Windows Media Encoder : How to set average bitrate in audio Bitrate-based mode

How to set average bitrate in audio Bitrate-based mode? In Wi开发者_运维知识库ndow media encoder SDK, it tell that I must specify average bitrate. Is it using the same audience.SetAudioConfig(0, 2, 44100, 192000, 16); to set the bitrate as CBR?

I just know that Bitrate-based VBR, encoder must start(encoder.Start();) twice. Now, I can record the sound.