Aspect ratio selector for video players

This has been something on my mind for a while, but I haven’t posted this yet.
As it stands right now, there are a handful of video players that display a 16:9 image stretched into 4:3. This means 16:9 content looks taller than it actually is, and 4:3 content is letterboxed even if the video would perfectly fit otherwise.
I think there should be an option for all condo video players to choose between a 4:3 and a 16:9 video window. Maybe options for wider aspect ratios like 18:9 and 21:9, but 4:3 and 16:9 would cover most use cases.