How to Dub a Video into Another Language on iPhone

Dubbing replaces what's said in your video with speech in another language. Until recently that meant hiring voice actors. Now an app can translate the speech and generate a new voice track from your phone.

This guide uses CapCap, the iPhone app we make.

How it works

CapCap transcribes the speech in your video, translates the text, then generates a voice reading the translation, sentence by sentence. You get the dubbed audio and matching subtitles in the new language.

Step 1: Start a project

Open CapCap, tap New Project and pick the video from Photos.

Step 2: Choose the languages and output

• Video language: the language spoken in the video.
• Translation language: the language you want it dubbed into.
• Output mode: choose Translate audio + captions.

Step 3: Pick a voice

Under Voice you have three kinds of choice:

• Auto picks a voice that matches the speaker, based on the voice it detects in your video.
• Original voice dubs in a voice modeled on the speaker's own, so it still sounds like you.
• Or choose one of the voice models yourself. Tap play to hear a preview before you pick one.

Step 4: Transcribe and dub

Tap Transcribe now. When it's done, play the video back and listen to the whole thing once.

Step 5: Check it and export

Read the translated subtitles while you listen, and check that names and numbers came through correctly. When it sounds right, tap Export and Save Video to Photos App.

Getting a better result

Start with a video where one person speaks clearly. Background noise, people talking over each other and loud music all make the transcription less accurate, and the dub can only be as good as the transcription.

Listen for pacing too. Some languages need more words than others to say the same thing, so the dubbed voice can run past the moment it belongs to.

For your first few videos in a new language, ask someone who speaks it to watch before you post.

What it doesn't do

CapCap changes the audio, not the picture. It doesn't move the speaker's lips to match the new language, so close-up shots of someone talking will look out of sync to viewers who watch closely. Dubbing works best on voice-overs, tutorials, product demos and videos where the speaker isn't filling the frame.

If you'd rather keep your own voice, translated subtitles are the other option.