Add AI Voiceovers to Generated Videos: The Complete Workflow
Combine AI video generation with text-to-speech to create fully narrated product demos, explainers, and social content — all from a single widget.
A video without audio is only half the story. Motion and lighting can carry a brand, but narration turns a clip into a story: what the product is, why it matters, and what to do next. Combining AI-generated video with AI voiceover gives you polished, narrated content without a recording studio, voice talent booking, or a heavyweight video editor for every iteration.
ImageLayer now supports the full narrated-video path inside the same widget: generate the base clip in Video mode, open the finished preview, click Add voiceover, and receive an updated MP4 with the narration merged in. The standalone audio file is still available if you want to reuse the same read in a longer edit.
The workflow
Step 1: Generate the video
Switch Output mode to Video, choose Veo 3.1 Fast, and write a director-style prompt: subject, environment, camera behavior, and lighting. Set duration and resolution (for example, 8 seconds at 720p) to match where the asset will ship. This step produces the visual backbone—b-roll you can pair with speech.
Step 2: Add the voiceover
Once the clip finishes, click Add voiceover on the video preview. ImageLayer seeds the narration prompt from your last video prompt, but you can rewrite it, pick a voice that fits your brand (for example Kore or Charon), and submit. The voiceover run is billed separately from the base video; short scripts typically cost a single credit, making narration cheap to iterate while you tighten copy.
Step 3: Download the merged export
ImageLayer synthesizes the narration, keeps the approved video stream, and returns an updated MP4 with the voiceover merged in. You still get the audio asset for reuse, but the primary result is a narrated video that is ready to review, download, or hand off.
Example: Narrated product demo
Base video: Prism product demo generated from the product still with a slow cinematic dolly move. 8 seconds, 720p, 12 credits.
Voiceover prompt: “Meet Prism — the smart lamp that transforms any room…” using Kore. 1 credit.
Merged result: Prism narrated product demo — updated MP4 with Kore voiceover
Total: 13 credits for the narrated version.
The result is channel-ready as a short narrated clip: ImageLayer keeps the visual pacing of the original eight-second demo and merges in the generated read. If you also want a longer edit, keep the standalone voiceover file and reuse the same script elsewhere.
Example: Narrated coffee brand clip
Base video: NovaCraft latte-pour brand teaser — cinematic barista shot with realistic milk-stream and latte art. 8 seconds, 720p, 12 credits.
Voiceover prompt: “Every cup tells a story. At NovaCraft…” using Charon. 1 credit.
Merged result: NovaCraft narrated social teaser — updated MP4 with Charon voiceover
Total: 13 credits for this narrated clip.
This is the exact pattern the in-product voiceover action is built for: approve the motion first, then layer in brand narration without leaving the widget.
Matching audio length to video
Short clips (six to eight seconds) are easy to iterate but unforgiving for copy. Before you generate audio, read your script aloud at a natural pace and time it. If the voiceover runs longer than the video, you have three practical options:
- Tighten the script so the spoken line fits the clip—strongest for ads and teasers where every word competes with the scroll.
- Use the merged export for the short cut and keep the standalone MP3 for a longer edit, landing page loop, or second asset.
- Adjust video strategy—generate a second, longer take when the narration genuinely needs more beats.
Pacing also matters: list-heavy or technical sentences need more seconds than a single emotional hook. If you standardize on eight-second video, aim for one clear idea per line and avoid stacking two claims in the same breath.
Programmatic fallback
ImageLayer’s native voiceover workflow uses the same underlying idea you would use in CI or a custom backend: keep the rendered video stream, map in the generated narration, and stop at the shorter stream so the export stays channel-ready. If you need to mirror that behavior outside the widget, ffmpeg works well:
ffmpeg -i video.mp4 -i voiceover.mp3 -map 0:v:0 -map 1:a:0 -c:v copy -c:a aac -shortest output.mp4-shortest finishes when the shorter stream ends—useful when your narration is longer than the clip and you still want a clean social-length MP4. If you need a longer final asset, regenerate a longer video or reuse the standalone audio in a full editor timeline.
Keep exploring
- AI Video Generation: Create Cinematic Product Demos and Social Clips — Templates, prompts, and pricing for Veo clips.
- AI Voiceovers in Seconds: Generate Professional Audio with Text-to-Speech — TTS voices, models, and writing for speech.
- From Zero to Product Launch: Creating a Complete Demo Package with AI — Prism demo video, stills, VO, and copy in one kit.
Try it in the playground
Generate the clip in Video mode, click Add voiceover on the finished preview, choose the narration prompt and voice, and download the updated MP4 when processing finishes. Open the playground to run the full flow on your account and ship narrated clips without leaving one widget.