Aspect ratio

Running an android 5.1 with Kodi 16.1 and having issues with aspect ratio. Searched the forum and saw someone else figured out that you click on the ‘reel’ while running a video to change from wide/zoom/16:9 etc. only on my system these do not come up as options. Only stereoscopic 3D settings. What am I missing? I want to watch movies in the original letterbox format but they are getting automatically stretched vertically to fill the screen. The zoom is not on so it should be in normal 16:9 ratio. It’s like this on all movies I watch.