To dub a video in another language with AI, you no longer need a translator, a voice actor, and a separate sync session, you need a pipeline that transcribes the original, translates the script, and revoices it in a consistent voice. CoreReflex handles that end to end through its voiceover seam and Vertex AI speech stack, so a finished narration in a new language is minutes of work rather than a multi-vendor project. Here is the full workflow.
Dubbing vs. subtitling: pick the right one
Before you dub, be clear on what you actually need. Subtitles add translated text on screen and keep the original audio; dubbing replaces the spoken narration with a new-language voice track. Subtitles are cheaper and preserve the original performance; dubbing is more immersive and works for viewers who will not read captions.
Many creators do both, a dubbed track for accessibility and reach, plus burned-in captions for sound-off viewing. If subtitles are all you need right now, how to translate video subtitles with AI covers that path, and animated on-screen text is handled in how to add animated captions to a video with AI. This guide is about replacing the voice.
How AI dubbing works under the hood
Good dubbing is three steps stacked into one flow: speech-to-text, translation, and text-to-speech. CoreReflex runs all three on its owned Vertex AI stack, which means the transcript, the translated script, and the new voice all live inside one pipeline instead of bouncing between apps.
- Transcribe. Vertex STT converts the original narration into accurate, timestamped text.
- Translate. The transcript is translated into the target language, with the timing preserved so the new track can line up with the picture.
- Revoice. The translated script is read by a voice from the voiceover seam, a named HD voice, a voice you designed, or a consent-gated cloned voice.
Because the whole chain is one system, you are not exporting an SRT to a translation tool and a script to a separate TTS service and praying the timing survives. It stays coherent.
Step-by-step: dub a video in another language
Step 1: Bring in the source and transcribe it
Start with the video whose narration you want to dub. The pipeline runs speech-to-text to produce a clean, timestamped transcript of the original. Review it, accurate source text is the foundation, and a quick proof here prevents errors from cascading into the translation.
Step 2: Translate the script
Translate the transcript into your target language. This is the moment to localize, not just translate literally: adjust idioms, units, and phrasing so the script sounds native rather than machine-converted. Keep the timestamps intact so each line maps back to its moment in the video. Translation is part of the free editing surface, you only spend credits when you generate the new audio, so refine the wording as much as you like first.
Step 3: Choose the dubbing voice
This is where the voiceover seam earns its keep. You have real options for how the dub sounds:
- A named HD voice in the target language for a clean, professional read.
- "Design a voice" to build a voice to a spec when you want something specific that no stock voice nails.
- A consent-gated cloned voice if you want the dub to resemble the original speaker, used only with proper consent.
- A managed custom-voice adapter for a brand voice you reuse everywhere.
The payoff is consistency: the same brand voice that narrates your films can read your scripts and even answer the phone through real-time voice agents, so your identity holds across every language and every channel.
Step 4: Generate and sync the new track
Generate the translated voiceover and lay it against the picture. Because the translation kept the original timestamps, the new track lines up close out of the gate; nudge timing where a language runs longer or shorter than the source. Translated speech often expands, a line that is tight in English can run long in German or Spanish, so leave a little room in fast-cut sections.
Step 5: Add captions and render a deterministic cut
Burn in target-language captions for sound-off viewers, then render. CoreReflex assembles the result through a real Remotion render-worker on a deterministic path, claim the job, render the manifest, upload the file to your storage, record the asset, so the same manifest produces the same cut every time, with retry and faststart handling baked in. The dubbed file you download is exactly what you approved.
If you are dubbing for a specific platform, you will likely also want a re-framed version; how to resize a video for any platform with AI covers turning one cut into the right ratio for each destination.
Keep the dub on brand
A dub is not just words. It is tone. Reusing a designed or managed brand voice across languages keeps your sound recognizable, which matters more than most teams expect when they expand into new markets. The voiceover seam is engine-agnostic, so you are choosing the voice that fits the brand rather than being locked to whatever a single vendor offers. The same approach powers other work too, coaches use it to localize course promos, as shown in AI video for coaches: course and offer promos, and Shorts creators use it to dub a back catalog covered in how to make a YouTube Short with AI.
Frequently asked questions
Can CoreReflex translate and revoice narration?
Yes. The pipeline transcribes the original with Vertex speech-to-text, translates the script into your target language, and revoices it through the voiceover seam, all on one owned stack. You can refine the transcript and translation for free, then generate the new voice track and render a finished cut. It replaces the multi-vendor process of separate transcription, translation, and voice-acting steps.
Will the dubbed voice match the original?
It can, within the bounds of consent. The voiceover seam supports consent-gated voice cloning, so a dub can resemble the original speaker when you have permission to use that voice. If you prefer, you can instead pick a named HD voice, design a voice to a spec, or reuse a managed brand voice for a consistent identity across every language you publish in.
How many languages are supported for dubbing?
Dubbing relies on the languages available through the Vertex AI speech and translation services that power the pipeline, which span a wide range of major world languages. Because the stack is the source of truth for what is supported, check the current language coverage in the docs rather than assuming a fixed list. Practically, the common languages teams localize into are well covered.
Is AI dubbing as good as a human voice actor?
For most marketing, social, and instructional video, modern HD voices are clean, natural, and more than good enough, and far faster and cheaper than booking talent per language. A human actor still has the edge for high-emotion dramatic performance. The advantage of the seam is choice: use a designed or HD voice for scale, and reserve human talent for the rare project that truly needs it.
Reach a wider audience in minutes
Dubbing used to be a logistics problem, translators, voice talent, sync sessions, and a fragile hand-off between them. With transcription, translation, and a flexible voiceover seam in one pipeline, you can revoice a video into a new language and render a deterministic, on-brand cut without leaving the studio. Check how generation credits map to plans on the pricing page, then start free, no credit card required and dub your first video today.