There are a large range of video codecs available that do not come pre-installed in Windows. There are a lesser number of audio codecs as well. On commonly used codec is DivX and is a popular codec for videos. Additionally there are a variety of DV codecs for cameras and also MPEG2 as used in home video.

Identifying the Codec for a file

You will a codec to play a video using Windows Media Player (or Prism) and to convert from such a file or to convert to it as well. If you have an existing file try playing it with 'Windows Media Player' (not the excellent Windows Media Player Classic as it has codecs built in). If the video plays then you have the needed codec installed and Prism can convert it.

If the video still does not play you will need to locate a codec for it. There a a number of good utility programs that can tell you the codec for a given video. Listed below are two such programs

- GSpot Codec Information Appliance
- VideoInspector Investigates Coded issues

These applications will also provide download links for the codec in question.

Locating the Codec

There are a large range of sites you can download a codec from. Listed below are a few

- Free-Codecs
- VideoHelp Also contains a large amount of help for general video work
- Doom9 Similiarly lots of news and guides