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  1. /*
  2.  * RAW H.264 video demuxer
  3.  * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
  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.  
  25. static int h264_probe(AVProbeData *p)
  26. {
  27.     uint32_t code = -1;
  28.     int sps = 0, pps = 0, idr = 0, res = 0, sli = 0;
  29.     int i;
  30.  
  31.     for (i = 0; i < p->buf_size; i++) {
  32.         code = (code << 8) + p->buf[i];
  33.         if ((code & 0xffffff00) == 0x100) {
  34.             int ref_idc = (code >> 5) & 3;
  35.             int type    = code & 0x1F;
  36.             static const int8_t ref_zero[] = {
  37.                  2,  0,  0,  0,  0, -1,  1, -1,
  38.                 -1,  1,  1,  1,  1, -1,  2,  2,
  39.                  2,  2,  2,  0,  2,  2,  2,  2,
  40.                  2,  2,  2,  2,  2,  2,  2,  2
  41.             };
  42.  
  43.             if (code & 0x80) // forbidden_bit
  44.                 return 0;
  45.  
  46.             if (ref_zero[type] == 1 && ref_idc)
  47.                 return 0;
  48.             if (ref_zero[type] == -1 && !ref_idc)
  49.                 return 0;
  50.             if (ref_zero[type] == 2)
  51.                 res++;
  52.  
  53.             switch (type) {
  54.             case 1:
  55.                 sli++;
  56.                 break;
  57.             case 5:
  58.                 idr++;
  59.                 break;
  60.             case 7:
  61.                 if (p->buf[i + 2] & 0x03)
  62.                     return 0;
  63.                 sps++;
  64.                 break;
  65.             case 8:
  66.                 pps++;
  67.                 break;
  68.             }
  69.         }
  70.     }
  71.  
  72.     if (sps && pps && (idr || sli > 3) && res < (sps + pps + idr))
  73.         return AVPROBE_SCORE_EXTENSION + 1;  // 1 more than .mpg
  74.  
  75.     return 0;
  76. }
  77.  
  78. FF_DEF_RAWVIDEO_DEMUXER(h264, "raw H.264 video", h264_probe, "h26l,h264,264,avc", AV_CODEC_ID_H264)
  79.