Casting

Casting plays the song on a Google Cast device on the network, a Chromecast, a Nest speaker or a television with Cast built in, instead of through this machine's own sound output. The terminal stays the player: the screens keep running and the keys keep working, and the sound comes out of the device. Paula finds the devices itself, over mDNS, and serves them the sound over HTTP, with no Cast library in between.

Press c in the player, or click cast in the footer, and Paula lists this machine and every Google Cast device on the network. Choose one and the song moves there without stopping; choose this machine to bring it back. --output cast plays there from the start and --cast NAME says which device, by the name it was given or its address.

A Cast device fetches the sound rather than being sent it, so Paula serves it an endless wave file, paced so the device runs some four seconds behind; --cast-lag SECONDS asks for less, down to what the device keeps of its own. That lag is measured from where the device says it is, and the spectrum, the scopes and the position follow the sound being heard rather than the sound being sent. Screens show a card with the song, the musician and a picture from Demozoo, the release's file_id.diz or the party's logo. Seeking hands the song to the device again from where the player stands.

The sound is served on port 7373, or the one --cast-port names, from the address the device was reached through; a firewall between the two must let the device fetch from that port.