What is HLS Streaming? When Should You Use It?
Table of Contents
What is HLS?
How HLS Works?
When Should We Use HLS?
A few years earlier, uploading videos and streaming them online used to be a tedious job and rarely even today due to the lack of high-speed data coverage. In such a scenario, consumers have gone crazy over live streaming and on-demand video content and moreover many platforms have turned to offer live video feed services on multiple devices.
As per the reports, about 80% of consumers would rather prefer to watch live video than reading a blog to get the same message. Considering this craze among people especially for this format, the delivery of video content has undergone several developments to give viewers the best live streaming experience. One such development is the emergence of HTTP live streaming or well-known as HLS.
What is HLS?
HLS-HTTP Live Streaming is an adaptive bitrate streaming communication protocol that is used to deliver audio and video content over the internet. HLS was initially developed by Apple to communicate with its devices such as AppleTV, Macs, and iOS devices.
However, it works on all adaptive streaming technologies giving users a multi-channel live video streaming experience. Since it’s an HTTP-based technology, it requires no special configuration and can be served from a standard web server, thus, all the switching logic resides on the player’s end.
Technically speaking, HLS-HTTP Live Streaming is a truly adaptive bitrate technology. When a video is encoded to HLS, multiple files are created for various bandwidths and with different resolutions. The streams are later mapped to the client in real-time using an index file based on the screen size & available bandwidth. Adaptive bitrate video delivery gives a superior experience as it delivers a static video file at a single bitrate and the video stream is adjusted to the client’s bandwidth capacity.
How HLS Works?
The most significant feature of the HTTP Live Streaming protocol is its ability to adapt the bitrate of the video to the actual speed of the network connection. This optimizes the quality of the viewing experience.
HLS videos are encoded in distinct renditions at distinct resolutions and bitrates, which is usually referred to as the bitrate ladder. When a connection gets slower, the HLS protocol automatically adjusts the suitable bitrate to the available bandwidth. HLS avoids re-buffering and stalling effects.
Server---An HLS video stream originates from a server where the media file is stored as well as the stream is created. As HLS is a HTTP-based technology, any ordinary web server can serve the stream.
Two key processes take place on the server:
Encoding---In this process the video data is reformatted as per the video-compression standards of either H.264 or H.265 encoding so that any device can recognize and interpret the data. During encoding, multiple video copies are encoded with variable bit-rates, in simpler words video copies are created with varying quality levels.
Segmenting---the video is formatted into multiple smaller segments that have a few seconds of length. The length of the segments can vary between 6-10 seconds. HLS creates an index file where it manages the order and timing of playing individual segments. HLS also creates several duplicate sets of video segments at various quality levels, such as 480p, 720p, 1080p, and so on.
Distribution---Once the video gets encoded and segmented, it will be ready to get streamed to the viewers devices over the internet when client devices request the stream. Generally, a CDN-Content Delivery Network will help distribute the stream to geographically diverse areas. It also caches the stream data and enables faster delivery to the client devices.
top ott platforms ---The client devices receive the stream and play the video. The client device uses the index file as the reference and assembles the video segments in order. As per the index file sequence the video segments are played. It switches from lower to high quality picture and vice versa as needed.
When Should We Use HLS?
There are some cases where videos are not that heavy. For instance, you could have a sequence of images encoded as a 1-2 seconds video, with a size of less than 1 MB. HLS is undoubtedly the best protocol to use with HTML5 video players. The main reason is that HLS content tags are programmable into a website’s HTML code. Additionally, its ease of implementation and customizability for video publishers and remaining free of charge for users are what set HTTP Live Streaming protocol apart from its alternatives.
Currently, HLS is the most widely used protocol for streaming, it is a safe bet for the majority of broadcasts. Anyone streaming content to connected devices must consider it especially when broadcasting sports, live events and asynchronous videos, where the quality is key. Low latency is worth considering as a reason to opt for HLS. When streaming to mobile devices, HLS is the ideal choice. HLS is also effective when we want to deliver high resolution videos with a size over 3MB.
While a video streaming platform reliant on HLS could be implemented and deployed in-house with the help of open source tools, it may be probably a good idea to use video publishing services, if you are not an expert in the technology. They can bring advanced features and take care of all technical aspects and let you focus on customization needs.