I have already tried a few such devices. I would at least like to achieve reasonable SD at 720 X 480. HD would be a plus, but not necessary. My camera has HDMI, SDI, and Component and composit out. I have already tried a couple of capture devices, and the results were as follows.
SIIG USB 2.0 Video Capture Device - JU-AV0012-S1
Pretty clear as to why this was so cheap. It claims full NTSC support, but that is only on the input. Output is 320 X 240 only.
DIAMOND USB 2.0 HD Game Console Video Capture Device GC500 USB 2.0 Interface
Again, this unit claims "HD" but that is only on the input. Output is 640 x 480. The image quality was terrible with the supplied software, or with Adobe FMLE. Noisy, and well below full NTSC quality. Even when fed with the component out of a Sony NX5. Unacceptable. Even for the bargain price at Frys.
Hauppauge HD PVR 2 Gaming Edition
Seems I bought a dud. I went back and forth with Hauppauge support, and never could get this to be detected by FMLE, or the included software. On doing a search online for the error message I received, I discovered many similar trouble reports on various forums. I bought this one at a discounted price. Perhaps this is the reason why.
The notebook I have is a Windows unit, with no expresscard slot, or 1394 input (unfortunately). I did look briefly at the Blackmagic Intesity Shuttle, but it needs USB 3.0.
Curious to hear of any sucess with USB capture and FMLE, and with a device under (hopefully well under?)$200.