The speed of light is the final barrier to live online entertainment

A live game freezes for a moment. We interrupt our interlocutor on a video call because there’s a half-second delay between us. In both cases, it’s not necessarily a bad application. It’s often a matter of physics that software can’t quite overcome.

Latency is the sum of several costs that add up along the data path. Engineers can reduce some of them, but one they can’t eliminate. The last one is the speed of light. It’s the speed of light that sets the lower limit for anything that needs to work in real time.

The limit that code can’t overcome

Light in fiber optics doesn’t travel at full speed. Due to the properties of glass, it travels at about 200,000 kilometers per second, about two-thirds the speed of a vacuum.

This makes for a simple calculation. For every 100 kilometers of distance, the signal takes about a millisecond to travel there and back, and that’s under perfectly ideal conditions.

In practice, it’s slower. There are routers, several intermediate stations, and the last, slowest step to the device.

Human perception is relentless. A delay of about 100 milliseconds seems instantaneous, but above that limit we start to perceive it as a clumsiness.

Why this is important is best seen when the image needs to be synchronized with the action. A real-time online game must render the image on the screen in less than a second or two, otherwise the movement and display will be distorted.

The same applies to video calls and e-sports. Where people are interacting in real time, every extra tenth of a second immediately goes wrong.

The milliseconds that are hidden in the processing

Physics is only one part of the equation. A lot of the delay is created during the processing itself.

The image has to be captured, compressed with a codec, sent over the network, and then developed again on the other side. Each of these steps adds a few milliseconds.

Here lies another trade-off. Stronger compression saves bandwidth, but it takes more time to process, so you have to find a balance between size and speed.

The most insidious part of the journey is the last part of the journey. Your home WiFi or mobile network is often a bigger source of delay than the entire journey across half of Europe.

The trade-off between smoothness and speed

Data packets do not arrive evenly. Some are late, others arrive quickly, and this unevenness is called jitter.

The solution is a buffer, which holds the data for a moment and then plays it smoothly. But this solution itself adds delay.

Here is the central trade-off of live streaming. A smaller buffer means less delay, but a greater risk of stutter, while a larger one means the opposite.

In live chat, the limit is low. When the total delay exceeds about half a second, the two speakers start to overlap and the conversation becomes laborious.

Proximity instead of pure speed

Because physics cannot be outpaced, engineers are working around it. Instead of sending data far away, they are bringing it closer to the user.

Content delivery networks keep copies at the edge, close to where users live. Live streaming is handled by protocols like WebRTC, which are designed for sub-second latency.

As a result, many things that were once impossible now seem self-evident.
Some processing is moving even closer, to the very edge of the network.

Fewer paths mean less latency, so computing is increasingly happening where the request is made.

Slovenia and the advantage of a good connection

That’s why it matters how close and how well someone is connected. A country with a dense and modern network has a natural advantage in everything that goes live.

Slovenia is better equipped than it seems at first glance. Fast connections and widespread mobile networks mean low actual delays for everyday services.

This is part of the story described by the digital side of Slovenia, which visitors often overlook – a developed digital infrastructure beneath the country’s peaceful tourist image.

For the user, this is felt as less lag and a smoother picture, without them even realizing why.

The difference is added up by small advantages. A shorter path to the server, more modern equipment and a less loaded network together save enough milliseconds to make the experience noticeably better.

Silent race against time

The next time a live broadcast runs without lag, there is a silent race against time and distance behind it.

And when it lags, you now know where to look for the cause. It’s often not in the application, but in the distance, in the last meter of the connection or in the buffer that chose smoothness over speed.

This is also a good test of a serious service. Anyone who brings a live stream close to the limit allowed by physics has done a difficult job.

Therefore, it doesn’t matter where the service is hosted and how it is built. Two seemingly identical applications can behave completely differently when streaming the same stream.

Online gaming should remain a form of entertainment, not a way to make money; play responsibly!