How to rescue a cutout that lost its transparency
Send the cutout to Vizard Agent and say what you see. It composites the file over a checkerboard and over a flat colour to look at the matte directly, separates the colour and alpha planes, and works out whether the transparency is genuinely missing or simply not being decoded, before rebuilding anything.
What do you type into Vizard Agent?
Describe the symptom rather than diagnosing it. "The transparency is missing" is a conclusion, and it's wrong about half the time. Say what the picture does when you put it over a background, and send Vizard Agent the actual file, not a screenshot, because the question is what's inside the container.
Prompt
What does Vizard Agent actually do?
A solid rectangle has two explanations that look identical: the transparency was never written, or it's there and the decoder ignored it. Regenerating in the second case produces another perfect file that also composites as a rectangle. So Vizard Agent diagnoses first, without changing the file. In the session behind this article it:
- Checked the cutout's alpha, inspected the file's real streams and format rather than its extension, and viewed a frame over a checkerboard and over magenta.
- Separated the colour and alpha planes and viewed the colour plane on its own.
- Read the background-removal log, scanned the alpha across the clip and checked whether the decoder exposed the alpha plane at all.
- Tested a ProRes conversion and re-ran the background removal, then tried the alpha-aware decoder instead of the default one.
- Verified the recovered alpha at three timestamps over green, tightened the edge to remove the halo and viewed the tightened composite to confirm.
When does this not work well?
Some formats can't carry transparency at all, and a matte that was never written can't be recovered from the colour pixels, by Vizard Agent or anyone else. A flattened export has the background baked in. Edge tightening has limits too: on very soft or hairy edges it costs detail, and heavy compression shows in the alpha.
Common questions
Why does it look solid if the alpha is there? Because the default decoder can drop it silently. Vizard Agent tests for that.
Can it recover alpha from a flat file? No. If the background is baked into the colour, Vizard Agent has to re-key it.
What is the halo? Old background clinging to the edge. Vizard Agent tightens the matte to remove it.