variable bit rate aac mp4 with itunes?

My understanding is that AAC, by the very definition of the codec, is inherently variable bit rate.

In support of that, check out this page at Apple's Web site explaining the AAC codec (http://www.apple.com/mpeg4/aac/). The last sentence in the second paragraph says:

The AAC codec in QuickTime 6 builds upon new, state-of-the art signal processing technology from Dolby Laboratories and brings true variable bit rate (VBR) audio encoding to QuickTime.

And, in case you didn't know, iTunes 4 uses QT's AAC codec.

Tom

Originally posted by i_wolf
Sorry the reason i post this here instead of the pc section is that being made from apple, the ipod will support apples' version of aac. Thing is I am encoding stuff using the ahead nero aac plugin on the pc.. this plugin gives the option of cbr (which i know in the truest sense is really cbr) and also a vbr version.

No problem!

I just was interested in knowing whether i would be able to get the vbr ones to play when i get my ipod.

I would think you can. I believe you'll need to change the files' extension from *.mp4 (which I assume it is now) to *.m4a. This is the unprotected AAC files iTunes encodes as opposed to the protected AAC files downloaded from the iTunes Music Store which have an extension of *.m4p.

Inicdentally, when itunes 4 encodes an aac file, does it add the id3 tags to the track? ? (maybe a stupid question, im a noob here!)
Kind Regards,
i_wolf
Yes, iTunes adds ID3 tag info to the AAC files it encodes.

Tom