HLS Streaming demystified: Apple's Pioneering Contribution to HTTP Live Streaming, as seen by an industry insider from the beginning

Video streaming has become an integral part of content delivery. With the rise of new technologies and the need for improved streaming protocols, HTTP Live Streaming (HLS, sometimes incorrectly referred to as "HLS Streaming") has emerged as the dominant force in the industry. In this article, we will delve into the evolution of video streaming protocols, focusing on the significance of HLS streaming and its advantages over other protocols.

The Birth of HLS Streaming at Apple

The HLS streaming protocol was born out of the innovative efforts of Apple, spearheaded by the team led by Roger Pantos. It was first introduced to the world with the release of iPhoneOS 3, aligning perfectly with the launch of the iPhone 3. This protocol was a breakthrough in the industry, addressing the challenges of streaming content on early smartphones.

Author's Experience in HLS Deployments

During the initial release of HLS, the author of this article had the privilege of being involved in several groundbreaking deployments. Notably, the author participated in the HLS streaming implementations for leading broadcasters and telecom providers such as BSkyB, Canal+, and Orange. These deployments marked the pioneering steps in adopting HLS streaming technology, providing viewers with a seamless streaming experience on their devices. In the latter part of 2012, the author embarked on the journey of developing the pioneering VOD2Live solution. Building upon this achievement, in 2015, he went on to introduce the groundbreaking concept of viewer-personalized TV channels utilizing the HLS standard. These channels, now widely recognized as FAST channels, revolutionized the way viewers engage with content, offering a personalized and dynamic TV experience.

Key Benefits of HLS Streaming

HLS streaming offers several advantages that have made it the go-to protocol for content delivery:

Wide Compatibility: HLS leverages open-source web servers such as Apache, lighttpd, and Nginx, making it compatible with a broad range of platforms, operating systems, and devices. This versatility ensures widespread accessibility for viewers.

Adaptive Bitrate Streaming: HLS supports adaptive bitrate streaming, dynamically adjusting video quality based on viewers' internet speed and device capabilities. This adaptive feature ensures smooth playback and optimal viewing experience, regardless of network conditions.

Scalability and Global Distribution: Leveraging ordinary web servers and content delivery networks (CDNs), HLS enables scalable delivery of live streams and video content to global audiences. CDNs distribute the workload across a network of servers, ensuring smooth and reliable content delivery.

Security and DRM Support HLS offers robust support for digital rights management (DRM) technologies, providing content creators with the necessary tools to protect their intellectual property and prevent unauthorized distribution and piracy.

Comparing HLS Streaming to Other Protocols

While HLS has become the de facto standard for video streaming, it's essential to understand how it compares to other protocols:

MSS (Microsoft Smooth Streaming): MSS, primarily used in conjunction with IIS servers and Microsoft Silverlight, had its niche in Microsoft-centric environments. However, HLS surpassed MSS in terms of broader compatibility, support, and adoption.

RTMP (Real-Time Messaging Protocol) RTMP, often associated with Flash video streaming, had its heyday in the past. However, with the decline of Flash and the rise of HLS, RTMP usage has significantly decreased, making HLS the preferred choice for video streaming.

MPEG-DASH (Dynamic Adaptive Streaming over HTTP) MPEG-DASH is a newer streaming protocol aiming to become a standard. While it shares similarities with HLS, HLS currently boasts wider adoption, support, and compatibility.

HLS Ingest: A Crucial Step in the Content Delivery Workflow

In addition to its widespread adoption for video playback, HLS also plays a crucial role in the content delivery workflow through the process of HLS ingest. HLS ingest involves preparing and delivering video content in the HLS format for distribution across various streaming platforms and content delivery networks (CDNs).

One notable requirement for HLS ingest is the Akamai MSL4 protocol, where HLS is now mandatory. Akamai, a leading CDN provider, has made HLS ingest an essential part of its content delivery infrastructure. This means that content creators and broadcasters who wish to utilize Akamai's MSL4 CDN must ensure their content is prepared and delivered in the HLS format.

However, it's worth noting that the support for HLS ingest is not yet universal among all online video platforms and encoding software. While HLS has become the de facto standard for video streaming, only a limited number of platforms and encoding software offer built-in support for HLS ingest. Content creators and broadcasters should carefully select their online video platform and encoding software, ensuring they choose one that supports HLS ingest to seamlessly integrate into their content delivery workflow.

By leveraging the power of HLS ingest, content creators can ensure compatibility with Akamai's MSL4 and other HLS-based content delivery systems. This enables them to reach a broader audience and deliver high-quality video content efficiently. As HLS continues to solidify its position as the industry standard, it is expected that more online video platforms and encoding software will incorporate HLS ingest capabilities, further expanding the options available to content creators and streamlining the content delivery process.

The Future of HLS Streaming

HLS streaming continues to dominate the video streaming landscape. As technology advances, we can expect further improvements in video delivery, reduced latency, enhanced security, and support for newer codecs like H.265/HEVC. The open nature of HLS allows for customization and enhancements to meet the evolving needs of the industry. In a recent development, the iReplay.tv team, known for their pioneering spirit, has incorporated support for audio lossless codecs into their repertoire. This addition reflects their commitment to staying at the forefront of technological advancements and enhancing the offerings available to their users.

HLS streaming revolutionized the way video content is delivered over the internet. With its wide compatibility, adaptive bitrate streaming, scalability, and robust security features, HLS has become the go-to protocol for broadcasters, content creators, and businesses worldwide. By embracing HLS and staying up-to-date with evolving technologies, content creators can ensure the best possible viewing experience for their audiences. As the streaming industry continues to evolve, HLS remains at the forefront, providing a reliable and efficient solution for delivering high-quality video content.

Article written by
Sylvain Corvaisier

Independent streaming and iOS engineer

Last modified: February 25th, 2025