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SPDIF in for darkice and icecasr2

Richard Shepherd

January 02, 2022 11:05

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I bought a Digi+ I/O (eyes open about its limitations) because it was an inexpensive experiment. I have a Pi4 with my USB turntable attached and stream to my Sonos with Icecast. This works fine. The Digi I/O was an experiment to get my CD player into the setup. This works fine IF the player is playing something before another darkice instance is started using the I/O input. Once the CD player stops or is tuned off then darkice exits with an I/O error. If darkice is started with no input then it exits similarly. All as expected.

I believe a DSP solution is what I now need to get an input which won't error out with no signal but just record silence.

Is the DAC+ DSP what I need and how do I permanently set the SPDIF input to mix with the Pi Audio?

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5 comments

• 0
  
  HiFiBerry team January 03, 2022 08:19

  This can work, but you need a DSP profile that routes the SPDIF input on the DSP to the Pi via the ASRC. Have a look here:

  https://support.hifiberry.com/hc/en-us/community/posts/360008515418-DAC-DSP-Toslink-input-to-RPI

• 0
  
  Richard Shepherd January 03, 2022 17:18

  Thanks for the link

  Having followed it I get to https://www.hifiberry.com/docs/software/using-the-dac-dsp-to-record-audio-from-s-pdif/

  I assume this is how to set it up. I have installed dsptoolkit and it seems to accept commands okay. Don't have the hardware yet.

  Does the DSP programming "stick" between power cycles or do I have to call the script on every boot?

• 0
  
  HiFiBerry team January 04, 2022 06:41

  What's in the DSPProfile will "stick", everything that you just write to the DSP memory will be gone after a reset of the DSP (e.g. during a reboot)

• 0
  
  Lev September 02, 2023 20:10

  I'd like to do this too, ie. capture the SPDIF PCM stream and send it to icecast and then to Sonos.

  Can I do this with the DAC+ DSP? Is it capturing the pure PCM stream, or is there any processing involved?

  Thanks

• 0
  
  HiFiBerry team September 03, 2023 15:21

  Yes, this can work.
  There is always processing involved when sampling from the TOSLink as the signal has to be passed through the sample rate converter.