The SUB file extension is used for subtitles which used in DivX movies and other movie formats. SUB file is a text file, it contains subtitle text and time point for when subtitle should be displayed. SUB files are text files used in video playback. Therefore, they do not contain any video data.
The SUB file extension is used by CloneCD, a popular CD/DVD cloning tool for Microsoft Windows. SUB file contains sub channel data. SUB file and CCD and IMG files have the same file name, for example, file.sub, file.ccd and file.img.
The SUB file extension is associated with SubTerra, a fast-moving, exciting arcade puzzle game. SUB file contains level layout information, objects and events included in the level.