How to make Real-time blur layer for camera preview part?

Question

Android

Friends, we need help. I have a task to make a blur layer that will be in real mode on the video that is broadcast from the camera. In principle, this was done thanks to GLSurfaceView and Open Gl. But the problem is that I need this effect to apply only to part of the broadcast image, and the rest should be unchanged. Tell me if anyone knows. Or maybe someone knows a more convenient solution for creating a real time blur layer?

Answer 1

And in OpenCV there are no similar solutions?