I am trying to play and then record audio using ALSA inside a docker container, based on Ubuntu 16.04. Starting with a fresh container, I've tried following the example found in the official ALSA documentation on the loopback device, and using QXIP/baresip-docker as a starting point, but whenever I run
arecord -L, I get the following message:
arecord: device_list:268: no soundcards found...
How can I initiate a loopback audio system inside a docker container?