You can find a list of capture cards that we have tested and confirmed are supported on our website, using the below link.
This is not by any means the only devices we support, just the devices we've been able to test and confirm supported. None of these have the hardware converting the captured content to MPEG-2. If you know that your end result will be MPEG-4, you really do not want a capture device that will automatically convert the captured content to MPEG-2.
We support any capture card that is 'DirectShow' compatible.
And soon, though not soon enough, we will grow this list for support of additional capture devices.