Overlay

An overlay is any element placed on top of the primary video footage in a video composition — existing on a layer above the base footage and interacting with it visually through transparency, blending modes, or position. Overlays encompass an enormous range of content types: text annotations explaining what's happening on a product demo, lower thirds identifying speakers, logo watermarks in the corner of the frame, graphic callouts highlighting specific UI elements, emoji reactions in social video, countdown timers, progress bars, and decorative frames. What distinguishes an overlay from the primary footage is its compositional relationship — it's always on top, added to enhance or supplement the base layer, and typically does not replace it.

The technical implementation of overlays in video editing relies on alpha channels (transparency information) and layer stacking in the NLE timeline. An overlay element is placed on a video track above the primary footage track; where the overlay is opaque, it shows through to the viewer; where it is transparent, the underlying footage shows. Partial transparency (semi-opaque overlays) creates the "lower third" aesthetic where text is readable over footage because a semi-transparent bar sits behind the text. Motion graphics overlays that animate on screen, display for a period, then animate off are typically delivered as pre-rendered files with embedded alpha channels, which editors simply place on the appropriate track.

For B2B video, overlays are the primary visual communication tool for screen recordings, software demos, and tutorial content. A raw screen recording contains only the product UI — overlays add the explanatory layer: animated arrows, highlight circles, text labels calling out specific features, zoom-in animations on particular UI elements. These annotations are overlays applied over the screen capture footage. In live-action product demos, overlays add text context that the presenter's narration communicates verbally, creating reinforcement across multiple sensory channels simultaneously. The discipline of overlay design is not cluttering the base footage to the point where both the overlay and the footage become less readable — each overlay element should add genuine communicative value to justify its visual presence.