Easier DRM from Audible
by Curtis Lee Fulton (G2 News)
March 25, 2002
Digital rights management (DRM) technology is often cursed as too cumbersome and confusing for consumers. The way a lot of DRM solutions work seems more appropriate to B2B transactions than B2C. EMI VP of new media Ted Cohen claims consumers will continue to demand CDs over digital media until DRM becomes more humane.
Audible Inc, on the other hand, is supposed to have easy DRM, at least for spoken word recordings. Unfortunately it's not transferable to other segments such as music, which would sound as though it was being sung under water. Otherwise, the company has 32,000 hours worth of content for sale, including books, magazines, newspapers and radio programs. Over the seven years it's been in business, it's developed a DRM system that hides the ugly geeky side from the consumer.
Audible consumers can play recordings on their PC or transfer them to a portable device. Either way, the playback device must be activated using software called AudibleManager. Consumers can only play the content on activated devices. If a recording is copied to another computer or an unactivated device, the file won't play.
Once a playback device has been activated consumers can purchase and download content from Audible's e-commerce portal, Audible.com. If the consumer loses the files, he can download them again free of charge. Before the content leaves Audible's content servers, it is stamped with a digital signature that's tied to a unique identifier generated by AudibleManager. The signature tethers the content to the playback devices activated by AudibleManager.
So if a consumer has activated his PC and two portable players, Audible content can be shared by the three devices. Audible uses the National Institute of Standards and Technology's (NIST) digital signature algorithm (DSA) for signatures.
Audible's DRM rules are enforced with an encryption layer. The company wouldn't say exactly what algorithm it's using, only that it's in the public domain, which means Audible is probably using either a DES or RSA cypher, the two most common encryption algorithms in the public domain.
For compression, Audible encodes its content in a format licensed from telecom technology provider, VoiceAge. Audible chief scientist Guy Story says Audible went with VoiceAge because the algorithm was "specifically designed for speech."
Story says that Audible follows the phone business for compression because its content is voice-oriented. In fact, when Audible first launched in 1995, it used the G.723.1 compression algorithm, commonly used today for compressing telephone calls.
Audible licenses its media format to portable device makers free of charge. Once its format works on a device, Audible will test the widget and brand it AudibleReady. There are now dozens of AudibleReady devices on shelves today, including players from Sonicblue, HP and Compaq. Audible's format is also available as an extension codec for Microsoft's Windows Media player and RealNetworks' RealOne player.
Audible sells its content by item or subscription. A basic monthly subscription cost $12.95, which includes one periodical and one book a month. Its premium monthly subscription runs $15.95 for two books a month. Books average $16 each and periodicals $4.95 each. A yearly newspaper subscription runs $59.95.
Audible's servers are almost all Solaris-based. It uses Broadvision's software for its e-commerce portal. The sound recordings are served using proprietary software written in Perl, Java and C++.
Audio sources are edited using Sonic Foundry's Sound Forge digital audio-editing software. It uses an NT server farm to compress recordings into the VoiceAge format.