ITU proposes audio standards for 'immersive’ sound for future TVs

December 02, 2013 // By Graham Prophet
The International Telecommunication Union (ITU) has announced a draft Recommendation for next-generation ‘immersive’ and ‘personalised’ audio systems for television and radio. Audio data will be transmitted with 'metadata' that will describe how the sound is to be rendered.

Audio is an essential part of the television experience, as the quality and perception of sound enhances the image on screen. A number of new techniques have been developed that will heighten the experience and bring it to a new level, while allowing the audience to personalise their experience.

Twenty years ago, the ITU Radiocommunication Sector’s Study Group 6 approved Recommendation ITU-R BS.775 which established 5.1 channels as the surround sound system for broadcasting. This involved the optimum use of five loudspeakers set at ear level surrounding the audience plus a low-frequency sub-woofer.

Now, Study Group 6 has developed a system for the next-generation ‘immersive’ and ‘personalised’ audio system, which will allow TV audiences to be ‘‘enveloped’ in the sound as it traces the source of the audio track both laterally and vertically across the screen

Deciding which technique the ITU-R should specify has been one of the hottest subjects of the audio world for many years. A single coherent approach was needed that could provide sufficient flexibility to allow a variety of techniques to co-exist. The newly agreed system has now achieved this.

In the new approach, the audio landscape that surrounds the viewer is delivered either by supplying more channels of audio that can be ‘rendered’ for use by any additional loudspeakers that may be present, or by delivering audio elements that are ‘dynamically rendered’ into the existing speakers.

The audience can make use of the new sound system with existing stereo and 5.1 channel speakers systems; or they can choose to enjoy more ‘immersiveness’ by installing additional speakers around the room, including elevated speakers. The key to the new system is that the delivered channels and sound elements are fully described by metadata labelling that drives the rendering as well as the reproduction.

The new system may be used with forthcoming ultra-high definition or UHDTV systems, existing HDTV or even older SDTV, as well as for immersive