Erlangen, Germany — Fraunhofer IIS has announced the HD-AAC MPEG audio coding scheme that extends proven MPEG-4 AAC encoding to near- and true-lossless compression - enabling a new way of storing and distributing music. According to the company, the new codec will enable music produced in the 24-bit 96-kHz format to be made more efficiently available to consumers, electronic music distribution and the consumer electronics industry.
Based on the MPEG-4 Scalable to Lossless Coding (SLS) technology, the coding scheme can be used to preserve content unchanged and also stream or output the AAC core or higher bitrate versions for professional applications. The HD-AAC encoding process preserves all of the information contained in the uncompressed original music track while offering lossless compression rates comparable or superior to that of other lossless formats.
Due to its AAC-LC core layer, an HD-AAC file can be directly played on existing music players and millions of mobile phones. For decoding of the fully lossless signal, upcoming devices will be equipped with an HD-AAC decoder.
In the connected home, music stored on media servers in the HD-AAC format can be streamed to multiple devices at varying bitrates. This maximizes the sound quality under difficult network conditions by matching the bitrate to the available bandwidth.
"Consumers will be able to buy content in online music stores that sounds better than CDs, and preserve their existing CD collection for the future by encoding it in HD-AAC", says Harald Popp, head of the Multimedia Realtime Systems department at Fraunhofer IIS. "For casual listening, HD-AAC files conveniently play on existing AAC devices."
HD-AAC software is offered for both PC and embedded devices, including microprocessors or DSPs from ARM, MIPS, Texas Instruments, Analog Devices, Intel, AMD, and IBM. Licensees can certify their products in the HD-AAC conformance program and if completed successfully, identify their products with the HD-AAC logo.
Fraunhofer IIS, +49 (0) 91 31 / 7 76-0, www.iis.fraunhofer.de/EN
HD-AAC white paper (PDF)