How can I join / combine / concatenate two Windows Media (ASF, WMA, WMV) files?
Windows Movie Maker and Sound Forge 6.0 allow you to do this, and the “wmvappend” utility in the WM Format SDK also offers this functionality. Also, Peck’s PowerJoin is now offering ASF joining. ASFTools should also work (also repairs ASFs, joins, cuts, and indexes them). (Another repair tool is this old ASF Video Repair tool, but I think generally the very old ASFTools is probably the better choice.) Windows Movie Maker (in Windows Me and Windows XP) is also a really easy way to join clips – just File:Import the files you want to join, then toss them onto the timeline, and choose File:Save Movie. (You can validate any ASF files you think are corrupt using ASFView.