Copy Management in the Digital Era

 

An AES Workshop at the

Audio Engineering Society Convention

Amsterdam, May 16-19, 1998

 

Abstract - The migration from analog to digital platforms for audio and multimedia applications not only provides enhanced quality but also greatly facilitates the development of new services and features. Meanwhile, the casual user may get the possibility to make unlimited, perfect quality digital copies, which can be a serious threat to the content industry.

The development of robust and fair mechanisms to control copying is a technological and regulatory challenge. It may involve the innovative use of (embedded) signaling of copyright states, physical markers for storage media as well as cryptography. Moreover a regulatory framework is needed to enforce compliance of user devices and to deter piracy. On the other hand, if copy protection mechanisms hinder the legal use and functionality of Consumer Electronics devices or PC's, new digital products may not be accepted in the market.

This workshop addresses technical and legal tools for copy control, as well as the challenge to find a satisfactory system solution.
 

 
 

Chairman: Jean-Paul M.G. Linnartz, Philips Research. 
Panel participants: Representatives from music industry, consumer electronics manufacturers, IT industry.   Panelists:  
  • Paul Jessop, IFPI
  • Don Jerrard, Backer & McKenzie
  • Dave Aucsmith, Intel
  • Gerry Wirtz, Philips Electronics
  • Markus Erne, ETH Zurich

Programme

Paul Jessop introduces the copy-protection issues from the phonographic industry's point of view. He represents the International Federation of Phonographic Industries (IFPI), with 1300 member companies world-wide, including the major players, such as BMG, EMI, Polygram, Sony, Universal and Warner. These companies create, protect and exploit copyrights. Digital technology is both a threat and an opportunity. The internet and new optical storage media provide new mechanisms for trading audio assets, but also facilitate piracy and illegal copying.

The IFPI sees cryptography and embedded signalling as viable mechanisms to protect digital audio. Currently, these methods are under extensive research for DVD video applications and the IEEE 1394 digital interconnect, and can play an important role for audio as well. Embedded signalling, also called watermarking, is being studied in the European MUSE project. The first results of tests are planned to be released by June 1998. Meanwhile several companies promote their proprietary solution.

Cryptographic protection of digital audio is addressed in further detail in the second presentation. Recently five Information Technology (IT) and Consumer Electronics (CE) companies have agreed over a common standard to encrypt all copyrighted digital content over the IEEE 1394 interface. The interface also supports bi-directional authentication, to ensure that both the source and the sink are compliant devices that adhere to copy protection rules.

Copy protection measures increasingly dictate the functionality of IT and CE products and start to influence the architecture of the historically very open PC platform. While the versatility of the PC leads to almost unlimited possibilities to store, process, modify, filter, edit, and copy content, copy control issues may in future restrict certain uses. It is already seen that for DVD video playback, the user will not get access to copyrighted video, except for playback on a screen.

The number of digital devices with compliant and cryptographically protected digital interfaces is growing, but content must eventually be converted to high-fidelity analogue. The crux of any copy control mechanism is to distinguish between a user's personal creation, e.g., his two year old son singing his first lullaby, and copyrighted commercially released content. It would be unfair to a consumer not to provide facilities to record, process, copy and distribute his personal works of art, only to satisfy the desires of an entertainment business. For the copy protection to be effective, this distinction must available from both digital and analogue representations of the audio. Watermarks are regarded as a solution

Markus Erne, of ETH Zurich, researches embedded signalling, particularly for MPEG 4 standardisation. He will give an overview of the features of watermarking methods for audio. The basic principle is that pseudo-random noise is added to the music signal at a level that is imperceptible by the human ear. This can for instance be at a level just below the masking curve of the human ear or a level that is similar to the dithering and quantization noise shaping used in a state-of-the-art CD mastering process. This pseudo-noise signal can be detected by spreadspectrum-type correlation methods. Presence of a watermark then indicates the copyright status of the audio. Embedded signalling has been demonstrated for automated logging of FM radio broadcasts, but it is unsure whether this technology will meet the audio-quality criteria for new optical storage media, such as SA-CD or DVD audio while being cheap enough to implement in all consumer electronic audio products.

The consequences of the use cryptography and watermarking for a consumer are addressed by Gerry Wirtz of Philips Electronics. Copy control as proposed for IEEE 1394 do not only have an aspect of significant added cost for consumer products because of more complex hardware. Unique cryptographic keys needs to be installed in every product, which complicates manufacturing processes. Consumer products, such as walkmans, also have limitations which prohibits many solutions which were designed for computer systems with an on-line internet connection. Any upgrading of cryptographic solutions is not feasible.

Consumer recording devices may check for embedded signals. The copy control system can be strengthened by checking the copyright status (signalled by a watermark) against the origin of the storage medium (e.g. the disc) during playback. This avoids that pirates, who can modify their recorder can sell illegal copies to customers with regular playback equipment.

Don Jerrard of Backer and McKenzie addresses the Intellectual Property issues from a legal point of view. Customers have rights to copy content, but it is sometimes not clear what and to which medium. Court cases have learned us that in some countries that apply a levy on blank tapes, customer have implicitly bought the right to make a copy for personal (back-up) use. Another critical legal aspect is the regulatory setting for compliance to copy control rules. Can manufacturers be forced by law or patent licensing contract to provide technical measures to prevent illegal copying? In the mind set of the Agency that licences the Content Scrambling System for DVD video, it is assumed that only those manufacturers that restrict the functionality of their devices to a standard defined by CSS will be granted a license to use esential patents to decrypt scrambled video. In the short history of this agency, this assumption has never been testing in court against for instance US federal anti-trust laws. For manufacturers and content owners, it is unclear who is liable for breaches of the copy control system.

Further information