342 Views 1 Reply Latest reply: Jan 4, 2006 11:35 AM by SpaceMonkey
If you want to use VBR, I would stay away from the iTunes encoder, which doesn't really use VBR in the way that it is commonly accepted in most audio circles. Typically, VBR is used to target a perceived quality level, adjusting the bitrate to keep quality constant. There isn't really an easy way to do this using the settings that iTunes provides.
I would give the LAME MP3 encoder a try. It is an open source MP3 encoder that has been heavily tested to give transparent results--that is, files that sound indistinguishable from the original CD. Most tests show it to rival the sound quality of even AAC files. There is even an iTunes plugin that allows you to use LAME from within iTunes. Get it here.
It comes with a somewhat outdated version of LAME, but that can easily be remedied. Just download the current Mac OS X build of LAME here. Assuming you have installed the iTunes-LAME plugin, find it in your User Folder/Library/iTunes/Scripts, and right-click or ctrl-click on it and select "Show Package Contents." In the "Contents" folder that appears, go to the "Resources" folder and replace the file labeled "lame" with the one that you downloaded from the link above. This will update the iTunes-LAME plugin to use the new version of LAME.
There is also a stand-alone program available called Max that uses the current version of LAME. Unfortunately, you can't use it from within iTunes like the iTunes-LAME plugin, but you may find it more convenient because you won't have to update its LAME build.
As for what settings to use, LAME uses a command-line system to activate different presets or switches. Using the presets "V 2 --vbr-new" or "V 3 --vbr-new" will generally give transparent results. "V 2 --vbr-new" will usually give average bitrates between 160 and 220 kbps, depending on the complexity of the music. "V 3 --vbr-new" will give slightly lower bitrates, and will most likely still be transparent, but you may notice some degredation depending on your ears and equipment. For more on the LAME preset system, see this page. Right now, Max for some reason doesn't give you access to the command line settings (or at least, I haven't found it), but its default setting for LAME is equivilent to "V 2 --vbr-new."