My editing PC is running x64, I know this isn't "officially supported" but I've used Vegas 6 and Vegas 7 without issue.
In Vegas 8, I cannot capture any HDV. Select "Capture Video" then "HDV or SDI", click "OK" and... and... nothing happens. Nothing at all. There are no errors and Vegas continues to run as normal.
This is with my Canon HV20, which works fine in Vegas 7 on the same machine.
Capturing from a DV source in Vegas 8 works as it always did, bringing up the applicable interface.
Could someone else on x64 (or perhaps even Vista 64) please confirm that the HDV capture interface works for them - or exists at all?! ;-)