Higher quality sound

Annoying pauses and delays when listening to sound files over the Internet could soon be a thing of the past thanks to a pioneering new approach to coding digital audio signals.

NESTA (the National Endowment for Science, Technology & the Arts), the organisation that invests in UK creativity and innovation, has invested £70,000 in Scala Technology through its Invention & Innovation programme to develop scaleable audio coding technology that improves the quality of digital streaming over busy networks.

Scala Technology is owned and run by Dr. Chris Dunn from North London. Dunn has fifteen years experience developing audio signal processing technologies, and has previously worked as a postdoctoral researcher at King’s College London, and as a design engineer at Dolby Labs in San Francisco. He has been developing Scala’s coding technology for three years.

At present, the most established methods of audio coding are based on fixed bit-rate techniques, where a predetermined number of information bits are transmitted each second. This approach can be satisfactory where the quality of the communication network is guaranteed, for example, when used to store audio files on PCs. However, on networks with variable quality like the congested Internet there is no certainty that the minimum necessary data rate can be maintained, leading to signal dropouts and pauses in transmission.

Scala has developed scalable bit-rate coding technology that addresses these problems by encoding audio signals in a way that ensures continuous transmission regardless of the instantaneous network bandwidth. When the network bandwidth is high, a good quality signal can be received and decoded, while to compensate for any reduction in bandwidth the receiver simply decodes a lower quality version of the signal. As well as internet audio streaming applications, this technology could also be beneficial in streaming across third generation mobile phone networks, where moving between cells or a variable number of active users changes the bandwidth available to each individual user from instant to instant.

NESTA support, over 12 months, will help Scala to develop coding algorithms to a stage where the technology can be commercially exploited. It is planned to extend coding to accommodate stereo audio signals, and develop a Java codec that allows simple streaming to Java-enabled devices.

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