[Vertigo]

So if I buy the right amp that does cec properly and doesn't drop hdmi audio, and I cable tie my acer revo on the back, I essntially have whay you seek.

Close to it. Of course Id expect the amp to be fully configurable through the XBMC interface and all audio processing to be handled on the PC as well, rather than being passed through over HDMI. Id also expect to be able to switch HDMI sources while having XBMC menu's layered on top, regardless if you are watching netflix, a bluray disc or live tv from a cable box.

But yeah, essentially the idea is to have a "dumb" multichannel amplifier controlled by an xbmc box with several HDMI inputs. Perhaps something like this for the amp:
http://www.ebay.com/itm/6-X-100-Watt-6-O...51a0972fd4

[nickr]

OK so we need to write an xbmc addon to control the amp. [1]

Not sure why you want the PC to do audio decode. R pi has not enough cpu and only L/R audio out. (or are you wanting 7.1 LPCM over HDMI to the amp?)

Not sure why you even need HDMI switching if this box does everything. Guess you might have xbox or something.

EDIT [1] e.g. http://www.madeo.co.uk/?p=896

EDIT2 - I see from persuing his software github.com/arfoll/rs232server.git it presently supports LG TV serial connection - I have an LG and have played with serial control, so the cable is in place! I'll report back.

[Vertigo]

OK so we need to write an xbmc addon to control the amp. [1]

Not sure why you want the PC to do audio decode. R pi has not enough cpu and only L/R audio out. (or are you wanting 7.1 LPCM over HDMI to the amp?)

You want to decode the audio on the SoC, so that its future proof (upgrade via software) and so you dont duplicate hardware resources. A pi may not be fast enough (although actually, it probably is, if you can obtain a DTS license and use the hardware decode functions that are available, but currently unused), but I never said it had to be a pi. Something like a Pi. And since the Pi is pretty old school now, you might as well integrate a much faster SoC that allows you to do a lot more, including even gaming. Something like this:
http://www.hardkernel.com/renewal_2011/p...5341370451

And again, Im not talking about that board, as you probably will need more (and better?) DACs and probably other stuff, like a HDMI switch and some misc IO. Perhaps for a prototype you can use such an off the shelve PCBs, but you almost certainly want to design a custom a PCB that integrates such a SoC and whatever else you need.

Current networked AVRs already have a (very slow) SoC and run embedded linux, have a network interface and run software for audio decoding, streaming, etc. Id want to have one box running one OS and software stack on one SoC with one user interface.

Not sure why you even need HDMI switching if this box does everything. Guess you might have xbox or something.

Most users will have other HDMI sources; be it a DVD/BR player, cable box or gaming console. Of course you want to be able to integrate that, and HDMI is the obvious way.

EDIT [1] e.g. http://www.madeo.co.uk/?p=896

Nice find. Although so far it seems limited to turning the amp on/off. Im much more ambitious, Im also thinking about sound and DSP settings, calibration, etc. Basically everything the preamp does.

EDIT2 - I see from persuing his software github.com/arfoll/rs232server.git it presently supports LG TV serial connection - I have an LG and have played with serial control, so the cable is in place! I'll report back.

Now that looks way more interesting. Youd still have duplicate everything, but from what Ive seen, this would allow a fair amount of the software development for what I have in mind. Thanks for the link!

[nickr]

Can you buy a 5.1 or 7.1 dac off the shelf? hdmi in, analogue out?

[Vertigo]

Not sure, but a soundcard is basically a glorified DAC, thats probably not the hardest part of this concept. Id very much prefer to have it integrated on the SoCs PCB though (and if thats not possible for a prototype, I wouldnt want to use HDMI, but SPDIF or even USB audio).

BTW, I was over at my neighbors yesterday. They just spent a small fortune redoing their living room, with a (very expensive, but not so impressive IMHO) Bose lifestyle home theater hooked up to a bunch of Sonos stuff. The Lifestyle center is basically an AV receiver with some media functions. My neighbors tried to impress me by showing how it could play music from a NAS or iphone. WIth an UI thats, well, Ill be fair, I have seen worse, but it was hardly impressive. Best I could tell, it had no video playback or library capabilities of its own at all. For the price they paid, imagine what an XBMC based "lifecenter" could do. I did like the remote tho .

[nickr]

I assume we are targeting this imaginary device at movie/media enthusiasts. We need 7.1 and HD audio, so:

No spdif
no 6 channel amp (but maybe two of the 4 channel ones)

you need a method to take digital (and in some cases proprietary encoded) audio (from mono through to DTS-HD) and turn it into up to 8 channels of analogue input to the power amp. Whether that is a hardware black box, or a SoC with clever programming (and a license for each codec) is perhaps moot.

Argghhh I should have finished that electrical engineering degree instead of giving up and becoming a lawyer!

[Vertigo]

Im not convinced 7.1 is a must. Bose seems to do allright selling 2.1 and 3.1 setups for several $1000. Many people just dont want to cope with the cable clutter, and one of the aims of this project would be to reduce cable clutter and offer ease of use and installation. In that sense, a lack of 7.1 wouldnt be that much of a loss IMHO. Anyway, if you do need 7.1, and you need a separate "off the shelve" DAC, it might make more sense to use several SPDIF connections to separate DACs/preamps. But my only relevant experience is building an SW radio when I was 10, so I have no idea what Im talking about!