good way to add spdif Input to the RPI

HI all,
I have a blu-ray player with only digital coaxial out. I already have a good usb sound card with my pc. So I would like to use my RI instead to deal with all sound sources. Either by reading directly from my Nas and then getting stereo sound via USB to my sound card, or from the blue ray via spdif input,ideally multi-channel DD or DTS.
The real catch is the spdif input. Does anyone do that already and can help me out?

I’m sorry but I’m not aware of any S/PDIF input for the PI… Furthermore there’s no way to use that even if it exists…

On top of that this makes no sense… Pi is designed (with Volumio) to be a source, not a preamp or hub…

maybe I’m wrong but it seems that if you get a DAC such as : … 18k2m.html you can get a spdif input

Can you explain why I could not use it pls?
I asked the question here because I know people around here have interests in sound and RPI, I’m not sure I can do what I want only using RPI. But I thought that if I already use the RPI as my source of music then why not just use it for all sound related stuff. Moreover I plan to only use simple amplifiers so I only have to update the one thing that decodes all sound format, namely my RPI if it’s possible.


thanks for the idea. I am not sure how it works for spdif input though and it does way more than I want. Basically I just want to be able to get the spdif input as a source for the RPI to decode whatever is thrown at him.

Yeah, great idea dissing the founder and developer of this great solution. :imp:

I think Michelangelo’s answer says it all - this is not what Volumio is for, even if it could be done.
Volumio is an excellent source, which should be used to obtain bit perfect delivery of the digital signal to your device.

first I was not dissing anyone, I just wanted to ask if someone could tell me what was preventing me from plugging an spdif input to the RPI as I have read in a rather old article that the RPI could not handle the load to decode multi-channel ac3, DD or DTS; this could have changed as things evolve pretty fast.
Also I know it is not directly related to Volumio but I know there are knowledgeable people here who could have ideas that i did not find elsewhere.

I also thing Manu was not dissing anyone. I agree on submitting this to the community, here there are lots of talented persons wanting to push RPI capabilities. So:

  • It is possible to play an input with Volumio. We should add an input section on /etc/mpd.conf
  • The S\PDIF driver should direct the input to a file, a fifo or a stram
  • We add this fifo, stream or file to mpd queue and play it

This is how the logic will work… Let’s see if someone has ideas on how to achieve this technically

Hi Manu, that sounds tricky. SPDIF is a digital format which requires the receiver to guess its clock rate. You can feed its input to an RPi GPIO port, but I think you would need to write your own routine to do clock recovery before you can read the signal.

Maybe easier would be to get a USB audio interface (1, 2, 3) and try to get MPD (or ALSA) to talk to it.

@eallaud, @michelangelo - Apologies for my bad tempered post - not my business to comment. :blush:

Note to self: Don’t post when in a bad mood.

No problem :slight_smile:

Here are the possibilities: either direct input from spdif to gpio but this is perhaps a bit complicated as already mentioned. The second more palatable one is to have either a spdif input via a Wolfson audio card or via USB. I just found that the one I use has optical and coaxial input but the Linux driver does not support it. Anyway any good card would at least present the stream via USB. The one part that would be harder is in case the stream is compressed et AC3 or DD/DTS, I am not sure if the RPI can deal with that in real time.

hi… i’m a pc idiot… but try to digest what i mean then u work it out.
if u wana get a stereo sound.

  • u will need a Digital to Analoge Converter (DAC)
  • check ur controller pc does it support.
  • there are few types of digital sound formats not only DTS DD etc…
    if u wana try whether playback is possible. check with ur friends do they have a digital format CD & try playing. DSD & DXD are another type of digital format used in SACD.
  • To end it always remember in order to get stereo sound from a digital source a converter is a must. DAC. even it can play back from a SACD. that CD might be a Hybrid form.

sorry to add on… even your sound card or whatever can do a conversion. does not mean by your CD drive is capable of reading. sorry.
for high res audio your processor must be able to playback min sampling frequency of 96/16.