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 libavcodec/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 "libavutil/intreadwrite.h"
  39 #include "avcodec.h"
  40
  41 #define PALETTE_COUNT 256
  42 #define CHECK_STREAM_PTR(n) \
  43   if ((stream_ptr + n) > s->size ) { \
  44     av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
  45       stream_ptr + n, s->size); \
  46     return; \
  47   }
  48
  49 typedef struct Msvideo1Context {
  50
  51     AVCodecContext *avctx;
  52     AVFrame frame;
  53
  54     const unsigned char *buf;
  55     int size;
  56
  57     int mode_8bit;  /* if it's not 8-bit, it's 16-bit */
  58
  59 } Msvideo1Context;
  60
  61 static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
  62 {
  63     Msvideo1Context *s = avctx->priv_data;
  64
  65     s->avctx = avctx;
  66
  67     /* figure out the colorspace based on the presence of a palette */
  68     if (s->avctx->palctrl) {
  69         s->mode_8bit = 1;
  70         avctx->pix_fmt = PIX_FMT_PAL8;
  71     } else {
  72         s->mode_8bit = 0;
  73         avctx->pix_fmt = PIX_FMT_RGB555;
  74     }
  75
  76     s->frame.data[0] = NULL;
  77
  78     return 0;
  79 }
  80
  81 static void msvideo1_decode_8bit(Msvideo1Context *s)
  82 {
  83     int block_ptr, pixel_ptr;
  84     int total_blocks;
  85     int pixel_x, pixel_y;  /* pixel width and height iterators */
  86     int block_x, block_y;  /* block width and height iterators */
  87     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
  88     int block_inc;
  89     int row_dec;
  90
  91     /* decoding parameters */
  92     int stream_ptr;
  93     unsigned char byte_a, byte_b;
  94     unsigned short flags;
  95     int skip_blocks;
  96     unsigned char colors[8];
  97     unsigned char *pixels = s->frame.data[0];
  98     int stride = s->frame.linesize[0];
  99
 100     stream_ptr = 0;
 101     skip_blocks = 0;
 102     blocks_wide = s->avctx->width / 4;
 103     blocks_high = s->avctx->height / 4;
 104     total_blocks = blocks_wide * blocks_high;
 105     block_inc = 4;
 106     row_dec = stride + 4;
 107
 108     for (block_y = blocks_high; block_y > 0; block_y--) {
 109         block_ptr = ((block_y * 4) - 1) * stride;
 110         for (block_x = blocks_wide; block_x > 0; block_x--) {
 111             /* check if this block should be skipped */
 112             if (skip_blocks) {
 113                 block_ptr += block_inc;
 114                 skip_blocks--;
 115                 total_blocks--;
 116                 continue;
 117             }
 118
 119             pixel_ptr = block_ptr;
 120
 121             /* get the next two bytes in the encoded data stream */
 122             CHECK_STREAM_PTR(2);
 123             byte_a = s->buf[stream_ptr++];
 124             byte_b = s->buf[stream_ptr++];
 125
 126             /* check if the decode is finished */
 127             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
 128                 return;
 129             else if ((byte_b & 0xFC) == 0x84) {
 130                 /* skip code, but don't count the current block */
 131                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
 132             } else if (byte_b < 0x80) {
 133                 /* 2-color encoding */
 134                 flags = (byte_b << 8) | byte_a;
 135
 136                 CHECK_STREAM_PTR(2);
 137                 colors[0] = s->buf[stream_ptr++];
 138                 colors[1] = s->buf[stream_ptr++];
 139
 140                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 141                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 142                         pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
 143                     pixel_ptr -= row_dec;
 144                 }
 145             } else if (byte_b >= 0x90) {
 146                 /* 8-color encoding */
 147                 flags = (byte_b << 8) | byte_a;
 148
 149                 CHECK_STREAM_PTR(8);
 150                 memcpy(colors, &s->buf[stream_ptr], 8);
 151                 stream_ptr += 8;
 152
 153                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 154                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 155                         pixels[pixel_ptr++] =
 156                             colors[((pixel_y & 0x2) << 1) +
 157                                 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
 158                     pixel_ptr -= row_dec;
 159                 }
 160             } else {
 161                 /* 1-color encoding */
 162                 colors[0] = byte_a;
 163
 164                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 165                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
 166                         pixels[pixel_ptr++] = colors[0];
 167                     pixel_ptr -= row_dec;
 168                 }
 169             }
 170
 171             block_ptr += block_inc;
 172             total_blocks--;
 173         }
 174     }
 175
 176     /* make the palette available on the way out */
 177     if (s->avctx->pix_fmt == PIX_FMT_PAL8) {
 178         memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
 179         if (s->avctx->palctrl->palette_changed) {
 180             s->frame.palette_has_changed = 1;
 181             s->avctx->palctrl->palette_changed = 0;
 182         }
 183     }
 184 }
 185
 186 static void msvideo1_decode_16bit(Msvideo1Context *s)
 187 {
 188     int block_ptr, pixel_ptr;
 189     int total_blocks;
 190     int pixel_x, pixel_y;  /* pixel width and height iterators */
 191     int block_x, block_y;  /* block width and height iterators */
 192     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
 193     int block_inc;
 194     int row_dec;
 195
 196     /* decoding parameters */
 197     int stream_ptr;
 198     unsigned char byte_a, byte_b;
 199     unsigned short flags;
 200     int skip_blocks;
 201     unsigned short colors[8];
 202     unsigned short *pixels = (unsigned short *)s->frame.data[0];
 203     int stride = s->frame.linesize[0] / 2;
 204
 205     stream_ptr = 0;
 206     skip_blocks = 0;
 207     blocks_wide = s->avctx->width / 4;
 208     blocks_high = s->avctx->height / 4;
 209     total_blocks = blocks_wide * blocks_high;
 210     block_inc = 4;
 211     row_dec = stride + 4;
 212
 213     for (block_y = blocks_high; block_y > 0; block_y--) {
 214         block_ptr = ((block_y * 4) - 1) * stride;
 215         for (block_x = blocks_wide; block_x > 0; block_x--) {
 216             /* check if this block should be skipped */
 217             if (skip_blocks) {
 218                 block_ptr += block_inc;
 219                 skip_blocks--;
 220                 total_blocks--;
 221                 continue;
 222             }
 223
 224             pixel_ptr = block_ptr;
 225
 226             /* get the next two bytes in the encoded data stream */
 227             CHECK_STREAM_PTR(2);
 228             byte_a = s->buf[stream_ptr++];
 229             byte_b = s->buf[stream_ptr++];
 230
 231             /* check if the decode is finished */
 232             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
 233                 return;
 234             } else if ((byte_b & 0xFC) == 0x84) {
 235                 /* skip code, but don't count the current block */
 236                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
 237             } else if (byte_b < 0x80) {
 238                 /* 2- or 8-color encoding modes */
 239                 flags = (byte_b << 8) | byte_a;
 240
 241                 CHECK_STREAM_PTR(4);
 242                 colors[0] = AV_RL16(&s->buf[stream_ptr]);
 243                 stream_ptr += 2;
 244                 colors[1] = AV_RL16(&s->buf[stream_ptr]);
 245                 stream_ptr += 2;
 246
 247                 if (colors[0] & 0x8000) {
 248                     /* 8-color encoding */
 249                     CHECK_STREAM_PTR(12);
 250                     colors[2] = AV_RL16(&s->buf[stream_ptr]);
 251                     stream_ptr += 2;
 252                     colors[3] = AV_RL16(&s->buf[stream_ptr]);
 253                     stream_ptr += 2;
 254                     colors[4] = AV_RL16(&s->buf[stream_ptr]);
 255                     stream_ptr += 2;
 256                     colors[5] = AV_RL16(&s->buf[stream_ptr]);
 257                     stream_ptr += 2;
 258                     colors[6] = AV_RL16(&s->buf[stream_ptr]);
 259                     stream_ptr += 2;
 260                     colors[7] = AV_RL16(&s->buf[stream_ptr]);
 261                     stream_ptr += 2;
 262
 263                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 264                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 265                             pixels[pixel_ptr++] =
 266                                 colors[((pixel_y & 0x2) << 1) +
 267                                     (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
 268                         pixel_ptr -= row_dec;
 269                     }
 270                 } else {
 271                     /* 2-color encoding */
 272                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 273                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 274                             pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
 275                         pixel_ptr -= row_dec;
 276                     }
 277                 }
 278             } else {
 279                 /* otherwise, it's a 1-color block */
 280                 colors[0] = (byte_b << 8) | byte_a;
 281
 282                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 283                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
 284                         pixels[pixel_ptr++] = colors[0];
 285                     pixel_ptr -= row_dec;
 286                 }
 287             }
 288
 289             block_ptr += block_inc;
 290             total_blocks--;
 291         }
 292     }
 293 }
 294
 295 static int msvideo1_decode_frame(AVCodecContext *avctx,
 296                                 void *data, int *data_size,
 297                                 const uint8_t *buf, int buf_size)
 298 {
 299     Msvideo1Context *s = avctx->priv_data;
 300
 301     s->buf = buf;
 302     s->size = buf_size;
 303
 304     s->frame.reference = 1;
 305     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
 306     if (avctx->reget_buffer(avctx, &s->frame)) {
 307         av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
 308         return -1;
 309     }
 310
 311     if (s->mode_8bit)
 312         msvideo1_decode_8bit(s);
 313     else
 314         msvideo1_decode_16bit(s);
 315
 316     *data_size = sizeof(AVFrame);
 317     *(AVFrame*)data = s->frame;
 318
 319     /* report that the buffer was completely consumed */
 320     return buf_size;
 321 }
 322
 323 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
 324 {
 325     Msvideo1Context *s = avctx->priv_data;
 326
 327     if (s->frame.data[0])
 328         avctx->release_buffer(avctx, &s->frame);
 329
 330     return 0;
 331 }
 332
 333 AVCodec msvideo1_decoder = {
 334     "msvideo1",
 335     CODEC_TYPE_VIDEO,
 336     CODEC_ID_MSVIDEO1,
 337     sizeof(Msvideo1Context),
 338     msvideo1_decode_init,
 339     NULL,
 340     msvideo1_decode_end,
 341     msvideo1_decode_frame,
 342     CODEC_CAP_DR1,
 343     .long_name= NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
 344 };