What is HLS Streaming? How does it work?

On-Demand video and live streaming is dictating the way entertainment is being delivered online to the world right now! However, there have been shifts in the way of delivering video content that some know of and some might not. Back in the 1990s, one had to download an entire software package just to play a single video file. Adding to the ache, video quality was never predictable and primitive connectivity speeds made video streaming more difficult. 

Emergence in video content delivery protocols have encouraged streaming solution providers to seek the best standards and protocols to deliver high quality video. 

And this is where video streaming with HLS comes into play. 

This short blog will give you a simple explanation of HLS video streaming, how it works and what more it brings to video streaming.

So, let’s begin with,

What is HLS?

HLS (HTTP Live Streaming) is an adaptive bitrate streaming protocol that is used for delivering audio and video content to viewers over the Internet. It was initially designed for Apple devices and is a key streaming format for iOS devices. However, it is also supported by Android, Windows, Linux, Microsoft, Microsoft Edge, and other platforms as well.

Why is HLS popular? 

• Supported by multiple platforms, devices, and browsers:

HLS can play your video content almost anywhere. It’s interoperability is the catch here! There are freely available HLS players on every other major platform such as mobile, web, and TV.

One very crucial point here is that Apple mandatorily requires HLS. 

So, if you want to stream your On-Demand video content or broadcast live events and don’t want to miss out a large segment of viewers using iOS Apps or devices, HLS is the protocol your video streaming platform must deploy. 

• Relatively simple: 

HLS uses common existing video formats (like MP4 or TS, along with codecs like HEVC(High Efficiency Video Codings), i.e. H.264, H.265. 

HEVC, touted as a next-generation codec, promises to deliver 4K content with higher compressing performance than H.264. 

• Works over HTTP: 

As it is functional over HTTP, you don’t require to run special servers. This makes it much easier to scale with HLS as compared to any other protocol.

Now, let’s understand,

How does HLS video streaming work?

Technically, HLS works by regulating three key components: video data, distribution channels and client devices. 

Video Data

Here, two primary sources are used by HLS to stream videos:

• • Content servers: These are used specifically when streaming on-demand video content

• • Real time video sources: These are used during live broadcasting

To begin streaming, two essential processes have to take place, typically on a server, before video data distribution takes place. 

• Encoding: 

During encoding, video data is formatted according to video-compression standards of either H.264 or H.265. This enables the devices to identify and decode data accurately. During this process, multiple video copies are created with different quality levels, or technically, encoded with variable bit rates.

In simpler words, the video copies are formatted in such a way that multiple platforms and devices can interpret them.

• Segmentation: 

The origin server breaks down the video file into multiple smaller segments that have a standard length of 6-10 seconds. Index files are then created to specify the order and timing of playing individual segments.

• Distribution Channels

Videos, once encoded and segmented, can now be streamed to the viewers’ devices as a direct response to the requests made to a content server. 

On the other hand, a CDN(Content Delivery Network) can also be used to distribute the video stream easily across a geographic area. In this case, it also happens to cache data for faster delivery to the client devices. 

To know more about CDN, check out our blog on Role of CDN in Video and Audio Streaming!

• Client Devices

These receive and display streamed video data on smartphones, desktops, laptops, tablets, smart TVs, and other connected devices. 

Once a video file is received, the client device determines the sequence in which the segments are to be played as per the index file. Meanwhile, client devices work on determining which stream quality to adopt. And this happens as per the available connection speed, screen dimensions, and local system resources. 

• Client Support and Latency

HLS happens to be a common and universally supported protocol to stream video right from mobile devices to HTML5 video players.

Initially, HLS latency happened to be higher than that of the other streaming protocols. Low latency HLS, back then, required changes in the way video streams were served along with needing special support by CDNs and clients.

However, it is in late 2019 that a dynamic shift was brought by Apple with the introduction of a low latency mode of HLS that has sub-two-second latency for live streaming. 

Thus, low latency is one big advantage of the HLS protocol. 

Now let’s talk about the benefits of HLS in video streaming:

• Adaptive bitrate capabilities:

  With its ABR capabilities, HLS ensures that broadcasters and video content providers deliver the optimal viewer experience. Buffering is minimized by adapting the video quality to the device and the Internet connection of the viewer. 

To know more about Adaptive Bitrate Streaming, check out our blog on “Adaptive Bitrate Streaming: Simplified for One & All!

• Adaptation to network speed variables:

  HLS enabled video players can automatically adapt and adjust to the changing network speed. Thus, it prevents stalls during network fluctuation. 

• Native support:

   HLS is natively supported on iOS Safari 3.2+, Safari 6+,  Android Browser 3+, Microsoft Edge 12-18, Chrome for Android 81+, and Opera Mobile 46+.

• High compatibility:

  HLS can be deployed on almost every client device via an HLS-compatible video player. 

Now, considering that all online video streaming service providers and broadcasters take content protection very seriously, HLS gives peace of mind here too with video encryption.

What is HLS Video Encryption?

HLS video encryption provides an extra layer of protection to your content when video streaming. This makes it very difficult for the viewers or end users to save the video to their devices. 

During the transcoding process, video content is encrypted with a unique key specific to the video owner. Here, HLS video encryption acts as a DRM solution as it exchanges and checks the encryption keys before the video is played on the user’s device. 

Taking the security factor into account, it is one of the best methods for delivering video content online. And for site owners with paid(protected) video content like elearning courses, PPV(Pay Per View) content, etc, HLS video encryption stands as the perfect solution.

Final Note,

HLS is popular in the broadcasting industry because of its inherent compatibility with HTML5 Players, the default playback method on web browsers. So, it automatically connects with users irrespective of the device they use. It has the edge over its counterpart RTMP as HLS protocol leverages HTTP to transfer video content in chunks to viewers. 

So, if your platform supports multi CDNs as Muvi supports, you can stream video to any part of the world without compromising the quality. [Read on our blog on HLS vs RTMP:Decoding Streaming Protocols]   

Muvi supports HLS feeds for your audio/video streaming and enables you to create audio/video playlist for On-Demand streaming by embedding the HLS URL to any third-party player and device.

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