How can I convert an HDMI output from streaming devices like Roku or Amazon Fire into a USB input? I want to connect streaming device like Roku to USB input of 4k Blu Ray player.
I don't think you can do that. A BD player isn't a computer so the functions that USB can handle are limited.
Not sure why you would want to do that anyway..
If you don't have enough HDMI inputs on the display get an HDMI input selector to expand the number.