Hi again,

With ALSA, there's a special device (a "dmixer") that should allow multiple access to the Octo

Here's how to check for it (from a console):  aplay -L | grep -i dmix

Also refer to:  https://alsa.opensrc.org/Dmix#The_Dmix_Howto

Disclaimer: I don't use it, so I don't know if it works.

Marc

Le 2022-04-22 à 15 h 45, Marc Lavallée via People a écrit :
Hi Chris,

I'm not from the AudioInjector team (so don't take my advice as authoritative).

My comprehension of audio on Linux is that if an ALSA device is opened for output (or input), for example using a sound file player, it can't be used by a second application (or process).

Usually a sound server is required, that sits on top of ALSA. It can be Pulseaudio, Jack or PipeWire (but it's not yet mainstream).
For anything serious, I have a preference for Jack, and Pulseaudio can be used along with Jack.
The signal flow would then be: Octo <-> ALSA <-> Jack <-> Pulseaudio

Marc

Le 2022-04-22 à 14 h 58, Chris Fernandez via People a écrit :
Hello,

I recently purchased an Octo and I am trying to demonstrate its capabilities. I have connected it to a Raspberry Pi 3B+ with a fresh install of Raspbian (v11). I've gone through the GitHub octo installation instructions, and I have been able to play 1x audio output from the AudioInjector card. Sound quality is good!

However, I am struggling to get more than one audio output working at a time. I've tried opening multiple instances of VLC media player to play two different audio files. This works if I send one audio stream to the AudioInjector, and another to HDMI. However, the AudioInjector is only showing up as a single audio sink. I don't see how I can send other audio streams to the other channels of the AudioInjector.

I have spent a few days looking into this, and playing around with aplay and other Asla tools. No luck for me so far. 

Is the basic installation from GitHub intended to default to a 1x output mode? Are there other steps I need to do to enable multiple independent outputs? Is there something like a tutorial or demo that I could use to validate the hardware and test operation with 6x inputs and 8x outputs? What is the easiest way to test the full functionality of the Octo board?

Any guidance would be greatly appreciated! Thanks in advance!

     -Chris

--
Chris Fernandez
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Hardline, Inc.
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