How to flip the hdmi display

I would like to build a "mirror" using a camera, a RPI and a led monitor which has a hdmi input. But I don't have the right to change anything of the RPI, so I have to first receive the display from the RPI hdmi output and then flip it and feed it to the monitor. Initially I check with some hdmi transceiver, like this one:
http://www.epmi.com.tw/pro_d.php?pk=119

But I wonder if one could do that easily with an arduino. For example, if one can simply change some part of the hdmi signal and then feed the whole thing to the monitor. Any idea? suggestion?

BTW, I would like to have as low delay as possible. Because this system is for a vehicle.