Audio

sudo apt install pulseaudio pulseaudio-module-zeroconf gstreamer1.0-plugins-base-apps gstreamer1.0-pulseaudio

/etc/systemd/system/pulseaudio.service

# systemd service spec for pulseaudio running in system mode -- not recommended though!
# on arch, put it under /etc/systemd/system/pulseaudio.service
# start with: systemctl start pulseaudio.service
# enable on boot: systemctl enable pulseaudio.service 
[Unit]
Description=Pulseaudio sound server
After=avahi-daemon.service network.target
 
[Service]
ExecStart=/usr/bin/pulseaudio --system --disallow-exit --disallow-module-loading
ExecReload=/bin/kill -HUP $MAINPID
 
[Install]
WantedBy=multi-user.target

/etc/pulse/system.pa

load-module module-native-protocol-tcp auth-ip-acl=127.0.0.1;192.168.0.0/16
load-module module-zeroconf-publish

/etc/pulse/client.conf

default-server = 127.0.0.1

gst-launch-1.0 audiotestsrc ! audioresample ! autoaudiosink