Tips & Tricks

Video Latency: What Is It & How Does It Matter in Streaming?

10 min read
Video Streaming Latency

If you stream live video, you know how important it is to have a smooth and uninterrupted stream. Streaming a live video is about more than having good internet speed. Other factors matter, too. One is Video Latency- the time it takes for a video signal to travel from the source to the viewer. The lower the latency, the better the video quality and viewer experience.

Understanding video latency and other factors that affect video streaming can help you improve your live streams. In this blog, we’ll discuss video latency, what it is, why it’s important, and how to measure and reduce it for better video streaming.

So, let’s dive in and learn more about achieving low latency in live video streaming!

What is Video Latency?

Video latency is the time delay between when a video is captured and when it is played on your screen. Imagine you’re watching a live video stream, like a sports game. If there’s a delay in the video reaching you, that’s video latency. Many things can cause this. For example, your internet connection might be slow, or the video might take a long time to travel from where it’s captured to your screen. This is why low-latency video streaming is so important. It means the video gets to you faster, so you can watch it in real time.

Video Latency

This is especially important for live streaming, where you want to see the action as it happens. So, to have a good live streaming experience, you must ensure your video latency is as low as possible.

How does latency affect streaming video?

Latency is a big deal regarding streaming video, especially live streaming. It’s time for a video signal to go from the source to the viewer’s screen. When latency is high, it can cause problems like delays and buffering.

Think of it like this: you are watching a live soccer game video. If there is high latency, you might see the goal a few seconds or even minutes after it happened. This is not good for viewers who want to see the action as it happens in real-time.

On the other hand, low-latency streaming is all about speed. It makes sure the video gets to the viewer as quickly as possible. This is great for live sports, video conferencing, and online gaming, where every second counts.

Latency can make or break a live stream. That’s why it’s important to always aim for low latency. This ensures the best video quality and a great viewing experience.

Remember, the goal is to keep viewers happy and engaged. And low latency is a big part of that.

What Causes Video Latency?

Let’s take a look at some of the main reasons for high video latency:

Internet Connection:

One of the main causes of video latency is a slow or unstable internet connection. The data must travel from your location to the viewer’s device when streaming live video. If your internet connection is slow, it can take longer for this data to reach the viewer, causing a delay. Similarly, if your internet connection keeps dropping out, this can also cause latency as the data transfer is interrupted.

Streaming Protocol:

The protocol you use to stream your video can also affect latency. Some streaming protocols can cause high latency because they send the video data in large segments. This means that the viewer’s device needs to wait for the whole segment to arrive before it can start playing the video, causing a delay. On the other hand, protocols like Real Time Messaging Protocol (RTMP) can achieve lower latency because they send the video data in smaller, more manageable pieces.

Video Encoder Settings:

The settings you use on your video encoder can also cause latency. If you’re using high-quality settings, your encoder must process much data. This can take time and cause a delay in the video stream. On the other hand, if you use lower-quality settings, your encoder can process the data faster, reducing latency. However, this can also reduce the quality of your video.

Content Delivery Network (CDN):

A CDN is a server network that delivers your video content to viewers. If your CDN is slow or overloaded, it can cause latency. This is because the video data needs to travel from your location to the CDN and then to the viewer’s device. If there are any delays in this process, it can cause latency in your video stream.

Segment Duration:

Lastly, the segment duration of your video stream can cause latency. This is the length of time that each piece of video data represents. If your segment duration is long, it can take longer for each piece of data to reach the viewer’s device, causing a delay. However, if your segment duration is short, the data can reach the viewer’s device faster, reducing latency.

How to Measure Video Latency?

Measuring video latency is important to ensure a smooth live-streaming experience. Here’s a simple way to do it. First, you need two devices: one for streaming the video and another for watching it. Start the live stream and record the time. Watch the live stream on the other device and note when the video shows up. The difference between these two times is your video latency. Remember that a good internet connection and speed can influence video latency. If you’re streaming high-quality video content, you may experience high latency. But don’t worry, you can reduce latency. Try using a content delivery network (CDN) or adjusting your encoder settings. Remember, achieving low latency is crucial for a great live-streaming experience. So, measure your video latency regularly and make necessary adjustments for a smooth live stream.

How is Video Latency Categorized?

Video latency is grouped into different categories based on time delay. Here’s how it’s divided:

  • Standard broadcast latency: This delay lasts 5-18 seconds. It’s common in TV and some online video-on-demand (VOD) services.
  • Low latency: This is a delay of 1-5 seconds. You’ll find this in cable TV and some VOD services.
  • Ultra-low latency: This is a delay of less than 1 second. You get into real-time streaming when your video streaming reaches this level of delay. It’s great for two-way chats, but you might see a small pause if you’re doing something that needs more data, like playing music over the connection.
  • Real-time latency: This is a delay of just a few milliseconds. In most cases, you won’t notice any delay. But even this small delay can be noticeable for things that need exact timing, like playing music together online.

How to Reduce Latency While Streaming?

Streaming live video can be a fun and exciting way to share content with others. However, one common issue affecting your live stream’s quality is latency. Latency refers to the delay between when a video frame is captured and displayed to the viewer. High latency can lead to a poor viewing experience, with video that lags behind real-time events. So, how can you reduce latency while streaming? Let’s look at some tips.

1. Use a Fast Internet Connection

The speed of your internet connection is a key factor in determining the latency of your live stream. If your internet speed is slow, it will take longer for your video stream to reach your viewers. Therefore, using a fast internet connection can lower latency.

2. Choose the Right Streaming Protocol

Streaming protocols are the methods to send your video stream over the internet. Some streaming protocols are better at handling latency than others. For example, LL-HLS (Low Latency HLS) is known for its low latency. So, choosing the right streaming protocol can make a big difference in reducing your streaming latency.

3. Use a Content Delivery Network (CDN)

A content delivery network (CDN) is a network of servers that deliver your video content to viewers. Using a CDN can help to reduce latency because it ensures that your video stream is delivered from a server that is close to your viewer. This reduces the distance that your video stream has to travel, which can lower latency.

4. Adjust Your Encoder Settings

The settings on your video encoder can also affect the latency of your live stream. For example, setting your encoder to a high bitrate can increase the size of your video stream, leading to higher latency. On the other hand, reducing the bitrate can help to lower latency. However, keep in mind that reducing the bitrate too much can also reduce the quality of your video.

5. Use Adaptive Bitrate Streaming

Adaptive bitrate streaming is a technique that adjusts the quality of your video stream in real time, based on the viewer’s internet speed. This can help to reduce latency because it ensures that your video stream is not too large for the viewer’s internet connection to handle.

6. Reduce the Segment Duration

When your video stream is sent over the internet, it is divided into small pieces or segments. The length of these segments can affect the latency of your live stream. If the segments are too long, it can increase latency. So, reducing the segment duration can lower latency.

What is a Good Video Latency for Live Streaming?

For a good experience, you want ultra-low video latency. This means the video plays almost right away.

Video Latency Tiers High (seconds) Low (seconds)
Reduced Latency 18 6
Low Latency 6 2
Ultra-Low Latency 2 0.2


Most streaming services aim for a latency of less than 30 seconds. Some even get it down to 3-5 seconds. The lower the latency, the better your live stream. So, when choosing a streaming solution, look for one with low latency. This will make your live streaming more enjoyable for your viewers.

Castr provides two cutting-edge protocols to ensure Low Latency streaming, delivering your viewers a seamless and real-time streaming experience.

LL-HLS (Low Latency HLS): With LL-HLS, viewers can experience a significantly minimized delay, reducing latency to less than 15 seconds. This protocol allows for a smoother streaming experience on mobile and desktop platforms.

ULL (Ultra-Low Latency): Going one step further, ULL reduces the stream latency to an impressive less than 2 seconds, offering near-real-time engagement for your audience.

Why is Low Latency Important in Video Streaming?

Low latency is also important for interactive live streams. For example, in a live online class, students must be able to ask questions and get answers in real-time. If there’s too much delay, it can disrupt the flow of the class.

Many things can affect latency. One is the encoding process. This is when the video data is prepared for transmission. Another is the performance of the content delivery networks or CDNs. These are the systems that deliver the video data to the viewer.

Luckily, there are solutions to these problems. For example, Low-Latency HTTP live streaming (LL-HLS) and dynamic adaptive streaming can help reduce latency. And many online video platforms offer low-latency options.

So, if you’re in the video streaming business, it’s worth looking into these streaming technologies. After all, a better viewing experience means happier viewers. And happier viewers are good for business.

Video Streaming Latency on Castr

Castr is a video streaming solution that focuses on reducing video streaming latency. This means that when you use Castr for streaming, your viewers will experience less delay between the actual event and when they see it on their screens. This is important for a great viewer experience, especially during live events like sports games or concerts.

Castr uses two modern ways to make sure streaming is fast. The first is called LL-HLS. With this, the delay is cut down to less than 15 seconds. This makes the streaming experience smoother on both computers and phones.

The second way is ULL or Ultra-Low Latency. This is even faster, reducing the delay to less than two seconds! This is like being there in person. This is useful for live sports broadcasts, webinars, live auctions, and concerts. When the delay is this low, viewers can interact in real-time and get more involved in what they are watching.

So, if you want to give your viewers the best experience with the least delay, try Castr. With its focus on low latency, it’s a great choice for any live streaming.

Final Thoughts

The world of live video streaming is growing fast. With the right streaming service and online video platform, you can reach your audience in real-time with ultra-low video latency. It’s all about choosing the right streaming solution that uses the latest technologies. This includes dynamic adaptive streaming and reliable content delivery networks.

The encoding process also plays a big role in the quality of your stream. Remember, the goal is to fall in the low latency category to ensure your viewers have the best experience.

So, if you’re looking for a video streaming solution that offers real-time experience, Castr is the way to go. With advanced features like Low Latency HLS and Ultra-Low Latency, you can expect less than a 15-second delay, even as low as 2 seconds! This is perfect for live sports, webinars, live auctions, and concerts.

Castr makes sure your viewers get the best experience, no matter if they’re on a mobile or desktop platform. So why wait? Give Castr a try and see how it can improve your live video streaming.

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