I have an application (that I do not own and cannot control) that plays audio. I want to capture the audio coming from this application and process it realtime.
Although there are multiple guides on how to do that in PulseAudio and Pipewire, I want to run this inside a docker container without using the privileged mode, so I want to avoid sound servers.
To my understanding, if I can create a virtual device directly with ALSA, this can do the trick but I do not know where to start.
What I want to do is to create a virtual device that is an audio sink, make it default output, create another device that is an audio source, and connect the first to the second, run the application that produces audio (so it writes to the first) then have another application reading from the second one.
Will this approach work? Any clues where to start from?