I had a project about using a capture card (not NI) with LabVIEW to record TV programmes. I found some video capturing programs supported ActiveX and called the program functions in LabVIEW through ActiveX. However the performance was not good because sometime the program was hanged when it ran for a certain time. I still don't know the reason (maybe incompatible of the card and the capture program) but you can try.
Bill
