Help Help changing video orientation

[kindakooky]

I have a video which I shot in landscape mode, thinking i would just as easily be able to watch it back in landscape but it seems this isn't the case as when I play it back it automatically switches to potrait instead. Anyone know how I can change and save it to landscape mode please?

 

[Deleted User]

Is it only affecting that one file or does it do this to all video files? And it sounds obvious but do you have screen rotation turned on or not?