Ok, so this isn't really an arduino specific question (although maybe it can be answered with arduino, I don't know!), but I figured all the expert tinkerers around here might be able to point me in the right direction.
I'm wondering how / what do I need to build a device capable of receiving an decoding HDMI audio in order to output it to speakers (just like a receiver does).
A little more detail about exactly what I want to achieve. I have a carputer project that I've been working on off and on for the past few years. Right now my solution to audio is rather basic and not what I'd like for it to be. The LCD controller board that I'm using has an analog audio out for 2 channel output. I just duplicate that to have front and rear channels (but I have no way to adjust their volumes individually), and feed off the rear to amp for pass filtering on the subwoofer. This sounds ok, but I'd really like to beef it up. What I would like to do is build a device that would serve as an amplifier for the door speakers, as well as have preamp outputs for the subwoofer amp. I figure if I built this device it would be great if I could just split the HDMI cable from my motherboard, send one to the LCD for video and one to this receiver unit for true 5.1 audio. I know it should be possible since living room recievers can do it, I just don't know what it would take to build one of my own. And then I'd be able to adjust all the sound levels individually (both in software on the motherboard side as long as the output is actually 5.1, as well as the possibility of adjusting it in this device I would build).
I'm also hoping it would be possible to analyze the signal during processing and see if the source is 5.1 audio or if it's only 2 channel audio and if it's 2 channel audio duplicate the signal to the rear channels and preamp outs automatically so that I don't get a situation where something is only playing on the front speakers or such. Would be even better if during that processing if it's duplicated like that to the preamp outs that I can do a software based filtering instead of relying on the amplifier to do it all, I think that could clean up the signal going to the amp resulting in better bass from the subs.
Thanks for any advice!