Understanding Stream Latency: HLS, LL-HLS and StreamShark’s Optimized Latency

In the streaming world, latency, the delay from capturing a live event to the playback on viewer’s screen, is a critical factor for both content creators and audiences. The content format and interactivity requirement further influence operational decisions to strike a balance between reliability and interactivity, as discussed by James here not too long ago.

At StreamShark, we are constantly evolving our technologies to deliver the best balance between latency, reliability and scalability. In this blog post, we’ll review how latency behaves among StreamShark’s Event platform when using RTMP input with HLS output, the benefits of low-latency HLS (LL-HLS), and our latest Optimized Latency solution, which is now available, for improved real-time experiences.

Standard HLS: A Reliable but Delayed Experience

When streaming using RTMP as input and HLS as output, the standard HLS configuration typically introduces a 20-30 seconds delay. Standard HLS has been a trusted solution for many years due to its proven:

• Reliability: Capable of delivering high-bitrate streams seamlessly across all devices and platforms.
• Scalability: Efficiently manages massive viewership without performance degradation.
• Security: Easily integrates with encryption and DRM solutions.

However, for use cases requiring low latency or near real-time interaction, such as live sports, auctions, or interactive broadcasts with features like polling and Q&A, this delay may hinder the overall experience and responsiveness.

Low-Latency HLS: Reduce Delay to ~5 seconds

LL-HLS was introduced at StreamShark as an Event option from 2023, it significantly reduces playback latency to around 5 seconds. This is achieved by utilizing smaller segment size (typically 1-2 seconds compared to the standard 6 seconds) and delivering partial segments progressively for improved responsiveness.

This makes LL-HLS an excellent option for interactive use cases where real-time viewer engagement is critical. However, this approach comes with some limitations:

• Reliability & Scalability: While LL-HLS performs well, ensuring reliability and maintaining scalability at high viewership and bitrate quality levels can be resource-intensive compared to standard HLS
• Security: LL-HLS supports encryption and DRM, but its implementation is often complex and less universally supported.
• Compatibility: Adoption of LL-HLS is growing, but it is yet to be universally compatible across all devices and players.

While LL-HLS is a game-changer for delivering low-latency streams, these trade-offs may require additional infrastructure and careful planning to ensure consistent performance.

Introducing StreamShark’s Optimized Latency

While LL-HLS is a powerful option, we understand that not every use case can fully adopt its model due to scalability, security, or compatibility concerns. Moreover, not every use case needs to reach ~5 seconds latency. To provide a middle ground, we are excited to announce the Optimized Latency event type. This approach balances latency, reliability, and performance to deliver streams with a latency of 10-12 seconds.

Key Features of Optimized Latency RTMP:

• Reduced Segment Size: By lowering segment size from 6 seconds to 2 seconds, stream delivery is sped up.
• Optimized Player Buffering: The player buffer time is optimized, cutting down on playback delays.
• Support for All Existing Features: Unlike LL-HLS with certain limits and restrictions, all StreamShark platform features supported with Standard HLS – including DRM, DVR, Multistream, CMCD, Captioning and more – are supported with Optimized latency event type, ensuring no compromise while improving event delivery.
• Compatibility: Optimized Latency event works seamlessly with existing players and browsers across all platforms.

Here’s a quick comparison:

Type	Standard HLS	LL-HLS	Optimized Latency
Latency	20-30 seconds	~5 seconds	10-12 seconds
Reliability	High	Moderate to high	High
Scalability	Excellent	Good, but resource intensive	Excellent
Security	Strong encryption & DRM	Supported, but complex and not universal	Strong encryption & DRM
Segment Size	6 seconds	1-2 seconds	2 seconds
Player Buffering	Standard	Reduced	Optimized
Device Compatibility	Universal	Still growing adoption	Universal

What’s Ahead

At StreamShark, we recognize that every streaming use case is unique. Whether you prioritize low latency with LL-HLS, maximum reliability with standard HLS, or a balanced approach with our Optimized Latency, we offer solutions to meet your needs. Our goal is to ensure your audience gets the best experience possible, without sacrificing stability, scalability, or security.

The Optimized Latency event type has been rolling out to selected customers. If you would like to try it to optimize your streaming workflows, contact our team today to learn how Optimized Latency can transform your live-streaming experience and elevate audience engagement.