[rockdoe]

Which is not the default ffmpeg encoder, and due to licensing you can't distribute libfdk_aac and x264 in the same ffmpeg binary.

There's a built-in ffmpeg AAC encoder too, but despite the author's claims it is not as good as libfdk_aac.

And libfdk_aac itself isn't as good as Apple's AAC codec either. There's a Hydrogenaudio listening test demonstrating that.