Implement listening along with friends

[ungive]

It would be great to be able to listen along with friends by sending your current song to another media player or a website that can play media and sync media playback.

I've already experimented with this in the past by controlling the YouTube Music web app which worked flawlessly. An initial implementation could be made by controlling streaming service websites, as this is the simplest way to control a media player and these kind of sites are able to play any song within seconds. Writing plugins for desktop media players is much more involved.

Already started work on the browser extension: https://github.com/ungive/media-control-extension

For TIDAL specifically, one could write a Neptune plugin: https://github.com/twnlink/neptune-plugins. In theory, this should work similarly to a browser extension. This would be a good initial proof-of-concept of an official integration with streaming service desktop apps.

All of this obviously requires infrastructure to communicate live data over the internet in a secure and authenticated way. This should be planned in tandem with the open developer platform: #318

In the future, with co-operation of music streaming services, Music Presence could be made available as an app to connect to (similar to last.fm) so that media players can be synced directly within the streaming service desktop or mobile player, which would be a much more seamless experience and would mean an incredible leap in how people experience shared music listening sessions over the internet.

[ungive]

Note to self: Don't rely on a user's clock for synchronization of playback positions. The Discord status already shows incorrect progress bars when the listener's system time is out of sync, even when (and especially when) the viewer's system time is correct.

Use a time server for accurate timestamps that need to be synced between systems.