The term latency often comes up with video streaming over the Internet. But what exactly does latency mean, what are the different types of latency, and how does latency occur? Our blog post explains when low latency makes sense, which protocols are suitable for this, and what to consider if you want to stream with low latency.
What is latency?
During a (live) video stream, there is usually a delay. A few minutes to seconds typically pass between the moment of the event and the transmission on an Internet-capable end device. This delay is called latency. It refers to the delay between the start of the recording and the actual transmission.
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How does latency occur?
Several factors are involved in the delay. The three main ones are:
Encryption
In many cases, video files are sent over the Internet in encrypted form and are only decrypted again at the user's end device with the player's help. This often results in a latency of 0.1 to 3 seconds.
Streaming server
Depending on how far away the server from which the original file is sent is, or how many servers are interposed in the form of a CDN, a latency of 0.1 to 5 seconds results.
Video player
Depending on which video player is used and how it processes the stream data, a 4-60 seconds latency can occur here.
In addition, the available bandwidth, the Internet protocol used, the file size, and many other components can impact latency.
Types of latency
Latency in video streaming is divided into different classes:
Isn’t latency the one term you’ve always wanted to learn more about? In our free Streaming Dictionary, you will get a detailed overview and precise explanations of various streaming-related terms. Click here to download.
When do you need low latency?
Low latency is not attempted for every stream due to the more demanding technical implementation. Often it is not needed at all. However, low latency becomes important when broadcasting live events where there is a critical time factor. These include, above all, live streams in which viewers are involved interactively, for example, in the form of a chat, as is often the case at digital company events or learning sessions. But sports events, VR applications, gaming, or any broadcasts where real-time spoilers are to be avoided also depend on low latency.
Low Latency Streaming Protocols
An eCDN can ensure that digital events are possible even with many viewers without fearing poor video quality, long buffering, or entire network collapse.
HLS
Apple's HLS protocol has an extension since 2020 that enables low latency streaming.
Read more about HLS here!
WebRTC
WebRTC is also suitable for transmitting streaming with low latency. However, it is particularly suitable for streaming one-to-one streams such as video calls.
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Check out our Streaming Dictionary for even more interesting terms and definitions of the streaming industry!