Buffering on Mobile Data but Not on Wi-Fi

A stream that is spotless at home stutters outside on mobile data, and the speed test says 80 Mbit. It looks like a contradiction and it is not: on a mobile line what decides the result is stability rather than speed, and a speed test does not measure stability.

Three causes

• Cell handover: while you move, the phone changes base station, and the connection drops for half a second at that moment. For a stream that is enough.
• Throttling after a cap: when the allowance runs out the speed is cut, and that cut shows late in a speed test.
• Variable latency: on a mobile line latency is not constant; in a busy cell it can double within the same second.

What can be done

1. 01Pin the qualityFix the resolution to HD in the player's settings. Automatic quality keeps stepping up and down on a mobile line, which increases freezing.
2. 02Raise the bufferOn a mobile line a large buffer is the right choice: the half-second gap at handover disappears inside it.
3. 03Stay stillWatching in a car or on a train makes handover continuous. At a fixed spot the result improves noticeably.

An HD stream on mobile data uses roughly 1.5 GB an hour. Lowering the quality does not only reduce freezing — it doubles what your allowance covers.