slow usb port?
USB is quite fast, as long as you are using a computer that is not from 2000 with USB1.0
I am not aware of a particular thing that will solve this, the green lines is what one of the devices I own would make when (wrongly) set on NTSC while digitizing PAL sources. (@latreche34 +1)
Are you in PAL land (Europe) or in France (SECAM)?
you sent a 480p video with 25fps and you talk about SCART...resized PAL?
Your capture card is probably going to need to be replaced, but since you changed VCRs and laptops there are only 2 constants, the capture card and the tape. I don't know if a bad tape would generate such a thing...?
I would say the chances of the device being the culprit are higher.
The device being cheap is not the problem, it is just because it is bad, I have owned an 8$ easy cap, it worked fine for its price, never saw anything like this with it.
Can you plug any of the VCRs to a TV to test?
If budget is really a big concern and you just want to make a test you can look for August vgb on
Amazon, costs about 20 pounds/euros, comes with SCART adapter and it is very acceptable (especially for its price).