HDMI - SPDIF convertor

DO you want a HDMI -SPDIF convertor

  • No

    Votes: 10 11.8%

  • yes < $200

    Votes: 62 72.9%

  • Yes > $200

    Votes: 13 15.3%
  • Total voters
    85
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#21
ashaw said:
HDMI PCM audio -> 4*SPDIF digital outputs

Is anyone interested in this, as I am trying to convince the HDFury people to add it
Click to expand...

I'd like to do this too. Cracking out the various channels in the digital domain seems to be the essential first step in building a DIY surround system.

The Ambery box does the job, but why does it output via "3.5mm stereo phone jacks x 4 for multi channel surround sound decoding from LPCM audio". At the price, it's worth just pulling it apart and moving the bits into a DIY DAC, but I'd like to know what's inside.
 
#24
Yes, there are legal issues. DMCA in USA, signed by Bill Clinton. There are other laws in many of European countries that are in efect simmilar. OK, maybe except Sweden and some other ex-red states 🙂

I think it is illegal even to sneeze around one of those decoders. That's why that box is only LPCM (that is a not encoded digital signal).

Why do you think that HDMI is encripted with HDCP? And DenonLinkIII is also encripted? And why there is no 3x SPDIF output from any universal player?
 
#25
Its All in THE Plans!!!! :grouphug:

This article is almost 5yrs old but was written by the 'Program Manager Windows Media Tech.' All his suggestions and predictions are what HDMI, HDCP, PAP, etc ARE (%*&$$#4) today. "....only audio outs HDMI and 5mm phono jack for analog.....SPDIF must be phased-out ...eliminated " see near 4.6.

http://download.microsoft.com/download/5/D/6/5D6EAF2B-7DDF-476B-93DC-7CF0072878E6/output_protect.doc
Dave(5.mm dave)?.....Dave's not Here!

More future 'jammer' insight from Dave! :headshot:
http://download.microsoft.com/download/5/b/9/5b97017b-e28a-4bae-ba48-174cf47d23cd/MED038_WH06.ppt

Sure there is much more....I've read enough.

A rather well known and very well written argument against all of above. Hollywood and RIAA obviously won this round .
A Cost Analysis of Windows Vista Content Protection

Go Matroska !!!!!!!

Charles
 
#26
Here's the bottom line from the first Msoft doc (section 4.6.1):
Unfortunately, different content protection rules apply to S/PDIF compared with HDMI. As soon as there is a new connector type, new rules apply. It is not allowed to expose an HDMI audio codec as an S/PDIF codec.
Click to expand...
So, if I've got this right, in order to do DIY surround sound, we need a DAC that inputs from an HDMI connector and outputs analog for each of the channels. Are there any good DACs in this category? I'm currently using a TPA Buffalo II with the ESS Sabre DAC, but I presume that it's only outputting stereo.

Thanks, I'm a digital newbie, so I appreciate the background.
 
#27
I can be done, of course. But DIY you're going to have to hack someone else's box.
Looked into this whole HDMI DAC thing last year for the company I worked with. It's very expensive for the little guy.

Lot's of license fees, NDAs for any datasheets or chip samples, etc. It's held pretty closely. And of course you need a software key - which can be revoked at any time. So it's tough for the DIY guy. That's why hacking an existing device would be the logical way to go.

If anyone has better info, please let us know!
 
#28
Before I offer too much potential mis-information about this, can you please confirm that:

1. You want the ability to strip out 5.1 (6 channels) and/or 7.1 (8 channels) of digital HD audio from the HDMI feed?

2. You want the HD audio output to be in the S/PDIF format (RCA/Coax)?

3. You want the ability to handle up to 24/96 for each channel (BluRay)?

If the answer is yes to all of the above then I'm doing this already. BUT, I'm running pro equipment for my processing. You can not do this with a regular consumer prepro because you need to ability to handle all 3x or 4x S/PDIF channels simultaneously.
 
#29
Yes to all except I want 192/24. As this is for DIY, all I need to do is to re-clock the SPDIF with a common word clock. SPDIF is not necessary by the way, I would even go for I2S...
SO

HDMI /w HDCP -> 4/3*SPDIF/I2S + HDMI sans AUDIO.
 
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#30
Okay. That's one interesting project you've got going there and best of luck with it. I can't help unfortunately.....at least not with 12S.

I settled for 24/96 HD audio stripping since my gear can't process any higher (@192kHz) than that anyway. Also, I needed S/PDIF output from the transceiver board since the pro gear I'm using runs AES(3) as a digital carrier and I had to link into it from my HTPC.

It took me a long time and a lot of reading to work all this out (and then track down the necessary bits to make it happen). HDCP, DRM, PAP etc......what a headache😡
 
#34
I found out about this chip when investigating a product at work.
This chip is available on a board that is made by a US company, but I cant remember their name now. I will try to find out and get back to you.

I was mostly posting the link, so that interested people could see that you can get pure multi channel i2s out of the HDMI and then wire up to an i2s to spdif transmitter if thats what you want to do.
As for getting the chips? Perhaps you could ask your local distributor of analog devices?
 
#38
It is because I want to make my own Audio Receiver from scratch as a modular system. The whole spirit of DIY audio is creating a system that is of consistent high quality, and frankly the digital stage of most preamp-processors sucks.
 
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