Raspberry Pi music player with I2S out over HDMI

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Raspberry Pi music player with I2S out over HDMI

Postby Audio Dandy » Wed Jan 14 2015 13:11

hi all,

my name is Audio Dandy, and I have a question
I would like to know if there are projects about how to use Raspberry Pi (with Volumio) as a music server/player
with I2S out over HDMI

So I don't want to use the Raspberry as I2S DAC, but only as a music player that sends the I2S data to it's HDMI output
I have a another DAC with HDMI input myself.

I hope you can help me!

thanks in advance,
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Raspberry Pi music player with I2S out over HDMI

Postby fm-maniac » Thu Jan 15 2015 10:28

Which DAC are you planning to use with such a RasPi configuration?

BR
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Raspberry Pi music player with I2S out over HDMI

Postby PatrickB » Thu Jan 15 2015 13:34

In short, NO

I haven't seen any dedicated DAC's with HDMI input, only as part of something else like an A/V Receiver. Which DAC are you planning to use?

Little longer; i2s is an Inter IC Sound serial bus interfacing standard (http://en.wikipedia.org/wiki/I%C2%B2S) and a different standard than HDMI. HDMI supports interfacing for more purposes than only between sound chips (like video, network, etc. and audio).

But if you want to connect your volumio device through HDMI with something else that can use the audio signal (like an A/V receiver), check for example http://volumio.org/forum/hdmi-audio-out-raspberry-t307.html on how to get it working if it doesn't by default.
Raspberry PI B+ with Hifiberry Digi+ (Audio-GD DAC) and NAD A/V receiver with Dali speakers.
Also working on a Pi 3A+ connected over USB to in-car DSP
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Raspberry Pi music player with I2S out over HDMI

Postby fm-maniac » Fri Jan 16 2015 08:49

Patrick,

PS Audio for example offers I2S over HDMI inputs on it's DACs and equivalent outputs on it's transport. They in fact defined the "standard" for I2S over HDMI.
It's only the physical cable and connector used for signal transmission and has nothing to do with the embedded audio signal of the HDMI protocol. Instead a differental current signal is used for each I2S signal (SDA, LRCLK, BCLK, MCLK).
Other solutions are using Ethernet connectors and cables or BNC.

I took from the webpage of the thread starter that he's using Audio GD DACs from China. Audio GD is also offering I2S over HDMI modules.

The only problem with the RasPi is, that it doesn't provide a MCLK. So it needs some sort of clock recovery or upsampling on the DAC to get it running without it. The SABRE chips used by Audio GD as well as by many others perform such a clock recovery. So I'm pretty sure that this will work out of the box, as long as you connect the IIS signals from the RasPi's P5 connector in the right manner.

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Re: Raspberry Pi music player with I2S out over HDMI

Postby PatrickB » Fri Jan 16 2015 19:26

fm-maniac wrote:Patrick,

PS Audio for example offers I2S over HDMI inputs on it's DACs and equivalent outputs on it's transport. They in fact defined the "standard" for I2S over HDMI.
It's only the physical cable and connector used for signal transmission and has nothing to do with the embedded audio signal of the HDMI protocol. Instead a differental current signal is used for each I2S signal (SDA, LRCLK, BCLK, MCLK).
Other solutions are using Ethernet connectors and cables or BNC.

I took from the webpage of the thread starter that he's using Audio GD DACs from China. Audio GD is also offering I2S over HDMI modules.

The only problem with the RasPi is, that it doesn't provide a MCLK. So it needs some sort of clock recovery or upsampling on the DAC to get it running without it. The SABRE chips used by Audio GD as well as by many others perform such a clock recovery. So I'm pretty sure that this will work out of the box, as long as you connect the IIS signals from the RasPi's P5 connector in the right manner.

BR
Thanks for the interesting read. I wasn't aware of these possibilities.

Actually, I am using an Audio GD DAC also [SMILING FACE WITH OPEN MOUTH] But one without an (rj45) I2S input.

Maybe a suggestion for the topic starter, send a mail to Hifiberry if they consider developing a small board that adds an hdmi or rj45 output to the RPI for I2S output [SMILING FACE WITH SMILING EYES]

Is there anyone that has some schematics on how create an I2S transport using ethernet cabling on a RPI?


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Raspberry PI B+ with Hifiberry Digi+ (Audio-GD DAC) and NAD A/V receiver with Dali speakers.
Also working on a Pi 3A+ connected over USB to in-car DSP
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Raspberry Pi music player with I2S out over HDMI

Postby Audio Dandy » Sat Jan 17 2015 08:30

Thank you all for the feedback,

yesterday I received my new dac, It's a Audio-GD Master 7 with I2S HDMI input
Now it's playing with a i7 passive cooled pc, with a Pink Faun I2S Bridge, which works very fine
but the I7 consumes too much power to leave it on almost the whole day...

The Raspberry would be better for this job, but after reading your answers the sollution must be found in an
extra addon board with I2S HDMI output and master clock?
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Raspberry Pi music player with I2S out over HDMI

Postby fm-maniac » Sat Jan 17 2015 13:49

You need the USD20 I2S over HDMI board from audio GD:

http://www.audio-gd.com/Pro/diy/I2Skits/I2SEN.htm

Connecting this board to the Pi should be an easy job.

As I said Audio GD uses SABRE chips on most of it's products. So no Master clock is needed. BUT(!) the Master 7 you use has a PCM1704 DAC and I'm not sure if this works works without the master clock. Check the datasheet or ask Audio GB. They should know.

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Raspberry Pi music player with I2S out over HDMI

Postby Audio Dandy » Thu Jan 22 2015 16:58

fm-maniac wrote:You need the USD20 I2S over HDMI board from audio GD:

http://www.audio-gd.com/Pro/diy/I2Skits/I2SEN.htm

Connecting this board to the Pi should be an easy job.

As I said Audio GD uses SABRE chips on most of it's products. So no Master clock is needed. BUT(!) the Master 7 you use has a PCM1704 DAC and I'm not sure if this works works without the master clock. Check the datasheet or ask Audio GB. They should know.

BR


Thank you very much for your info, I knew this sets but I didn't thought about the idea to use them for the Raspberry Pi...
I can continue now!
Best regards,
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Raspberry Pi music player with I2S out over HDMI

Postby NWTStuff » Thu Jan 22 2015 23:22

Fm-maniac,

Just to be clear. Are you saying it is not possible to use i2s rpi to ps-audio hdmi because there is no MCLK ?

Have you found anyway to communicate on i2s from rpi to ps audio hdmi ?

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Raspberry Pi music player with I2S out over HDMI

Postby fm-maniac » Fri Jan 23 2015 08:52

Hi Kevin,

it depends on the converter chip your DAC uses. The SABREs as well as the often in RasPi add on modules like HiFiBerry or IQaudio used PCM510x or PCM512x chips don't require a MCLK as they recover it from the BCLK.

I had a short view on the datasheet of the PCM1704 being of interest here. It also only needs the LRCLK (WCLK), BCLK and SDATA. So it might work also. But it's pretty much limited on the data formats and to 96kHz max. SR. It's an old design... Pay attetion that this is a pure DA converter w/o any upsampling or digital filtering. So there may be a digital filter used in front of it.

Regarding the PS Audio PWD II, I got the information from Paul McGowan that no MCLK ist required as long as the SR converter is used. Only the Native modes require a MCLK. For the new Direct Stream no MCLK in general is needed as the FPGAs transfer all incoming data to DSD. I ordered a I2S over HDMI module made by Aune from Audiophonics, but it turned out to be a receiver. Short after they took the Audio GD modules into their shop. I have to get one first, before I can report.

BR

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