libavcodec/msrle.c

   1 /*
   2  * Micrsoft RLE 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 msrle.c
  24  * MS RLE Video Decoder by Mike Melanson (melanson@pcisys.net)
  25  * For more information about the MS RLE format, visit:
  26  *   http://www.pcisys.net/~melanson/codecs/
  27  *
  28  * The MS RLE decoder outputs PAL8 colorspace data.
  29  *
  30  * Note that this decoder expects the palette colors from the end of the
  31  * BITMAPINFO header passed through palctrl.
  32  */
  33
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <unistd.h>
  38
  39 #include "avcodec.h"
  40 #include "dsputil.h"
  41
  42 typedef struct MsrleContext {
  43     AVCodecContext *avctx;
  44     AVFrame frame;
  45
  46     const unsigned char *buf;
  47     int size;
  48
  49 } MsrleContext;
  50
  51 #define FETCH_NEXT_STREAM_BYTE() \
  52     if (stream_ptr >= s->size) \
  53     { \
  54       av_log(s->avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (1)\n"); \
  55       return; \
  56     } \
  57     stream_byte = s->buf[stream_ptr++];
  58
  59 static void msrle_decode_pal4(MsrleContext *s)
  60 {
  61     int stream_ptr = 0;
  62     unsigned char rle_code;
  63     unsigned char extra_byte, odd_pixel;
  64     unsigned char stream_byte;
  65     int pixel_ptr = 0;
  66     int row_dec = s->frame.linesize[0];
  67     int row_ptr = (s->avctx->height - 1) * row_dec;
  68     int frame_size = row_dec * s->avctx->height;
  69     int i;
  70
  71     /* make the palette available */
  72     memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
  73     if (s->avctx->palctrl->palette_changed) {
  74         s->frame.palette_has_changed = 1;
  75         s->avctx->palctrl->palette_changed = 0;
  76     }
  77
  78     while (row_ptr >= 0) {
  79         FETCH_NEXT_STREAM_BYTE();
  80         rle_code = stream_byte;
  81         if (rle_code == 0) {
  82             /* fetch the next byte to see how to handle escape code */
  83             FETCH_NEXT_STREAM_BYTE();
  84             if (stream_byte == 0) {
  85                 /* line is done, goto the next one */
  86                 row_ptr -= row_dec;
  87                 pixel_ptr = 0;
  88             } else if (stream_byte == 1) {
  89                 /* decode is done */
  90                 return;
  91             } else if (stream_byte == 2) {
  92                 /* reposition frame decode coordinates */
  93                 FETCH_NEXT_STREAM_BYTE();
  94                 pixel_ptr += stream_byte;
  95                 FETCH_NEXT_STREAM_BYTE();
  96                 row_ptr -= stream_byte * row_dec;
  97         } else {
  98             // copy pixels from encoded stream
  99             odd_pixel =  stream_byte & 1;
 100             rle_code = (stream_byte + 1) / 2;
 101             extra_byte = rle_code & 0x01;
 102             if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
 103                 (row_ptr < 0)) {
 104                 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
 105                 return;
 106             }
 107
 108             for (i = 0; i < rle_code; i++) {
 109                 if (pixel_ptr >= s->avctx->width)
 110                     break;
 111                 FETCH_NEXT_STREAM_BYTE();
 112                 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
 113                 pixel_ptr++;
 114                 if (i + 1 == rle_code && odd_pixel)
 115                     break;
 116                 if (pixel_ptr >= s->avctx->width)
 117                     break;
 118                 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
 119                 pixel_ptr++;
 120             }
 121
 122             // if the RLE code is odd, skip a byte in the stream
 123             if (extra_byte)
 124               stream_ptr++;
 125             }
 126         } else {
 127             // decode a run of data
 128             if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
 129                 (row_ptr < 0)) {
 130                 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
 131                 return;
 132             }
 133             FETCH_NEXT_STREAM_BYTE();
 134             for (i = 0; i < rle_code; i++) {
 135                 if (pixel_ptr >= s->avctx->width)
 136                     break;
 137                 if ((i & 1) == 0)
 138                     s->frame.data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
 139                 else
 140                     s->frame.data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
 141                 pixel_ptr++;
 142             }
 143         }
 144     }
 145
 146     /* one last sanity check on the way out */
 147     if (stream_ptr < s->size)
 148         av_log(s->avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
 149             stream_ptr, s->size);
 150 }
 151
 152
 153
 154 static void msrle_decode_pal8(MsrleContext *s)
 155 {
 156     int stream_ptr = 0;
 157     unsigned char rle_code;
 158     unsigned char extra_byte;
 159     unsigned char stream_byte;
 160     int pixel_ptr = 0;
 161     int row_dec = s->frame.linesize[0];
 162     int row_ptr = (s->avctx->height - 1) * row_dec;
 163     int frame_size = row_dec * s->avctx->height;
 164
 165     /* make the palette available */
 166     memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
 167     if (s->avctx->palctrl->palette_changed) {
 168         s->frame.palette_has_changed = 1;
 169         s->avctx->palctrl->palette_changed = 0;
 170     }
 171
 172     while (row_ptr >= 0) {
 173         FETCH_NEXT_STREAM_BYTE();
 174         rle_code = stream_byte;
 175         if (rle_code == 0) {
 176             /* fetch the next byte to see how to handle escape code */
 177             FETCH_NEXT_STREAM_BYTE();
 178             if (stream_byte == 0) {
 179                 /* line is done, goto the next one */
 180                 row_ptr -= row_dec;
 181                 pixel_ptr = 0;
 182             } else if (stream_byte == 1) {
 183                 /* decode is done */
 184                 return;
 185             } else if (stream_byte == 2) {
 186                 /* reposition frame decode coordinates */
 187                 FETCH_NEXT_STREAM_BYTE();
 188                 pixel_ptr += stream_byte;
 189                 FETCH_NEXT_STREAM_BYTE();
 190                 row_ptr -= stream_byte * row_dec;
 191             } else {
 192                 /* copy pixels from encoded stream */
 193                 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
 194                     (row_ptr < 0)) {
 195                     av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
 196                     return;
 197                 }
 198
 199                 rle_code = stream_byte;
 200                 extra_byte = stream_byte & 0x01;
 201                 if (stream_ptr + rle_code + extra_byte > s->size) {
 202                     av_log(s->avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (2)\n");
 203                     return;
 204                 }
 205
 206                 while (rle_code--) {
 207                     FETCH_NEXT_STREAM_BYTE();
 208                     s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
 209                     pixel_ptr++;
 210                 }
 211
 212                 /* if the RLE code is odd, skip a byte in the stream */
 213                 if (extra_byte)
 214                     stream_ptr++;
 215             }
 216         } else {
 217             /* decode a run of data */
 218             if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
 219                 (row_ptr < 0)) {
 220                 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (2)\n");
 221                 return;
 222             }
 223
 224             FETCH_NEXT_STREAM_BYTE();
 225
 226             while(rle_code--) {
 227                 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
 228                 pixel_ptr++;
 229             }
 230         }
 231     }
 232
 233     /* one last sanity check on the way out */
 234     if (stream_ptr < s->size)
 235         av_log(s->avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
 236             stream_ptr, s->size);
 237 }
 238
 239 static av_cold int msrle_decode_init(AVCodecContext *avctx)
 240 {
 241     MsrleContext *s = avctx->priv_data;
 242
 243     s->avctx = avctx;
 244
 245     avctx->pix_fmt = PIX_FMT_PAL8;
 246     s->frame.data[0] = NULL;
 247
 248     return 0;
 249 }
 250
 251 static int msrle_decode_frame(AVCodecContext *avctx,
 252                               void *data, int *data_size,
 253                               const uint8_t *buf, int buf_size)
 254 {
 255     MsrleContext *s = avctx->priv_data;
 256
 257     s->buf = buf;
 258     s->size = buf_size;
 259
 260     s->frame.reference = 1;
 261     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
 262     if (avctx->reget_buffer(avctx, &s->frame)) {
 263         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
 264         return -1;
 265     }
 266
 267     switch (avctx->bits_per_sample) {
 268         case 8:
 269             msrle_decode_pal8(s);
 270             break;
 271         case 4:
 272             msrle_decode_pal4(s);
 273             break;
 274         default:
 275             av_log(avctx, AV_LOG_ERROR, "Don't know how to decode depth %u.\n",
 276                    avctx->bits_per_sample);
 277     }
 278
 279     *data_size = sizeof(AVFrame);
 280     *(AVFrame*)data = s->frame;
 281
 282     /* report that the buffer was completely consumed */
 283     return buf_size;
 284 }
 285
 286 static av_cold int msrle_decode_end(AVCodecContext *avctx)
 287 {
 288     MsrleContext *s = avctx->priv_data;
 289
 290     /* release the last frame */
 291     if (s->frame.data[0])
 292         avctx->release_buffer(avctx, &s->frame);
 293
 294     return 0;
 295 }
 296
 297 AVCodec msrle_decoder = {
 298     "msrle",
 299     CODEC_TYPE_VIDEO,
 300     CODEC_ID_MSRLE,
 301     sizeof(MsrleContext),
 302     msrle_decode_init,
 303     NULL,
 304     msrle_decode_end,
 305     msrle_decode_frame,
 306     CODEC_CAP_DR1,
 307     .long_name= "Microsoft RLE",
 308 };