Installed Codec (via Shell Extension City) is another fine NirSoft tool that displays all installed codecs of a Windows 2000, 2003, XP or Vista system in a table. All meaning all Codec drivers and DirectShow but not binary codecs which are used by some applications like MPlayer.

The software lists the name of the codec, its installation path and file, the company that developed it and if it is enabled on the system. Each codec in the list can be disabled which has the effect that this codec will not be used to play the supported multimedia files. Excellent if you want to make sure that a specific codec is playing certain videos.

Removing some of the installed codecs can be achieved by disabling the codecs first and checking if the videos still play fine. If that is the case I would temporarily move them to another directory and if nothing bad happens delete them from the system. Most of the codecs installed on my Windows XP system are from Nero 8 which is kinda strange because I have not installed all those additional converters and tools that come with it. The codecs seem to get installed nevertheless.