07 · Phone and house, as oneLog in once, and the two learn from each other
The phone app and the house version began as separate things. Now they are linked over the home network, so a login, a listening history, a "not for me" and a set of suggestions are shared, and a song can move between the phone and any room without losing its place.
A private link
The house makes a secret key the first time it runs, and the Music page shows it once to be typed into the app. Every request is signed with it, and the YouTube login is also encrypted inside the request, so nothing usable crosses the network in the clear. A wrong key is refused, guessing is locked out, and making a new key locks out every phone at once.
Log in once
A button sends the app's own YouTube login to the house, which checks with YouTube that it really works before keeping it. A login copied out of a browser tab had stopped working within about two hours; the phone's own login is a separate session, so it lasts.
House speakers in "Play on…"
Choose a speaker and the phone hands over its queue and its place in the song. The house then holds the queue, so the phone can be switched off, and the app becomes a remote for it.
Warnings you'd otherwise miss
The house asks YouTube every half hour whether the login still works, and warns the phone when it expires, when songs stop loading, or when the nightly update had to roll back. Each problem warns at most once every six hours, even across restarts.
Even volume
Songs are mastered at wildly different loudness. Loud ones are turned down to a common level once, when they are stored on the Pi. Quiet ones are never boosted, which would only add distortion.
Move the music
"Move the music to the living room" carries on with the same queue from the same place, and stops the first speaker. The Echo Show and Dot can't start part-way, so the house gives them a copy of the song cut to begin there. They also answer "stop" by pausing with the old song still loaded, so a stop is followed by a moment of silence that leaves them truly idle.
Lyrics in time
Time-synced lyrics on the Music page, lit line by line as the song sings, and a full-screen version for the Echo Show's display.
Suggestions
A For you page on the Music page and in the app: songs and collections picked from your likes and everything you play, each saying why ("Because you play…"), with YouTube Music's own personalised shelves underneath. "Not for me" hides a song or an artist everywhere. "Play something I might like" does it by voice.
Play together
Pick any speakers, no fixed groups, and one queue plays on all of them. The house asks each Cast speaker where it really is in the song and corrects one that drifts, with a quick jump past the target and back, because a Nest Hub ignores small seeks. A speaker's position still isn't what you hear (each model takes a different time to turn it into sound), so every speaker has a trim you set by ear, with Sooner and Later buttons and a click track that makes it easy. The Echo Show and Dot can join, but can only be started together, not fine-tuned.
One listening history
What the phone plays is sent to the house, so the stats and the suggestions cover everything, and what the house plays comes back into the phone's stats. Nothing is counted twice, and ListenBrainz hears each play exactly once.
More things you can say
Move the music to the living room
Same queue, same place in the song; the speaker it left stops. "Bring the music here" moves it to the speaker you're talking to.
Play this in the kitchen too · take the bedroom out
Adds a room to what is playing, in step, or lets one drop out while the others carry on. "Play my Favourites in the bedroom and the living room" starts them together.
Show the lyrics
Puts the lyrics on the Echo Show in the room, line by line.
Play something I might like · surprise me
Plays the suggested songs, picked from your likes and listening. Add "in the bedroom" to choose a room.
