ffmpeg/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
  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 #include "internal.h"
  38
  39 #define PALETTE_COUNT 256
  40 #define CHECK_STREAM_PTR(n) \
  41   if ((stream_ptr + n) > s->size ) { \
  42     av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
  43       stream_ptr + n, s->size); \
  44     return; \
  45   }
  46
  47 typedef struct Msvideo1Context {
  48
  49     AVCodecContext *avctx;
  50     AVFrame *frame;
  51
  52     const unsigned char *buf;
  53     int size;
  54
  55     int mode_8bit;  /* if it's not 8-bit, it's 16-bit */
  56
  57     uint32_t pal[256];
  58 } Msvideo1Context;
  59
  60 static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
  61 {
  62     Msvideo1Context *s = avctx->priv_data;
  63
  64     s->avctx = avctx;
  65
  66     /* figure out the colorspace based on the presence of a palette */
  67     if (s->avctx->bits_per_coded_sample == 8) {
  68         s->mode_8bit = 1;
  69         avctx->pix_fmt = AV_PIX_FMT_PAL8;
  70         if (avctx->extradata_size >= AVPALETTE_SIZE)
  71             memcpy(s->pal, avctx->extradata, AVPALETTE_SIZE);
  72     } else {
  73         s->mode_8bit = 0;
  74         avctx->pix_fmt = AV_PIX_FMT_RGB555;
  75     }
  76
  77     s->frame = av_frame_alloc();
  78     if (!s->frame)
  79         return AVERROR(ENOMEM);
  80
  81     return 0;
  82 }
  83
  84 static void msvideo1_decode_8bit(Msvideo1Context *s)
  85 {
  86     int block_ptr, pixel_ptr;
  87     int total_blocks;
  88     int pixel_x, pixel_y;  /* pixel width and height iterators */
  89     int block_x, block_y;  /* block width and height iterators */
  90     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
  91     int block_inc;
  92     int row_dec;
  93
  94     /* decoding parameters */
  95     int stream_ptr;
  96     unsigned char byte_a, byte_b;
  97     unsigned short flags;
  98     int skip_blocks;
  99     unsigned char colors[8];
 100     unsigned char *pixels = s->frame->data[0];
 101     int stride = s->frame->linesize[0];
 102
 103     stream_ptr = 0;
 104     skip_blocks = 0;
 105     blocks_wide = s->avctx->width / 4;
 106     blocks_high = s->avctx->height / 4;
 107     total_blocks = blocks_wide * blocks_high;
 108     block_inc = 4;
 109     row_dec = stride + 4;
 110
 111     for (block_y = blocks_high; block_y > 0; block_y--) {
 112         block_ptr = ((block_y * 4) - 1) * stride;
 113         for (block_x = blocks_wide; block_x > 0; block_x--) {
 114             /* check if this block should be skipped */
 115             if (skip_blocks) {
 116                 block_ptr += block_inc;
 117                 skip_blocks--;
 118                 total_blocks--;
 119                 continue;
 120             }
 121
 122             pixel_ptr = block_ptr;
 123
 124             /* get the next two bytes in the encoded data stream */
 125             CHECK_STREAM_PTR(2);
 126             byte_a = s->buf[stream_ptr++];
 127             byte_b = s->buf[stream_ptr++];
 128
 129             /* check if the decode is finished */
 130             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
 131                 return;
 132             else if ((byte_b & 0xFC) == 0x84) {
 133                 /* skip code, but don't count the current block */
 134                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
 135             } else if (byte_b < 0x80) {
 136                 /* 2-color encoding */
 137                 flags = (byte_b << 8) | byte_a;
 138
 139                 CHECK_STREAM_PTR(2);
 140                 colors[0] = s->buf[stream_ptr++];
 141                 colors[1] = s->buf[stream_ptr++];
 142
 143                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 144                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 145                         pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
 146                     pixel_ptr -= row_dec;
 147                 }
 148             } else if (byte_b >= 0x90) {
 149                 /* 8-color encoding */
 150                 flags = (byte_b << 8) | byte_a;
 151
 152                 CHECK_STREAM_PTR(8);
 153                 memcpy(colors, &s->buf[stream_ptr], 8);
 154                 stream_ptr += 8;
 155
 156                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 157                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 158                         pixels[pixel_ptr++] =
 159                             colors[((pixel_y & 0x2) << 1) +
 160                                 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
 161                     pixel_ptr -= row_dec;
 162                 }
 163             } else {
 164                 /* 1-color encoding */
 165                 colors[0] = byte_a;
 166
 167                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 168                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
 169                         pixels[pixel_ptr++] = colors[0];
 170                     pixel_ptr -= row_dec;
 171                 }
 172             }
 173
 174             block_ptr += block_inc;
 175             total_blocks--;
 176         }
 177     }
 178
 179     /* make the palette available on the way out */
 180     if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8)
 181         memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
 182 }
 183
 184 static void msvideo1_decode_16bit(Msvideo1Context *s)
 185 {
 186     int block_ptr, pixel_ptr;
 187     int total_blocks;
 188     int pixel_x, pixel_y;  /* pixel width and height iterators */
 189     int block_x, block_y;  /* block width and height iterators */
 190     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
 191     int block_inc;
 192     int row_dec;
 193
 194     /* decoding parameters */
 195     int stream_ptr;
 196     unsigned char byte_a, byte_b;
 197     unsigned short flags;
 198     int skip_blocks;
 199     unsigned short colors[8];
 200     unsigned short *pixels = (unsigned short *)s->frame->data[0];
 201     int stride = s->frame->linesize[0] / 2;
 202
 203     stream_ptr = 0;
 204     skip_blocks = 0;
 205     blocks_wide = s->avctx->width / 4;
 206     blocks_high = s->avctx->height / 4;
 207     total_blocks = blocks_wide * blocks_high;
 208     block_inc = 4;
 209     row_dec = stride + 4;
 210
 211     for (block_y = blocks_high; block_y > 0; block_y--) {
 212         block_ptr = ((block_y * 4) - 1) * stride;
 213         for (block_x = blocks_wide; block_x > 0; block_x--) {
 214             /* check if this block should be skipped */
 215             if (skip_blocks) {
 216                 block_ptr += block_inc;
 217                 skip_blocks--;
 218                 total_blocks--;
 219                 continue;
 220             }
 221
 222             pixel_ptr = block_ptr;
 223
 224             /* get the next two bytes in the encoded data stream */
 225             CHECK_STREAM_PTR(2);
 226             byte_a = s->buf[stream_ptr++];
 227             byte_b = s->buf[stream_ptr++];
 228
 229             /* check if the decode is finished */
 230             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
 231                 return;
 232             } else if ((byte_b & 0xFC) == 0x84) {
 233                 /* skip code, but don't count the current block */
 234                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
 235             } else if (byte_b < 0x80) {
 236                 /* 2- or 8-color encoding modes */
 237                 flags = (byte_b << 8) | byte_a;
 238
 239                 CHECK_STREAM_PTR(4);
 240                 colors[0] = AV_RL16(&s->buf[stream_ptr]);
 241                 stream_ptr += 2;
 242                 colors[1] = AV_RL16(&s->buf[stream_ptr]);
 243                 stream_ptr += 2;
 244
 245                 if (colors[0] & 0x8000) {
 246                     /* 8-color encoding */
 247                     CHECK_STREAM_PTR(12);
 248                     colors[2] = AV_RL16(&s->buf[stream_ptr]);
 249                     stream_ptr += 2;
 250                     colors[3] = AV_RL16(&s->buf[stream_ptr]);
 251                     stream_ptr += 2;
 252                     colors[4] = AV_RL16(&s->buf[stream_ptr]);
 253                     stream_ptr += 2;
 254                     colors[5] = AV_RL16(&s->buf[stream_ptr]);
 255                     stream_ptr += 2;
 256                     colors[6] = AV_RL16(&s->buf[stream_ptr]);
 257                     stream_ptr += 2;
 258                     colors[7] = AV_RL16(&s->buf[stream_ptr]);
 259                     stream_ptr += 2;
 260
 261                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 262                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 263                             pixels[pixel_ptr++] =
 264                                 colors[((pixel_y & 0x2) << 1) +
 265                                     (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
 266                         pixel_ptr -= row_dec;
 267                     }
 268                 } else {
 269                     /* 2-color encoding */
 270                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 271                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
 272                             pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
 273                         pixel_ptr -= row_dec;
 274                     }
 275                 }
 276             } else {
 277                 /* otherwise, it's a 1-color block */
 278                 colors[0] = (byte_b << 8) | byte_a;
 279
 280                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
 281                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
 282                         pixels[pixel_ptr++] = colors[0];
 283                     pixel_ptr -= row_dec;
 284                 }
 285             }
 286
 287             block_ptr += block_inc;
 288             total_blocks--;
 289         }
 290     }
 291 }
 292
 293 static int msvideo1_decode_frame(AVCodecContext *avctx,
 294                                 void *data, int *got_frame,
 295                                 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     if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
 306         return ret;
 307
 308     if (s->mode_8bit) {
 309         const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
 310
 311         if (pal) {
 312             memcpy(s->pal, pal, AVPALETTE_SIZE);
 313             s->frame->palette_has_changed = 1;
 314         }
 315     }
 316
 317     if (s->mode_8bit)
 318         msvideo1_decode_8bit(s);
 319     else
 320         msvideo1_decode_16bit(s);
 321
 322     if ((ret = av_frame_ref(data, s->frame)) < 0)
 323         return ret;
 324
 325     *got_frame      = 1;
 326
 327     /* report that the buffer was completely consumed */
 328     return buf_size;
 329 }
 330
 331 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
 332 {
 333     Msvideo1Context *s = avctx->priv_data;
 334
 335     av_frame_free(&s->frame);
 336
 337     return 0;
 338 }
 339
 340 AVCodec ff_msvideo1_decoder = {
 341     .name           = "msvideo1",
 342     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
 343     .type           = AVMEDIA_TYPE_VIDEO,
 344     .id             = AV_CODEC_ID_MSVIDEO1,
 345     .priv_data_size = sizeof(Msvideo1Context),
 346     .init           = msvideo1_decode_init,
 347     .close          = msvideo1_decode_end,
 348     .decode         = msvideo1_decode_frame,
 349     .capabilities   = CODEC_CAP_DR1,
 350 };