Exported Video very choppy
I am trying to film a documentary-style video, with the use of my iPhone 11 as a camera. On my phone, I have the settings set to 1080p at 30fps. When uploading the videos (converting them to mp4 so that Hitfilm accepts them), I edit them and all is good. My project settings are the same as before, 1080p at 30fps. When I did the editing, I export my contents but all the time my exported video is VERY laggy/frame ratey. This was not the case literally a week ago, and I haven't change any settings. I have even tried to change my project settings to 720p at 30fps in case I got my phone properties wrong, with no prevail.
One theory I have is that when I'm putting my recorded videos onto the timeline, I'm getting that message that the project and the video are not in the same resolution (even if they are supposed to?) and I'm clicking ignore as they should be the same. Please help I've got a deadline due soon!