Capture Sony 8 video to mp4 through USB

I have a Sony 8 camcorder, and the appropriate wires to take the video output from the camera in to my PC through the USB port.  This is all working as it should.

I am looking for software to capture this input video to a digital format.  I'd prefer MP4, but right now I am more interested in translation/capture.  Most of the software that I have found captures SCREEN and works well with the built in video camera on my PC, but capturing this input feed seems problematic.

I am willing to pay for the software.  Just need a good solution.  I have over 70 hours of video that I would like to start converting asap.