A subtitle offset moves the displayed timing of subtitle text relative to the video. It can help when a compatible subtitle track is consistently early or late. It does not repair every mismatch: different edits or gradually drifting timings can require the correct subtitle edition rather than one fixed adjustment throughout the programme.
A practical example
If dialogue and its text remain two seconds apart throughout a clip, a supported offset control may align them. If the gap changes later, the subtitle may belong to another edit or use timing that does not match the current video.
A common misunderstanding
Avoid changing a global subtitle delay to fix one mismatched file. Keep the scope local where possible, and distinguish a constant timing shift from an increasing mismatch across the programme.
Related terms
Stable technical definition. Editorial approach