Free Video Rotator is a free app that allows you to rotate videos 90 degrees when taken with the wrong orientation.
Free Video Rotator has a relatively easy-to-use interface, with a "user guide" provided in large text to guide you in the right direction. There is also a link to their website called "How to use the software," but it already has the same information.
It promises to open and rotate the most popular movie formats, including AVI, MP4, FLV, MOV, and MKV.
To open your video, Open a file, Browse, or Find Target. Find Target was a little unclear when we tried it because the app attempted to open our DVD drive. It took us a minute to realize this is the output folder. Your best bet is to use Open File or Browse. We found Open File shows your Video folder immediately, so we recommend that.
Once your video is open, click Clockwise Rotation as often as needed. If the video is upside down, for example, two clicks of the Clockwise Rotation will restore it right-side up. Most videos shot sideways will only need one click. Next up, click start and wait for it to process. Our very short test video took a minute to rotate a small, 6-second video. You will be notified that the file has been completed, and you might not be able to close that window. You will need to force the app to quit by right-clicking on the icon in your system tray. Our video wasn't saved on a second attempt when we forced the app to close.
Our output test video was rotated, but the orientation was not.
While Free Video Rotator has a few bugs, they are easily overlooked when you need to rotate a video. We'd like to see a portable version, as this is an app most people use infrequently.