A station or radio mix from your music service plays one song after another, and then they're gone. Doppelgänger notes each song as it plays and saves the list as a Sonos playlist, so you can play them again.
A Sonos playlist is a list of songs, and so is this one: each entry points to the song on your music service. Doppelgänger doesn't record or download any music. When you play the playlist, Sonos plays the songs from your music service again, so you need to stay subscribed to it.
The playlist is saved on your Sonos system, so the Sonos app shows it too.
No. It notes which songs play and saves a playlist that points to them on your music service. No audio is recorded, downloaded or stored.
The list is kept only while Doppelgänger runs. If songs haven't been saved yet, Doppelgänger asks before it quits.
A Mac with Apple silicon, a Sonos S2 system on the same network, and a music service on your Sonos system. Noting the songs is free. Saving them as a playlist, or as a text file, needs a licence after the 14-day trial, €29.95 once.
Saving playlists needs a licence after the trial.