Sony VAIO Music Clip MC-P10 Operating Instructions Manual page 32

ATRAC3 (Adaptive Transform Acoustic Coding 3)
ATRAC3 is a sound compression technology based on
"ATRAC3," a sound compression technology used for
Mini Disc, with the addition of a new technology to
increase the compression rate (approximately one
tenth).
MP3
MP3 is the abbreviation for "MPEG-1 Audio Layer3"
fixed in one of the working group of ISO named
MPEG. This is an audio codec standard which can
compress audio signal almost one tenth. As this
technology is opened, there are may variety of
products.
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