I have a few questions about encoding audiobook CD's.

I want to use either HE-AACv1 or HE-AACv2.

Based on this link I found somehow through Google:

http://www.iis.fraunhofer.de/EN/bf/amm/products/heaac.jsp

I guess I'd probably want to use HE-AACv2 correct? Though those bitrates seem a lot lower than what I've seen on the varies parts of the forum. Could this due to the subjective meaning of the word good?

Additionally, what sampling rate should be used?

I know that my headphones have a frequency response of 20kHz max. Does that mean any sampling rate over 40kHz would be pointless since I believe half of the sampling rate would be equal to the max possible frequency correct?

Or can audiobooks be generally sampled at an even lower rate?

I do plan to do mess around with different encoding options to see what I'd like but a general idea of what I should be aiming for would be appreciated.

Mono compresses better than stereo, and human voice, with little high frequencies, would also compress very well. Use of a lower sampling rate should be appropriate here.

The sampling rate should be a little bit higher than twice the highest frequency, but not much.

Hmm...there isn't an encoding option or method that checks my source wav file, find the highest frequency, and then encoding the sound file with a sampling rate of double the frequency is there?

Try encoding at lower and lower sampling rates until you hear a difference.

Hmm...is this a fault on my end or something?

Whenever I try to encode with the HE-AACv2 with a -q also set, Nero says that is an "Unsupported encoding configuration".

I wanted to encode a test file with HE-AACv1 profile forced and then HE-AACv2 profile forced.

I'm guessing that it is normal that Nero doesn't allow me to use VBR and force HE-AACv2?

edit: Oh, it doesn't seem to work ever if I force HE-AACv2.

HE-AACv2 is only for stereo files: HE-AACv2 = HE-AAC + PS (PS = Parametric Stereo).

Oh. I guess I don't need to worry about whether my phone supports HE-AACv2 then. The audiobook CD's are mono anyway. Well, both channels are the same.