Conversion from AAC 320(VBR) to AAC 320(CBR)
Hello --
I have a question regarding using iTunes to convert a AAC 320(VBR) (variable bit-rate) file to an AAC 320(CBR) (constant bit-rate) version. When using the built-in iTunes conversion algorithm, will it treat the parent file (the AAC 320 (VBR) file) as a lossless file, and then downsample to creat the AAC 320 version? Or will it go 'across the board' and treat the parent file as an already downsampled file, and just make a file without the VBR label? The files were imported via iTunes, and I must have had the VBR box checked when doing the import.
Namely, I just don't want to lose any audio quality when doing a conversion - most of the files are classical musical files, and as such, I can notice the difference in the audio of lower bit-rate files versus true lossless or 320 bit-rate formats, at least when played over high-end speakers.
Normally when doing a VBR import, the actual bit-rate will change per song (as far as I've experienced, say one song is 289, the next 274, etc.) and all of the songs that I have talking about are 320 (VBR) quality. I'm assuming that iTunes imported them all at a 320 constant bit-rate, but labeled them as VBR regardless due to the checked setting in the import settings; I had the other import settings maxed out at highest quality otherwise (aside from the AIFF file format, which I know is true lossless).
Thanks!
MacBook Pro (15-inch Early 2008), OS X Mountain Lion (10.8.3)