HD-AAC Format Takes On CD

Boffins behind the original MP3 and MPEG4 codecs have come up with a new audio format which could make CDs obsolete.

Scientists at the Fraunhofer Institute for Integrated Circuits IIS say the new HD-AAC codec delivers better-than-CD-quality sound in file sizes that are small enough to be offered online - like on Apple's iTunes Store, for example.

The codec is based on MPEG-4 SLS - a scalable lossless format. HD-AAC enables you to enjoy high quality 24-bit / 96KHz files on a home media server, for example, and then use the base version (called the AAC-LC layer) of the same file to play back on an iPod or other AAC player. There's no need for you to rip different versions of your music at different codecs for different devices. Hurrah.

The Fraunhofer Institute says that future devices - like iPods - may also be able to play back the full lossless audio files once they're equipped with suitable decoders. It even says that because HD-AAC is scalable you can use it to fire files over a network, with the file size scaled depending on the amount of available bandwidth. Handy for wireless multi-room audio streams, for example.
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To do all this, of course, you'll need to have a decent amount of storage space to begin with - HD-AAC files are around half the size of uncompressed 16-bit / 44.1KHz CD audio files.
Lossless audio

Lossless audio codecs are nothing new - Meridian Lossless Packing [PDF link] popped up on DVD-Audio discs in 2001. And Apple has had its own iPod-compatible lossless codec, Apple Lossless, since 2004. It delivers spectacular sound quality, but isn't scalable - so you end up with massive file sizes compared to their AAC equivalents. HD-AAC then has Apple Lossless beat.

The arrival of HD-AAC could also spell good news for Apple's rivals - Sony, Creative and others also offer AAC playback on their portable audio players.

Story source: tech.co.uk.