"Keith G" wrote in message ...

Interesting. I've discounted MP4 for the moment on the grounds that it's a
bit of a red herring.

Some months ago there was a listening test over various codecs at 128
Kbps, performed by a multitude of people, using double-blind methods.
You can look at the results at he

http://audio.ciara.us/test/128extension/results.html

At the end of the page is the overall score of each codec. At the
beginning of the page there is a link to the codecs and options used.