Video Compositing — Assembling Multi-Element Videos

Last updated: April 18, 2026

Video compositing combines separate elements — video clips, images, audio tracks, voiceovers, and text overlays — into a single finished video ready to use as an ad creative. Instead of switching between external editing tools, you assemble everything directly inside Wevion's Creative Hub.

This is the final step in the AI-powered creative workflow. Generate the individual pieces (an AI video clip, a TTS voiceover, a text headline) and composite them into one cohesive ad. The result is a production-ready MP4 saved to your Creative Hub folder, ready for Campaign Launcher.

Prerequisites

An active Wevion account with a valid subscription
At least Media Buyer role or higher
Sufficient AI credits — compositing consumes credits per render (Understanding AI Credits)
At least one element to include (video clip, image, audio file, or text)

If you have not generated any elements yet, start here:

Generating AI Videos for AI video clips
Text-to-Speech (TTS) — Voice Generation for voiceover audio
Generating AI Images for static images

What Is Video Compositing?

Video compositing layers multiple elements together on a single timeline. Think of it as a simplified video editor built for advertising — you are assembling a 15-to-60-second ad from parts you have already created or uploaded.

A typical composite ad might include:

A video clip as the main background visual (AI-generated or uploaded)
A voiceover track providing the sales message (generated via TTS)
A text overlay showing a headline, offer, or call to action
An image such as a product shot or logo placed on top of the video

The compositing engine renders everything into a single MP4 file at the resolution and aspect ratio you specify. The output is delivered to your Creative Hub folder automatically — no download step, no file conversion, no manual export.

Accessing the Compositor

Open Creative Hub from the left sidebar navigation.
Click the magic wand icon in the toolbar to open the AI Generation panel.
You will see four tabs on the left: AI Video, Avatar, Voice, and Assemble.
Click the Assemble tab (the layers icon).

📸 Generate Creative panel open with the Assemble tab selected, showing the layers icon highlighted in the left sidebar and the composite configuration area in the main content region

Step-by-Step Guide

Step 1: Prepare Your Elements

Gather the assets you want to combine. Each element needs a URL — meaning it should already exist in your Creative Hub library or be a publicly accessible link. The recommended workflow:

Generate your video clip using the AI Video tab (Generating AI Videos)
Generate your voiceover using the Voice tab (Text-to-Speech (TTS) — Voice Generation)
Wait for jobs to complete in the Generation Jobs list (Managing AI Jobs — Status and Download)
Each completed asset has a result URL ready for compositing

Step 2: Add Elements

For every element in your composition, specify:

Field	Description
Type	`video`, `image`, `audio`, or `text`
Source	URL of the asset, or literal text content for text overlays
Start Time	When the element appears, in seconds (default: 0)
Duration	How long it stays visible/audible, in seconds
Position	X and Y coordinates as percentages (e.g., `x: 50, y: 50` for center)
Style	Optional overrides for text: font size, color, weight

Example configuration:

Element	Type	Start	Duration	Position
Background video	video	0s	Full length	Full frame
Voiceover	audio	0s	Full length	N/A
Headline "50% Off"	text	2s	5s	x: 50, y: 20
CTA "Shop Now"	text	8s	4s	x: 50, y: 80

Step 3: Set Output Dimensions

The default is 1080 x 1920 (9:16 portrait) for Stories and Reels. Common options:

Placement	Dimensions	Aspect Ratio
Stories / Reels	1080 x 1920	9:16
Feed (square)	1080 x 1080	1:1
Feed (portrait)	1080 x 1350	4:5
Landscape	1920 x 1080	16:9

Step 4: Submit and Wait

Click Assemble Video to submit. Your job appears in the Generation Jobs list with these status updates:

Queued — Waiting to be processed
Processing — Rendering in progress
Completed — Ready to view or use. Click View Result to preview
Failed — Check the error message for details

📸 Generation Jobs list showing a composite job with "Completed" status, a green checkmark, the cost in credits, and a "View Result" link

Rendering typically takes 1 to 5 minutes. You do not need to keep the panel open — the finished MP4 is saved to your Creative Hub folder (or the specific Drive folder you had open when launching the panel).

Element Types You Can Combine

Video — The visual backbone of your composition. Use an AI-generated clip, an uploaded MP4, or any video accessible via URL. Plays for its natural duration unless you set a custom one.

Image — Static images for backgrounds, product shots, logos, or overlays. For best results, use images that match or exceed your output resolution.

Audio — Voiceovers, background music, or sound effects. Audio has no visual position — only start time and duration. You can layer multiple audio tracks in one composition.

Text — Overlays rendered directly onto the video frame. The source field contains the actual text (not a URL). Defaults: white (#FFFFFF), bold Inter font, responsive size, positioned at the bottom center. Override any of these via the style field.

Use Cases

Product launch ad. AI video of your product + TTS voiceover explaining the benefit + text overlay with price. Assembled into a 15-second Stories ad.

Testimonial-style UGC. Avatar spokesperson video + background music + end-screen CTA. Polished UGC without hiring talent.

Multi-language variants. Same video + different TTS voiceovers per language + localized text. Five variants in minutes.

A/B testing. Same video, different headlines or voiceovers. Launch as separate ads to find the winner.

Tips for Effective Compositions

Keep it short. Under 15 seconds for Stories/Reels, under 30 for Feed. Shorter videos achieve higher completion rates.
Front-load the hook. Put your most attention-grabbing element in the first 2-3 seconds.
Sync text to voiceover. Text should appear at the moment the voiceover mentions it.
Match resolution to placement. Use 9:16 for Stories, 1:1 or 4:5 for Feed. Mismatched resolutions cause black bars or cropping.
Use high-contrast text. White on dark works well. For bright videos, add a semi-transparent background style.
Layer audio carefully. Background music should not overpower the voiceover.
Preview before launching. Click View Result to check timing and sync before putting the ad live.
Save to a dedicated folder. Open the AI panel from within a specific folder (e.g., Composites / Campaign Name) so outputs land there automatically.

FAQ

How much does a composite render cost in credits? Each render consumes credits from your account. Check your account settings for current pricing. Understanding AI Credits

How long does rendering take? Typically 1 to 5 minutes. Jobs that exceed the maximum rendering time fail with a timeout — simplify the composition or reduce duration.

Can I use my own uploaded files? Yes. Any file in Creative Hub has a URL you can use as a source element. Publicly accessible URLs also work.

Can I edit a composition after rendering? There is no saved project file. To make changes, adjust your elements and submit a new job. Since source elements remain in your library, re-compositing is fast.

What is the output format? MP4 — the standard format accepted by Meta for all ad placements.

Can I use a template? Templates are currently managed through the API. The template library is not accessible from the Wevion user interface.

What happens if a source element is unavailable? The job fails. Ensure all source URLs are accessible before submitting. Check the error in Generation Jobs. Managing AI Jobs — Status and Download