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
  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 <string.h>
  30
  31 #include "libavutil/internal.h"
  32 #include "libavutil/intreadwrite.h"
  33 #include "avcodec.h"
  34 #include "codec_internal.h"
  35 #include "decode.h"
  36
  37 #define PALETTE_COUNT 256
  38 #define CHECK_STREAM_PTR(n) \
  39   if ((stream_ptr + n) > s->size ) { \
  40     av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
  41       stream_ptr + n, s->size); \
  42     return; \
  43   }
  44
  45 typedef struct Msvideo1Context {
  46
  47     AVCodecContext *avctx;
  48     AVFrame *frame;
  49
  50     const unsigned char *buf;
  51     int size;
  52
  53     int mode_8bit;  /* if it's not 8-bit, it's 16-bit */
  54
  55     uint32_t pal[256];
  56 } Msvideo1Context;
  57
  58 static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
  59 {
  60     Msvideo1Context *s = avctx->priv_data;
  61
  62     s->avctx = avctx;
  63
  64     if (avctx->width < 4 || avctx->height < 4)
  65         return AVERROR_INVALIDDATA;
  66
  67     /* figure out the colorspace based on the presence of a palette */
  68     if (s->avctx->bits_per_coded_sample == 8) {
  69         s->mode_8bit = 1;
  70         avctx->pix_fmt = AV_PIX_FMT_PAL8;
  71         if (avctx->extradata_size >= AVPALETTE_SIZE)
  72             memcpy(s->pal, avctx->extradata, AVPALETTE_SIZE);
  73     } else {
  74         s->mode_8bit = 0;
  75         avctx->pix_fmt = AV_PIX_FMT_RGB555;
  76     }
  77
  78     s->frame = av_frame_alloc();
  79     if (!s->frame)
  80         return AVERROR(ENOMEM);
  81
  82     return 0;
  83 }
  84
  85 static void msvideo1_decode_8bit(Msvideo1Context *s)
  86 {
  87     int block_ptr, pixel_ptr;
  88     int total_blocks;
  89     int pixel_x, pixel_y;  /* pixel width and height iterators */
  90     int block_x, block_y;  /* block width and height iterators */
  91     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
  92     int block_inc;
  93     int row_dec;
  94
  95     /* decoding parameters */
  96     int stream_ptr;
  97     unsigned char byte_a, byte_b;
  98     unsigned short flags;
  99     int skip_blocks;
 100     unsigned char colors[8];
 101     unsigned char *pixels = s->frame->data[0];
 102     int stride = s->frame->linesize[0];
 103
 104     stream_ptr = 0;
 105     skip_blocks = 0;
 106     blocks_wide = s->avctx->width / 4;
 107     blocks_high = s->avctx->height / 4;
 108     total_blocks = blocks_wide * blocks_high;
 109     block_inc = 4;
 110     row_dec = stride + 4;
 111
 112     for (block_y = blocks_high; block_y > 0; block_y--) {
 113         block_ptr = ((block_y * 4) - 1) * stride;
 114         for (block_x = blocks_wide; block_x > 0; block_x--) {
 115             /* check if this block should be skipped */
 116             if (skip_blocks) {
 117                 block_ptr += block_inc;
 118                 skip_blocks--;
 119                 total_blocks--;
 120                 continue;
 121             }
 122
 123             pixel_ptr = block_ptr;
 124
 125             /* get the next two bytes in the encoded data stream */
 126             CHECK_STREAM_PTR(2);
 127             byte_a = s->buf[stream_ptr++];
 128             byte_b = s->buf[stream_ptr++];
 129
 130             /* check if the decode is finished */
 131             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
 132                 return;
 133             else if ((byte_b & 0xFC) == 0x84) {
 134                 /* skip code, but don't count the current block */
 135                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
 136             } else if (byte_b < 0x80) {
 137                 /* 2-color encoding */
 138                 flags = (byte_b << 8) | byte_a;
 139
 140                 CHECK_STREAM_PTR(2);
 141                 colors[0] = s->buf[stream_ptr++];
 142                 colors[1] = s->buf[stream_ptr++];
 143
 144                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 145                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 146                         pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
 147                     pixel_ptr -= row_dec;
 148                 }
 149             } else if (byte_b >= 0x90) {
 150                 /* 8-color encoding */
 151                 flags = (byte_b << 8) | byte_a;
 152
 153                 CHECK_STREAM_PTR(8);
 154                 memcpy(colors, &s->buf[stream_ptr], 8);
 155                 stream_ptr += 8;
 156
 157                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 158                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 159                         pixels[pixel_ptr++] =
 160                             colors[((pixel_y & 0x2) << 1) +
 161                                 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
 162                     pixel_ptr -= row_dec;
 163                 }
 164             } else {
 165                 /* 1-color encoding */
 166                 colors[0] = byte_a;
 167
 168                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 169                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
 170                         pixels[pixel_ptr++] = colors[0];
 171                     pixel_ptr -= row_dec;
 172                 }
 173             }
 174
 175             block_ptr += block_inc;
 176             total_blocks--;
 177         }
 178     }
 179
 180     /* make the palette available on the way out */
 181     if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8)
 182         memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
 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, AVFrame *rframe,
 295                                  int *got_frame, AVPacket *avpkt)
 296 {
 297     const uint8_t *buf = avpkt->data;
 298     int buf_size = avpkt->size;
 299     Msvideo1Context *s = avctx->priv_data;
 300     int ret;
 301
 302     s->buf = buf;
 303     s->size = buf_size;
 304
 305     // Discard frame if its smaller than the minimum frame size
 306     if (buf_size < (avctx->width/4) * (avctx->height/4) / 512) {
 307         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
 308         return AVERROR_INVALIDDATA;
 309     }
 310
 311     if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
 312         return ret;
 313
 314     if (s->mode_8bit) {
 315 #if FF_API_PALETTE_HAS_CHANGED
 316 FF_DISABLE_DEPRECATION_WARNINGS
 317         s->frame->palette_has_changed =
 318 #endif
 319         ff_copy_palette(s->pal, avpkt, avctx);
 320 #if FF_API_PALETTE_HAS_CHANGED
 321 FF_ENABLE_DEPRECATION_WARNINGS
 322 #endif
 323     }
 324
 325     if (s->mode_8bit)
 326         msvideo1_decode_8bit(s);
 327     else
 328         msvideo1_decode_16bit(s);
 329
 330     if ((ret = av_frame_ref(rframe, s->frame)) < 0)
 331         return ret;
 332
 333     *got_frame      = 1;
 334
 335     /* report that the buffer was completely consumed */
 336     return buf_size;
 337 }
 338
 339 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
 340 {
 341     Msvideo1Context *s = avctx->priv_data;
 342
 343     av_frame_free(&s->frame);
 344
 345     return 0;
 346 }
 347
 348 const FFCodec ff_msvideo1_decoder = {
 349     .p.name         = "msvideo1",
 350     CODEC_LONG_NAME("Microsoft Video 1"),
 351     .p.type         = AVMEDIA_TYPE_VIDEO,
 352     .p.id           = AV_CODEC_ID_MSVIDEO1,
 353     .priv_data_size = sizeof(Msvideo1Context),
 354     .init           = msvideo1_decode_init,
 355     .close          = msvideo1_decode_end,
 356     FF_CODEC_DECODE_CB(msvideo1_decode_frame),
 357     .p.capabilities = AV_CODEC_CAP_DR1,
 358 };