Since the youtube video has a 1440p option, it doesn't seem like it's the version that would have be cached during the flight. However, as mentioned, it looks like a result of noise. Digital sensors often struggle in dark scenes, especially when running at the highest resolution. Some cameras are able to use additional sensor pixels to effectively improve light gathering capability, but I don't believe our phantoms can do it (someone please correct me if I'm wrong). In the end, I believe it's simply a limitation of the camera.