What is HLS Streaming?: The Ultimate Guide to HTTP Live Streaming
In 2009, the HLS video streaming protocol reimagined the entire streaming industry. It made it possible for viewers to access online video content from their mobile devices.
The HLS protocol was game-changing because it allowed businesses, creators, and publishers to access their audiences on the devices that they carried with them everywhere they went. This was a major catalyst for the explosion in video streaming that would occur over the next decade and lead us to where we are today.
In this article, we will discuss everything you need to know about the HLS streaming protocol and its role in the world of online video. We will discuss the pros and cons of HLS and provide a technical overview of how HLS works. We will also compare HLS with RTMP, another important streaming protocol.
Table of Contents
- What is HLS?
- How Does HLS Work?
- Top Benefits of HLS
- The Drawbacks of HLS
- HLS and RTMP: A Comparison
- Is HLS the Future of Streaming?
- Stream with Maestro
What is HLS?
HTTP Live Streaming (HLS) is a streaming protocol that was created to make mobile streaming possible. It is currently one of the most prominent technologies for delivering video and audio streams over the internet.
As the name suggests, HLS is an HTTP-based protocol. It is capable of adaptive bitrate streaming, which is a definite value add in the current online video streaming landscape.
This streaming protocol is compatible with streaming to a wide variety of devices and browsers since it works seamlessly with the HTML5 video player.
The History of HLS
Adobe’s Flash player was the original video player that was widely used for online streaming. This player worked on laptops and desktops but was incapable of mobile streaming.
As smartphones grew in popularity, a need for a mobile-compatible video player arose, so Apple developed the HTML5 video player.
Previously, Flash player had used Real Time Messaging Protocol (RTMP) to deliver content to the user-facing player, but this protocol was not compatible with Apple’s new HTML5 video player. A new protocol would be required to deliver content to the video player, and that’s how HLS came to be.
How Does HLS Work?
HLS works by splitting a video signal into small chunks that are easy to transport over the internet. These chunks are given the “.ts” file extension, which stands for “MPEG2 Transport Stream.”
The chunks are then stored and subsequently delivered with the support of an HTTP server. The server also indexes the chunks so that the stream can be accessed for playback.
In addition to the HTTP server, this process is facilitated by codecs and is made visible to viewers with an HTML5 video player.
Top Benefits of HLS
Streaming with the HLS protocol has many benefits, including enhanced compatibility, adaptability, and more. Let’s take a closer look at some of the top benefits of HLS streaming.
The key benefit of HLS is that it is highly compatible with all sorts of devices and browsers. Although Apple originally created it to enable mobile streaming, specifically for their devices, it works seamlessly with many companies' technology.
Some HLS-compatible browsers and devices include:
- Browsers: Google Chrome, Safari, Android Browser, Microsoft Edge, Opera, Mozilla Firefox
- Devices: Android smartphones, Apple smartphones, smart TVs, Linux devices, Microsoft devices, Samsung devices
Since HLS is compatible with virtually every type of browser and device, it allows brands and creators to reach a very large audience.
Adaptive Bitrate Streaming
HLS is capable of adaptive bitrate streaming, which means that the video is automatically delivered to viewers in the quality that is most suitable for their internet speed.
This means that if a specific user has a slow internet connection, they will be served a lower-bitrate video signal to avoid buffering, lagging, or other disruptions.
Although adaptive bitrate streaming automatically chooses the appropriate quality based on feedback from the video player, some streaming setups that use HLS enable users to choose their own bitrate. This is called multi-bitrate streaming.
Subtitles and Ad Insertion
Another interesting benefit of HLS is that it seamlessly integrates subtitles and advertisements into the video stream. This is valuable for both accessibility and monetization.
Dynamic ad insertion is particularly valuable since it makes it easy to incorporate advertisements in live streams.
The Drawbacks of HLS
There is only one significant drawback of HLS: it is not a great option for ingesting video from a source or encoder to an online video platform. This is because of limited compatibility with popular encoders.
This drawback does not devalue HLS in any way since it is still very practical for streaming to an HTML5 video player, but it is worth calling out this limitation.
It is also worth mentioning that latency was a previous issue for the HLS streaming protocol, but it has since been resolved with the creation of low-latency HLS.
HLS and RTMP: A Comparison
HLS and RTMP are currently two of the most significant protocols in online video streaming.
As we briefly mentioned, RTMP used to be used to deliver video to the Flash video player. HLS quickly overcame RTMP since it was essential for delivering video content to mobile devices.
After the demise of Flash player, RTMP assumed the role of ingesting for many streaming workflows. In some circumstances, HLS has been used for ingesting content from the encoder to the online video platform, as well.
Although HLS was designed for enhanced compatibility, there have been a couple of roadblocks that have prevented it from becoming the de facto standard for streaming ingest. The most significant issue is that many of the most powerful and accessible encoders are set up for compatibility with RTMP, not HLS.
Is HLS the Future of Streaming?
The online video streaming industry is constantly evolving, so the best technology of today will probably not be the best technology in the future. With that said, HLS is currently a crucial piece of the puzzle in many streaming workflows, but it will likely be replaced moving forward.
Other Streaming Protocols
Some other streaming protocols and technologies to keep an eye out for include the following:
- Secure Reliable Transport (SRT)
Each of these has slightly different structures, making them suitable for different use cases.
Stream with Maestro
Maestro uses HLS to deliver streams to viewers around the world. Our powerful video technology is packaged in an easy-to-use platform so brands and solopreneurs can create powerful streaming experiences without worrying about any technicalities.
Our platform enables users to offer premium streaming experiences to their audience, complete with monetization, interactivity, and audience management. Plus, create a branded video website with our drag-and-drop builder to house your on-demand video content, social links, and more.
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