Fine-Tuning Compression Settings


Adjusting MP3 Settings

iTunes is set up to encode MP3 at a bit rate of 160 kbps. To change the bit rate and other MP3 settings, choose Custom from the Setting pop-up menu.

Adjusting AAC Settings

iTunes is set up to encode AAC at a bit rate of 128 kbps. To change the bit rate, choose Custom from the Setting pop-up menu, then choose the desired bit rate.

Converting from MP3 to AAC and Apple Lossless

iTunes can convert existing MP3s to AAC, but you'll lose quality in the process. That's because both AAC and MP3 are lossy formats: each discards audio information in order to save disk space. Thus, when an MP3 file is compressed with AAC, the lossiness is compounded.

Bottom line: to take advantage of AAC's space savings, re-rip your original CDs instead of recompressing existing MP3s.

This re-ripping requirement also applies if you want to take advantage of the Apple Lossless encoder. You can't convert an MP3 (or an AAC) file into Apple Lossless and gain the quality benefits of the latterthe sonic damage has already been done.

iTunes has some smarts that make re-ripping less laborious: if you re-rip a CD that iTunes already has in its library, iTunes tells you that the songs have already been imported and asks if you want to import them again. Thus, you're spared from having to rebuild your playlists, retype any song information, or manually delete your old MP3s.

Note

If you've edited a song's informationchanged its name or that of the artist or album as described on page 28 iTunes won't recognize that you're importing it again, and you'll end up with two copies of the same song.


To avoid this, make the same edits before you import the CD, or edit the song information of the existing MP3s to match that of the audio CD. Or just make a mental note to delete the old MP3 files after re-ripping.




The Macintosh iLife '06
The Macintosh iLife 06
ISBN: 0321426541
EAN: 2147483647
Year: 2004
Pages: 229
Authors: Jim Heid

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