In a lot of my videos I like to apply a “letterbox template” to give my 16:9 footage that cinematic look.  16:9 refers to the aspect ratio of the frame.  Old SD footage was displayed in 4:3 format, and the commonly used “widescreen” format for videos and television is now 16:9.  However, traditional films shown in theaters have always had a slightly wider aspect ratio.  This is because the cinema industry began shooting on anamorphic lenses that gave the footage a much shorter and wider look.  To this day, we associate this shorter and wider aspect ratio with video and film that feels more cinematic.