Latency for Streamers, Without the Folklore

"Lower your latency" is the most repeated advice in streaming and the least specific. Latency is not one thing. It is four things stacked, and you can only fix the ones you can see.

I'll show the arithmetic so you don't have to take my word for any of it.

Source one: frame time

Every frame your game draws takes time. At 60 frames per second, one frame lasts 1000 divided by 60, about 16.7 milliseconds. At 144 it's about 6.9. That doesn't sound like much, and for a single frame it isn't. But input, game logic and drawing are queued like cars, and a game that drops from 144 to 60 adds roughly ten milliseconds to every action you take.

Sixty frames a second has long been treated as the floor for smooth play. If you're below it, the game is the problem and the network is innocent.

Source two: distance

Light in optical fibre travels at around 200,000 kilometres per second, about two thirds of its speed in a vacuum. So every thousand kilometres of cable costs five milliseconds one way, ten for the round trip.

That's physics, not a setting. If the server is 4,000 kilometres away, 40 milliseconds of your ping is the planet, and no router will give it back. The real cable is longer than the map distance, so treat the figure as the best case.

Source three: encoding

Your streaming software has to compress each frame before it can send it. A faster encoder preset uses less processor time but produces a bigger file for the same quality, so you pay in upload bandwidth instead. A slower preset looks better and adds delay.

The practical rule: your upload speed should sit comfortably above your stream's bitrate, with room to spare for the bad minute. If it doesn't, frames queue, and the delay grows until the software drops them.

Check your upload with the game closed, at the time of day you really stream.

Source four: the viewer's buffer

Here's the one that surprises people. Even with a perfect connection, your viewers see you several seconds late, because the service buffers video to keep playback smooth. A low-latency mode shortens that buffer, but it also makes playback less forgiving of a slow connection on their side.

The delay between what you say and what chat replies to is mostly this. Don't blame your internet for it. Check what your service calls its low-delay setting, read its documentation, and test with a friend watching.

What I actually do

• Cap the game's frame rate slightly below what my machine can hold, so the picture stays steady

• Use a wired connection, always

• Leave the encoder preset on the middle setting

• Turn on low-latency mode for chatty streams and off for long, quiet ones

The rest is superstition. Measure each part, fix the biggest one first, and ignore anyone who sells a single number as the answer.

Names, places and events in this demo are fictional.