Current Events > How to upright a video?

(+) Yeah! (+)

On my android phone if you know an app and tell me the step for it. You ever watch a video like on YouTube for example that is vertical when it's the regular size , but then when you open full screen it's sideways? I ve encountered some videos like this and can't figure out how to make it be upright while full screen. Rotating the video didn't seem to do much unless I did it wrong. Thanks for any help