Which codecs should I install?

I'm going to format my computer and reinstall Win XP so now I need to know what codecs etc. to install. I want to be able to watch all types of videos. Also I do some basic video editing in VirtualDub and AviSynth. I also want to be able to use subtitles. So what codecs should I download and install?

Whenever you get a new video that won't play, find out what codec it needs and install it. Over time, you will have all the codecs that you need.

Most AVIs can be at least watched after installing - Haali Media Splitter (MatroskaSplitter.exe + activated AVI handling) - ffdshow If ffdshow doesn't handle it, get the original codecs / DirectShow filters.

You should be able to view practically any file you can find after installing the Gordian Knot codec pack. I just built a new media PC, and the only other thing I needed was Lame ACM.

ac3 filter, and divx codec if you install wmp10-11, usually u have some codecs automatically installed.I avoid codeck pack to keep my system clear of what i do not need.