Invention: Digital audio compression
Convenient audio streaming, storage and playback would hardly be imaginable without the contributions of Swedish sound specialist Lars Liljeryd. Blending his lifelong love of music and his largely self-taught knowledge of electronics, this iconoclastic inventor designed one of the world's most popular digital audio compression codecs.
Spectral band replication (SBR) is a novel method for
compressing digital audio files that has made it possible for millions of
people around the world to enjoy higher-quality sound conveniently and affordably.
It was conceived by Swedish inventor Lars Liljeryd and taken from drawing board
to market with the help of a team of engineers that included Martin Dietz from
Germany and Kristofer Kjörling, Per Ekstrand and Fredrik Henn from Sweden.
Without SBR, many of today's smartphones, portable music devices, digital
radios, video cameras, TVs and personal computers would be much less efficient
at downloading, storing and streaming audio media.
Liljeryd's ideas revolutionised an entire industry. His concept for improving upon existing coding formats raised the bar for digital audio technology to levels never thought possible. It expanded on other audio compression techniques, notably MP3 and Advanced Audio Coding (AAC), which many experts believed had already reached their full potential. And, probably most important to the wide, global audience that relies on SBR - and to the music aficionado who developed it - SBR ensures that music still sounds really, really good.
Societal benefit
Hitting the market in full stride in 2002 as part of the MPEG High-Efficiency Advanced Audio Coding standard (HE-AAC), SBR came at a time when bandwidth and storage space were not keeping up with the public's love of music and streaming radio. In one fell swoop, SBR improved audio compression by 30-50%, effectively doubling the music that could be saved on a device or the speed at which it could be transmitted.
SBR's efficiency and high fidelity quickly won over satellite broadcasting, mobile phone and internet companies. It was soon added to popular music players, most notably Apple's iTunes, and supported by multimedia plug-ins like Adobe Flash Player. People in the US might know SBR from streaming music services like Pandora Radio or Rhapsody as well as from satellite radio services such as SiriusXM. Europeans are more likely to have used it on the Digital Radio Mondiale broadcasting network, which includes Deutsche Welle, BBC World Service and Radio France Internationale. SBR is also used to compress audio in digital TV broadcasting signals in many countries.
Now standard on an estimated six billion devices around the globe, ranging from video cameras to smartphones and personal computers, if ubiquity alone is indicative of societal benefit, then SBR has the numbers to support it. However, SBR's true value is the high sound quality it provides while paring down storage and transmission space, giving a global audience a wider choice and greater control of the music and audio programmes they listen to.
Economic benefit
Llijeryd created a small start-up with three master's graduates - Kjörling, Ekstrand and Henn - to begin realisation of his initial idea. He then sought help from specialists at the Fraunhofer Institute in Erlangen, Germany, which had developed both MP3 and AAC, to help integrate SBR into these codecs. With some additional investment capital, Liljeryd formed Coding Technologies AB in Sweden and - together with the Fraunhofer institute - its German subsidiary Coding Technologies GmbH and hired Fraunhofer's MP3 specialist Dietz to head both companies.
In 2002, SBR was successfully integrated into HE-AAC, which remains one of the most popular MPEG-standardised audio codecs. Five years later, Coding Technologies, along with its key SBR patents, was acquired by US-based Dolby Laboratories - a leading company for audio encoding/compression and audio noise reduction - for approximately EUR 170 million (at 2007 rates).
This acquisition was the key to the mass licensing of SBR technology. Dolby, with annual sales of around EUR 950 million, is one of the leading companies in the audio codec market, which was valued at EUR 5.2 billion in 2015 and is expected to reach almost EUR 7 billion by 2022, according to industry analysts.
Aside from directly employing around 100 audio coding experts in Stockholm and Nuremberg to support refinement and future upgrades of SBR, the coding technology also helps support software developers, products designers and manufacturers downstream.
