compile a working binary of sox for the mac that includes support for AMR-WB and AMR-NB codecs.
details at [url removed, login to view] sox supports .amr file playback with "optional" libraries that are not included in the default binary.
specifically, sox supports "AMR-WB & AMR-NB (with optional libamrwb & libamrnb libraries)"
again, just looking for this one extra features to be added to the mac version of sox. I'm running OS X leopard if it matters.