I've got a project in which I have video output from a camera which I can have in either video out or HDMI out. This signal, then, is to be sent to a Raspberry Pi to be used in a computer vision application. The Raspberry Pi can process video through MIPI/CSI-2 or through USB as a standard webcam. I have looked at HDMI to MIPI/CSI-2 conversion boards, and they can run pretty expensive. I think this is because of low demand. At the core of these conversion boards is a TC358743XBG chip from Toshiba.
My question is
a) How feasible is it for me (I have soldering experience) to make my own conversion board (purely from a hardware perspective- I'll worry about drivers later)?
b) Might there be a better way?