Free Video Editor that Supports many Codecs?

Is there a free video editor that support loads of codecs like VLC Media Player does?

If there isn't a free one, is there one you can buy outright and not have to pay monthly or licencing fees?

I've tried editing only with Windows Movie Makers but that doesn't support any of the codecs of the videos I'm trying to edit.

I don't want to do major editing, I just want to add a watermark to the videos and maybe a short clip at the start of them.

Thanks.

Easy Video Maker is a good, free (shareware) editing program - although it doesn't support as many codecs as VLC Media Player. Incidentally, the good folks at VLC are working on an editing program. It was in alpha release, but last time I visited the site I saw it had been taken down . I'm sure there will be a beta release at some point.