How to film with placeholder screens and drop the real clips in later

Last updated 2026-09-04 · 7 min read

What is the short version?

Referring to a clip you have not inserted yet is the awkward part of recording a piece to camera. Film with something physically there — a green card, a tablet, a board — and the gesture, the eyeline and the timing all come out right.

1. Film your piece with a coloured placeholder in shot.
2. Go to Vizard Agent with the footage and the clips.
3. Say which clip goes in which placeholder, in order.

What do you need before you start?

A placeholder that is one flat colour and stays visible. Green is conventional, but what matters more is that it is evenly lit and nothing in your clothing matches it — Vizard Agent keys on the actual colour it measures, not on a preset.

• The footage. Placeholder in shot.
• The clips. In the order they appear.
• The placeholder's colour. It measures it, but say if it is unusual.
• Any framing changes. Different takes, different geometry.
• What is behind it. A screen has reflections; card does not.

What do you type into Vizard Agent?

Say out loud that the placeholders are placeholders. Left unexplained, a green rectangle sitting in shot reads to Vizard Agent as exactly that — a green rectangle — so the useful version of this instruction names it as a slot and says which clip fills it.

Prompt

Variants worth knowing:

• "Placeholders for the clips." Names them as slots.
• "My framing changes." Triggers a per-section measurement.
• "Use your judgement on the rest." Lets it design around them.

What does Vizard Agent actually do?

Here is the order Vizard Agent worked in on a real teleprompter piece filmed with green placeholder screens in shot. Step one is the decision the entire job rests on: the placeholder gets measured separately in every section rather than once at the top.

1. Measures the placeholder geometry in each section separately.
2. Views the framing sections at full quality.
3. Fits the shape — a disc, in this case, not a rectangle.
4. Tests the key on each section individually.
5. Builds the background, the masks and the placeholder cards.
6. Runs a single-frame composite test for each section.
7. Views the composites side by side.
8. Simulates a colour-and-brightness key rule to find clean thresholds.
9. Tests a tight key using the exact measured screen colour.
10. Views the tight composites to confirm nothing is eaten.
11. Fixes one section's crop where the framing had drifted.
12. Views the corrected section.
13. Assembles the cut and re-checks the inserted screens.
14. Reviews the screens as a grid before delivery.

Step eight is worth understanding. A key threshold picked from a colour name works in a studio and fails in a room, because a placeholder lit from one side is two colours. Simulating the rule against the real pixels finds a threshold that holds across the whole section rather than one that works on the frame you happened to check.

Step three matters more often than people expect. Placeholders are not always rectangles — a tablet held at an angle, a round card, a screen seen off-axis — and fitting the clip to the measured shape is what stops the insert looking stuck on.

What does the result look like?

A piece to camera where you gesture at a clip and the clip is there, at the angle the placeholder was at, moving with it if you moved. Your eyeline is right because you were looking at something real.

Where your framing changed between sections, each one was keyed on its own measurement, so the second half does not have a green fringe the first half does not.

When does this not work well?

Keying is unforgiving about lighting and about colour collisions, and most of the failures Vizard Agent runs into here were created at the shoot rather than in the edit. None of them are fixable afterwards without visible cost, so they are worth reading before you film rather than after.

• Uneven lighting on the placeholder. Two colours, one threshold.
• Green in your clothing. It keys out with the placeholder.
• A reflective screen. Reflections survive the key.
• Motion blur at the edges. The boundary becomes ambiguous.
• A placeholder that leaves frame. Nothing to key in that shot.

How do you fix a result that came back wrong?

Name the section that is wrong rather than the video. Vizard Agent keeps the per-section geometry, the measured placeholder colour and the key threshold it settled on, so a green fringe or a badly fitted clip is a re-key of that one section rather than of the whole piece.

• "There is a green edge." The threshold re-simulated for that section.
• "It ate my sleeve." Tightened; the sleeve restored.
• "The clip is the wrong shape." Re-fitted to the measured geometry.
• "Wrong clip in slot two." Swapped; nothing else re-keyed.

How does Vizard Agent compare to doing it yourself?

By hand this is a keying job with a tracking job on top, per section, and it is entirely doable in any compositing tool. The part that catches people is measuring per section — one key pulled from the first shot and applied throughout is why the second half fringes.

Common questions

Does the placeholder have to be green? No. Vizard Agent measures whatever colour you used; green is just convenient.

Can I use a tablet or a laptop screen? Yes, though reflections make it harder. Vizard Agent will say if the key struggles.

What if I moved between takes? Say so. Vizard Agent measures each section separately.

Can it track a placeholder I hold? Yes, within reason. Fast movement blurs the edge.

Does the clip have to be the same shape? No. Vizard Agent fits it to the measured geometry.

What if I wear green? It keys out with the placeholder. Change the placeholder colour instead.

Can it add a frame or a border? Yes. Ask and Vizard Agent designs the insert rather than just filling it.

How many placeholders can one video have? As many as you filmed. Vizard Agent keys each on its own measurement.

Is this better than adding clips in post? Usually. Your eyeline and gestures are right, and Vizard Agent has real geometry to fit to.

What if the placeholder is partly hidden? Vizard Agent keys the visible part and tells you what it could not reach.

Can it match the lighting of the room? Yes. Ask and Vizard Agent grades the insert to the shot.

Does it work on a moving camera? Yes. Vizard Agent tracks it, but say so up front.

Can I see a test before the full render? Yes. Vizard Agent composites a single frame per section first.

Why measure per section? Because a threshold that fits the first shot leaves a fringe on the second, and nobody checks the second one as carefully.