Tag: WebAssembly

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The evolution of HbbTV through the Awards – Part 1: Enhancing the television experience

Posted on by Matthew Huntington

Since the inaugural HbbTV Awards in Rome in 2017, the awards have reflected the changing ways broadcasters, platform operators and technology providers use HbbTV to create new services and experiences for viewers.

The evolution of the award categories mirrors the evolution of HbbTV itself. Early awards recognised broadcast enhancement, multiscreen services and content discovery, while more recent categories reflect the growing importance of advertising, accessibility, operator applications and audience measurement. Together, the winners show how HbbTV has developed from enhancing linear television into a platform supporting comprehensive streaming services.

In this three-part series, we look back at some of the notable winners and use cases from across the history of the HbbTV Awards, exploring what they reveal about the evolution of hybrid television.

Entries for the 2026 HbbTV Awards are now open. If you have developed an innovative HbbTV product, service or application, we encourage you to submit an entry via the HbbTV Awards 2026 entry form.

Enhancing broadcast television

Enhancing the traditional broadcast television experience has been at the heart of HbbTV from the beginning. By combining a broadcast service with applications and content delivered over broadband, HbbTV gives broadcasters opportunities to add experiences that cannot be provided through the broadcast signal alone.

That role was clearly visible at the first HbbTV Awards in Rome in 2017, where there was a dedicated category for Best Use of HbbTV for Broadcast Enhancement.

The inaugural winner was Band Camp Berlin developed by German broadcaster Rundfunk Berlin-Brandenburg (rbb) and Fraunhofer FOKUS. Launched in late 2016 for the KiKA youth channel, it accompanied a 20-part documentary series following five young musicians, allowing viewers to access interactive video content and 360° footage. The judges described the entry as “original”, a “nice idea” and “very comprehensive”. It demonstrated something that would become a recurring theme among subsequent winners: HbbTV could be used not simply to provide an additional menu of content but to add something directly to the television viewing experience.

2016: Band Camp Berlin

A year later, interactivity was again at the centre of a winning entry. Russia’s Channel One won an award with its HbbTV voting services, which supported programmes including Voice, Who Wants to Be a Millionaire and Let’s Get Married. The service enables real time voting while viewers watched the live shows. The judges summed up the appeal neatly: “Interactive TV shows at their best: Engaging and enhancing.”

2018: Real time voting for ‘Voice’

Finland provided another example that year. Sofia Digital and Digita were runners-up with Participation TV with HbbTV, which the judges praised for bringing interactive entertainment to a sizeable audience.

These services illustrate one of HbbTV’s fundamental strengths. Linear television can retain the reach and simplicity of broadcasting while the broadband connection provides a return path and an application environment through which the audience can participate.

Going beyond the main screen

Another theme in the early HbbTV Awards was the opportunity to extend the television experience beyond the main screen.

A strong example came from BT in 2018 with its Multi Screen MotoGP concept. This was a broadcast innovations and augmented reality prototype developed by BT (British Telecommunication/BT Sport) to enhance live motorcycle racing coverage through multi-feed, hybrid TV and 5G-powered extended reality platforms. The service won Best Multiscreen HbbTV Service and was also runner-up for the Judges’ Grand Prix Prize. The judges described it as a “very sophisticated application” demonstrating “HbbTV 2.0 and Multiscreen at the highest level.”

The concept demonstrated how HbbTV could be used to create a richer experience around live television, with additional screens and devices complementing what viewers were watching on the TV. Sport is particularly well suited to this approach, with opportunities to provide additional information, alternative content and interactive features alongside the main event.

2018: Multi Screen MotoGP concept

More broadly, multiscreen experiences demonstrated an important aspect of HbbTV’s evolution. The television did not have to operate as an isolated device. HbbTV technologies could connect the main television experience with other devices in the home, allowing broadcasters and application developers to explore new ways for viewers to interact with and experience their content.

It was another example of the expanding possibilities created by combining broadcast television with an increasingly capable application environment.

Making television more accessible

Awards is accessibility. HbbTV’s combination of broadcast television and web technologies provides opportunities to create services that make television more accessible and inclusive.

Accessibility was already being recognised in the early years of the awards, even without a dedicated category. In 2018, German broadcaster ARD won Best Technology Innovation in an HbbTV Product or Service for its Signing Livestream App, which delivered sign-language interpretation streams for live television broadcasts over broadband. The service also received a special commendation from the judges.

Their comments emphasised both the innovation and its wider value. The application was described as a “great accessibility enhancement” with “high social value”, while the special commendation praised a service that solved a real problem in an innovative way.

2018:  Signing Livestream App

The following year, Bayerische Medien Technik (bmt) won Best Multiscreen HbbTV Experience for Fernsehen für ALLE/TV for EVERYONE, which leveraged HbbTV standards to merge broadcast video with internet-based accessibility features. The project also received the Judges’ Award for Best Technology Innovation in an HbbTV Product or Service, providing another example of accessibility being recognised through the broader awards categories.

2019: TV for EVERYONE

Accessibility received particular recognition in 2025 with a dedicated Best Accessibility Solution in an HbbTV Service award. The winner was 3Cat in Spain for its Sign language service in HbbTV with WebAssembly, which allows viewers to stream a personalized, resizable sign language video over broadband and display it picture-in-picture, perfectly synchronized with a standard broadcast TV program. The judges described it as “a highly innovative approach, taking advantage of modern web technology combined with HbbTV.”

2025: Sign language service in HbbTV with WebAssembly

The dedicated accessibility category was specific to the 2025 Awards, but it highlighted a use case that has been visible among award-winning HbbTV services over many years. From signing services to the application of newer web technologies such as WebAssembly, the winners demonstrate how HbbTV can be used to make television services accessible to a wider audience.

They also illustrate a broader strength of HbbTV: its ability to combine the reach of television with the flexibility of web technologies to address viewer needs that can be difficult to meet through the broadcast service alone.

From enhancement to sophisticated applications

Looking across these winners also reveals how the idea of “broadcast enhancement” itself has changed.

FTV Prima won Best Use of HbbTV for Enhanced TV Services in 2019 for TVOD previews of prime-time series. The TVOD service know as Video Půjčovna allows viewers to purchase a previews of a series 7 days before its airing in liner broadcast. This combined the immediacy and promotional power of linear television with the ability to access additional content through an HbbTV service.

2019: TVOD previews of prime-time series

As HbbTV deployments have matured, however, applications have become increasingly sophisticated. Features that might once have been presented as standalone broadcast enhancements can now form part of much larger applications combining linear television, streaming, interactivity, personalisation and other services.

This change is reflected in the awards themselves. Categories specifically dedicated to broadcast enhancement and multiscreen experiences were prominent during the first few years but have subsequently given way to broader categories recognising application and technology innovation.

For 2026, for example, the HbbTV Application Innovation Award provides a much broader canvas for recognising innovative applications than the early categories tied to individual types of enhancement.

This evolution reflects the increasing maturity of HbbTV. Developers have a growing range of capabilities at their disposal, while broadcasters and platform operators increasingly use them together rather than as isolated features.

A continuing role for broadcast enhancement

Nearly a decade after the first HbbTV Awards, enhancing the television experience remains fundamental to HbbTV, even if the terminology has changed.

The early award winners demonstrate the breadth of ideas that emerged from combining broadcast and broadband: viewers participating in television programmes, companion screens synchronised with the television, additional content related to linear programmes, and services designed to make television more accessible.

Many of these ideas are no longer treated as separate categories of innovation. They have become ingredients from which increasingly sophisticated HbbTV applications can be built.

The awards provide an interesting record of that progression. What began with individual enhancements around a linear television service has developed into an application environment capable of supporting much richer experiences.

And the evolution does not stop at enhancing the programme being watched. HbbTV has increasingly influenced how viewers find, access and navigate television services themselves.

In Part 2 of this series, we will look at the evolution of content discovery and operator applications, from early programme guides and on-demand portals through HD+ and LOVEStv to services such as Freely and the arrival of AI-assisted content discovery.

Become part of the story

The HbbTV Awards continue to recognise the products, services and applications shaping the future of hybrid television. If your organisation has developed an innovative HbbTV solution, now is the opportunity to join the growing list of award-winning services featured throughout this series.

Entries for the HbbTV Awards 2026 are now open. Find out more about the categories and submit your entry through the HbbTV Awards 2026 entry form.

The HbbTV Awards 2026 winners will be announced during the HbbTV Symposium and Awards in Barcelona on 18 November 2026.

HbbTV innovation showcase: quickfire presentations from the HbbTV Symposium 2025

Posted on by Matthew Huntington

Alongside the keynotes, technical presentations and roundtables, for the first time the HbbTV Symposium 2025 featured a series of quickfire presentations highlighting emerging ideas, innovative projects and future challenges for the HbbTV ecosystem. Covering topics ranging from media authenticity and accessibility to streaming platforms, interoperability testing and application discovery, the sessions demonstrated the breadth of innovation taking place across the industry.

Assuring provenance and authenticity: challenges and solutions for HbbTV

Naomi Schoppa, Research Associate, Fraunhofer FOKUS

Naomi Schoppa, Research Associate, Fraunhofer FOKUS

Naomi Schoppa addressed one of the most pressing challenges facing the media industry: how to maintain trust in digital content in an era of AI-generated media, deepfakes and disinformation. As content becomes easier to manipulate, audiences increasingly question whether the images and videos they see can be trusted.

Schoppa outlined the growing threat posed by misinformation, disinformation and fake news, alongside technical attacks such as signal hijacking and compromised media platforms. In response, she highlighted the importance of provenance and authenticity data, metadata that can record where content originated and how it has been modified throughout its lifecycle.

A range of technical approaches already exist, including digital watermarking, fingerprinting and embedded provenance information. The challenge now is how these technologies can be integrated into broadcast and streaming ecosystems. Schoppa posed an important question for the HbbTV community: should future standards define how authenticity and provenance information is transported, verified and presented to viewers? As media consumption increasingly spans broadcast, OTT and social platforms, ensuring trust in content may become a critical requirement for future television services.

Watch the presentation and explore further

You can watch the full quickfire talk from the HbbTV Symposium 2025 here:  Watch the Video

The presentation slides are also available to download: Download the presentation

Sign language on DTT with WebAssembly decoding in HbbTV

Rafael Bermúdez, R&D Team Product Owner, 3Cat – CCMA

Rafael Bermúdez, R&D Team Product Owner, 3Cat – CCMA

Rafael Bermúdez presented an innovative approach to improving accessibility by delivering sign language services through HbbTV. His goal was simple but ambitious: to make sign language as easy to access and personalise as subtitles are today.

Traditional sign language services often rely on dedicated broadcast channels, limiting flexibility and scalability. Bermúdez described a hybrid approach in which the main television programme is delivered via DTT, while the sign language video stream is delivered over broadband and synchronised using HbbTV technologies.

To overcome technical limitations, the solution uses WebAssembly (WASM) to decode a secondary video stream directly within the HbbTV application. Combined with low-latency DASH delivery and HbbTV Media Synchronisation, this allows sign language content to remain synchronised with the broadcast programme while offering viewers control over size, position and presentation.

The solution is built entirely on open standards and has been demonstrated across a wide range of HbbTV devices. Bermúdez called for wider industry collaboration to standardise sign language delivery as a first-class media component, alongside subtitles and audio description, making accessibility services easier to deploy and use across the industry.

Watch the presentation and explore further

You can watch the full quickfire talk from the HbbTV Symposium 2025 here:  Watch the Video

The presentation slides are also available to download: Download the presentation

The new ZDF streaming portal

Amelie Jakob, Product Owner HbbTV, ZDF

Amelie Jakob, Product Owner HbbTV, ZDF

Amelie Jakob provided an overview of ZDF’s newly launched streaming platform, representing a significant evolution in the German broadcaster’s digital strategy.

For the first time, ZDF adopted a “big-screen first” approach, placing connected TVs and HbbTV devices at the centre of the user experience. The aim was to move beyond the traditional concept of a broadcaster catch-up service and create a true streaming platform capable of competing with commercial streaming providers.

A key part of the transformation was a complete redesign built around metadata. New recommendation algorithms, automated content organisation and enhanced personalisation capabilities are all driven by a richer metadata structure. The platform also introduces larger visuals, autoplay trailers and improved content discovery features designed specifically for television viewing.

Jakob also highlighted innovations such as sustainability settings, which allow viewers to reduce the environmental impact of streaming, and enhanced support for live events and channels. Perhaps most importantly, the platform is delivered through a single code base that supports more than 30 platforms and over 10 operating systems, helping ZDF navigate the increasingly fragmented smart TV landscape.

Watch the presentation and explore further

You can watch the full quickfire talk from the HbbTV Symposium 2025 here:  Watch the Video

The presentation slides are also available to download: Download the presentation

Advancing HbbTV interoperability: latest developments in the CTA WAVE Streaming Media Test Suite

Louay Bassbouss, Senior Project Manager R&D, Fraunhofer FOKUS

Louay Bassbouss, Senior Project Manager R&D, Fraunhofer FOKUS

Louay Bassbouss provided an update on the Consumer Technology Association (CTA) Web Application Video Ecosystem (WAVE) Streaming Media Test Suite, an important industry initiative aimed at improving interoperability across connected TV devices.

The CTA WAVE project focuses specifically on media playback, testing implementations of technologies such as Media Source Extensions (MSE), Encrypted Media Extensions (EME), adaptive streaming and DRM systems. Unlike traditional manual testing, the framework automates much of the validation process, using video capture and analysis to measure playback performance, startup times and compliance.

Over the past year, the project has introduced a major new release featuring expanded test coverage, improved documentation and additional support for audio-only services. Significant work has also been undertaken to improve testing of HEVC, HDR and commercial DRM implementations.

Bassbouss highlighted the close collaboration between CTA WAVE and HbbTV, with elements of the test suite already contributing to HbbTV interoperability efforts. As streaming services become increasingly sophisticated, robust testing frameworks will play a vital role in ensuring consistent experiences across the growing range of connected TV devices.

Watch the presentation and explore further

You can watch the full quickfire talk from the HbbTV Symposium 2025 here:  Watch the Video

The presentation slides are also available to download: Download the presentation

Tracking global adoption of HbbTV with ADB

William Cooper, Chief Executive, Service List Registry

William Cooper, Chief Executive, Service List Registry

William Cooper concluded the session by examining how Application Discovery over Broadband (ADB) is providing new insights into the global adoption of HbbTV.

ADB allows HbbTV devices to discover and launch applications over the internet without relying on broadcast application signalling. Operated through the Service List Registry, the system acts as a global discovery mechanism, resolving service identifiers into application locations using standard DNS infrastructure.

The scale of deployment is already significant. Cooper revealed that the registry processes around half a million requests every hour, equating to approximately 10 million requests per day. This provides valuable insight into where HbbTV-compatible devices are being used around the world and which services viewers are accessing.

The data highlights strong adoption not only in established HbbTV markets such as Germany, Italy and the UK, but also in countries where HbbTV services are less visible. Cooper argued that service providers could gain additional value by registering services, enabling application discovery, collecting anonymous usage insights and extending support for enhanced services such as addressable advertising.

As television services increasingly move online, ADB demonstrates how HbbTV can support discoverability and interoperability beyond traditional broadcast environments.

Watch the presentation and explore further

You can watch the full quickfire talk from the HbbTV Symposium 2025 here:  Watch the Video

The presentation slides are also available to download: Download the presentation

Next in the series

Several of the ideas introduced during the Symposium’s quickfire presentations became the focus of deeper discussion during the unconference on the second day. Topics including media authenticity, enhanced sign language services, AI-powered television experiences, sustainable streaming and Application Discovery over Broadband were explored in greater detail as delegates worked together to identify future requirements, potential standards activities and opportunities for industry collaboration. In the final article in our HbbTV Symposium 2025 series, we report on the unconference discussions and the key themes that emerged from this 

Advancing the HbbTV specifications for a changing market

Posted on by Matthew Huntington

This article is part of a series based on presentations from the HbbTV Symposium and Awards 2025, bringing together insights from across the industry on the future of broadcast services and connected television. Covering topics from broadband-only delivery and addressable advertising to interoperability and evolving standards, the series captures key discussions and expert perspectives shaping the next phase of HbbTV and the wider TV ecosystem.

Jon Piesing, Vice-Chair, HbbTV Association & Chair, HbbTV Specification Group
Jon Piesing, Vice-Chair, HbbTV Association & Chair, HbbTV Specification Group

At the HbbTV Symposium 2025, Jon Piesing, Vice-Chair of the HbbTV Association and Chair of the HbbTV Specification Group, provided a detailed update on the evolution of the HbbTV specifications and the work underway to ensure they remain aligned with real-world deployment and future industry needs.

His presentation offered insight not only into upcoming features, but also into how the specification itself is developed and maintained. The HbbTV process is built around several coordinated groups, including requirements, specification, testing and interoperability. Together, these ensure that new features are defined, implemented and validated in a way that supports both developers and device manufacturers.

A central theme of the session was the importance of aligning the specification with market reality. Rather than introducing entirely new concepts, recent work has focused on formalising capabilities that are already widely deployed, making them more consistent, testable and reliable across devices.

This is particularly evident in the upcoming HbbTV 2.0.5 specification. Two of the most significant additions are WebAssembly and digital rights management (DRM). Both technologies are already present in many television environments, but standardising their use within HbbTV provides greater confidence for developers and content providers.

The introduction of a formal DRM specification is especially important. Historically, uncertainty around DRM integration led to fragmentation and inconsistent implementations. The new specification addresses this by defining how HbbTV applications can work with DRM systems such as PlayReady and Widevine, supported by reference applications and testing across a wide range of devices.

Alongside these additions, HbbTV 2.0.5 includes a number of refinements designed to modernise the platform. Improvements to video codec handling make it easier to support newer formats such as AV1 and VVC, while optional support for technologies like HTTP/3 reflects the ongoing evolution of streaming delivery. At the same time, legacy features that are no longer widely used are being deprecated or made optional, helping to simplify implementation and reduce complexity.

This process of refinement reflects a broader philosophy. As Piesing noted, the current focus is on fine-tuning and consolidating the platform, ensuring that it keeps pace with how televisions and services are actually being used today.

Looking further ahead, work is already underway on the next iteration of the specification. HbbTV 2.0.6 is currently in the requirements phase, with input being gathered from across the membership. Areas under consideration include improved deep linking into broadcaster applications, enhancements to the usability of the red button experience and better support for accessibility features such as content filtering and discovery.

One particularly interesting area of exploration is the ability to run multiple HbbTV applications simultaneously, potentially from different providers. This reflects the increasing complexity of service delivery and the need to support more flexible and dynamic user experiences.

Testing and interoperability remain a critical part of this work. The HbbTV test suite continues to expand, now comprising more than 3,400 tests, with ongoing improvements to coverage and quality. Recent updates include the addition of DRM-related tests and enhancements to addressable advertising and operator application scenarios.

Supporting tools are also evolving. Reference applications, validation tools and interoperability initiatives help ensure that specifications translate into consistent behaviour across devices. This is essential in a fragmented connected TV environment, where differences in implementation can quickly impact service quality.

Overall, the update highlighted a mature and evolving standard that is adapting to industry needs while maintaining stability for existing deployments. By focusing on real-world usage, simplifying where possible and extending capabilities where necessary, the HbbTV specifications continue to provide a robust foundation for interactive television services.

As the market moves further towards IP delivery and increasingly sophisticated user experiences, this ongoing work ensures that HbbTV remains both relevant and reliable for the next generation of connected TV services.

Watch the presentation and explore further

You can watch the full presentation from the HbbTV Symposium 2025 here: Watch the Video

The presentation slides are also available to download: Download the presentation

Next in the series

Explore the latest global TV and video market trends, as Dataxis analyst Ophélie Boucaud breaks down the rise of connected TV, shifting revenues and increasing fragmentation shaping the future of viewing and monetisation.

HbbTV Association publishes HbbTV 2.0.5 core specification

Posted on by Matthew Huntington

Geneva, 2 March 2026 – The HbbTV Association, a global initiative dedicated to providing open standards for advanced interactive TV services via broadcast and broadband networks, has published version 2.0.5 of its core specification, marking a major step in the evolution of the HbbTV standard. The specification was approved at the latest meeting of the HbbTV Steering Group.

HbbTV 2.0.5 is an incremental update to HbbTV 2.0.4, published two years ago, and represents a significant technical advancement for hybrid and interactive television services. The most notable change is the formal integration of Digital Rights Management (DRM) into the core specification. While HbbTV devices have supported DRM for many years, this is the first time it has been explicitly defined, providing a harmonised, interoperable approach across the ecosystem. Support for at least one of the DRM systems listed in the HbbTV DRM specification published six months ago – Microsoft PlayReady or Google Widevine – is required. This formalisation is essential for enabling secure delivery of premium content and meeting the requirements of broadcasters, platform operators, rights holders, and content owners, ensuring a compelling experience for viewers.

WebAssembly support, already present to some extent in HbbTV devices via browser engines such as Chrome or WebKit, is now formally included in the specification. This allows advanced features such as efficient decoding of auxiliary video streams, including sign language services demonstrated by Catalan public broadcaster 3Cat at trade shows IBC 2025 and HbbTV Symposium and Awards 2025. Additional web security measures have been incorporated, and support for the VVC and AV1 video codecs has been defined, although implementation of these codecs is optional. Several simplifications for implementers have also been introduced: unused features have been removed, others marked for deprecation, and some requirements relaxed to improve interoperability.

The integration between HbbTV and DVB-I introduced in HbbTV 2.0.4 is further improved in 2.0.5. The specification now clarifies how DVB-I applications associated with entire service lists can be supported, enabling platforms or service aggregators to obtain GDPR consent or agreement to terms and conditions. Implementation feedback, particularly regarding HbbTV and DVB-I integration, has resulted in numerous technical corrections being included.

The HbbTV Association plans to issue a Request for Proposals (RfP) in the coming weeks to extend its Conformance Test Suite to support HbbTV 2.0.5.

“HbbTV 2.0.5 represents an important step forward in the evolution of hybrid TV services,” said Vincent Grivet, Chair of the HbbTV Association. “With formalised DRM, support for next-generation codecs such as AV1 and VVC, enhanced DVB-I integration, and WebAssembly capabilities, the specification aligns to the most recent and impacting market trends, enabling more sophisticated, secure and feature-rich services. It demonstrates HbbTV’s continued commitment to advancing the connected TV ecosystem for broadcasters, platform operators, content owners and viewers alike.”

The HbbTV 2.0.5 specification and an associated explainer document are now available in the HbbTV Resource Library.

The potential of WebAssembly in HbbTV

Posted on by Matthew Huntington

WebAssembly (WASM) has revolutionized the way web applications are developed and executed. It is a powerful tool, enabling near-native performance for complex applications within browsers. As an essential technology for modern web development, WASM is transforming the capabilities of web applications, making them more efficient, secure, and versatile than ever before.

One area where WASM shows significant potential is in Hybrid Broadcast Broadband TV (HbbTV). This open standard for the delivery of interactive TV services integrates traditional broadcast TV with internet-based content. WASM can enhance HbbTV applications by providing a more efficient and performant execution environment for interactive features, making HbbTV services more responsive and capable of handling complex tasks including software based video decode.

What is WebAssembly (WASM)?

WebAssembly (WASM) is a low-level, binary instruction format designed to provide a portable, efficient, and secure execution environment for web applications. Often described as a “virtual machine for the web,” WASM enables developers to run code written in various programming languages, such as C, C++, and Rust, directly in web browsers. Its primary goal is to bridge the gap between native and web performance, making complex and compute-intensive applications feasible within the browser environment.

WASM operates as a complement to JavaScript, leveraging the WebAssembly runtime embedded in modern browsers. Developers compile source code into the WASM binary format, which browsers can execute at near-native speeds. Importantly, WASM is secure by design, running in a sandboxed environment to prevent malicious access to the underlying system.

WASM binary format is a bytecode like Java bytecode and the Common Intermediate Language of .net. There is a human readable version of the WASM known as WebAssembly text. WASM binary files have the extension .wasm, WASM text files have the extension .wat. 

A brief history of WebAssembly

WASM emerged in 2015 as a collaborative effort among key players in the web development community, including Google, Mozilla, Microsoft, and Apple. The motivation was to overcome the limitations of JavaScript for performance-critical applications, such as games, video editing, and scientific simulations. 

Initially conceived as an evolution of asm.js (a subset of JavaScript optimized for performance), WASM quickly gained traction for its versatility and efficiency. It became a W3C standard in 2019, cementing its role in the web ecosystem. Over time, its use has expanded beyond browsers, finding applications in server-side development, edge computing, and embedded systems. 

WASM is now considered as the fourth language of the web after HTML, JavaScript and CSS. 

In 2024 W3C published WASM 2.0, a new snapshot incorporating feature extensions that had been deployed with mature implementations.

WASM continues to evolve through a feature development process. 

Major use cases of WASM

Major use cases for WASM include:

  • High-Performance Web Applications: WASM powers compute-heavy applications, including 3D games, CAD tools, and video editors, delivering near-native performance in the browser.
  • Cross-Platform Development: Developers can compile code written in languages like C++ or Rust into WASM, ensuring it runs seamlessly across different platforms.
  • Server-Side Computing: Frameworks like Node.js now support WASM, enabling high-performance server-side workloads.
  • Edge Computing: WASM’s portability makes it ideal for edge environments, where it can execute securely and efficiently on resource-constrained devices.
  • Embedded Systems: Its compact size and sandboxing make WASM suitable for use in IoT devices and other embedded systems.

A brief overview of HbbTV

HbbTV (Hybrid Broadcast Broadband TV) is a global standard that integrates traditional broadcast television with internet-based content and services. It allows broadcasters to enhance TV experiences with interactive applications, such as video-on-demand, targeted advertising, and gaming. 

HbbTV applications are built using HTML5 and JavaScript, leveraging web technologies to deliver these services. However, as the complexity and demands of applications grow, the limitations of JavaScript become apparent, this is where WASM could play a transformative role.

How WASM could enhance HbbTV

The potential ways in which WASM could enhance HbbTV include:

  • Improved Performance for Interactive Applications: WASM’s ability to run high-performance code could enable smoother and more responsive HbbTV applications. 
  • Complex Media Processing: Tasks like video encoding, decoding, or image manipulation could be performed using WASM, enabling new classes of applications.
  • Cross-Language Development: By supporting multiple languages, WASM enables developers to reuse existing codebases written in C++ or Rust, reducing development time for HbbTV applications.
  • Security for Third-Party Apps: WASM’s sandboxed execution aligns well with HbbTV’s need to run third-party apps securely, ensuring a robust and isolated environment for interactive content.
  • Resource-Constrained Devices: WASM’s compact binary format and efficient runtime make it suitable for HbbTV-enabled devices with limited hardware capabilities, such as older smart TVs or set-top boxes. Though, unless already enabled, back porting of WASM to older smart TVs is unlikely. 

Challenges and considerations

While the potential is clear, integrating WASM into the HbbTV ecosystem presents challenges:

  • Adoption of WASM Runtimes: HbbTV devices need to support a WASM runtime, which may require updates to existing software. Many existing television models already have support for WASM but widespread support will only come in future years.
  • Developer Learning Curve: Transitioning from JavaScript to WASM or incorporating WASM into workflows may require upskilling development teams.
  • Standardization: There are many feature extensions to WASM and aligning WASM capabilities with HbbTV specifications is necessary to ensure interoperability across devices. This is being resolved through the inclusion on WASM in the HbbTV 2.0.5 specification. 

WASM and HbbTV 2.0.5

When building WASM application it is important to have a consistent core and set of feature extensions as a target.

For HbbTV 2.0.5 the following have been mandated:

This set has been supported by Chrome since May 2023, by Firefox since April 2023, by Safari since March 2024 and node.js since October 2023.

The feature extension in WebAssembly Core 2.0 and ‘Extended constant expressions’ maps to the WASM target known as Lime1. Limes are a series of defined and stable subsets of WASM features that producers and consumers can both use to promote interoperability. Once a Lime configuration is defined, it will be stable with no features added or remove. To date only Lime1 has been defined.

WASM application can be complied against a Lime1 target to make them compatible with HbbTV 2.0.5.

emcc -mpcu=lime1 …

WASM is available in existing HbbTV implementation, but available features may vary. There are packages to help detect WASM feature availability including one from GoogleChomeLabs.

HbbTV 2.0.5 will be published in the middle of 2025, with the test suite and devices supporting 2.0.5 being available in 2026 and beyond.

Accessibility proof-of-concepts

During IBC 2024 3CAT the Catalonian broadcaster demonstrated two WASM based HbbTV proof-of-concept applications running on off-the-shelf televisions. The proof-of-concepts were based on improving accessibility services, through enhanced subtitling and sign-language. 

3CAT had looked at WASM as they need to perform CPU intensive tasks that were time constrained as they needed to be synchronized with the audio and video of the service. 

Subtitling

3CAT has developed and deployed a HbbTV application to display EBU-TT-D subtitles for its viewers. It ran on all devices but on low-end devices the user experience was poor with subtitles going out of sync with the video.

By moving the parsing and selection of EBU-TT-D subtitles to WASM, including traversing all subtitles, selecting the one matching the timecode and preparing it for display, they saw an impressive improvement in performance.

ActionMean time in js (ms)Mean time in WASM (ms)Improvement (%)
Ebu-tt-d parsing1,650.30231.0486%
Subtitles rendering3.801.0672%

More details are available on GitHub here.

Signing service

3CAT believed the best way to show sign language to viewers is through a second video that is separate the main video. This enables the signing video to be repositioned on the television screen as a picture-in-picture.

The latest television models have the capability to concurrently decode multiple video  streams, but this capability is not exposed to the applications due to the complexity of implementing this.

Software decode of video in JavaScript was not practical but 3CAT thought that with WASM this might be possible. For IBC 2024 they successfully demonstrated an Ogg based video decoding at 25 frames a second. They have since updated their proof-of-concept to show H.264 and H.265 video with a resolution of 400×500 and a bitrate of 300Kbps. 

Signing application

The updated proof-of-concept was run at the plugfest in London in 2025 with the following results across the television available:

FormatZero dropped framesSome dropped framesA lot of dropped framesDoes not run
MP4 with H2645310
MP4 with H2653420
MPEG-DASH with H2646300

With the proof-of-concept 3CAT has shown they can improve accessibility with WASM. They have also demonstrated that software video decode is possible enabling a wide range of additional use cases.

Other WASM use cases

WASM use cases under consideration include:

  • Video mosaics and multiple camera angles
  • Games engines and volumetric video
  • White box cryptography

Video mosaics and multiple camera angles

Sports like F1, golf, and tennis offer multiple camera angles, but managing these can be complex and can be impractical for service side rendering. In F1, following 3 out of 20 cars creates 6,840 combinations; with viewer controlled order, it becomes 41,040. Adding more angles increases these permutations greatly, reaching millions. Similar complexity could exist with other sporting events like Wimbledon or the Olympics. Music festivals like Glastonbury would also face challenges, with 10 main stages among 100.

WASM with multiple software decodes would allow a viewer to choose the array of multiple camera angles they would like to see. This concept could be extended to user interfaces that could benefit from user controlled video mosaics.

F1 Multi-camera angle mock-up

Games engines

Many common game engines (e.g., Unity, Unreal) are already being utilized with WASM to facilitate the porting of console game elements into web browsers. While gaming may not be a primary use case for HbbTV, these game engines are also employed to support volumetric video, which could have potential applications within HbbTV. 

Volumetric video experiences are frequently rendered using game engines. This type of capture is designed primarily for individuals with VR headsets, enabling them to immerse themselves fully in the content. However, it can also be rendered on any screen for broader inclusion. Client-based rendering is particularly advantageous when it is desirable to provide the viewer with control over their viewing perspective.

Games engines running in WASM could bring volumetric video to HbbTV based televisions.

White box cryptography

White-box cryptography is a cryptographic key protection strategy that presumes an attacker has complete access to the cryptographic implementation. It aims to protect keys by obfuscating them within the code, thereby making it challenging to extract them even in compromised environments. WASM is being employed for this purpose. 

For HbbTV, white-box cyptography could enable application developers to utilize Digital Rights Management (DRMs) that are not natively supported on a television, or when the native DRMs are inaccessible. 

Conclusion

WebAssembly represents a significant step forward for web and embedded applications, offering unmatched performance, security, and versatility. Its integration into HbbTV could unlock a new era of interactive, high-performance television experiences. By addressing challenges like runtime adoption and standardization, broadcasters and developers can leverage WASM to push the boundaries of what’s possible in hybrid TV.

As WASM continues to evolve, its application in HbbTV could set a benchmark for the future of interactive media delivery, combining the best of broadcast and broadband technologies.

Innovation will come from developer experimenting with the technology. It is important to get the message to HbbTV developers that the technology is becoming widely available and they should start experimenting now. 

Learn more at the HbbTV developer portal, by joining the HbbTV developer Slack community and by watching the HbbTV webinar on WASM.

Matthew Huntington
Manager of the HbbTV Developer Programme

Update on HbbTV specifications and related activities

Posted on by Matthew Huntington

To keep aligned with industry needs and web technology trends, the HbbTV specification continues to evolve. This article is a summary of the recent and upcoming advancements in HbbTV specifications and related activities.

HbbTV 2.0.4: Key updates

The HbbTV 2.0.4 specification, published by HbbTV in March 2023 and by ETSI in September 2023, lays the foundation for the next wave of product innovation. The incorporation of 2.0.4 test cases in the 2024-1 and 2024-2 HbbTV test suite releases (the latter released in August 2024), has paved the way for HbbTV 2.0.4 compatible products in 2025. 

Key features

Key feature of HbbTV 2.0.4 include:

  • Accessibility Integration: As the European Accessibility Act becomes law in 2025, accessibility is becoming more of a focus. While HbbTV does not mandate specific accessibility features, this integration is structured to accommodate external regulatory requirements.
  • DVB-I Compatibility: Enables “red button” broadcast-related apps in a DVB-I DASH delivered channel.
  • Voice Assistant Support: Voice interaction improvements address the need for seamless app control without requiring users to change from voice to remove control when an HbbTV application is started.  
  • Feature Deprecation: While certain less-used functionalities are marked for future removal, they remain part of 2.0.4 for now to allow for smooth transitions.

For more details see the HbbTV 2.0.4 article on developer portal.

HbbTV 2.0.5: A glimpse ahead

The upcoming HbbTV 2.0.5 specification is set for release in 2025, targeting possible implementation in products in 2026 or 2027. It introduces major enhancements and addresses feedback from implementers and test developers on previous releases. 

Highlights

Key enhancements include:

  • WebAssembly (WASM): Demonstrated at IBC by 3CAT, WASM enables advanced use cases like software video decoding. While already widely available, formally specifying this feature ensures consistent performance and usability.
  • New Video Codecs: Optional support for AV1 and VVC codecs, with AV1 already functional in some current TVs.  
  • HTTP/3 Support: Enabling the integration of HTTP/3 and QUIC for improved streaming efficiency.  
  • Streamlining Features: Unused or historical features are being retired, such as multi-stream synchronization between broadcast video and OTT audio.  

Digital Rights Management (DRM) guidelines

Historically, HbbTV avoided addressing DRM, leading to fragmented solutions. To counter this, the HbbTV Association has:  

  • Developed a DASH-DRM reference app, consolidating market insights on DRM system compatibility.  
  • Introduced a comprehensive DRM integration document covering PlayReady, Widevine, and criteria for adding new systems.  
  • Defined guidelines for content providers, platforms, and operators to streamline DRM implementations.  

HbbTV 2.0.5 will require support for at least one DRM system specified in the guidelines, ensuring consistency and compatibility across devices.  

Country-specific tests and harmonization 

Several countries, such as Italy and the UK, developed their own HbbTV test extensions, particularly for DRM. Recent reviews have highlighted opportunities for consolidating these tests into the main HbbTV suite. HbbTV aims to include these extensions in the 2025-2 test suite release, making things simpler for implementers by reducing the need for country-specific test suites.  

Looking ahead

The HbbTV Association’s ongoing commitment to accessibility, integration, and innovation ensures its relevance in a rapidly evolving media landscape. By aligning with industry needs and regulatory frameworks, HbbTV is positioned to support broadcasters, content providers, and device manufacturers well into the future.  

Jon Piesing
Vice Chair of HbbTV Association and Chair of Specification Group