FaceDetectionListener not working

Camera.FaceDetectionListener (FaceActivity) is not working in this source.

@override
public void onFaceDetection(Camera.Face[] faces, Camera camera) {

}

Camera.Face[] faces is always empty.

Unfortunately, we have been unable to replicate what you are seeing. Can you provide detailed step-by-step description of how you are generating this error?

I simply run gocoder sample android app (https://github.com/fabiojapa/gocoder-sdk-samples-android) provided by you guys.
with SDK compile ‘com.wowza.gocoder.sdk.android:com.wowza.gocoder.sdk:2.0@aar’