TOPIC: DIY solution for HDMI to 8ch digital out

Hi

I have been playing with miniDSP boards and my own DAC experiments and nanoAVR seems like an interesting processor for multichannel system (which I don't have atm). It immediately gives me an idea of the chain: sources -> nanoAVR -> 8ch DAC -> 8ch preamp/amp. The problem, or the new thing, is the HDMI.

Does someone know a way to include HDMI in your DIY solution and get the 8 channels of digital audio out of it? HDMI uses some kind of handshaking so I'm thinking of some kind of interface IC or evaluation module I could put in front of 8 channel DAC. Or is DSP/FPGA the only option? Also some ready-made or semi-ready-made solutions can be suggested although it would be very neat to have just one HDMI cable going to the DIY box which then outputs 8 analog channels.

@nihtila

Thanks for your interest in the nanoAVR, unfortunately I'm afraid that this product isn't a DIY product due to licensing issue. i.e. we can't provide a way to perform HDMI to I2S with this board.

Sorry we're not able to help.

DevTeam

I did some googling yesterday and yes, I also think such is the case. I thought it would be license-free since Dolby Digital / DTS is not involved anymore but obviously HDMI has similar harm. We should have a representative of DIY-community in those boards deciding about the standards and their licensing

So I guess I will continue my projects in 2.1-channel world. However, nanoAVR indeed is an interesting product and if I go (back) to multichannel it will most probably stand between my sources and av-receiver.

In case someone is still interested there has been a solution for a while if I understand the goal here: JVB modded Oppo - > 7.1 channel dac

In the use case above the connection would be: source -> NanoAvr -> JVB modded Oppo -> exasound e28 multichannel dac or a DIY 8 channel PCM DAC -> PreAmp/Amp
Oppo has hdmi/optical input that excepts Dolby Digital/DTS and will convert to PCM so you can get DD/DTS. But you would need 2 Oppos: Source/Tivo/Apple TV -> oppo -> NanoAvr -> JVB modded Oppo -> exasound e28 multichannel dac or a DIY 8 channel PCM DAC-> PreAmp/Amp

I was thinking of going this route with the trinnov EQ that excepts dig PCM upto 16 channels. I was going to do: source-> JVB modded Oppo - > Trinnov -> PreAmp. But luckily they invented the DL & saved me $12-14K. So maybe my research can benefit somebody.

www.octavainc.com/HDMI%20switch%204x2_7_1audio.html

In this box the four data, bit clock, word clock and L/R select lines are easy accessible.
With 4 digital interface transceiver or sample rate converter chips it isn't too difficult to get 4 spdiff outputs.
It might even be possible to use one of the JVB mod boards to get the 4 spdiff outputs.

The Octava box also has editable edit configurations so the player will output 8 channels LPCM.

My nanoAVR's ouput is connected to this hdmi switch and I get 4 spdiff channels into my Denon AV Amp that has the ability to combine four spdiff inputs into an 8 channel ext digital input.

devteam wrote:
So, I suspect that this answers my question. But, I'll ask it straight out. Can I get the nanoAVR HDA board/s without the case? I'm interested in integrating everything (amps etc) into one case and saving a few bucks on the case (and shipping) since I wouldn't be using it. And while on the topic of the case, does it really come with that silk screen of a band and crowd? I certainly hope that it's available in plain.

@ chmed,

Unfortunately we don't have a product offering of the nanoAVR without the case (i.e. not really adding much cost actually/same shipping cost). If you don't like the front panel, you can easily replace it by tearing it off. It's easy.

DevTeam

Any info on the I2S lines for this box?
fderks wrote:

Not yet. I'm planning to back engineer the pinout of the expansion headers early next year.

From what I can see, the nanoAVR DSP sports 8 programmable serial interfaces, and one of the formats is I2S. Assuming they interface to Analog Devices HDMI transceivers, their audio interface is I2S. So, there's a good chance there's I2S on the board.

But, one can't make an HDMI to digital audio interface without violating HDMI licensing so zi would expect miniDSP to offer no assistance in this regard.

Pity, because a dual nanoAVR solution INSIDE an Oppo transport that does Bass Management and Dirac Live would be a killer mod. Is is readily available inside the Oppo.

I know this is stale, but in case someone is still interested, there IS a solution: you can convert non-HCDP protected HDMI to SDI with a Blackmagic converter, and from there deembed 4x digital AES/EBU audio, on four 1/4" TRS connectors with another Blackmagic converter. From there, you can use Blackmagic or AJA converters to convert 2x AES/EBU to 4x balanced audio out (the AJA ADA4 does a fine job, and even supports consumer +10dBV or professional +24 dBu 0dBFS signal levels).

It's what I am planning to use after a nanoAVR DL in lieu of a "real" AVR.

Is the "non-HCDP protected" requirement not an issue for watching movies etc?

Not if you use the "secondary" HDMI outputs of players that are designed to interface audio over HDMI to AVRs. They usually send black video, no HDCP, and either bitstream or LPCM audio over the HDMI link. Better players like the Oppo do this, and also decode various formats like Dolby TruHD to LPCM, so you can use them with old AVRs that don't decode that format. The Oppo players also have HDMI inputs that decode HDCP to do video and audio processing so processed external audio can be output as LPCM over HDMI.

Did you ever do this? Details?