Why an opaque plate is a different problem
With thin text, most of the marked area is still background: the gaps between letters, the counters inside an O, the space between two words. The repair only has to guess a fraction of the box. With a plate, the whole rectangle is missing, and the only source is the picture around it — what sits above the bar, below it, and to either side.
On a wall, a sky or a plain backdrop that extrapolates cleanly. On texture or on anything moving, it does not, because there is no structure to continue across a gap that wide.
- Mark the plate edge to edge, including its border and drop shadow
- A semi-transparent plate is harder than a solid one: the background is faintly present but contaminated by the tint
- A plate that overlaps a person leaves a smear in the shape of the plate
The shoulder problem
Lower thirds are placed where the subject is not, but that is a rule of thumb rather than a guarantee. On a wide interview shot the bar sits in empty space and comes out clean. On a tighter shot it lands across a shoulder, a chair back, or a hand — and nothing in the other frames says what was underneath, because the person moved.
This is the same geometry as our crowd test, where pedestrians walked through a caption band. That clip scored 19.8 dB and left visible vertical ghosts where each person crossed. A lower third over a shoulder fails the same way, for the same reason.
What to do instead, when it fails
If the plate covers a person, three options in order of quality. Re-export from the original project with the graphic hidden — exact, and free if you still have it. Crop so the bar falls outside the frame. Or accept the smear, which is only reasonable when the bar sits at the very edge over a plain area.
Reconstruction earns its place when the plate sits over scenery and the original project is gone. That is the common case for anything already published.