I am using Vegas 12 and an Ultrastudio SDI USB 3.0 capture device, and am hearing a clicking sound when capturing. It is random, but intensifies during louder volumes. Its timing aside from that seems random. I hear it both in the preview capture window and in the clip on the timeline, although the clip on the timeline has it alot less.

I have checked all my sample rates, and when using Blackmagic's Desktop Video software I am able to capture uncompressed perfectly without any audible clicking. Any help is appreciated, thanks.