Free AI Voice Over Generator

What a voice over generator has to get right

Three things, in order. Pace: a voice over sits under pictures, and a listener who is also reading a screen needs the words to arrive slightly slower than in conversation. Most generated voice overs fail here first, not because the voice is wrong but because it is quick and even, and evenness reads as indifference. Clarity: product names, numbers and acronyms are the parts people actually need, and they are the parts a synthetic voice most often trips on. Register: an explainer, an advert and a compliance module want three different presenters, and a tool with one house voice cannot give you that.

CastDub approaches all three from the script rather than from a settings panel. Pace is set per line on Plus and Pro and, on every plan, by punctuation — a full stop is a real pause, an ellipsis a longer one, a line break a gap. Clarity is handled by auditioning the difficult words on their own and fixing them in the text. Register is a casting decision: forty characters with written personas, from a newsreader to a bedtime narrator to an arena announcer, and any of them can be the narrator.

The part that most voice over tools do not attempt is the second voice. Explainers keep sneaking dialogue in — a customer asking the question the video answers, a colleague objecting, a testimonial read in someone else's voice — and in a one-voice tool those lines are either read flat by the narrator or produced separately and glued on. Here they are lines with a name in front of them, cast to a second character, mixed into the same file with the right gap before and after.

Explainers, ads, product videos, e-learning: how the script changes

An explainer wants a presenter who sounds interested in the subject without performing interest. Quill was written for exactly this, and Hale is the calmer alternative for anything longer than three minutes. Keep sentences short, put the product name on its own line the first time it appears so you can audition it, and write the transitions — "here is the catch", "so what does that mean for you" — as separate lines, because those are the moments the voice should change gear.

Adverts and trailers are the one place where a pushed read is correct. Duke exists for the thirty-second spot; Axel for the sports-adjacent version of it. The trick is contrast: two lines pushed, the rest plain. A whole advert at trailer intensity is exhausting by the second sentence, and the call to action lands harder if the line before it is quiet.

E-learning and compliance modules are the largest voice over category by volume and the most sensitive to pace. Learners replay, so a slightly slow read is a feature. Noor's newsreader clarity suits definitions and procedures; Wren or Halcyon suit anything meant to lower the temperature. If the module includes a scenario — a manager and an employee, a customer and an agent — write it as a dialogue with names, and the scenario will be performed by two people instead of narrated by one.

Voice over, narration and dubbing are different jobs

Narration is a voice over that carries a story rather than a message; the same tools apply, but the casting leans towards the audiobook and bedtime voices, and the script leans towards longer sentences. Dubbing is something else again: it means replacing the speech already in a video with speech in another language, timed to the picture and ideally to the mouths. CastDub does not take a video as input and does not do that. What it does is generate the replacement track from a script you supply — which is most of the work of a simple dub, provided you translate the script yourself and are prepared to slide lines to picture afterwards.

If your actual need is to take an existing video and get it speaking another language automatically, a dedicated dubbing tool will serve you better. If your need is a clean, directed voice track from a script — in any of nine languages, with more than one voice when the script calls for it — that is what this page is for.

Timing a voice over to picture

There is no video import and no timeline here; the timing work happens in whatever editor you cut the video in. Two exports make that work easy. The mixed MP3 is the fast path: lay it on the timeline, and if the whole track runs a little long, trim the pauses between paragraphs rather than speeding up the voice. The per-line ZIP is the precise path: one MP3 per sentence and a CSV that lists each line's speaker, text and duration in milliseconds, so you can place every sentence exactly where the picture needs it.

Two habits save time. Write the script in the order the pictures will appear, with one visual beat per line, so the line list already matches your shot list. And decide the length before you record — a sixty-second video with a hundred and eighty words of script is going to be fast whatever voice reads it, and no amount of direction fixes a script that is simply too long for its slot.

Expect generated speech to run slightly faster and more evenly than a human session, and to leave no room for on-screen action unless you write it in. A line consisting of a few dots is the simplest way to reserve a beat for the picture; a line break between sentences is the second simplest.