Another subject that I know something about (and get paid very well for knowing).
First, CGI has a VERY long way to go to reach the point where it is even close to “real” video.
Second, video forensics is very similar to document forensics. One might as well say that photocopying a page produces a document that is indistinguishable from the original. To an expert, there are obvious differences.
On the other hand, I have to admit that any video or image is simply a set of pixels with certain numerical values. In theory, it is possible to manipulate the values of pixels to make a video or image that is absolutely identical to a video or image created in “real time” using a camera. But I’ve never seen one that came close.