This (black screen / bad video on AMCap) sounds like one of the issues I covered in my EasyCap driver installation document here
here. Go to the second paragraph in the "COME BACK HERE FOR THE NEXT USB PORT:" section.
I am using the 1 input version though, not the 4 input EasyCap002.
Once you get the default settings set correctly using AMCap, your other software will probably work correctly.
Cliff