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Layered encryption for audio parameters Disclosure Number: IPCOM000022281D
Publication Date: 2004-Mar-04
Document File: 1 page(s) / 26K

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The Prior Art Database



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Layered encryption for audio parameters

Layered bitstream formats for audio are emerging. Examples of techniques that make use of so-called enhancement layers are spectral band replication (SBR), such as used in mp3-PRO and AAC+, and parametric spatial coding such as disclosed in WO03/090208-A1 and ISO/IEC 14496-3:2001/FDAM2 Parametric coding for High Quality Audio. These techniques use a core audio coder which runs at a small bandwidth (SBR) or at reduced spatial properties (e.g. mono instead of stereo or 2-channel instead of 5.1 channel). Combinations of these techniques are also possible. An idea is to encrypt such layers in such a way that an individual key is required to decode the enhancement layer (e.g. in a way as disclosed in WO02/087241-A1). Without the correct key, the core layer can be decoded (hence a mono and/or limited-bandwidth version of the audio is obtained). If a consumer has the correct key (which is preferably personalized), the enhancement layer(s) can be decoded and a high-quality file is obtained during playback. If the file is shared (e.g., other people copy the file) consumers can playback the core layer. They cannot playback the file using the enhancement layer since their personal key does not correspond to the encryption key of that particular file. When this person buys the file him or herself, he or she obtains the file with an encrypted enhancement layer that matches his or her personal encryption key. The personal key can be stored...