Tienes que editar media_profiles.xml asi:
<AudioEncoderCap name="aac" enabled="true"
minBitRate="128000" maxBitRate="128000"
minSampleRate="48000" maxSampleRate="48000"
minChannels="1" maxChannels="1" />
Tienes que cambiar el 1 a 2:
<AudioEncoderCap name="aac" enabled="true"
minBitRate="128000" maxBitRate="128000"
minSampleRate="48000" maxSampleRate="48000"
minChannels="1" maxChannels="
2" />