Cover and Reveal — effect skill for transitions

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B slides in over a still A (cover), or A slides away to uncover B (reveal). Variants: cover*/reveal* in four directions.

What it does

Built on Cover Transitions by HeyGen (HyperFrames), Apache-2.0. The write-up and recipes below are varg's.

One shot stays put while the other moves over or off it, like a card sliding over a card.

When: Stacking scenes in a product walkthrough, deck-style explainers, card-based layouts.

Watch out: Covering with a shot whose edge has no shadow — the layers look flat; add a soft shadow in HTML engines.

Timing: 0.4–0.6 s, ease-out on cover, ease-in on reveal.

Also called: Cover (CapCut), Uncover, Slide over

In FFmpeg

Both inputs need the same size, frame rate, timebase, SAR and pixel format (settb=AVTB fixes the timebase error that fps alone leaves). offset is where the transition starts on the first clip's timeline (its length minus the overlap).

ffmpeg -i a.mp4 -i b.mp4 -filter_complex \
 "[0:v]fps=30,scale=1920:1080,setsar=1,settb=AVTB,format=yuv420p[a];[1:v]fps=30,scale=1920:1080,setsar=1,settb=AVTB,format=yuv420p[b];\
  [a][b]xfade=transition=coverleft:duration=0.5:offset=4.5[v];[0:a][1:a]acrossfade=d=0.5[a]" \
 -map "[v]" -map "[a]" out.mp4

In HyperFrames

npx hyperframes add transitions-cover shows the family; tween the top clip's x with a box-shadow on it.

In CapCut

Transitions → Slide → Cover / Uncover.

Ready-made components

Where this comes from

Use when

Not for

Install

Example output

https://s3.varg.ai/how-to/previews/023d8a23fd09/take-xfade-cover-reveal.mp4 — coverleft between two shots, with the timeline strip of the edit. Footage: WING IT! (2023), Blender Studio | studio.blender.org, CC BY 4.0; Coffee Run (2020), Blender Studio | studio.blender.org, CC BY 4.0. (credit: Rendered by varg · WING IT! (2023) + Coffee Run (2020))

More transitions skills

Run the generation on varg

varg is one API key for the models these skills drive — Seedance 2.5, Kling 4, Veo 3.1, Wan 3, Nano Banana 2.1, GPT Image 2.5, ElevenLabs v4 and 200+ more — billed in credits, with a cost estimate before anything runs.