                 colors[((pixel_y & 0x2) << 1) +
 266                                     (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
 267                         pixel_ptr -= row_dec;
 268                     }
 269                 } else {
 270                     /* 2-color encoding */
 271                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 272                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 273                             pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
 274                         pixel_ptr -= row_dec;
 275                     }
 276                 }
 277             } else {
 278                 /* otherwise, it's a 1-color block */
 279                 colors[0] = (byte_b << 8) | byte_a;
 280
 281                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 282                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
 283                         pixels[pixel_ptr++] = colors[0];
 284                     pixel_ptr -= row_dec;
 285                 }
 286             }
 287
 288             block_ptr += block_inc;
 289             total_blocks--;
 290         }
 291     }
 292 }
 293
 294 static int msvideo1_decode_frame(AVCodecContext *avctx,
 295                                 void *data, int *data_size,
 296                                 const uint8_t *buf, int buf_size)
 297 {
 298     Msvideo1Context *s = avctx->priv_data;
 299
 300     s->buf = buf;
 301     s->size = buf_size;
 302
 303     s->frame.reference = 1;
 304     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
 305     if (avctx->reget_buffer(avctx, &s->frame)) {
 306         av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
 307         return -1;
 308     }
 309
 310     if (s->mode_8bit)
 311         msvideo1_decode_8bit(s);
 312     else
 313         msvideo1_decode_16bit(s);
 314
 315     *data_size = sizeof(AVFrame);
 316     *(AVFrame*)data = s->frame;
 317
 318     /* report that the buffer was completely consumed */
 319     return buf_size;
 320 }
 321
 322 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
 323 {
 324     Msvideo1Context *s = avctx->priv_data;
 325
 326     if (s->frame.data[0])
 327         avctx->release_buffer(avctx, &s->frame);
 328
 329     return 0;
 330 }
 331
 332 AVCodec msvideo1_decoder = {
 333     "msvideo1",
 334     CODEC_TYPE_VIDEO,
 335     CODEC_ID_MSVIDEO1,
 336     sizeof(Msvideo1Context),
 337     msvideo1_decode_init,
 338     NULL,
 339     msvideo1_decode_end,
 340     msvideo1_decode_frame,
 341     CODEC_CAP_DR1,
 342     .long_name= NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
 343 };