How to recolour an object in a video and replace its soundscape

Last updated 2026-08-19 · 6 min read

What is the short version?

Changing one thing's colour in a video is a selective operation, and doing it badly turns everything else in the frame the same shade. The safe route is to test the filter on stills, look at the result, and only then apply it to the footage.

1. Go to Vizard Agent and upload the video.
2. Name the object and the colour it should become.
3. Say what the audio should be instead of the music.

What do you need before you start?

The video, the object and the target colour. Vizard Agent locates the segments the object appears in by itself, so timecodes are optional, and the useful extra is telling it what the sound should become, because a recolour with the original music over it rarely reads as a new piece.

• The video. Any length. Vizard Agent finds the relevant stretches.
• The object. Named plainly: the machine, the car, the jacket.
• The colour. As specific as you can be.
• The audio. Effects, ambience, silence, new music.
• New on-screen text. If the old title should not survive.

What do you type into Vizard Agent?

Name the object, the colour and the audio in one instruction. Vizard Agent handles all three as one job and sequences them sensibly, and separating them into three requests costs you the passes where it checks whether one change damaged another.

Prompt

Variants worth knowing:

• A new title card. Vizard Agent will remove the old burnt-in text first.
• Ambience only. No music at all is a valid and common answer.
• A specific shade. Say it; Vizard Agent tunes the filter towards it.

What does Vizard Agent actually do?

Here is the order Vizard Agent worked in on a real recolour job. Almost everything before the render is a test on a still frame, which is what keeps a selective colour change from spilling across the whole picture.

1. Probes the video and extracts frames into a review grid.
2. Analyses the shot list and samples frames across the full length.
3. Detects the crop area and rebuilds the contact sheets at the target ratio.
4. Finds the segments containing the object and narrows the start and end points to the second.
5. Samples frames every half second around the cut points for precision.
6. Tests three colour approaches on stills — a straight adjustment, a high-precision pass and a selective-colour filter — and looks at each result.
7. Checks whether the recolour changed the on-screen text, then removes the old text and tests four title treatments.
8. Generates the vehicle and river-ambience sound effects, balances them and measures the combined loudness.
9. Renders the recoloured cut with the new audio, builds a quality-control sheet, refines the text timing and re-renders.

Step 7 is the check most people skip. A selective colour filter does not know the difference between the machine and the caption sitting next to it, so Vizard Agent looks at the text after the change rather than assuming it survived.

What does the result look like?

From the run this page is written from, probed on the delivered file: 1280x720, H.264, 30fps, 14.53 seconds, AAC audio. Widescreen, under fifteen seconds, with the object recoloured, the original burnt-in title replaced and an audio bed built from generated effects rather than music.

Fifteen seconds is short and the work is dense. Almost all of the effort sits in the tests that never appear on screen, which is the usual shape of a job where one element has to change and everything around it has to stay exactly as it was.

When does this not work well?

Recolouring is not replacement. Vizard Agent changes how an object looks in the frames you already have and cannot change what that object actually is, and the distance between those two things is where this kind of request disappoints people.

• A recolour is not a different model. Asking for one brand of machine to become another gets you the first one in a new colour.
• Similar colours bleed. Anything else in frame near that hue shifts too, which is why Vizard Agent tests on stills first.
• Burnt-in text may be affected. Vizard Agent checks and can remove and replace it.
• Motion blur resists selection. Fast-moving edges hold the original colour longer.
• Changing the setting is a different job. Recolouring cannot turn a road into a forest; that needs generated shots.

How do you fix a result that came back wrong?

Say which part drifted. Vizard Agent keeps the segment boundaries, every tested filter, the still comparisons and the generated effects, so tightening the selection or shifting the shade means one more test on a still frame and then a render.

• "The colour is too bright." Retuned and shown on a still first.
• "The sky changed too." A tighter selective filter, tested the same way.
• "The title is on screen too long." Re-timed against the measured appearance.

How does Vizard Agent compare to doing it yourself?

By hand this is masking the object across every frame it appears in, discovering afterwards that the filter caught the background too, and then sourcing engine and water effects from a library and lining every one of them up against the picture manually.

Common questions

Can it change the object into a different one? No. Vizard Agent changes the colour; the object stays what it is.

Will other things in frame change colour? Vizard Agent tests on stills to prevent it, and similar hues are the risk.

Can it remove the old on-screen text? Yes, and it will check whether the recolour affected it first.

Does it have to remove the music? Only if you ask. Effects-only is a common choice for this kind of edit.

Can it change the setting as well? Not by recolouring. Changing where a scene takes place needs generated shots instead, which is a separate job with a different method.

Will it show me the colour before rendering? Yes. Vizard Agent tests the filter on a still and looks at the result before it touches the footage.

How specific can the colour be? Name the shade and Vizard Agent tunes the filter towards it, showing you a still before rendering.

Does it work on moving objects? Yes, and fast motion is the hard case. Vizard Agent samples frames at half-second intervals around the cut points for exactly this reason.

Can it generate the new sound effects? Yes. Vizard Agent builds them per scene and balances them against a measured loudness target.

How long does the object need to be on screen? Long enough to see. Vizard Agent locates every segment it appears in and works only on those.