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 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32
  33 #include "libavutil/internal.h"
  34 #include "libavutil/intreadwrite.h"
  35 #include "avcodec.h"
  36 #include "internal.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 = av_frame_alloc();
  75     if (!s->frame)
  76         return AVERROR(ENOMEM);
  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 == AV_PIX_FMT_PAL8)
 178         memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
 179 }
 180
 181 static void msvideo1_decode_16bit(Msvideo1Context *s)
 182 {
 183     int block_ptr, pixel_ptr;
 184     int total_blocks;
 185     int pixel_x, pixel_y;  /* pixel width and height iterators */
 186     int block_x, block_y;  /* block width and height iterators */
 187     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
 188     int block_inc;
 189     int row_dec;
 190
 191     /* decoding parameters */
 192     int stream_ptr;
 193     unsigned char byte_a, byte_b;
 194     unsigned short flags;
 195     int skip_blocks;
 196     unsigned short colors[8];
 197     unsigned short *pixels = (unsigned short *)s->frame->data[0];
 198     int stride = s->frame->linesize[0] / 2;
 199
 200     stream_ptr = 0;
 201     skip_blocks = 0;
 202     blocks_wide = s->avctx->width / 4;
 203     blocks_high = s->avctx->height / 4;
 204     total_blocks = blocks_wide * blocks_high;
 205     block_inc = 4;
 206     row_dec = stride + 4;
 207
 208     for (block_y = blocks_high; block_y > 0; block_y--) {
 209         block_ptr = ((block_y * 4) - 1) * stride;
 210         for (block_x = blocks_wide; block_x > 0; block_x--) {
 211             /* check if this block should be skipped */
 212             if (skip_blocks) {
 213                 block_ptr += block_inc;
 214                 skip_blocks--;
 215                 total_blocks--;
 216                 continue;
 217             }
 218
 219             pixel_ptr = block_ptr;
 220
 221             /* get the next two bytes in the encoded data stream */
 222             CHECK_STREAM_PTR(2);
 223             byte_a = s->buf[stream_ptr++];
 224             byte_b = s->buf[stream_ptr++];
 225
 226             /* check if the decode is finished */
 227             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
 228                 return;
 229             } else if ((byte_b & 0xFC) == 0x84) {
 230                 /* skip code, but don't count the current block */
 231                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
 232             } else if (byte_b < 0x80) {
 233                 /* 2- or 8-color encoding modes */
 234                 flags = (byte_b << 8) | byte_a;
 235
 236                 CHECK_STREAM_PTR(4);
 237                 colors[0] = AV_RL16(&s->buf[stream_ptr]);
 238                 stream_ptr += 2;
 239                 colors[1] = AV_RL16(&s->buf[stream_ptr]);
 240                 stream_ptr += 2;
 241
 242                 if (colors[0] & 0x8000) {
 243                     /* 8-color encoding */
 244                     CHECK_STREAM_PTR(12);
 245                     colors[2] = AV_RL16(&s->buf[stream_ptr]);
 246                     stream_ptr += 2;
 247                     colors[3] = AV_RL16(&s->buf[stream_ptr]);
 248                     stream_ptr += 2;
 249                     colors[4] = AV_RL16(&s->buf[stream_ptr]);
 250                     stream_ptr += 2;
 251                     colors[5] = AV_RL16(&s->buf[stream_ptr]);
 252                     stream_ptr += 2;
 253                     colors[6] = AV_RL16(&s->buf[stream_ptr]);
 254                     stream_ptr += 2;
 255                     colors[7] = AV_RL16(&s->buf[stream_ptr]);
 256                     stream_ptr += 2;
 257
 258                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 259                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 260                             pixels[pixel_ptr++] =
 261                                 colors[((pixel_y & 0x2) << 1) +
 262                                     (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
 263                         pixel_ptr -= row_dec;
 264                     }
 265                 } else {
 266                     /* 2-color encoding */
 267                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 268                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 269                             pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
 270                         pixel_ptr -= row_dec;
 271                     }
 272                 }
 273             } else {
 274                 /* otherwise, it's a 1-color block */
 275                 colors[0] = (byte_b << 8) | byte_a;
 276
 277                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 278                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
 279                         pixels[pixel_ptr++] = colors[0];
 280                     pixel_ptr -= row_dec;
 281                 }
 282             }
 283
 284             block_ptr += block_inc;
 285             total_blocks--;
 286         }
 287     }
 288 }
 289
 290 static int msvideo1_decode_frame(AVCodecContext *avctx,
 291                                 void *data, int *got_frame,
 292                                 AVPacket *avpkt)
 293 {
 294     const uint8_t *buf = avpkt->data;
 295     int buf_size = avpkt->size;
 296     Msvideo1Context *s = avctx->priv_data;
 297     int ret;
 298
 299     s->buf = buf;
 300     s->size = buf_size;
 301
 302     if ((ret = ff_reget_buffer(avctx, s->frame)) < 0) {
 303         av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
 304         return ret;
 305     }
 306
 307     if (s->mode_8bit) {
 308         const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
 309
 310         if (pal) {
 311             memcpy(s->pal, pal, AVPALETTE_SIZE);
 312             s->frame->palette_has_changed = 1;
 313         }
 314     }
 315
 316     if (s->mode_8bit)
 317         msvideo1_decode_8bit(s);
 318     else
 319         msvideo1_decode_16bit(s);
 320
 321     if ((ret = av_frame_ref(data, s->frame)) < 0)
 322         return ret;
 323
 324     *got_frame      = 1;
 325
 326     /* report that the buffer was completely consumed */
 327     return buf_size;
 328 }
 329
 330 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
 331 {
 332     Msvideo1Context *s = avctx->priv_data;
 333
 334     av_frame_free(&s->frame);
 335
 336     return 0;
 337 }
 338
 339 AVCodec ff_msvideo1_decoder = {
 340     .name           = "msvideo1",
 341     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
 342     .type           = AVMEDIA_TYPE_VIDEO,
 343     .id             = AV_CODEC_ID_MSVIDEO1,
 344     .priv_data_size = sizeof(Msvideo1Context),
 345     .init           = msvideo1_decode_init,
 346     .close          = msvideo1_decode_end,
 347     .decode         = msvideo1_decode_frame,
 348     .capabilities   = AV_CODEC_CAP_DR1,
 349 };