Next Generation Audio – NGA – will allow consumers to experience audio content in optimized quality wherever and however they consume it. Additionally, metadata will facilitate other valuable features, such as personalization of different audio elements, a key enabler for access services for those with disabilities.
The best way to learn about NGA is to experience it! Put on your headphones and watch the video below.
(Video credit: Fraunhofer IIS)
NGA frees producers from the need to create multiple audio mixes for content by allowing them to deliver a single, multi-purpose audio package instead. This can then be rendered and played back appropriately on anything, from mono devices to sophisticated and fully immersive audio setups. Accessibility features are designed into the format, such as the ability for users to control the relative playback volume of voice commentaries over the rest of the programme audio, a feature often requested by elderly viewers and listeners.
- There are millions of devices that can decode NGA already in the market from several companies.
- Consumer devices are avaiable that bring NGA experiences to the living room: TVs, set-top boxes, sound bars, AV receivers.
- NGA has been specified into several European and international standards, including those from the ITU, DVB and SMPTE.
- NGA has been used in various trials and is on-air.
- Professional devices exist for producing NGA
What does NGA offer?
Next-generation audio adds several dimensions compared to legacy audio.
- NGA provides an opportunity to bring immersive audio to the listener. In contrast to traditional multichannel, a height dimension can be added; and it can go beyond the multichannel paradigm by adding object-based audio.
- NGA can provide personalized experiences. For the first time, listeners can interact with the audio and adapt it to their preferences, including for accessibility reasons.
- NGA is more bit rate efficient than previous technologies, so these new features don't come at the cost of higher bit rates.
The role of the Renderer
One of the key concepts that makes NGA possible is the renderer. In this context, a renderer is like a combination of upmixer and a panel that can attenuate or amplify individual sources and place them in three dimensional space. Sources could be individual objects, complex beds, or scene-based audio.
The renderer is built into the end-user devices and sources are delivered as separate components to the devices. This is the change that makes it possible to personalize the experience to the listener's situation.
The renderer is controlled by rendering metadata originating at the mixing desk, but it can interpret that metadata against device capabilities and user preferences, such as dialogue level preference. The ITU Audio Definition Model (ADM), specified in ITU-R BS.2076, is a set of agreed grammar and format rules for that metadata. Usage of ADM metadata is recommended to describe audio formats used in programme production for NGA systems
EBU ADM Renderer (EAR)
The EBU ADM Renderer was developed to provide an open and accepted renderer that can be used by all who wish. It was developed by an alliance of R&D and broadcast organizations – the IRT, BBC, France Télévisions, b<>com and the EBU. The EBU believes that providing an open reference renderer for ADM metadata in production, evaluation and monitoring will be beneficial to the health of the NGA ecosystem as a whole.
The EAR implementation, which is based on established and open standards and designed to be a reference platform for further development, facilitates creative innovation by allowing the broadcast community to explore and make use of the potential of the technology.
(Video credit: IRT)
Use cases for the EAR
- Production of NGA programmes
- Archiving of NGA programmes
- Verification of ADM metadata
- Subjective evaluations
- Conversion of metadata from different NGA systems to ADM metadata
This webinar on NGA in DVB specifcations was presented by Simon Tuff (BBC) and authored by representatives of Dolby, Fraunhofer IIS and Xperi.