Use DEMUXER_TYPE_UNKNOWN define.

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@36507 b3059339-0415-0410-9bf9-f77b7e298cf2
Make PES detection less sensitive.

Should fix potential mis-detection of some AAC streams.

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@36508 b3059339-0415-0410-9bf9-f77b7e298cf2