Файл SUB

A .sub file is a plain-text file that contains video subtitles. Two dialects share the extension: MicroDVD, where each line encodes a start and end frame number in braces - e.g., {0}{50}Hello world - and SubViewer, which uses HH:MM:SS.hh timecodes instead. Both are human-readable and can be opened in any text editor.

The extension is also used by the binary VobSub format, but that variant always comes paired with a matching .idx index file and is not human-readable text.

Subtitle configuration

.sub subtitle files are simple and don't offer built-in styling or advanced text effects. However, many media players offer functions to apply effects to text, including:

• Font settings such as size and color,
• timestamp editing,
• subtitle offsets,
• subtitle reader functions.

.sub files are prepared for each video individually and are typically named the same as the related video but with a different file suffix, allowing players to auto-load them. Because MicroDVD timing is frame-based rather than time-based, a mismatch between the subtitle's assumed frame rate and the actual video frame rate will cause timing drift, which can be corrected with a subtitle editor such as Subtitle Edit. For modern projects, .srt or .ass are now more widely used alternatives.