Live Streaming Guide — Bandwidth, Buffering and Getting the Quality You Pay For

How much bandwidth do you actually need?

The commonly quoted figures are roughly 5 Mbps for standard definition, 10 to 15 Mbps for 1080p, and 25 Mbps or more for 4K. Those numbers are broadly right and also slightly misleading, because they describe what a single stream consumes at a single moment. They do not describe what your connection needs to have available.

The number that matters is headroom: bandwidth free while everything else in the house is also running. A 100 Mbps connection with four other people on it at eight in the evening is not a 100 Mbps connection for your television. If a stream is fine at three in the afternoon and unwatchable at nine at night, you have a headroom problem, not a service problem.

Why buffering happens

A player downloads a few seconds ahead of what you are watching and keeps it in a buffer. As long as data arrives faster than you consume it, the buffer stays full and playback is smooth. Buffering is what you see when that buffer empties.

There are only a few reasons it empties:

• Not enough bandwidth reaching the device, for any reason at any point in the chain.
• An unstable connection rather than a slow one. Wi-Fi that drops for a second every so often will empty a buffer even on a fast line.
• The device cannot decode fast enough, which looks like stuttering rather than pausing.
• The source is overloaded. This is the only cause that is genuinely the service's fault, and it typically hits during peak events when many people watch the same thing at once.

Distinguishing between these is the whole diagnostic problem, and it is easier than it sounds.

Diagnosing a bad stream in five minutes

Work through it in order. Each step rules out a layer.

• Try a different channel. If one channel is bad and the rest are fine, it is that source, not your setup.
• Try a different device on the same network. If the phone is smooth and the TV is not, the problem is the TV or its connection.
• Try the same device on a different network, for example a phone on mobile data instead of Wi-Fi. If it improves, the problem is your home network.
• Run a speed test on the streaming device itself, not on a laptop next to the router. What matters is what reaches the device.
• Plug in a cable if you possibly can, even temporarily. This resolves a surprising share of problems outright.

By the end you will know which layer is failing, which is most of the work.

Wi-Fi versus a cable

Wi-Fi is the single most common cause of streaming problems in homes with a perfectly adequate internet connection. It is shared, it is affected by walls and by neighbours, and its throughput varies second by second in a way a cable does not.

If a cable is genuinely impossible, the two changes that help most are using the 5 GHz band rather than 2.4 GHz for anything above standard definition, and physically moving the router — line of sight to the streaming device beats raw router specifications almost every time. Powerline adapters and mesh nodes are both reasonable middle grounds.

Codecs and why the numbers changed

The bandwidth figures people quote are mostly based on older video compression. Newer codecs deliver roughly the same visual quality at close to half the bitrate, which is why a modern 4K stream can be lighter than an older 1080p one.

The catch is hardware support. A device that decodes a newer codec in hardware handles it effortlessly. A device that has to fall back to software decoding will run hot, drain battery, and stutter — even though the stream itself is smaller. When comparing devices, hardware decoding support for current codecs matters more than the headline processor speed.

Our 4K streaming guide covers which resolutions and codecs are worth targeting for a given screen and connection.

What to expect at peak times

Live streaming has a structural problem that on-demand video does not: everybody wants the same content at the same moment. On-demand traffic spreads across the evening; a live broadcast concentrates it into a single hour.

This is why a service that is flawless on a Tuesday afternoon can degrade during a major live event, and it is the fairest way to judge one. Any service looks good when nothing is happening. Judge it during the busiest hour you care about — which is also the argument for actually using a free trial at a realistic time rather than whenever you happen to sign up.

A setup that holds up

• Wired connection to the streaming device wherever physically possible.
• Enough bandwidth headroom at your busiest hour, not your quietest.
• A device with hardware decoding for current codecs.
• Stream quality matched to the screen — 4K on a 1080p television costs bandwidth and gives nothing.
• A tested backup path, usually a phone on mobile data, for when the main connection fails.

For service-level comparisons see the USA rankings, Canada rankings and our live sports guide.

Frequently asked questions