Build a shot and overlay map
Mark every hard cut, dissolve, graphic animation, position change, and period when the overlay disappears. Record the start and end frame for each stable combination of scene and overlay layout.
Do not rely on a single early preview. A mask that works over sky may fail when the next shot places a face, product, or fine text behind the same corner.
Handle transitions separately
Dissolves and fades contain two scenes at once. Test them as their own short ranges because the available context changes continuously and low-opacity overlay edges can extend beyond the main graphic.
A hard cut may produce a one-frame flash if repaired texture from the previous shot bleeds into the next. Inspect the exact boundary frame by frame.
Use risk-based quality control
Prioritize faces, hands, straight lines, repeating patterns, subtitles, interface text, and fast pans. These features reveal spatial or temporal errors quickly.
When a single shot fails, choose a smaller mask, a clean plate, a replacement graphic, or the original source. Do not expand the mask across every shot to hide one local problem.
Recommended workflow
- Detect or manually mark each shot boundary in the authorized clip.
- Record overlay size, position, opacity, and animation for every shot.
- Create separate processing ranges for cuts, dissolves, and layout changes.
- Preview the first, busiest, and final frames of each range.
- Join the approved results and inspect every transition at normal speed.