A free program for Android, by Yogesh Dama.

The Rotation Manager is a handy app to help you to automatically rotate your device screen to landscape when you open the Youtube app or video player. You can also make it auto-rotate when you use the Calculator.

The app is designed to be easy to use, and you will not need to configure anything. It will work out of the box and you will not need to change any settings.

In order to be able to auto-rotate, the device must be in the Rotation mode. You will not be able to auto-rotate if you are in the Portrait mode.