Freeware utility VideoCacheView v1.50 by Nir Sofer allows you to convert .DAT files from the cache of your Internet Explorer or Firefox to .WMV, .WMA files. So if you play an MMS Windows Media stream fully, you may copy it from the cache of your browser with a freeware utility.

VideoCacheView is also useful for copying FLV files from the cache of your browser streamed through the HTTP protocol.