One problem with my HDMI Ambilight project is that it can’t handle encrypted content, or more accurately, it can only handle encrypted content if I spend a lot of money and get an HDCP license, which would then allow me to buy the version of the ADV7611 chip that has built-in HDCP keys. While this doesn’t cause me much of a problem as I tend to watch almost everything via MythTV, with the TV on the HDMI port and the HDMI Light on the DVI port, it would be nice to be able to use an HDMI splitter between my AV receiver and TV instead, and have it still work on the odd occasion when I watch a BluRay directly.
Luckily, my post announcing HDMI Light version 2 was featured on Hackaday, where a couple of people pointed out that it’s actually quite easy to disable the encryption in some HDMI splitters, effectively turning them into HDCP strippers. Even more helpfully, RoyTheReaper described exactly how to disable the encryption in an HDMI splitter I had lying around in my junk box.
While his method works perfectly as far as disabling the decryption is concerned, it has the side effect of also disabling all of the nice little extras that come with HDMI like automatic input switching and controlling the AV receiver volume from the TV remote. What I needed to do was find a way to let the microcontroller in the splitter continue to do all the other things it does while stopping it from enabling encryption.
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