Recent updates to the HTTP Live Streaming (HLS) standard have made new ways of standard-compliant low-latency streaming possible. But how low can the latency be, by how much do different low-latency flavours of HLS differ and what will the future of HLS bring in terms of delay? NativeWaves Andreas Unterweger and Bartosz Ziemski investigate
By Contributor
Published: April 22, 2021
Recent updates to the HTTP Live Streaming (HLS) standard have made new ways of standard-compliant low-latency streaming possible. But how low can the latency be, by how much do different low-latency flavours of HLS differ and what will the future of HLS bring in terms of delay? NativeWaves' Andreas Unterweger and Bartosz Ziemski investigate
target=_blank title=Share on LinkedIn class=share-linkedin>
Live streaming over the internet is an increasingly popular supplement to traditional broadcasting. With ever increasing demands regarding fast and scalable streaming, the widely adopted HTTP Live Streaming (HLS) standard has undergone recent (draft) revisions to enable lower end-to-end latencies. This version of the standard is commonly referred to as Apple Low-Latency HLS (LLHLS). It is different from previous efforts to supplement the old HLS standard with low-latency capabilities, commonly referred to as Community Low-Latency HLS (LHLS).
Simply put, Community LHLS advertises the most recent (edge) media segment to the receiver while it is still being produced, whereas Apple LLHLS advertises only those portions of it which are already available. Both approaches have their own upsides and downsides. Most prominently, Community LHLS breaks Adaptive Bit Rate (ABR) streaming due to chunked transfer and is already phased out in most implementations in favor of Apple LLHLS. The latter, however, makes caching through Content Delivery Network (CDNs) very hard due to very frequent and potentially client-dependent playlist updates.
While the choice of HLS flavour seems to boil down to the technical, logistical and practical pros and cons, it does not appear to be a question of delay - low latency is low latency after all, or is it not? Perhaps surprisingly, the practical delay bounds for each HLS flavour are not the same and their relative impact on end-to-end delay is larger than one might think. Let us investigate.
End-to-end delay comprises of many different factors, only some of which the sender (operating the live streaming source) can influence directly. Even the most creative engineers have very limited means against, for example, the transmission delay itself - the speed of light is quite a tough barrier to break in our Universe. However, accepting the physical limits of our Universe and thus our global network connections as they come, the remaining delay that can be influenced directly is worth analysing.
To explore the limits of HLS in terms of (influenceable) delay, engineers at NativeWaves set up a streaming server, a distribution (caching) server and a client (player) in a local network. The setup depicted in the image below is based on typical real-world setups for live events: The server captures a known Serial Digital Interface (SDI) input signal with a capture card, encodes it in hardware (on a Graphics Processing Unit (GPU)) and sends the encoded data via HLS directly to a distribution server which streams it to the client. Standard software (including FFmpeg with nvenc support) and typical settings (e.g., six seconds segment size) are used to make the results representative and as close as possible to practice.
data-src=https://www.tvbeurope.com/wp-content/uploads/2021/04/1-726x143.png alt= width=726 height=143 data-srcset=https://www.tvbeurope.com/wp-content/uploads/2021/04/1-726x143.png 726w, https://www.tvbeurope.com/wp-content/uploads/2021/04/1-353x69.png 353w, https://www.tvbeurope.com/wp-content/uploads/2021/04/1-768x151.png 768w, https://www.tvbeurope.com/wp-content/uploads/2021/04/1-1536x302.png 1536w, https://www.tvbeurope.com/wp-content/uploads/2021/04/1-2048x403.png 2048w data-sizes=(max-width: 726px) 100vw, 726px />Setup used for testing consisting of a streaming server, a distribution server and a clientThe end-to-end delay is measured - from the time of capture at the streaming server to the earliest possible playback time at the client in the same local network. The measurements are analysed statistically, but instead of reporting the mean or median delay values, the 95th percentiles are presented. Reasoning about the worst-case delay that 95 per cent of users encounter portrays practical latency experiences much more accurately than focusing only on the better half of experiences.
data-src=https://www.tvbeurope.com/wp-content/uploads/2021/04/2.png alt= width=198 height=148 data-srcset=https://www.tvbeurope.com/wp-content/uploads/2021/04/2.png 554w, https://www.tvbeurope.com/wp-content/uploads/2021/04/2-353x263.png 353w, https://www.tvbeurope.com/wp-content/uploads/2021/04/2-160x120.png 160w data-sizes=(max-width: 198px) 100vw, 198px />Comparison of delay between classical HLS, Apple LLHLS and Community LHLS with a segment size of 6 sSo, what do the results look like? The image on the right shows a comparison of the measured delay values for classical (non-low-latency) HLS (left), Apple LLHLS (middle) and Community LHLS (right). As expected, classical HLS produces orders of magnitude higher delay than the two low-latency flavours. The latter are nearly indistinguishable at this scale, but their differences will be broken down in more detail later. First, let us find out what causes the big difference between classical HLS and the two low-latency flavours.
data-src=https://www.tvbeurope.com/wp-content/uploads/2021/04/3.png alt= width=253 height=189 data-srcset=https://www.tvbeurope.com/wp-content/uploads/2021/04/3.png 554w, https://www.tvbeurope.com/wp-content/upl
Europe Stories
05/01/2027
Worlds first 802.15.4ab-UWB chip verified by Calterah and Rohde & Schwarz to be ...
04/08/2026
Dalet, a leading technology and service provider for media-rich organizations, t...
04/07/2026
April 7 2026, 19:00 (PDT) Detective Conan: Fallen Angel of the Highway Opens in...
01/06/2026
January 6 2026, 05:30 (PST) Dolby Sets the New Standard for Premium Entertainment at CES 2026
Throughout the week, Dolby brings to life the latest innovatio...
07/05/2026
Journalists reporting on Sudan are working in one of the most complex and fast-m...
07/05/2026
Seit dem Start im Jahr 2023 hat DJ (Beta) das personalisierte H rerlebnis von 94...
07/05/2026
Da quando stata presentata nel 2023, DJ (beta) ha aiutato a definire un'esperienza d'ascolto pi personalizzata per 94 milioni di utenti Spotify Premi...
07/05/2026
Since launching in 2023, DJ (beta) has helped shape a more personalized listenin...
07/05/2026
Desde o lan amento em 2023, o DJ (beta) j ajudou a deixar a experi ncia de ouvi...
07/05/2026
From our earliest days, Spotify has been built on a simple principle: Great audio should be easy to reach. It's what's driven us to expand from music to...
07/05/2026
Asian and Pacific Islander artists continue to shape the global soundscape, pushing creative boundaries and connecting with fans worldwide. This Asian & Pacific...
07/05/2026
Company announce long-requested choir instrument
In the latest expansion of their Symphonic Elements series, UJAM have introduced an all-new vocal instrumen...
07/05/2026
Modular-inspired sound generation with digital control
Buchla have introduced Ziggy, a new compact synthesizer built around the company's complex oscill...
07/05/2026
Combines analogue voices with digital synthesis and sequencing
Polyend have announced Drums, a new hybrid analogue and digital drum machine that combines sy...
07/05/2026
Control surface now officially supports four DAWs
When Nektar launched the Panorama CS12 control surface, it worked exclusively with Apple's Logic Pro, ...
07/05/2026
In the first quarter 2026, SGL Carbon generated consolidated sales of 184.5 million, which was 49.8 million, or 21.3%, lower than in the prior year (Q1 2025: ...
07/05/2026
Rohde & Schwarz and Greenerwave achieve precise and fast ESA antenna characteriz...
07/05/2026
January 8, 2024
Colorfront (colorfront.com), a leader in high-performance, on-s...
07/05/2026
February 9, 2024
Colorfront (colorfront.com), the multi-award-winning pioneer i...
07/05/2026
March 20, 2024
NAB 2024, Las Vegas - Colorfront (colorfront.com), the multi-awa...
07/05/2026
April 1, 2025
CINEMACON, APRIL 1, 2025 - Colorfront (colorfront.com), the multi-award-winning developer of high-performance dailies/transcoding/streaming syste...
07/05/2026
June 15, 2025
Colorfront (colorfront.com), an Academy and Emmy Award-winning de...
07/05/2026
June 15, 2025
Colorfront participated in the ICTA Barcelona Cinema Technology Summit on Sunday, June 15, 2025. Held at The Phenomena Experience, the event feat...
07/05/2026
July 1, 2025
Colorfront (colorfront.com), the multi-award-winning developer of high-performance dailies/transcoding/streaming systems for motion pictures, OTT,...
07/05/2026
July 1, 2025
Passion and dedication will take you places. Come with us on a short trip to the heart of India, where Annapurna Studios is living-up to the inspi...
07/05/2026
July 3, 2025
Colorfront (colorfront.com), the multi-award-winning developer of high-performance dailies/transcoding/streaming systems for motion pictures, OTT,...
07/05/2026
September 1, 2025
IBC 2025, Amsterdam - Colorfront (colorfront.com) - the Acade...
07/05/2026
April 17, 2026
LOS ANGELES - April 17, 2026 - Colorfront today announced Colorf...
07/05/2026
April 23, 2026
NAB 2026, Las Vegas - the Academy and Emmy Award-winning develop...
07/05/2026
Thursday 7 May 2026
Sky continues Sphere Abacus partnership with The Death of S...
07/05/2026
Thursday 7 May 2026
Sky Confirms Saturday Night Live UK will return this September for Series Two
Saturday Night Live UK will return for a second series, as S...
07/05/2026
Save 20% on the Sky Glass Gen 2 and Sky Glass Air TVsThursday 7 May 2026
How to watch the World Cup on Sky Glass
Tune into the World Cup on the BBC and ITV vi...
07/05/2026
Production sound mixer Dirk Sciarrotta has mixed Family Feud for 28 seasons. Thats up to 200 syndicated episodes per year, plus primetime celebrity specials - a...
07/05/2026
As audience expectations have evolved, Owen has stopped trying to hide microphones or excuse amplification. Instead, he treats sound as a fully immersive part o...
07/05/2026
Well known Irish faces pushed to the edge in new series of
Uncharted with Ray G...
07/05/2026
RT will premiere A Traveller Family, a compelling new documentary exploring the...
06/05/2026
New pricing tiers for vocal/dialogue restoration tool
NoiseWorks Audio's AI-powered vocal and dialogue processing plug-in is now available in three diff...
06/05/2026
Popular mixing & routing software overhauled
Following a recent public beta test, RME have launched the final release version of the powerful mixing and rou...
06/05/2026
New SOS Video Feature
Focusrites ISA C8X is a milestone product that brings together the companys analogue heritage and their expertise in digital audio. Yo...
06/05/2026
06 May 2026
VEON's Kyivstar Authorized to Resell Starlink for Businesses & ...
06/05/2026
UKTV has secured the exclusive rights to the early back catalogue of iconic Australian drama series Neighbours, following a landmark content deal with Fremantle...
06/05/2026
Wednesday 6 May 2026
Sky commissions feature documentary to mark 10th anniversa...
06/05/2026
Wednesday 6 May 2026
Sky and Formula 1 agree long-term partnership across UK, Ireland and Italy
Sky in the UK & Ireland to remain the home of Formula 1 until ...
06/05/2026
Sky Zero Footprint Fund-backed TV campaign launches nationwide, supported by new...
06/05/2026
Wuppertal May 6, 2026
Riedel Expands Leadership Structure, Appoints Marc Engro...
06/05/2026
SAN JOSE, Calif. - May 6, 2026 - Harmonic (NASDAQ: HLIT) today announced its latest broadband innovations for ANGA COM 2026, highlighting its vision for a new e...
06/05/2026
Statement from Rupert Murdoch, Chairman Emeritus, Fox Corporation on Ted Turner&...
06/05/2026
Friday 8 May on RT One and RT Player
Meet the NSPCA team caring for and protecting animals in need in this six-part series
Fly on the wall, six-part series...
Recent updates to the HTTP Live Streaming (HLS) standard have made new ways of standard-compliant low-latency streaming possible. But how low can the latency be, by how much do different low-latency flavours of HLS differ and what will the future of HLS bring in terms of delay? NativeWaves Andreas Unterweger and Bartosz Ziemski investigate
