Glossary (continued)SDMI

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-in/Check-out”

Check-out is to transfer music files from a personal computer to an external device/media (such as Network Walkman). Returning checked-out music files to the same computer is to check-in. (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.

Bit rate

Indicates the data amount per second. The rate is reflected in bps (bit per second).

In OpenMG Jukebox, the bit rate for recording an audio CD or converting MP3 and WAV format audio files into ATRAC3 format can be chosen from 132 kbps/105kbps/66kbps. 105 kbps means 105000 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, a 105 kbps data offers better sound quality than 66 kbps data, and 132 kbps data offers better sound quality than 105 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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