libavcodec/msvideo1.c

   1 /*
   2  * Microsoft Video-1 Decoder
   3  * Copyright (C) 2003 the ffmpeg project
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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
  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  */
  29
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33
  34 #include "libavutil/internal.h"
  35 #include "libavutil/intreadwrite.h"
  36 #include "avcodec.h"
  37
  38 #define PALETTE_COUNT 256
  39 #define CHECK_STREAM_PTR(n) \
  40   if ((stream_ptr + n) > s->size ) { \
  41     av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
  42       stream_ptr + n, s->size); \
  43     return; \
  44   }
  45
  46 typedef struct Msvideo1Context {
  47
  48     AVCodecContext *avctx;
  49     AVFrame frame;
  50
  51     const unsigned char *buf;
  52     int size;
  53
  54     int mode_8bit;  /* if it's not 8-bit, it's 16-bit */
  55
  56     uint32_t pal[256];
  57 } Msvideo1Context;
  58
  59 static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
  60 {
  61     Msvideo1Context *s = avctx->priv_data;
  62
  63     s->avctx = avctx;
  64
  65     /* figure out the colorspace based on the presence of a palette */
  66     if (s->avctx->bits_per_coded_sample == 8) {
  67         s->mode_8bit = 1;
  68         avctx->pix_fmt = AV_PIX_FMT_PAL8;
  69     } else {
  70         s->mode_8bit = 0;
  71         avctx->pix_fmt = AV_PIX_FMT_RGB555;
  72     }
  73
  74     s->frame.data[0] = NULL;
  75
  76     return 0;
  77 }
  78
  79 static void msvideo1_decode_8bit(Msvideo1Context *s)
  80 {
  81     int block_ptr, pixel_ptr;
  82     int total_blocks;
  83     int pixel_x, pixel_y;  /* pixel width and height iterators */
  84     int block_x, block_y;  /* block width and height iterators */
  85     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
  86     int block_inc;
  87     int row_dec;
  88
  89     /* decoding parameters */
  90     int stream_ptr;
  91     unsigned char byte_a, byte_b;
  92     unsigned short flags;
  93     int skip_blocks;
  94     unsigned char colors[8];
  95     unsigned char *pixels = s->frame.data[0];
  96     int stride = s->frame.linesize[0];
  97
  98     stream_ptr = 0;
  99     skip_blocks = 0;
 100     blocks_wide = s->avctx->width / 4;
 101     blocks_high = s->avctx->height / 4;
 102     total_blocks = blocks_wide * blocks_high;
 103     block_inc = 4;
 104     row_dec = stride + 4;
 105
 106     for (block_y = blocks_high; block_y > 0; block_y--) {
 107         block_ptr = ((block_y * 4) - 1) * stride;
 108         for (block_x = blocks_wide; block_x > 0; block_x--) {
 109             /* check if this block should be skipped */
 110             if (skip_blocks) {
 111                 block_ptr += block_inc;
 112                 skip_blocks--;
 113                 total_blocks--;
 114                 continue;
 115             }
 116
 117             pixel_ptr = block_ptr;
 118
 119             /* get the next two bytes in the encoded data stream */
 120             CHECK_STREAM_PTR(2);
 121             byte_a = s->buf[stream_ptr++];
 122             byte_b = s->buf[stream_ptr++];
 123
 124             /* check if the decode is finished */
 125             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
 126                 return;
 127             else if ((byte_b & 0xFC) == 0x84) {
 128                 /* skip code, but don't count the current block */
 129                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
 130             } else if (byte_b < 0x80) {
 131                 /* 2-color encoding */
 132                 flags = (byte_b << 8) | byte_a;
 133
 134                 CHECK_STREAM_PTR(2);
 135                 colors[0] = s->buf[stream_ptr++];
 136                 colors[1] = s->buf[stream_ptr++];
 137
 138                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 139                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 140                         pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
 141                     pixel_ptr -= row_dec;
 142                 }
 143             } else if (byte_b >= 0x90) {
 144                 /* 8-color encoding */
 145                 flags = (byte_b << 8) | byte_a;
 146
 147                 CHECK_STREAM_PTR(8);
 148                 memcpy(colors, &s->buf[stream_ptr], 8);
 149                 stream_ptr += 8;
 150
 151                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 152                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 153                         pixels[pixel_ptr++] =
 154                             colors[((pixel_y & 0x2) << 1) +
 155                                 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
 156                     pixel_ptr -= row_dec;
 157                 }
 158             } else {
 159                 /* 1-color encoding */
 160                 colors[0] = byte_a;
 161
 162                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 163                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
 164                         pixels[pixel_ptr++] = colors[0];
 165                     pixel_ptr -= row_dec;
 166                 }
 167             }
 168
 169             block_ptr += block_inc;
 170             total_blocks--;
 171         }
 172     }
 173
 174     /* make the palette available on the way out */
 175     if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8)
 176         memcpy(s->frame.data[1], s->pal, AVPALETTE_SIZE);
 177 }
 178
 179 static void msvideo1_decode_16bit(Msvideo1Context *s)
 180 {
 181     int block_ptr, pixel_ptr;
 182     int total_blocks;
 183     int pixel_x, pixel_y;  /* pixel width and height iterators */
 184     int block_x, block_y;  /* block width and height iterators */
 185     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
 186     int block_inc;
 187     int row_dec;
 188
 189     /* decoding parameters */
 190     int stream_ptr;
 191     unsigned char byte_a, byte_b;
 192     unsigned short flags;
 193     int skip_blocks;
 194     unsigned short colors[8];
 195     unsigned short *pixels = (unsigned short *)s->frame.data[0];
 196     int stride = s->frame.linesize[0] / 2;
 197
 198     stream_ptr = 0;
 199     skip_blocks = 0;
 200     blocks_wide = s->avctx->width / 4;
 201     blocks_high = s->avctx->height / 4;
 202     total_blocks = blocks_wide * blocks_high;
 203     block_inc = 4;
 204     row_dec = stride + 4;
 205
 206     for (block_y = blocks_high; block_y > 0; block_y--) {
 207         block_ptr = ((block_y * 4) - 1) * stride;
 208         for (block_x = blocks_wide; block_x > 0; block_x--) {
 209             /* check if this block should be skipped */
 210             if (skip_blocks) {
 211                 block_ptr += block_inc;
 212                 skip_blocks--;
 213                 total_blocks--;
 214                 continue;
 215             }
 216
 217             pixel_ptr = block_ptr;
 218
 219             /* get the next two bytes in the encoded data stream */
 220             CHECK_STREAM_PTR(2);
 221             byte_a = s->buf[stream_ptr++];
 222             byte_b = s->buf[stream_ptr++];
 223
 224             /* check if the decode is finished */
 225             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
 226                 return;
 227             } else if ((byte_b & 0xFC) == 0x84) {
 228                 /* skip code, but don't count the current block */
 229                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
 230             } else if (byte_b < 0x80) {
 231                 /* 2- or 8-color encoding modes */
 232                 flags = (byte_b << 8) | byte_a;
 233
 234                 CHECK_STREAM_PTR(4);
 235                 colors[0] = AV_RL16(&s->buf[stream_ptr]);
 236                 stream_ptr += 2;
 237                 colors[1] = AV_RL16(&s->buf[stream_ptr]);
 238                 stream_ptr += 2;
 239
 240                 if (colors[0] & 0x8000) {
 241                     /* 8-color encoding */
 242                     CHECK_STREAM_PTR(12);
 243                     colors[2] = AV_RL16(&s->buf[stream_ptr]);
 244                     stream_ptr += 2;
 245                     colors[3] = AV_RL16(&s->buf[stream_ptr]);
 246                     stream_ptr += 2;
 247                     colors[4] = AV_RL16(&s->buf[stream_ptr]);
 248                     stream_ptr += 2;
 249                     colors[5] = AV_RL16(&s->buf[stream_ptr]);
 250                     stream_ptr += 2;
 251                     colors[6] = AV_RL16(&s->buf[stream_ptr]);
 252                     stream_ptr += 2;
 253                     colors[7] = AV_RL16(&s->buf[stream_ptr]);
 254                     stream_ptr += 2;
 255
 256                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 257                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 258                             pixels[pixel_ptr++] =
 259                                 colors[((pixel_y & 0x2) << 1) +
 260                                     (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
 261                         pixel_ptr -= row_dec;
 262                     }
 263                 } else {
 264                     /* 2-color encoding */
 265                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 266                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 267                             pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
 268                         pixel_ptr -= row_dec;
 269                     }
 270                 }
 271             } else {
 272                 /* otherwise, it's a 1-color block */
 273                 colors[0] = (byte_b << 8) | byte_a;
 274
 275                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 276                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
 277                         pixels[pixel_ptr++] = colors[0];
 278                     pixel_ptr -= row_dec;
 279                 }
 280             }
 281
 282             block_ptr += block_inc;
 283             total_blocks--;
 284         }
 285     }
 286 }
 287
 288 static int msvideo1_decode_frame(AVCodecContext *avctx,
 289                                 void *data, int *got_frame,
 290                                 AVPacket *avpkt)
 291 {
 292     const uint8_t *buf = avpkt->data;
 293     int buf_size = avpkt->size;
 294     Msvideo1Context *s = avctx->priv_data;
 295
 296     s->buf = buf;
 297     s->size = buf_size;
 298
 299     s->frame.reference = 1;
 300     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
 301     if (avctx->reget_buffer(avctx, &s->frame)) {
 302         av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
 303         return -1;
 304     }
 305
 306     if (s->mode_8bit) {
 307         const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
 308
 309         if (pal) {
 310             memcpy(s->pal, pal, AVPALETTE_SIZE);
 311             s->frame.palette_has_changed = 1;
 312         }
 313     }
 314
 315     if (s->mode_8bit)
 316         msvideo1_decode_8bit(s);
 317     else
 318         msvideo1_decode_16bit(s);
 319
 320     *got_frame      = 1;
 321     *(AVFrame*)data = s->frame;
 322
 323     /* report that the buffer was completely consumed */
 324     return buf_size;
 325 }
 326
 327 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
 328 {
 329     Msvideo1Context *s = avctx->priv_data;
 330
 331     if (s->frame.data[0])
 332         avctx->release_buffer(avctx, &s->frame);
 333
 334     return 0;
 335 }
 336
 337 AVCodec ff_msvideo1_decoder = {
 338     .name           = "msvideo1",
 339     .type           = AVMEDIA_TYPE_VIDEO,
 340     .id             = AV_CODEC_ID_MSVIDEO1,
 341     .priv_data_size = sizeof(Msvideo1Context),
 342     .init           = msvideo1_decode_init,
 343     .close          = msvideo1_decode_end,
 344     .decode         = msvideo1_decode_frame,
 345     .capabilities   = CODEC_CAP_DR1,
 346     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
 347 };