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 ...
09/10/2026
September 10 2026, 06:00 (PDT) Dolby Expands Dolby OptiView Platform with New Capabilities at IBC 2026
New Sports Intelligence helps providers better unders...
07/10/2026
Dalet, a leading technology and service provider for media-rich organizations, today announced the latest Long-Term Supported (LTS) release of Dalet Flex. Build...
12/09/2026
Latest Obsolete Devices pedal announced
Great Eastern FX Co. have just launched the latest pedal in their Obsolete Devices series, a range of effects pedals...
12/09/2026
September 11, 2026
BUDAPEST & SEATTLE, 10 September 2026 - Qumulo and Colorfron...
12/09/2026
Calrec expands its IP ecosystem with new Type RT console and Apex M6 Modular I/O Platform at IBC 2026 Type RT is the centrepiece of Calrec's news at IBC 202...
11/09/2026
Spark series gains compact modelling stompbox
Positive Grid's Spark amps have become a popular part of the company's line-up, offering a convenient ...
11/09/2026
New flagship sequencing plug-in revealed
Rapid Flow have just launched a new 16-track sequencer plug-in which they say has been designed for total rhythmic...
11/09/2026
Rohde & Schwarz unveils the air-cooled R&S TM1 medium-power UHF transmitter at I...
11/09/2026
Friday 11 September 2026
Sky Sports extends US Open deal to 2030
Sky has agreed a three-year extension to its US Open deal, ensuring Sky Sports & NOW remains ...
11/09/2026
Wuppertal September 11, 2026
A Decade of Innovation: AMP VISUAL TV Builds on Ten Years of MediorNet EvolutionAMP VISUAL TV is continuing the evolution of its ...
11/09/2026
Wuppertal September 11, 2026
Mediacom Deploys Riedel Easy5G for Wireless Camer...
11/09/2026
Wuppertal September 11, 2026
Touring Video Expands Flexible Production Workflows With Riedel MediorNet and hiRiedel Communications today announced that Tourin...
11/09/2026
Wuppertal September 11, 2026
Riedel Technology Powers Record-Breaking Esports World Cup Production in ParisFrom July 6 to Aug. 23, 2026, Paris hosted the Espo...
11/09/2026
Article courtesy of Digital Production
Read the article
With Baselight 8 coming in 2027, the interesting part is not the number of new buttons. Some features...
11/09/2026
It's almost iPhone Pro time. Starting Saturday, September 12, at 1 p.m, cust...
11/09/2026
RT has today announced Benetti Menswear as the sponsor of its 2026 Amgen Irish Open coverage for a sixth consecutive year, further strengthening the heritage c...
10/09/2026
Editing, restoration & mastering suite upgraded Acon Digital Acoustica 8 audio editing restoration mastering software.
Acon Digital have just launched the la...
10/09/2026
Classic synths & drum machines available to play
Based in Reading, UK, Readipop are a music and arts charity with a long track record of innovative, partici...
10/09/2026
Popular model updated & new addition introduced
With many of the models in Neumann's KH family now boasting onboard DSP and support for the company'...
10/09/2026
Improved desktop interface announced
The latest iteration of Arturia's flagship desktop audio interface has just arrived, introducing improved preamps, ...
10/09/2026
Progress needs proof: Rohde & Schwarz showcases its trailblazing test solutions ...
10/09/2026
CUPERTINO, CALIFORNIA Apple today announced iPhone 18 Pro and iPhone 18 Pro Max,...
10/09/2026
CUPERTINO, CALIFORNIA Apple today introduced Apple Watch Ultra 4 - the ultimate ...
10/09/2026
CUPERTINO, CALIFORNIA Apple today introduced Apple Watch Series 12, engineered w...
10/09/2026
The beloved duo are back with big challenges and even bigger laughs as they discover if you're ever truly too old to try something new.
Previous praise for...
10/09/2026
Thursday 10 September 2026
Sky News Defence Insider app launches as new researc...
10/09/2026
Thursday 10 September 2026
Award-winning network Sky Mobile to offer Apple iPho...
10/09/2026
Thursday 10 September 2026
Sky unveils gripping teaser for The Good Daughter, coming this NovemberTurn on cookies to view this content. Go to Privacy options a...
10/09/2026
Harmonic Leads the New Era of Broadband Connectivity at SCTE TechExpo 2026 Showcase Spotlights Include:
New cOS SensAI intelligence fabric unleashing data-pow...
10/09/2026
RT to Broadcast Amgen Irish Open free-to-air
New multi-year agreement will see RT continue to bring the Amgen Irish Open to Irish audiences
Ryder Cup hig...
10/09/2026
More than 30 women report allegations of sexual harassment, misogyny and bullying within National Ambulance Service
Tonight on RT Prime Time, 9:35pm, RT One ...
10/09/2026
Series 3 of Nero's Class begins Friday 11 September on RT Listen
The third...
09/09/2026
New parts aimed at hip-hop and pop productions
The latest update to Celemony's innovative virtual session musician expands the collection of built-in in...
09/09/2026
Save up to 40% until 21 September 2026
Sonarworks are currently running their Autumn Sale, with discounts of up to 40% currently available across their rang...
09/09/2026
Upcoming title officially launches in September 2026
Bjooks' celebrations for this year's 909 Day will be welcome news amongst drum machine lovers, ...
09/09/2026
CUPERTINO, CALIFORNIA Apple today introduced iPhone Duo, the first foldable iPhone. Opened, it is the thinnest iPhone ever, with a 7.6-inch inner display that p...
09/09/2026
CUPERTINO, CALIFORNIA Apple today announced AirPods 5, delivering the industry&#...
09/09/2026
Chennai/Luxembourg, 9 September 2026 - SES, a leading space solutions company, today announced the inauguration of its new office in Chennai, India, marking a s...
09/09/2026
September 9 2026, 22:35 (PDT) Cinema Sunshine Becomes Japan's First Exhibit...
09/09/2026
Wednesday 9 September 2026
Tom Daley adds final stitch to giant Baa-Ewe' t...
09/09/2026
Red Seat Ventures Integrates Barometer into Speakeasy to Maximize Podcast Revenu...
09/09/2026
Baselight-powered color comes natively to Media Composer, connecting creative de...
09/09/2026
RT brings three packed days of live radio, entertainment, news, weather and fun
Join RT Radio 1: Morning Ireland, Oliver Callan, Today with David McCullagh,...
08/09/2026
Built for rap producers, by rap producers
Sauceware Audio, the independent plug-in company founded by Grammy-nominated producer Jacob (Travis Scott, 21 Sava...
08/09/2026
Classic Sound Techniques design revived
Warm Audio's latest release delivers a meticulous recreation of the preamp circuitry employed by the Sound Techn...
08/09/2026
Latest soft synth inspired by the Memorymoog
XILS Lab have just launched a software instrument that draws its inspiration from Moog's iconic Memorymoog,...
08/09/2026
September 08, 2026 NORTHRIDGE, Calif. - Soundcraft today announced the launch of its Signature Plus Series Analog Connected Mixing Consoles. As the next genera...
08/09/2026
Tuesday 8 September 2026
Sky Go gets a major upgrade for Sky Glass and Sky Stream customers
Today, Sky launches a new version of the Sky Go app for Sky Glass ...
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
