libavformat/vc1dec.c

   1 /*
   2  * VC-1 demuxer
   3  * Copyright (c) 2015 Carl Eugen Hoyos
   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 #include "avformat.h"
  23 #include "rawdec.h"
  24 #include "libavutil/intreadwrite.h"
  25 #include "libavcodec/vc1_common.h"
  26
  27 static int vc1_probe(AVProbeData *p)
  28 {
  29     int seq = 0, entry = 0, frame = 0, i;
  30
  31     for (i = 0; i < p->buf_size + 5; i++) {
  32         uint32_t code = AV_RB32(p->buf + i);
  33         if ((code & 0xffffffe0) == 0x100) {
  34             int type = code & 0x11f;
  35             i += 4;
  36             switch (type) {
  37             case VC1_CODE_SEQHDR: {
  38                 int profile, level, chromaformat;
  39                 profile = (p->buf[i] & 0xc0) >> 6;
  40                 if (profile != PROFILE_ADVANCED) {
  41                     seq = 0;
  42                     continue;
  43                 }
  44                 level = (p->buf[i] & 0x38) >> 3;
  45                 if (level >= 5) {
  46                     seq = 0;
  47                     continue;
  48                 }
  49                 chromaformat = (p->buf[i] & 0x6) >> 1;
  50                 if (chromaformat != 1) {
  51                     seq = 0;
  52                     continue;
  53                 }
  54                 seq++;
  55                 i += 6;
  56                 break;
  57             }
  58             case VC1_CODE_ENTRYPOINT:
  59                 if (!seq)
  60                     continue;
  61                 entry++;
  62                 i += 2;
  63                 break;
  64             case VC1_CODE_FRAME:
  65             case VC1_CODE_FIELD:
  66             case VC1_CODE_SLICE:
  67                 if (seq && entry)
  68                     frame++;
  69                 break;
  70             }
  71         }
  72     }
  73
  74     if (frame > 1)
  75         return AVPROBE_SCORE_EXTENSION / 2 + 1;
  76     if (frame == 1)
  77         return AVPROBE_SCORE_EXTENSION / 4;
  78     return 0;
  79 }
  80
  81 FF_DEF_RAWVIDEO_DEMUXER2(vc1, "raw VC-1", vc1_probe, "vc1", AV_CODEC_ID_VC1, AVFMT_GENERIC_INDEX|AVFMT_NOTIMESTAMPS)