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Listen to Spotify and Radio Helsinki from a Raspberry Pi

I describe how I build the Zynthian Raspberry Pi OS synthesizer from a kit in a previous blog post. It sits mostly idle connected to my sound card, so I decided to make it a bit more useful while it is idling.

The first goal was to make it play Radio Helsinki, one of my most played online radio stations. That's simple enough; I just created a systemd service which connects to the stream using mplayer.

[Unit]
Description=Radio helsinki
After=jack2.service network-online.target
Wants=network-online.target
Requires=jack2.service
[Service]
Restart=always
Type=simple
ExecStart=/usr/bin/mplayer -volume 31 -nogui -ao jack -cache 1032 -cache-min 10 "http://stream.radiohelsinki.fi:8006/;"
[Install]
WantedBy=multi-user.target
view raw radiohelsinki.service hosted with ❤ by GitHub

Note that I'm using jackaudio as an audio "sink." The synthesizer is thus perfectly playable, even if I am listening to something else meanwhile.

I get soon bored listening to only one channel. The next step is then to add Spotify. There is a pre-made debian package called raspotify, but alas, the bundled librespot Spotify client does not work with the jackaudio backend. I decided that the most comfortable choice is to compile librespot in the Raspberry Pi and then create a systemd service (after all, that is pretty much all raspotify does).

The Spotify client service is quite simple to run.

[Unit]
Description=Spotify player
After=radiohelsinki.service
Wants=network-online.target
[Service]
Restart=always
Type=simple
ExecStart=/root/librespot/target/release/librespot --name hima --backend jackaudio --username <REDACTED> --password <REDACTED> --bitrate 320 --disable-audio-cache --enable-volume-normalisation --mixer-linear-volume --initial-volume=100 --onevent /root/connect-spotify-jack.sh
[Install]
WantedBy=multi-user.target
view raw spotifyplayer.service hosted with ❤ by GitHub

I added a script that listens to the client's events to start/stop Radio Helsinki service accordingly. The music never stops!

#!/bin/bash
if [[ "$PLAYER_EVENT" == "start" || "$PLAYER_EVENT" == "playing" ]]; then
service radiohelsinki stop
n=0
until [ "$n" -ge 3 ]
do
jack_connect librespot:out_0 system:playback_1 &>/dev/null
jack_connect librespot:out_1 system:playback_2 &>/dev/null
n=$((n+1))
sleep 3
done
fi
if [[ "$PLAYER_EVENT" == "stop" || "$PLAYER_EVENT" == "paused" ]]; then
service radiohelsinki start
fi
if [[ "$PLAYER_EVENT" == "volume_set" && "$VOLUME" == "0" ]]; then
service radiohelsinki stop
fi
view raw connect-spotify-jack.sh hosted with ❤ by GitHub



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