Are you trying to this file to a different format, or
: Sending an edited video via AirDrop or email often triggers this automatic renaming.
: The "(2)" in the filename suggests that a file with the same name already exists in the destination folder, leading the operating system to add a number to prevent overwriting the original.
: Apps that process iPhone media (like specialized camera or editing apps) may use "FullSizeRender" as a default name for the final rendered output.