Describe AacPreset here 
[[!format txt """
[_presets_]
version=0.10
element-name=GstFAAC

[Profile Low Complexity]
_meta/comment=Low Complexity Profile
profile=LC

[Profile Main]
_meta/comment=Main Profile
profile=MAIN

[Profile Sample Rate Scalable]
_meta/comment=Sample Rate Scalable Profile
profile=SSR

[Profile Long Term Prediction]
_meta/comment=Long Term Prediction Profile
profile=LTP

[Quality Low]
_meta/comment=Low quality
bitrate=96000

[Quality Normal]
bitrate=128000

[Quality High]
bitrate=200000
"""]]