Sony Walkman NW-MS70D Operating Instructions Manual page 48

Glossary (continued)
SDMI (Secure Digital Music Initiative)
SDMI which stands for Secure Digital Music Initiative, is a forum that consists of over 130 companies in
the fields of recorded audio content, computers, and consumer electronics, dedicated to developing an
integrated method of copyright protection technology that can be used worldwide.
SDMI is working to create a framework for preventing improper usage of audio files and
to
promote legal
music distribution services.
The copyright protection technologies "OpenMG' and "MagicGate" are based upon the SDMI standard.
"Check-idcheck-out"
"Check-out" is to transfer music files from a personal computer to an external devicelmedia (such as
Network Walkman). "Check-in" is to return checked out music files to the same computer. (You cannot
move checked out music files to another computer.)
You can check out a music file, check it back in, and then check it out again an infinite number of times.
The SDMI rules provide that up to four copies of a music file can be checked out at one time. OpenMG
employs a method whereby three copies of a song can be checked out simultaneously, while the fourth
copy
is
maintained as a "master" on your PC. If three copies of the same song are checked out at a given
time, one copy of the song needs to be checked in to the computer in order to create an additional Check-
out.
ATRAC3
ATRAC3, which stands for Adaptive Transform Acoustic Coding3, is audio compression technology that
satisfies the demand for high sound quality and high compression rates.
The ATRAC3 compression rate is approximately 10 times higher than that of the Audio CD, resulting in an
increased data capacity for the media.
ATRACSplus
ATRAC3plus, which stands for Adaptive Transform Acoustic Coding3plus, is audio compression
technology that compresses data higher than ATRAC3. The ATRAC3pius is new audio compression
technology that enables equal or higher quality sound comparing to ATRAC3.
Bit rate
Indicates the data amount per second. The rate is reflected in bps (bit per second).
64 kbps means 64000 bits of information per second. If the bit rate is large, that means a large amount of
information is used to play music. Comparing music of the same format (e,g., ATRAC3plus), 64 kbps data
offers better sound quality than 48 kbps data. However, audio files in formats such as MP3 have different
encoding methods, and thus sound quality cannot be determined by simply comparing the bit rate.
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