MP3 · MP4 · WAV · MOV · and more

Replace the voice in any
video or audio file

Upload your file, let AI transcribe it, edit the script, and download a new AI voiceover synced to the original timing. No re-recording. No studio.

5 free minutes · No credit card required

How it works

1
Upload your file
Video or audio — MP4, MOV, MP3, WAV, and more. Up to 210 MB.
2
AI transcribes the audio
Whisper AI produces a time-stamped transcript automatically. No manual work.
3
Edit or translate
Fix wording, update the script, or switch the language entirely before generating.
4
Download new audio
MP3 synced to the original timing — drop it straight into your video editor.

Flubbed a take on your Loom or product demo? Re-voice the whole thing in minutes. No re-recording, no editing timeline.

Your subject matter expert left or the content is outdated. Upload the old recording, update the script, generate fresh narration.

Translate the transcript, generate a foreign-language voiceover timed to the original cuts. No dubbing studio required.

Swap a weak voice on an existing video without touching the edit. Export the audio track and drop it in your editor.

What video and audio formats does Recastr support?: Recastr accepts most common formats: MP4, MOV, MKV, AVI, MP3, WAV, M4A, FLAC, OGG, WEBM, and more. If your file plays in a standard media player, it will almost certainly work.
How long can my file be?: Files up to 30 minutes and 210 MB are supported. For longer content, split it into sections, process each one, and reassemble in your video editor.
How does the new audio stay in sync with the original?: Whisper AI assigns a precise timestamp to every sentence in the transcript. Recastr synthesises each segment individually and inserts silence between them so every word lands exactly on cue — no manual alignment needed.
Can I translate the audio to another language?: Yes. After transcription, use the built-in translation feature to convert the script to any supported language, then generate the voiceover. The result is a foreign-language audio track timed to the original cuts.
What's the difference between this and uploading an SRT file?: If you already have a subtitle file (SRT or VTT), use the SRT-to-audio workflow — it skips transcription entirely. This page is for when you start from a raw video or audio file and need Recastr to produce the transcript first.
What audio format does Recastr output?: MP3 by default — compatible with every video editor, podcast host, and LMS platform. WAV and other lossless formats are also available when you need them.

5 free minutes included · No credit card required