You cannot do it with Allcast, so you have to do it with your PC or Mac. You will have to download a video editor, such as <a href="https://www.blender.org/">Blender</a> or another free video editor. You will have to use that video editor to alter your screen rotation and then create a new video file. When you load the video file into your video editor, it will start by appearing with the same rotation as what you see on the TV when you cast. Fix the rotation, publish the file (create the file), and then cast your new video file to your TV.