A beginner's guide to streaming with low latency

A lot of us are acquainted with the delays of video data transfers.

So what exactly is low latency? Are you looking to cut down on the latency of all live occasions? Find out all the answers and more with this article.

An introduction to low latency

Low latency refers to the smallest delay in video data transfer from your player to your screens for viewers.

The reduced data transmission time makes for an excellent viewing experience and facilitates interaction. But here's the catch to get low latency: you need to compromise with less resolution or better quality video.

It is a good thing that no live event requires the use of low latency.

You need it when you live stream activities to allow for real-time interaction and viewing experience. In these cases, your audience expects to be able to watch or participate in the live stream as the event unfolds. This means you won't be able to afford the high-latency requirements and you will need to stream with less than 4K resolution.

While this is low latency streaming, let's dig deeper into the specifics of what it takes and how you can achieve it.

What is low latency

Translated, the term "latency" literally is a term that means "a delay in the transfer.'

When it comes to video latency, this means the amount of duration of the footage you have taken from your camera to it playing in your viewers' players.

Hence, low latency means lower time spent in moving video content to point A (your stream's headquarter) to point B (your viewers).

Similar to that, a higher latency means more time in transmission of video data from live streamer to their audience.

What constitutes as a low latency?

In accordance with industry standards low latency live streaming video is less than 10 seconds while broadcast television streaming is between 2- 6 seconds. In the case of your particular use, it's even possible to reach ultra-low latency that lies between 2 - 0.2 seconds.

What is the reason you're looking for low latency for video streaming? It's not necessary to have high latency on every live stream you host. However, you will need it for each live, interactive live streaming.

What is important here is the amount of interaction that your live event requires.

If your event is like auctions live, you'll need the lowest latency to stream your event. Why? To ensure all interactions show in real-time and not have delays as that can result in unfair advantage.

Let's look at more examples of these usage cases later.

Do you really need streaming that is low-latency?

The more participation live your event requires, the shorter transmission time you will require. So, your attendees will be able to take advantage of the event in real time without any delay.

Here are instances when you'll need low latency streaming:

• Two-way communicationsuch as live chat. Live events include live chats where Q&As take place.
• Real-time viewing experienceis essential such as with online games.
• Required audience participation. For instance, in cases of casinos online, bets on sports, as well as auctions that live.
• Real-time monitoring. This includes, for instance, searches and rescue operations, military-level bodycams, and baby and pet monitors.
• Remote operations that require consistent connections between remote operators and machinery that they are in control of. Example: endoscopy cameras.

When should you use low latency streaming

To summarize the various scenarios which we've previously discussed, you need low latency streaming when streaming:

• Content with a time limit
• Content that needs real-time audience interaction and engagement

But why not use low latency on all the video content you stream? After all, the lower the delay in your content getting to your viewers, the better? Well, not exactly. Low latency does comes with disadvantages.

These drawbacks are:

• Low latency compromises video quality. This is because high video quality can slow down process of transmission due to the high volume of files.
• It's the only buffered (or pre-loaded) content in line. This leaves little space for error should there be a network issue.

When you go live the streaming platform quickly pre-loads some content before broadcasting to viewers. In this way, if there's an issue with the network, it plays the buffered content, allowing the network-caused slowdown to catch up.

When the issue with network connectivity is solved The player will download the highest possible video quality. This, however, takes place behind the scenes.

In other words, viewers will enjoy the same high-quality, uninterrupted playback experience unless, of course, a major network mishap occurs.

If you choose to go with low latency however you'll see less replay video to be prepared by the player. This leaves you with minimal chances of error if the network issues strike out of the blue.

The fact is that high latency comes handy in certain circumstances. For example, the increased time-lag allows producers time to censor insensitive content as well as profane.

Also, in situations where you are unable to compromise on the quality of video broadcasting, you can increase the delay by a small amount to ensure a high-quality viewing experience as well as allow to correct errors.

How is latency measured

In the light of the definition of low latency streaming and its applications out of the way we'll look at ways you can measure it.

The technical term for low latency refers to the time defined by the unit the round-trip time (RTT). It is the amount of amount of time required for a packet to go between points A and B, and then for the response to reach back the source.

For calculating this number, an effective way is to include the timestamps of video and then ask a teammate to watch the live video.

Ask them to look out for the exact date and time frame which will show up on their monitor. Now add the timestamp's duration from the time the viewer was able to see the exact frame. That will calculate your time of arrival.

You can also ask a friend to watch your live stream and record a particular cue when it comes. Now take the time you played the cue in your live stream, and note the time your designated viewer saw it. It will provide you with time, although not as precise as the method above. But it's still good enough to give you a rough estimate.

How do you decrease the video latency

What are the steps to achieve the lowest latency?

The truth is that there are a variety of elements that influence the speed of your video. From encoder settings to streamer you're using, many factors come into play in.

So let's take a look at these elements and ways to optimize them for reducing streaming delay while also ensuring your video quality doesn't take the biggest hit.

• Internet connection type. Your internet connection is what determines your data transmission rates and speed. This is why Ethernet connections work better to stream live than wifi and mobile data (it's recommended to use them for backups, however).

• Bandwidth. A high bandwidth (the quantity of data that can be transmitted at one time) means less congestion and more speedy internet.

• Video file size. The larger sizes consume much more bandwidth for transferring video from point A to point B. This increases the latency and vice versa.

• Distance. It's how far you are from your Internet source. The closer you are to your source, the quicker the video stream you upload will be transferred.

• Encoder. Select an encoder that helps maintain low latency when sending signals directly from your device to the receiver device in the shortest period of time as is possible. However, make sure that the encoder you pick will work with the streaming service you use.
• Streaming protocol or the protocol that transfers the data you've collected (including video and audio) from your workstation to the screens of viewers. For achieving low latency, you'll have to choose a streaming protocol that reduces the loss of data while also introducing less latency.

We'll now look over the different streaming protocols that you are able to pick from:

• SRT The protocol efficiently sends video of high quality over long distances with very low latency. However, since it's relatively new, it's being utilized by various tech companies, such as encoders. How can you solve this problem? Combine it with other protocols.

• WebRTC: WebRTC is great for video conferencing however it has a few compromises on quality of video since it focuses on speed mainly. But the problem is that the majority of players don't work with it as it requires an elaborate setup for deployment.
• High-latency HLS: It's great to use for latencies that are low, ranging from 1 to 2 seconds. This makes it perfect for live streaming with interactive features. It's an emerging spec so implementation support is in the process.
  

Live stream that is low latency

The streaming of low latency is possible with a fast connection to the internet, a good bandwidth, the best-fit streaming technology, and an optimized encoder.

Additionally is that closing the gap between yourself and the internet and using lower-quality video formats help.