ios 检测声音支持

    BOOL bAudioInputAvailable = NO;
	AVAudioSession *audioSession = [AVAudioSession sharedInstance];
    if ([[UIDevice currentDevice].systemVersion floatValue] >= 6.0) {
        
        bAudioInputAvailable = [audioSession isInputAvailable];
        
    }
    else
    {
        
        bAudioInputAvailable = [audioSession inputIsAvailable];
        
    }