VLC media player is an open source video and audio player capable of playing almost any type of media including DVDs and VCDs. In addition to being able to play most video and audio files, VLC can also post free ads without registration
File extensions that can be opened by vlc-media-player

op.ASX	Advanced Stream Redirector
op.DTS	Digital Theater Systems Audio File
op.GXF	General eXchange Format
op.M2V	MPEG-2 Video
op.M3U	MP3 Uniform Resource Locator
op.M4V	MPEG-4 Video File
op.MPEG1	MPEG-1 Video
op.MPEG2	MPEG-2 Video
op.MTS	AVCHD Video File
op.MXF	Material eXchange Format
op.OGM	Ogg Multimedia Container File
op.PLS	Playlist
op.BUP	DVD Information File
op.A52	Dolby Digital AC-3 Compressed Audio File
op.AAC	Advanced Audio Coding Compressed Audio File
op.B4S	Winamp 3+ Playlist
op.CUE	Cue Sheet
op.DIVX	DivX Movie
op.DV	Digital Video
op.FLV	Flash Video
op.M1V	MPEG-1 Video
op.M2TS	MPEG-2 Transport Stream Videos
op.MKV	Matroska Video Stream
op.MOV	Apple QuickTime Movie
op.MPEG4	MPEG-4 Video
op.OMA	OpenMG Audio File
op.SPX	Ogg Speex Audio File
op.TS	DVD Video
op.VLC	VLC Media Player Data
op.VOB	DVD Video Object
op.XSPF	XML Shareable Playlist Format
op.DAT	VCD Video
op.BIN	Binary DVD Video
op.IFO	DVD Information File
op.PART	Partially Downloaded File
op.3G2	3G Mobile Phone Video
op.AVI	Audio Video Interleave
op.MPEG	MPEG Video
op.MPG	MPEG Video
op.FLAC	Free Lossless Audio Codec Compressed Audio FIle
op.M4A	MPEG-4 Audio File
op.MP1	MPEG-1 Audio Layer I
op.OGG	Ogg Multimedia Container File
op.WAV	Waveform Audio
op.XM	Extended Module Audio File
op.3GP	3G Mobile Phone Video
op.SRT	DVD Subtitles File
op.WMV	Windows Media Video
op.AC3	Dolby Digital AC-3 Compressed Audio File
op.ASF	Advanced Systems Format Video
op.MOD	MOD Audio File
op.MP2	MPEG-1 Audio Layer II
op.MP3	MPEG-1 Audio Layer 3
op.MP4	MPEG-4 Part 14 Multimedia Container
op.WMA	Windows Media Audio File
op.MKA	Matroska Audio Stream
op.M4P	Protected AAC File

aop   bop   cop   dop   eop   fop   gop   hop   iop   jop   kop   lop   mop   nop   oop   pop   qop   rop   sop   top   uop   vop   wop   xop   yop   zop   0op   1op   2op   3op   4op   5op   6op   7op   8op   9op