In VirtualDub, I'm geting this error below when trying to open a XVID file: "Couldn't locate decompressor for format XviD (Unknown) VirtualDub requires a Video for Windows (VFW) compatible codec to decompress video. DirectShow codecs, such as those used by Windows Media Player are not suitable." It use to work when I have DivX and XVID but eversince I installed FDDSHOW to have both, it doesn't work.
If you want to use ffdshow instead of XviD then you need to make sure that in ffdshow's VfW decoder config you have it enabled to handle XVID. If XviD is installed though, due to the way VfW works it will always be used as a decoder. XviD can handle decoding DivX 4.x, 5.x and 6 by the way.
How do I know if it handles Xvid or set it to handle Xvid? Here is a Screenshot of the config thing if it is differnet from other ones: http://img473.imageshack.us/img473/4665/ss6lk.jpg
Sorry if this is a stupid question but where is that? I can only seem to find the video and audio decoders.
There should be video and audio decoders as well as a config for video encoders, which has a decoder tab. Best way probably to make sure you get it right is to load the ffdshow config from within VirtualDub's compression/codec list. Once you are in there select the decoder tab. If ffdshow doesn't appear on the codec list then it isn't installed properly and won't work even if it was enabled for XviD. Perhaps you are just running a really old version from before ffvfw got merged?