Sync demo: the phone that listens

This page hears the room, finds which produced passage is playing and where, and broadcasts the position: on the demo channel for the receiver window, and on that passage's own study channel (the one its QR carries) so a phone that scans the QR follows this one.
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NOT LISTENING
loading the reference...
Lockoff
Confidence (votes in the last 2.5 s, and how far ahead of the runner-up)0
Match delay (compute time per update)0 ms
Round trip (this phone to the receiver and back, measured on this clock)waiting for an echo
Broadcasts sent (demo channel)0
Demo channelconnecting
Study channel (the passage's QR channel)none yet
Study positions sent / hellos answered0 / 0
Audio clock-
Landmarks in the window / matched0 / 0
Keep this page open and the screen on. The position is broadcast four times a second on the demo channel while locked and every 1.5 seconds on the passage's study channel (and at once when a joiner says hello); when the sound stops for more than a second it broadcasts paused. Add ?stale=2 to wait two seconds of silence before calling it paused (default one second).