What is HLS Streaming? When Should You Use It?

  • admin
  • January 21st, 2021
  • 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 a scenario where programs are available to consumers within a fraction of time and at any time, consumers have gone crazy over online streaming, and on-demand video content, and live streaming. With this technology, many platforms have turned to offer live video feed services on multiple devices.

    Broadly, the green revolution, in most instances motivates people to use eco-friendly products and services. Looking at today’s trends, people are more inclined to accessing whatsoever available resources online. So much so even the blog writing that brings awareness and boosts digital marketing is vanishing away to videos shared that help visualizes consumers. 

    Enthusiasm among the people streaming video content has undergone several developments to give viewers the best live streaming experience. One among such developments is the emergence of HTTP live streaming, and it is well-known under the abbreviation 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 designed by Apple, it deploys content using web-server and content delivery network to view on devices such as AppleTV, Mac, and iOS devices.

    A high-level HLS works on all adaptive streaming technology giving users a multi-channel live video streaming experience. Since it is an HTTP-based technology, it does not require a special configuration or streaming server and can be served from a standard web server. Thus, all the switching logic resides on the player itself.

    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 content to the actual speed of the network connection. This optimizes the quality of the viewing experience.

    HLS videos are encoded with 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 media server where the video and audio data is collected in bits and streamed over the player. As HLS is an HTTP-based technology, an ordinary web server can serve the stream.

    Two key processes take place on this 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. 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 viewer’s 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.

    Client Devices—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 a lower to a 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 is what sets 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.

    Bottom Line 

    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.