So I started to realize that I need to learn something on iPhone video input and output to deal with OpenGL ES and the thing is that I don't know how to start with it. They say that it is good for a beginner to purchase a book about iPhone development and read it till you completely understand. However the thing I want to stay focused is about the video I/O of iPhone and I don't want to study other than that.
So is there any book or resource that explains video I/O quite well in Objective-C? If not, it's okay to recommend some books written in Swift.