Automatic exposure is not application specific, it is a hardware feature controlled by CONTROL_AE_MODE, it is either ON or OFF. It has some hint in SceneMode. For example SceneMode will adjust ISO (Landscape has different ISO than Action). I was wondering if it can be "faked" and not computed in hw, but somehow in sw. It obviously cannot be done in automatic mode and then retrieve value of the other property (ISO vs. shutterspeed), but since there is preview I think it can somehow be calculated from...
I created account, I agree, the device is really rare BlackView5100, but I think something in exporimental settinsg for overriding it (like HedgeCam has it) would solve it. I does work only for main camera, not widelens, didnt try it on front camera (no reason to do long exposure with front camera). But maybe another of my solutions would solve this problem much better - there is already noise reduction algorithm, so no problem to do "noise addition" algorithm (just fake long exposure with multiple...