There is a very Good DShowInputDriver Plugin for
VirtualDub which allows VirtualDub to open Many
file types for example MP4 and MKV which by default
not supported by VirtualDub.
More information can be found here -
http://forums.virtualdub.org/index.php?act=ST&f=7&t=15093&st=0
http://forum.videohelp.com/threads/286901-VirtualDub-Now-Has-a-Directsho...
I think this Plugin must be included in the VirtualDub Portable Plugins Pack.