Download this to be able to view .ogm files in your media player.

Real Alternative will allow you to play RealMedia file without having to install RealPlayer or RealOne Player.

QuickTime Alternative will allow you to play QuickTime files (.mov, .qt and other extensions) without having to install the official QuickTime Player.

Use this if you have trouble editing your DV video files.

Download this to be able to play Matroska files. (.mkv) - Matroska container.

The famous XviD build by Koepi. Probably the best MPEG4 codec around.

FFDSHOW is a DirectShow decoding filter for decompressing DivX, XviD, WMV, MPEG-1 and MPEG-2 movies. It uses libavcodec from ffmpeg project for video decompression, postprocessing code from mplayer to enhance visual quality of low bitrate movies, and is based on original DirectShow filter from XviD, which is GPL'ed educational implementation of MPEG4 encoder.

The famous MPEG4 codec. Package is for Windows2000/XP and contains both the freeware and the trial of the Pro version.