Creative Labs JUKEBOX ZEN NX XTRA 60GB 70PD055000024 用户手册

Encoding is the second phase of making an MP3 file. Encoders are used to 
convert the stored audio tracks, usually WAV files, into MP3 files. MP3 
encoding is considered lossy compression, which means that some data is 
lost during compression. However, using the standard sampling rate and 
bitrates will ensure that your MP3 files retain much of their audio quality. The 
standard bitrate of most MP3 files is 128 Kbps, although some are set 
higher, at 160 or 192 Kbps. Higher bitrates will result in larger MP3 file sizes, 
with better audio quality. Use Creative MediaSource Organizer to extract 
audio tracks and encode MP3s.