Vuforia is really great. It works on almost every Android device.
But on some of my targeted Android devices, Vuforia just freezes at starting up the camera. I guess changing the preview size would solve the problem. Setting video mode to OPTIMIZE does not help.
The reason why I think about changing the camera preview size is because when I start the Camera application, I can see the resolution of the preview is very low.
If not possible for now, I suggest adding API calls to forcefully set camera preview size and FPS.