How to stop a transparent clip losing its colours when it is composited

Last updated 2026-09-15 · 8 min read

What is the short version?

A transparent overlay carries two things: the picture and the mask. Read by the wrong path, the mask gets folded into the picture, and the result is a clip whose colours are subtly and consistently wrong in a way no colour correction fixes.

1. Go to Vizard Agent with the transparent files.
2. Say they look wrong in other players too.
3. Ask it to check how the alpha is being decoded.

What do you need before you start?

The original transparent files. Vizard Agent inspects them rather than the version already in your edit, because the whole question is what happens between the file and the frame — and a re-exported copy has usually lost the evidence.

• The original files. Not a re-export.
• Where else they look wrong. Another player is useful.
• What they sit on. Black, white, or footage.
• Whether the edges matter. Soft edges suffer most.
• What the colours should be. A reference helps.

What do you type into Vizard Agent?

Report the symptom across players, not the colour itself. Saying the clip looks washed out invites a grade; saying it looks the same way in two unrelated players says the file is being read wrongly, which is a different investigation.

Prompt

Variants worth knowing:

• "They look wrong in other players too." Rules out your edit.
• "How the alpha is being decoded." The real question.
• "Show me a composited frame." The only proof.

What does Vizard Agent actually do?

Here is the sequence Vizard Agent worked through on a real set of transparent overlays that kept coming back discoloured. Notice that nothing gets corrected until the decoding question is settled, because correcting the symptom first would bake the fault permanently into the files.

1. Inspects the alpha channel and the files' real parameters.
2. Checks how transparency is being extracted from them.
3. Looks at the available ways to decode that format's alpha.
4. Tests an alternative decoder on the same frame.
5. Decodes correctly and composites onto the intended background.
6. Pulls a frame through the alpha-capable path to check.
7. Checks the background is not swallowing the transparent layer.
8. Confirms the colour on the composited result.
9. Rebuilds the edit from the correctly decoded clips.

Step four is the whole fix. Two decoders reading the same file can produce different pictures when one of them discards the alpha, and swapping the path costs nothing while adjusting the colour costs you the original.

Step seven is a failure that looks identical from the outside. If the layer is composited onto a solid background at the wrong stage, the background can eat the transparent areas entirely, and the result is also "wrong colours" — so Vizard Agent checks which of the two is happening.

Step eight matters because a source frame proves nothing. The file can be perfectly correct and still composite wrongly, so the check has to be on the frame as it will actually appear rather than on the clip in isolation.

Step nine is where the cost of getting this wrong early shows up. Every clip that was assembled from a badly decoded source has to be rebuilt, so settling the decoding path before the edit is put together is worth considerably more than any amount of careful work afterwards.

What does the result look like?

Overlays whose colours match what you originally made, on whatever background they end up sitting on. Vizard Agent also tells you which decoding path actually worked, which is worth writing down for the next batch of files from the same source.

When does this not work well?

Some files are simply wrong. If the transparency was baked in when the file was exported, or the alpha was flattened at some earlier point, there is nothing to decode and the colours you have are the colours you have.

• Alpha already flattened. Nothing to recover.
• Premultiplied vs straight alpha. They need different handling.
• Formats with no alpha at all. Then it is a keying job.
• Heavily compressed overlays. Soft edges fringe regardless.
• Colour differences that are real. Sometimes the file is just different.

How do you fix a result that came back wrong?

Say whether the whole clip is off or only its edges are. Because Vizard Agent treats decoding and compositing as two separate stages, a uniform colour shift across the frame and a fringe confined to the edges point at completely different halves of the problem.

• "The whole clip is off." Still a decoding question.
• "Only the edges fringe." Premultiplication, or compression.
• "It is right on black, wrong on footage." A compositing order issue.
• "It looks flat now." Check against the original file.

How does Vizard Agent compare to doing it yourself?

By hand a discoloured overlay gets graded until it looks right on the background it happens to be on. That bakes a correction into a file that was never wrong, and the next time it sits on a different background it is wrong again in a new way.

Common questions

Why do colours change at all? Because a mask read as picture data alters the picture it was masking.

How do I know it is not my grade? It looks wrong in unrelated players too. Vizard Agent starts there.

Can it just correct the colour? Vizard Agent can, but that bakes in a fix that works on one background only.

What is premultiplied alpha? A different way of storing transparency. Vizard Agent checks which you have.

Does the background matter? Yes. Vizard Agent checks the layer is not being swallowed by it.

Will the edges be clean? Cleaner than before, though Vizard Agent will note that compression can still fringe them.

Can it check a whole batch? Yes, and Vizard Agent usually finds the same decoding path serves all of them.

What if the alpha is gone? Vizard Agent will say so; then it becomes a keying job instead.

Does this affect exported graphics too? Yes. Vizard Agent checks any transparent asset the same way.

Will it re-render everything? No. Vizard Agent rebuilds only the clips that were decoded wrongly.

Can it show me before and after? Yes. Vizard Agent pulls the same frame through both decoding paths.

Does it change the source files? No. Vizard Agent reads them differently rather than rewriting them.

What about soft shadows in the overlay? Those suffer first, so they are the best place to check.

Why did one player look fine? Because that one handled the alpha and the others did not.