Got something for the Spotify recorder.

Instead of connecting java to dbus, which has 1 or 2 seconds of latency, playerctl provides a perfect way for recording when Spotify switched to the next track.

Now I'm recording a play list with w64 (wav but support more than 4GB), then try to slice them into individual wav files. Still having trouble on deciding the start of each track, since dbus is not really real time, I saw 300 to 500ms latency (from Spotify switch track to the script record timestamp).