MediaInfo is a free app for Windows, Linux, and Mac that supplies the user with useful technical and tag information about a video or audio file. CLI version and Portable (no dependencies) are also available.

With MediaInfo's graphical Interface, you can quickly gather and view the following information about an audio or video file; title, author, director, album, track number, date, duration, as well as video and audio codec, aspect, fps, bitrate, sample rate, channels, and language. You can customize any viewing method to suit your preferences. It also allows you to work through the Command Line or DLL if you wish and is fully integrated with the MS-Windows shell (drag 'n' drop and Context menu).

MediaInfo supports DivX, XviD, H263, H.263, H264, x264, ASP, AVC, iTunes, MPEG-1, MPEG1, MPEG-2, MPEG2, MPEG-4, MPEG4, MP4, M4A, M4V, QuickTime, RealVideo, RealAudio, RA, RM, MSMPEG4v1, MSMPEG4v2, MSMPEG4v3, VOB, DVD, WMA, VMW, ASF, 3GP, 3GPP, 3GP2, multiplexer, demuxer, mixer, mixer, video decoder, audio decoder, PAL, NTSC and numerous languages which will display on any version of your operating system.