There was a lot of discussion on this forum about a way to decode 7.1 audio from encrypted HDMI and provide it to us in a digital format (I2S or DSD for example).
Of course no commercial device will ever do this as they wouldn't get the HDMI licence if they wanted to do this.
An interesting chip for doing this is the SiI9135 and after a long time of searching I've found the datasheet of this chip:
Zippyshare.com - SiI-DS-0206-C-9135-RIET.PDF
This chip decodes all the formats including DTS-HD and Dolby TrueHD from HDMI, outputting to four I2S or DSD 192kHz outputs.
No need to worry about the HDCP encryption part as the chip has the keys already inside.
We can buy this chip on ebay or chinese websites in small quantities between $6 and $8 each.
It is a TQFP-144 package so it's still doable in DIY (not as with BGA).
Might be a good start for our perfect HDMI DAC.
Of course no commercial device will ever do this as they wouldn't get the HDMI licence if they wanted to do this.
An interesting chip for doing this is the SiI9135 and after a long time of searching I've found the datasheet of this chip:
Zippyshare.com - SiI-DS-0206-C-9135-RIET.PDF
This chip decodes all the formats including DTS-HD and Dolby TrueHD from HDMI, outputting to four I2S or DSD 192kHz outputs.
No need to worry about the HDCP encryption part as the chip has the keys already inside.
We can buy this chip on ebay or chinese websites in small quantities between $6 and $8 each.
It is a TQFP-144 package so it's still doable in DIY (not as with BGA).
Might be a good start for our perfect HDMI DAC.
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This is the datasheet for programming the chip, might be useful for someone:
SiI9135????????? - ???
(you have to wait 10secs before the viewer let you view the file, I've searched for a way to download the file for free but you can't without paying)
SiI9135????????? - ???
(you have to wait 10secs before the viewer let you view the file, I've searched for a way to download the file for free but you can't without paying)
I suggest you to search before being that sure
An externally hosted image should be here but it was not working when we last tested it.
And this one taken from another document about this chip (I still read "DTS-HD and Dolby TrueHD" on the second line) :
An externally hosted image should be here but it was not working when we last tested it.
I hope this helps clarify....
I am no authority on this, in fact, I am on the journey learning this stuff also.
Like many of us into DIY audio, we have spent many years designing and building our dream audio systems. In fact, if you have been playing around with this for a while, You might be like me, and have some respectable speaker builds and amps laying around. All of them sound better then AV receivers (that is not too hard to do), but as it is, we are limited to 2 channel output, as most Dolby and DTS applications "force" some kind of bottleneck somewhere, usually the DACs.
But that is not to say that we DIYer's can overcome this...
The trick is to see through the marketing, as it can be VERY misleading. The HDMI chip above "supports" high bit rate audio of both encoded and decoded Dolby HD and DTS HD soundtracks. Yet the SiI9135It does not "decode" Dolby or DTS encoded signals. You still need a decoder either before or after this HDMI chip. Marketing is all about semantics.
But here is the good news, depending on the system You have. If You have a Blu-ray player, like an OPPO 103 (earlier models may work too), that have a built in Dolby and DTS decoder, it can be set up to pass a 7.1 decoded LPCM (I2S) signal though its HDMI output. Plug that into the SiI9135It HDMI input then into your high end DACs and You are enjoying surround sound as You have always wanted to hear it. Some receivers have this option, even thought it is kind of redundant. I am sure there are cheaper Blu-ray players that have built in decoders also.
If you have a PC with an HDMI graphics card and Software that decodes Dolby and DTS (like PowerDVD), again send the decoded I2S audio through the HDMI to the SiI9135It and your DACs and enjoy.
Shame this chip does not support 12 channels of audio, as then it could be used with the new Dolby Atmos stuff, yet it might be able to handle a 5.1.2 Atmos rig. And I am pretty sure it could pass a Dolby Atmos encoded signal to an external decoder, but that is not our interest here.
Either way, the SiI9135It can work, but You need to find a way to decode the Dolby and DTS signal first.
Here is a commercial offering. Is this the kind of product you desire to build?
Evolve® HDMI 7.1 Channel LPCM DAC - Essence Electrostatic Speaker Systems
Note that it does not decode, but I would not be surprised that it uses the same HDMI chip.
Hope this helps....
Allen
I am no authority on this, in fact, I am on the journey learning this stuff also.
Like many of us into DIY audio, we have spent many years designing and building our dream audio systems. In fact, if you have been playing around with this for a while, You might be like me, and have some respectable speaker builds and amps laying around. All of them sound better then AV receivers (that is not too hard to do), but as it is, we are limited to 2 channel output, as most Dolby and DTS applications "force" some kind of bottleneck somewhere, usually the DACs.
But that is not to say that we DIYer's can overcome this...
The trick is to see through the marketing, as it can be VERY misleading. The HDMI chip above "supports" high bit rate audio of both encoded and decoded Dolby HD and DTS HD soundtracks. Yet the SiI9135It does not "decode" Dolby or DTS encoded signals. You still need a decoder either before or after this HDMI chip. Marketing is all about semantics.
But here is the good news, depending on the system You have. If You have a Blu-ray player, like an OPPO 103 (earlier models may work too), that have a built in Dolby and DTS decoder, it can be set up to pass a 7.1 decoded LPCM (I2S) signal though its HDMI output. Plug that into the SiI9135It HDMI input then into your high end DACs and You are enjoying surround sound as You have always wanted to hear it.
Some receivers have this option, even thought it is kind of redundant. I am sure there are cheaper Blu-ray players that have built in decoders also. If you have a PC with an HDMI graphics card and Software that decodes Dolby and DTS (like PowerDVD), again send the decoded I2S audio through the HDMI to the SiI9135It and your DACs and enjoy.
Shame this chip does not support 12 channels of audio, as then it could be used with the new Dolby Atmos stuff, yet it might be able to handle a 5.1.2 Atmos rig. And I am pretty sure it could pass a Dolby Atmos encoded signal to an external decoder, but that is not our interest here.
Either way, the SiI9135It can work, but You need to find a way to decode the Dolby and DTS signal first.
Here is a commercial offering. Is this the kind of product you desire to build?
Evolve® HDMI 7.1 Channel LPCM DAC - Essence Electrostatic Speaker Systems
Note that it does not decode, but I would not be surprised that it uses the same HDMI chip.
Hope this helps....
Allen
Suppose we use some chip like ADV3002 as 4:1 HDMI switch and then extract I2S signal from the selected source like shown in the attachment, will the audio (Stereo only) contained in this also be encrypted?
Or rather, does the shown method work to get I2S stereo?
Thanks!!
Or rather, does the shown method work to get I2S stereo?
Thanks!!
Attachments
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