Does the Raspberry Pi GPU support hardware video encoding when capturing from a USB video capture card?

Question

fmpeg

Good afternoon.
I read that raspberry supports hardware encoding (with the purchase of the appropriate license) in mpeg2, vc1.
The question is next. GPU hardware support for stock camera only?
If I encode video from a usb video capture card from an analog camera using ffmpeg, will there be hardware support or in this case all the load is only on the cpu?
Thank you.