Stable picture over mobile networks

Connection setup and picture quality were measured with a laptop on a mobile network and changed in several places.

• Quality control: the bitrate follows the rate the link actually carries instead of dropping to the minimum during short outages. After a reduction, it quickly returns to just below the last carried rate, without periodic overshooting on narrow links. Light content (scrolling, typing) no longer triggers a reduction during short radio dropouts.
• QUIC with BBR instead of CUBIC; the round-trip time is checked against the 10-second minimum.
• Quality modes work again and manual limits are remembered.
• Port search with relay only as a last resort; the direct path is up after 0.85 seconds.
• Relay behind port forwarding without configuration: clients translate the UDP ports; --public-udp-port is only needed for other offsets.
• In the same LAN, the local address takes precedence over the detour via the router; the status bar shows “P2P · LAN direct”.

The simulation with the real QUIC core is included as an integration test; the measurements can be recorded with a switch.