Custom settings in video grabber (fixed whitebalance, focus, flash led)

Hi. I’m doing image processing and I will need a fixed white balance, focus and a flash led turned on to improve robustness of algorithm. I checked the native iOS SDK and this is all possible using AVFoundation. However I’m having difficulties to apply those fixes in ofiPhoneVideoGrabber. I noticed it creates some ofPtr to AVFoundationGrabber but when I try to dig into this class xcode can’t find the source code (“symbol not found”). Can anyone guide me where should I look into?