Dolby AC-4

A powerful new audio format in the Dolby Audio family, Dolby AC-4 addresses the current and future needs of next-generation video and audio entertainment services, including broadcast and Internet streaming.

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Adoption for broadcast specifications around the world 

Ecosystem Momentum

Consumer Benefits

TVs and Set-Top Boxes

LG, Panasonic, Sony, TCL, Samsung, Sharp, Arris, Bang & Olufsen, HiSense, Huawei, Humax Co Ltd, Sagemcom, Skyworth, TPVision, Vizio, Vodafone, Philips, Kaon Media o Ltd, Wistron Neweb Corporation

Phones 

 

All Samsung devices, all Huawei P and Mate series, Sony, One Plus 7 & 7 Pro and OPPO Reno mobile devices deliver Dolby Atmos via Dolby AC-4. Oneplus, Lenovo, Sharp, Razer, Amazon tablets also deliver audio via Dolby AC-4. Dolby AC-4 can support immersive binaural output to headphones.

 

Phones 

 

All Samsung devices, all Huawei P and Mate series, Sony, One Plus 7 & 7 Pro and OPPO Reno mobile devices deliver Dolby Atmos via Dolby AC-4. Oneplus, Lenovo, Sharp, Razer, Amazon tablets also deliver audio via Dolby AC-4. Dolby AC-4 can support immersive binaural output to headphones.

 

SoC Partners

SoC Partners

Amlogic, Broadcom, Cadence, HiSilicon, LG,
Mediatek, MStar, Novatek, Realtek, Samsung, Synaptics

SoC Partners

Standard Adoption

Services

Music streaming services Tidal and Amazon Music use Dolby AC-4 to deliver Dolby Atmos Music on mobile. They are available in many countries across the globe.

No Cost?

The cost of Dolby AC-4 is clear and affordable

For Devices

The cost of Dolby AC-4 covers more than just a patent licensing fee. It includes a patent license, an optimized software development kit, test streams, documentation, three-tier support, and product certification services.

Dolby AC-4 is a complete solution that is standardized by the European Telecommunications Standards Institute (ETSI), the same organization that publishes DVB standards.

Dolby AC-4 is competitively priced, with rates that are actually lower than the rates for Dolby Digital and Dolby Digital Plus™. Dolby only charges for one technology per device, which means that Dolby AC-4 effectively costs nothing in devices that include our existing technologies.

Dolby AC-4 is a

complete package

 

We provide a complete technology package to the industry for Dolby AC-4. The package includes everything needed to implement Dolby AC-4, including object and source code as necessary, a reference implementation, test streams, and the backing of our global support teams.

 

The code that we provide is optimized, and we continually improve it to provide the highest efficiency for our partners’ processors, apps, and devices. It’s easy to implement and designed to solve real-world problems.

Dolby AC-4 is a

complete package

 

We provide a complete technology package to the industry for Dolby AC-4. The package includes everything needed to implement Dolby AC-4, including object and source code as necessary, a reference implementation, test streams, and the backing of our global support teams.

 

The code that we provide is optimized, and we continually improve it to provide the highest efficiency for our partners’ processors, apps, and devices. It’s easy to implement and designed to solve real-world problems.

Dolby Atmos

Are Dolby Atmos and Dolby AC-4 the same?

Dolby Atmos in broadcasting and beyond

Dolby Atmos is the immersive audio experience that has revolutionised cinema sound with an extra dimension that puts the audience inside the story. Now users can enjoy the same exciting experience in their living rooms. In addition to streaming services, discs, and games, Dolby Atmos is available through broadcast TV as well. With the adoption of Next Generation Audio (NGA) standards, Dolby Atmos can now be delivered using Dolby’s latest encoding standard Dolby AC-4, as well as with some earlier encoding systems.

Are Dolby Atmos and Dolby AC-4 the same?

Dolby Atmos and Dolby AC-4 are different but are often used together to deliver a high-quality audio experience. Dolby Atmos is a branded audio experience and Dolby AC-4 is a codec technology that can deliver that experience to your device. Dolby AC-4 describes the underlying audio technology, including the audio compression technology, metadata support, and system aspects. Dolby Atmos is Dolby's immersive audio experience that can be delivered through multiple Dolby audio codecs, including Dolby AC-4 and Dolby Digital Plus. Dolby Atmos can be viewed as the next logical step beyond traditional surround sound. Dolby AC-4 is the natural successor to Dolby Digital Plus and can deliver immersive Dolby Atmos audio as well as personalised NGA experiences.

To put it in simpler terms, Dolby Atmos is like a set of instructions that tells a device how to play the audio data it has received. Dolby AC-4 is one of the ways that those Dolby Atmos instructions can be encoded to be sent to the device, whether by streaming, on a disc, or by broadcast.

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Dolby Atmos and broadcast TV

Content in Dolby Atmos can be delivered to the user in many ways. Dolby AC-4 is one way. As part of the NGA standards being adopted in many countries and regions, Dolby AC-4 can be used to deliver Dolby Atmos content to TVs, including live sporting events. For example, the Polish broadcaster TVP has broadcast live, free-to-air, football matches in Dolby Atmos delivered through Dolby AC-4. The broadcasts included immersive stadium ambience from different parts of the stadium, as well as additional personalisation options using NGA delivered by Dolby AC-4, with multiple game commentators available in a selection of languages.

Dolby Atmos is a brand of immersive audio enjoyed by a growing number of consumers every day. Both original and reissued content is available in Dolby Atmos on streaming platforms such as Apple TV, Disney+, and Netflix. Dolby Atmos is also available in major videogames, such as Halo Infinite and Forza Horizon 5. Dolby Atmos Music is available on Apple Music, Amazon Music Unlimited, and TIDAL. Consumers are looking for the Dolby Atmos badge as the mark of a high-quality audio experience. Bringing Dolby Atmos to broadcasts makes them part of this trend.

 

Does experiencing Dolby Atmos mean upgrading your workflow?

As mentioned, Dolby Atmos can be delivered by broadcasts using the Dolby AC-4 codec. That’s a great way to do it but it’s not the only way. Dolby Atmos can be delivered in other ways as well. It can be delivered by Dolby Digital Plus. This is known as Dolby Digital Plus with Dolby Atmos or Dolby Digital Plus JOC (Joint Object Coding).

The latter is a technical term that can be found in some Dolby documentation, papers, and standards. Joint Object Coding describes the process by which Dolby Digital Plus with Dolby Atmos decoders, receiving a legacy 5.1 mix and sideband metadata, are able to reconstruct the original Dolby Atmos mix. A key feature of the Dolby Atmos launch using Dolby Digital Plus was that this allowed legacy Dolby Digital Plus systems to still receive and decode a surround sound experience. Dolby Atmos has been created to work with proven workflows, untethering the consumer experience from the technology used to deliver it.

 

How widespread is Dolby Atmos?

Dolby Atmos is available from many broadcasters worldwide and – with AC-4 incorporated in standards such as HbbTV, DVB, and ATSC 3.0 – is now an option for many more. National and regional tests and trials continue to show how the technology can be deployed to enhance broadcasts and delight consumers. Dolby Atmos is a consumer-facing brand that can attract viewers to broadcasters in an increasingly competitive landscape.

If you’d like to know more about how to add Dolby Atmos to your workflow, please contact us.

Dialogue Enhancement

How Dolby AC-4 makes dialogue enhancement possible

The living room is being transformed, and forward-looking broadcasters and content producers are seizing the opportunity to deliver their stories in ever-more engaging ways. Home and personal entertainment have been undergoing changes for years, of course. Now, Next Generation Audio (NGA) brings a killer feature — dialogue enhancement — that addresses a common viewer complaint.

Home entertainment — whether radio, TV, or recorded music — has always sought to provide the best, most lifelike experiences to consumers. The introduction of affordable smart TVs with UHD pictures, HDR, and immersive audio has shown consumers what is possible. But this new technology hasn’t reached perfection yet.

Enhanced dialogue addresses a major complaint

Surveys have found that viewers who are not deaf or hard of hearing are using subtitles as a regular part of their TV viewing. In the UK, 80 per cent of younger viewers say they use subtitles for some or all of their viewing. In the US, a survey found that half of viewers say they use subtitles most of the time when watching TV. The reason, say 55 per cent of respondents, is because TV is harder to hear than it used to be, with 78 per cent saying that background music and effects are the main issues when it comes to hearing dialogue. The survey also found that 57 per cent of viewers watch content in public places — such as on public transport, in waiting areas, or at work — where listening levels are lower in volume and background noise gets in the way. These surveys confirm what broadcasters — who have been on the receiving end of complaints about hard-to-hear dialogue — had already identified as an opportunity to improve service quality.

The good news is that it is one of the easiest upgrades to provide to viewers, thanks to NGA and Dolby AC-4.

NGA is currently shipping in over 80 per cent of the 4K TVs sold in Europe, meaning consumers will be ready as broadcasters expand their commercial NGA services. The Dolby AC-4 codec has been chosen for new UHDTV broadcast specifications in multiple European markets, including NorDig for the Nordic countries and Ireland. It has also been selected in Italy, and it is included as part of the draft UHDTV specification for France. And a pilot project for DVB’s next-generation TV platform called DVB-I, is underway in Germany. Dolby AC-4 NGA is also part of the NEXTGEN TV platform for the US. In North America, there are over 170 stations on air. Poland’s TVP has been offering Dolby Atmos immersive audio over AC-4 to more than 90 percent of the country’s terrestrial viewers since 2018 and has broadcast multiple football matches using the technology, including Euro 2020 and the 2022 World Cup. TVP is also broadcasting cultural programming in Dolby Atmos. Dolby AC-4 has been included in HbbTV and shipped with HbbTV implementations for more than 5 years by now. The latest version of HbbTV includes new functionalities to enable user interfaces to control dialogue enhancement - to be integrated into the service’s HbbTV application.

Dialogue enhancement is easy to provide

Dialogue enhancement doesn’t require any special steps in the production process when using Dolby AC-4. Dialogue enhancement happens the moment the audio is encoded using Dolby AC-4. It is an automatic process that analyses the signal in the encoder, even for a traditional stereo mix input, and uses a metadata-driven approach within the bitstream to deliver the information with the rest of the audio signal. When the viewer watches the content, the necessary data is decoded by the device. The user is then able to use controls in the device to adjust the level of dialogue compared to the background audio. This can be as simple as a few pre-defined options the viewer can choose or more complex controls, depending upon the device and the broadcaster’s settings. This puts viewers in control of their experience and lets the viewer focus on the main content, not on the subtitles.

Dialogue enhancement is an easy way to make a big improvement in the viewer experience and increase engagement. The built-in TV user interface for dialogue enhancement is automatically provided by simply encoding any of your content in Dolby AC-4.

HbbTV and DVB power modern viewing with Dolby

Are HbbTV and DVB-I the same?

HbbTV and DVB-I are both ways to deliver high-quality viewing to users of modern TVs. They’re complementary standards that can work together.

Hybrid broadcast broadband TV (HbbTV) is an initiative led by industry members with the goal of improving the viewing experience for consumers. This global initiative aims to simplify and harmonise the broadcast and broadband delivery of entertainment content and services to consumers through internet-connected TVs. The specification uses elements of existing specifications from other standards, including OIPF, CTA, DVB, MPEG-DASH, and W3C.

HbbTV is an open standard that enables broadcasters to provide viewers of smart TVs with additional options and experiences in a scalable way, by allowing broadcasters to develop online apps and services that work with almost all brands of smart TVs and can be linked to their broadcast delivery. The incorporation of DVB’s latest standards for next generation media formats into HbbTV 2.0.2 in 2018 enabled delivery of new media services, including Next Generation Audio (NGA) and High Dynamic Range (HDR) video, via the IP broadband interface of the receivers. Therefore, enhancement of the viewing experience can be included into services and delivered to households at a relatively low cost without needing the significant infrastructure investments required to upgrade traditional broadcast networks.

Digital Video Broadcasting (DVB) is a set of open standards for digital television maintained by the DVB Project, a consortium of industry organisations. DVB-I aims to maintain the normal and easy TV viewing experience using a channel-list interface, but to enable a linear TV channel to be discovered and viewed via the traditional broadcast networks as well as over the internet. Using HbbTV as a complementary technology can also bring interactivity, as well as linked services, to those TV channels. These could include video on demand (VOD), programme guides, OTT video, games, and interactive advertising.

In general terms, DVB-I is about bringing the type of broadcast content that broadcasters are known for to the viewer via all possible delivery paths, using devices connected to the broadcast network as well as to the internet. HbbTV makes it possible to deliver an integrated experience for broadcast TV and other services and capabilities via linked applications. DVB-I and HbbTV collaborate to ensure viewers can get the best possible experience.

 

How Dolby works with DVB-I and HbbTV

Both DVB-I and HbbTV are able to deliver next-generation audio (NGA) experiences – such as dialogue enhancement and multi-language commentary – using the Dolby AC-4 codec. They can both also use Dolby Vision to deliver mind-popping colour, darker darks, and brighter brights to viewers with TVs enabled with Dolby Vision. DVB-I and HbbTV allow broadcasters to deliver immersive audio experiences, delivering sound that hits deep using Dolby Atmos.

The result of these three powerhouse technologies – Dolby Vision, Dolby Atmos, and Dolby AC-4 – is a heightened, more immersive viewer experience. This unmatched experience showing puts viewers in the middle of the action. Consumers can enjoy these experiences on a range of devices, both at home and on the go, giving broadcasters a wider reach.

Dolby is ready today and built for future growth

Dolby’s triad of technologies – Dolby Vision, Dolby Atmos, and Dolby AC-4 – are delivering enhanced experiences to consumers around the globe, while making it easier for broadcasters to provide these experiences.

Franco-German TV channel ARTE, dedicated to presenting both traditional and modern cultural programming from across the creative spectrum, has quite a job on its hands. To help fulfill its mission, ARTE is testing a pilot of its next-generation HbbTV platform with Dolby Vision and Dolby Atmos via Dolby AC-4 to bring unrivalled flexibility, quality, and choice to programme creators, and a new consistency of experience to consumers.

Poland’s TVP has been using Dolby AC-4 in its workflow to deliver NGA and Dolby Atmos to viewers of both sporting events and cultural programming. Most recently, it used Dolby AC-4 as part of its FIFA World Cup coverage to make multiple audio commentaries available to viewers.

In the United States, the world’s third-largest TV market after China and India, NEXTGEN TV, the US branding for the ATSC 3.0 standard, has brought NGA to users across the country. Pearl TV, an industry group comprising the 9 largest broadcast companies in the US – companies that operate more than 820 TV stations – has embraced the innovations made possible by the technology. NEXTGEN TV continues to increase its footprint and is expected to be available to 75 per cent of US households by the end of 2023.

A group of industry participants is conducting a trial of DVB-I in Germany. Launched in late 2022, the pilot is scheduled to run into the spring of 2023. The trial aims to gather real-world information to evaluate and improve DVB-I. HbbTV is an integral part of the trial, helping with digital rights management (DRM), managing subscriptions, and NGA, among other services.

It’s an exciting time for broadcasters, which have new options to improve their products, to expand their offerings and provide consumers with enhanced experiences. Whether it’s using HbbTV, DVB-I, both, or even other options, one thing is consistent – Dolby. Dolby has a history of working with broadcasters to create standards that enable them to do more without restricting creativity. If you’d like to learn more, please contact us.

Dolby AC-4: Industry Integration

Trials and Interviews

Interviews

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Case Studies

Tech Blog

News from our labs

S-ADM workflow demo SRF IP-Lab

 

With the goal to optimize bandwidth-use and enable personalized audio experiences in the future, Swiss broadcaster Schweizer Radio und Fernsehen (SRF) has been experimenting to use S-ADM in their SMPTE ST2110 based IP environment. A selection of open-sourced prototype tools by Dolby were used to generate and analyze dynamic metadata in real-time. The balance of beds and objects of a typical sports production with mult-language commentaries were modified on a mixing desk, with changes traveling as metadata through the broadcaster‘s infrastructure.

S-ADM workflow demo SRF IP-Lab

 

With the goal to optimize bandwidth-use and enable personalized audio experiences in the future, Swiss broadcaster Schweizer Radio und Fernsehen (SRF) has been experimenting to use S-ADM in their SMPTE ST2110 based IP environment. A selection of open-sourced prototype tools by Dolby were used to generate and analyze dynamic metadata in real-time. The balance of beds and objects of a typical sports production with mult-language commentaries were modified on a mixing desk, with changes traveling as metadata through the broadcaster‘s infrastructure.

Technology Made Simple

 

Dolby AC-4 provides feature benefits to broadcasters that can be implemented now. Such as dialogue enhancement - audio description and voice clarity – multiple language versions, immersive audio, commentary choice, and automatic loudness levelling.

 

This video demonstrates what watching TV can look like for a consumer, and our diagram shows the delivery streams behind it.

Technology Made Simple

 

Dolby AC-4 provides feature benefits to broadcasters that can be implemented now. Such as dialogue enhancement - audio description and voice clarity – multiple language versions, immersive audio, commentary choice, and automatic loudness levelling.

 

This video demonstrates what watching TV can look like for a consumer, and our diagram shows the delivery streams behind it.

Serial ADM with Dolby AC-4

Dolby is collaborating with the EBU and other partners to enable solutions based on the Audio Definition Model (ADM), an ITU standard for professional audio metadata, and to enable interoperability with Dolby AC-4 workflows.

S-ADM is a frame-based representation of ADM metadata. It is designed for use in linear workflows such as live production, or playout for broadcasting and streaming applications. As productions move from delivery of pre-rendered mixes to stem or component-based outputs to allow for more advanced use cases, metadata is becoming an integral ingredient of production, adding essential information to what is delivered. In this series of short demos, we’ll cover use cases from multi-language to immersive and personalized audio production. Click on the links below to see S-ADM in action.

White paper: Dolby AC-4 Audio delivery

 

Dolby® AC-4 is an audio delivery system designed to exceed expectations. Integrating easily into content workflows and consumer devices, the system supports existing needs and ongoing innovation of broadcast and streaming services.

 

This white paper describes the technical features and capabilities of the system; and it provides a comprehensive view of the market adoption in standardization bodies, and implementations in pro partners’ products.

 

Download the white paper

White paper: Dolby AC-4 Audio delivery

 

Dolby® AC-4 is an audio delivery system designed to exceed expectations. Integrating easily into content workflows and consumer devices, the system supports existing needs and ongoing innovation of broadcast and streaming services.

 

This white paper describes the technical features and capabilities of the system; and it provides a comprehensive view of the market adoption in standardization bodies, and implementations in pro partners’ products.

 

Download the white paper