get_audio_format
Description:
Gets a CallAudioFormat object specifying the audio format used by the audio port if call audio is routed via the host.
Warning: 
      
        
    
    The values reported by this are not updated when the values in the interface change. Instead, the client is expected to call get_audio_format again to get a new CallAudioFormat with the new values.
Parameters:
| this | A Call. | 
Returns:
| A CallAudioFormat that must be freed with 
            unref or  |