ZIX archives are known to be distributed on torrents or other file sharing sites, but are nothing more than a slightly altered variant of ZIP that can be opened only with a malware program known as WinZIX. Some videos (.mp4 files for example) can be found packed in a ZIX archive, which makes users look for zix to mp4 conversion.
The best advice we can give you is to do not bother with .zix files at all and do not download them. In case you have no other option, use tools such as such UnZixWin or UnZixHTA that remove all the rubbish data from these archives and creates regular ZIP files.Open ZIX file Open MP4 file
A program for cleaning ZIX malware archives
A program for extracting WinZix files