MediaInfo
MediaInfo supplies technical and tag information about a video or audio file. This lets you know the video and audio codecs used during the encoding of the file.
What format (container) does MediaInfo support ?
Video : MKV, OGM, AVI, DivX, WMV, QuickTime, Real, MPEG-1, MPEG-2, MPEG-4, DVD... (Codecs: DivX, XviD, MSMPEG4, ASP, H.264, AVC...)
Audio : OGG, MP3, WAV, RA, AC3, DTS, AAC, M4A, AU, AIFF...
Subtitles : SRT, SSA, ASS, SAMI...