Open captions are synonymous with subtitles. They are burnt-in/hard encoded into the video files and cannot be turned on/off. Open captions can be styled in any font, colour or placement. In contrast, the video player determines the appearance of closed captions, not the subtitler. Closed captions are a timed-text file format such as SRT or WebVTT. When captions are turned on, e.g. on a Netflix show, the player renders the text on-screen.