New Technology Promises 5.1 Surround at Low Bitrates

Surround sound is increasingly a part of sports broadcasting, and a new technology developed by German research institute Fraunhofer IIS could bring 5.1 capability at low bitrates to digital TV, terrestrial and Internet radio, and IPTV services.

Running at stereo-coding levels, MPEG Surround (MPS) was standardised two years ago. Consumers will be able to use existing set-top boxes to receive expanded audio signals, which give 5.1 capability at bitrates from 64 kbps to 320 kbps.

Practical demonstrations of the codec were offered during IBC 2010 in September. Fraunhofer spokesman Matthias Rose describes MPS as a parametric system: it takes 5.1 inputs and converts them into a stereo downmix, which is mixed with parameters describing the surround information.

“Any audio codec can be used to compress the 5.1 material, for example, AAC,” Rose explains. “Then, you transmit a stereo file with some additional parameters. If the consumer has only a stereo playback system, then stereo will be reproduced, but, if he has MPS, the parameters will be used to re-create the surround image.”

Fraunhofer has spent one to two years introducing MPS into different broadcast standards, including DVB, ISDB (Integrated Services Digital Broadcasting) in Japan, World DMB, and DRM.

Besides broadcasters, Fraunhofer is working with equipment manufacturers to ensure that receivers capable of picking up MPS come on the market in good time. The car sector is regarded as particularly important, and the institute is in discussion with auto companies to install this new technology. “The car is the ideal environment for playing back surround sound,” Rose says.

Also at IBC, Fraunhofer demonstrated technology that allows small-scale, low-bitrate video services to be carried in Digital Radio Mondiale (DRM) signals. Diveemo is a joint venture of Fraunhofer, Thomson Broadcast & Multimedia, and NewStar Electronics.

The technology is intended for educational video programming that reaches a broad geographic audience, Rose says. “We are thinking of people who so far have not been able to receive television programmes.”

The video is carried alongside DRM radio signals and is encoded in the H.264 advanced MPEG-4 compression format, with audio in the HE-AAC (high-efficiency advanced audio coding) format.

Diveemo is awaiting standardisation approval from ETSI (European Telecommunications Standards Institute), but Rose says the intention is to promote the technology during this year and into next.