HLS streaming (HTTP Live Streaming) is the leading protocol for delivering video over the internet, used by broadcasters and enterprises. By breaking video into short segments and adapting quality to each viewer’s bandwidth, HLS ensures smooth playback across mobile, desktop, and smart devices. Built on open standards, it powers HTML5 players, boosts security, and improves scalability. This guide explains how HLS works, its benefits, and when to use it.
What is HLS streaming?
HLS (HTTP Live Streaming) is a video streaming protocol that delivers multimedia content over the internet by breaking it into small chunks of about 10 seconds. These segments are sent over standard HTTP, making HLS compatible with most devices, browsers, and firewalls. It is widely used in video streaming platforms to reach audiences anywhere in the world.
A major advantage of HLS is its adaptive quality. On the server side, a broadcast can be encoded in multiple versions, such as 480p, 720p and 1080p. The player then selects the most suitable quality dynamically, depending on the viewer’s internet connection at that moment. This adaptive bitrate streaming keeps playback stable, even when network conditions change. For example, a mobile user may begin watching in HD, but if they move into a poor coverage area, the player switches to a lower resolution to avoid buffering or freezing. Once the connection improves, it upgrades to higher quality again, keeping the viewing experience uninterrupted.
How does HLS work?
On the server side, the video stream is encoded using H.264 or H.265 and divided into small segments. Alongside these fragments, HLS creates an index file (M3U8 manifest) that tells the player which chunks to request and in what order.
A content delivery network (CDN) usually distributes these segments, caching them for faster access worldwide. On the client side, a device such as a phone or laptop requests the segments and assembles them in sequence. If bandwidth conditions change, the player automatically switches between quality levels to keep playback stable.
Why HLS is the standard for video hosting and streaming
With its device compatibility, adaptive bitrate streaming, and support for secure delivery over HTTPS, HLS has become the industry standard for video hosting and video streaming. It scales easily through CDNs, works natively with HTML5 players, and ensures a consistent viewing experience across mobile, desktop, and connected devices.
Here are the key strengths that explain why HLS is the preferred protocol for broadcasters, businesses and platforms delivering both live and on-demand video:
1. Broad compatibility
HLS runs over standard HTTP, which means it passes through firewalls, works on any browser with an HTML5 player, and reaches audiences across smartphones, tablets, laptops, and smart TVs.
2. Adaptive bitrate streaming (ABR)
Instead of forcing a viewer into one resolution, HLS encodes the stream in multiple qualities. The player automatically adjusts up or down depending on the user’s bandwidth, preventing buffering and maintaining uninterrupted playback.
3. Scalability with CDNs
Because HLS works on top of HTTP, it integrates with any content delivery network. This allows brands to stream to global audiences with low latency and stable performance, even during peak demand.
4. Security and accessibility
HLS supports delivery over HTTPS and enables features like encryption and closed captioning, making it suitable for businesses that need compliance-ready streaming.
5. Open standard, no licensing costs
Developed by Apple and adopted industry-wide, HLS is built on open standards. This removes dependency on proprietary software and keeps it cost-effective for long-term use.
What is HTTP?
HTTP is an application layer protocol that serves to transfer information between devices connected to a network. All websites and applications that give regular users access run over HTTP. Data transfers over HTTP are usually based on requests and responses. Most HTTP messages are a request or response to a request.
In streaming over HTTP, the classic request-response sequence does not apply. The connection between client and server remains open for the duration of the stream, and the server sends video data to the client so that the client does not have to request every segment of the video data.
How Does HLS Work?
Server:
An HLS stream originates on a server where the media file is stored (in on-demand streaming) or where the stream itself is created (in the live stream). Since HLS is HTTP-based, any regular web server can originate the stream.
Two main processes take place on the server:
Encoding:
The video data is reformatted so that each device can recognize and interpret it. HLS must use H.264 or H.265 encoding.
Segmentation:
the video is divided into segments, each of a few seconds in duration. The length of the segments can vary, even if the default length is 10 seconds.
In addition to splitting the stream into segments, HLS creates a video segment index file to record their order. To sum up, HLS also creates several segment duplicates at different quality levels: 480p, 720p, 1080p and so on.
Distribution:
Encoded video segments are sent to client devices over the Internet when they request the stream. Typically, a content delivery network (CDN) helps distribute the stream to different geographic areas. The CDN also caches the stream to send it to clients even faster.
Client device:
The client device is the one that receives the stream and plays the video, such as a user's smartphone or laptop. The client device uses the index file as a reference to assemble the video in the right order, and switches from higher to lower quality (and vice versa) as needed.
What is Adaptive Bitrate Streaming in HLS?
One of the advantages of HLS over other streaming protocols is its support for adaptive bitrate or ABR streaming, which is particularly beneficial for interactive video streaming. This feature allows the video quality to adjust dynamically during a stream to accommodate changes in network conditions, ensuring a smooth and engaging experience. With interactive video streaming, this capability becomes crucial, as it enables continuous playback even when network performance fluctuates, while also maximizing quality when conditions allow.
If the network slows down, the user's video player detects it and ABR streaming reduces the stream's quality, maintaining uninterrupted playback essential for interactivity. As bandwidth availability improves, ABR streaming enhances the data stream's quality, optimizing the viewer's experience.
This seamless adjustment is made possible because HLS, during the segmentation process, generates multiple segmented streams at varying quality levels. The user's video player effortlessly transitions between these streams, which is particularly advantageous for interactive video streaming, where maintaining a high-quality, real-time connection is key.
History Of The Creation Of HLS
HLS was originally launched by Apple in the summer of 2009, along with the iPhone 3. Previous iPhone models encountered problems with online transmission because they sometimes switched between Wi-Fi networks and mobile data transmission.
Prior to the release of HLS, Apple's primary media streaming protocol was Quicktime Streaming Server. This offered good service, but because it used non-standard ports for data transmission, its RTSP protocol was periodically blocked by firewalls. Together with the slow internet, this has led to the abandonment of this protocol. But the lessons learned from its implementation have been very helpful in developing HLS.
How HLS streams are built
An HLS stream is generated on the fly and stored on an HTTP server. The video file is divided into short fragments, each with the extension .ts (MPEG2 Transport Stream). These fragments make up the building blocks of the stream.
To organise playback, the server also creates a playlist file with the extension .M3U8, commonly referred to as the manifest. This manifest indexes all the video blocks and points to additional index files for each available quality level, such as 480p, 720p, or 1080p. Even if a stream is delivered in just one resolution, a manifest is still created to maintain playback order.
On the viewer’s device, the player constantly checks network conditions. If the internet connection worsens or improves, the player refers back to the manifest to decide which quality version to switch to. It then requests the appropriate index file and continues from the exact moment the viewer left off.
This entire process happens automatically and remains invisible to the user, ensuring uninterrupted playback. HLS also supports closed captioning, making it suitable for accessible and compliance-focused video delivery.
When to Use HLS For Online Streaming
It is recommended that you always use HLS because it is the most modern and widely supported media streaming protocol. You can't do without it if you want to cast on mobile devices. Furthermore, HLS is the most up-to-date and widely used protocol for streaming media and can be used in the following scenarios:
1. When Streaming to Mobile Devices
If you want to cast to mobile devices and tablets, HLS is mandatory. Since mobile devices now account for the majority of Internet traffic (about 75% of traffic in 2019), HLS is essential.
2. When Streaming With An HTML5 Video Player
Native HTML5 videos are not compatible with RTMP or HDS. So, if you want to use a purely HTML5 video player, HLS is the only option. In addition to reaching mobile devices, these considerations point to HLS as the standard. If you are currently stuck with Flash technology , RTMP will be a better delivery method - but only if you have no other option.
3. When Faster Playback is Required
Playback time is quite crucial for every streaming video player, and HLS technology effectively provides faster playback with the help of Amazon's web services with no downtime.
The HLS player provides end-end support to users with flawless and robust quality among other live streaming formats. To summarize, HLS streaming technology has several advantages like adaptive streaming method, supports different platforms, contains multi-bit speed, which can be deployed on desktop and various mobile devices without any problems.
Final thoughts: Turning HLS into growth with Cinema8
HLS streaming has established itself as the industry standard for online video delivery, ensuring high-quality playback across devices with adaptive bitrate streaming and secure distribution. Its open standard and wide adoption make it the protocol of choice for businesses, educators, and broadcasters.
If you want to go beyond delivery and turn your videos into tools for growth, explore Cinema8’s smart video hosting plans. Built on HLS, it adds interactivity, analytics, and lead generation features that help brands drive measurable impact from video.