I used the same connect method on the windows computer using vhs to dvd4.0 and it worked perfectly fine. Maybe Im having problems with my QuickTime? (macOS 10.12)
macOS 10.12 computer has type A USB port? Please check the macOS can read the USB-Video-Grabber correctly by referring to https://vtop.shop/pages/how-can-i-check-if-my-usb-device-is-properly-detected-by-mac-os
Please check what's the hardware name is if it can read it. Thank you!