Rotate And Save Video Using VLC Media Player
Here we consider how to rotate and save video using vlc media player.
First of open vlc media player and click on Show Extended Settings Icon as shown below.

This will open a window where you can select Video Effects tab --> Geometry Tab.

Here check the checkbox Transform where you can see some predifined angles like 90, 180 etc.
More angles can be available by checking the Rotate checkbox.
Then select the desired angle from the angle Selector as shown above.
Now open your video with vlc media player.
Now you will be watching your video in new angle.
Now lets consider how to save rotated video using vlc media player.
Keep the above configuration on vlc and click on Media --> Convert/Save Button.
Here you can add new files that needs to be rotated.
Then click on Convert link from Convert/Save Button List.
This will open a window as shown below.

Here ensue Convert Radio Button Should be selected.
And then from Profile DropDown List, select your desired format.
Here I have selected the Video for MPEG4 1080p.
After that Select Destination folder and give a name for your file with format extension.
Now click on the start button.
This will create a rotated video for you.