AfterDawn: Glossary


ATRAC stands for Adaptive Transform Acoustic Coding and ATRAC3 is an evolution of the earlier ATRAC1 system used with Sony's SDDS theater audio system and the MiniDisc format. ATRAC3 offers two separate modes, LP2 mode and LP4 mode. LP2 uses a uses a 132 kbit/s data rate, which is claimed to offer the same quality as MP3 audio at the same or similar bitrate, or so says Sony-funded tests of both audio formats. It is important to say however that when in dependant audio tests covering a wide variety of formats including OGG Vorbis, AAC and MP3 were carried out, ATRAC3 came in last place.

However, ATRAC3 also has its good points. While other audio compression formats have focused on quality and made little assumptions about power consumption when used with portable players, this factor was kept in mind with the evolution of ATRAC. In Sony players that support the ATRAC3 format, it is often found that playing back large amounts of ATRAC encoded audio will result in a longer lasting battery charge than using other, more common formats, such as MP3 (although there have been good improvements at the hardware level for MP3 decoding too, see here for example.)

LP4 mode requires the same padding as LP2, but it halves the data rate to 66 kbit/s over LP2 and other changes, which results in the possibility of storing up to 324 minutes of audio on an 80 minute MiniDisc. RealAudio8 is a popular implementation of ATRAC3.

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Some interesting ATRAC-related articles from the AfterDawn archives include..

Sony to dump Connect music service - (August 31st, 2007)
Sony acknowledged that its proprietary ATRAC music format was a market flop by shutting down all its Connect music stores and making its devices compatible with other formats.

Sony kills off ATRAC and SonicStage with latest MP3 player - (April 28th, 2007)
The Sony B100 series of portable MP3 players killed off the ATRAC format.

Sony admits ATRAC was a mistake - (January 23rd, 2005)
Ken Kutaragi has stated that Sony has missed out on the sales of MP3 players and other gadgets by sticking to proprietary formats such as ATRAC.

Sony to add MP3 support to its portable music players - (September 23rd, 2004)
Sony confirmed plans to add MP3 support to its players, loosening its reliance on the proprietary ATRAC format.

Sony Connect music service launched - (May 5th, 2004)
Sony opened its Connect music service which used the ATRAC format for downloadable music files.


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