Video to Audio
Video in. Audio out.
MP4 to WAV, in this tab.
Nothing is uploaded. Your browser does the work.
- 1Video
- 2Output
- 3WAV
The video
The output
16,000 Hz mono is what most speech-to-text engines want, and it is a fraction of the size.
- Runs offline
- No upload
- Full quality
- WAV only, no MP3
How it works, and what it cannot do
Your browser's own decoder reads the audio track out of the container and ignores the video frames. The result is resampled through an offline audio context and written as a RIFF/PCM WAV. Nothing is transcoded on a server, so quality is limited only by the original recording.
WAV is uncompressed: roughly 10 MB per minute at CD quality in stereo, or about 1.8 MB per minute at 16 kHz mono. The whole track is held in memory while it converts, so very long recordings can exhaust a tab — the page says so rather than hanging.
A file with no audio track, or one using a codec this browser cannot decode, is reported plainly instead of downloading an empty WAV. There is no MP3 output: MP3 encoding needs a licensed encoder this page deliberately does not ship.
Questions people actually ask
Pull the sound out of a recording without handing the video to a conversion site. Useful before transcription, for podcast edits, and any time you need the audio and not the pictures.
How do I convert MP4 to WAV for free?
Drop the file in, choose a sample rate and channel count, and press Extract audio. Your browser's own decoder reads the audio track and ignores the video frames; the result is written as a standard RIFF/PCM WAV.
Is my video uploaded?
No. Everything happens in the tab. That matters for client recordings, interviews and anything under NDA.
What settings should I use for transcription?
16,000 Hz mono. That is what most speech-to-text engines expect, and it is roughly a sixth the size of CD-quality stereo. There is a preset for exactly that.
Can it output MP3?
No, and deliberately. MP3 encoding needs a licensed encoder this page does not ship. WAV is uncompressed and universally readable — convert it afterwards if you need MP3.
Why does it say there is no audio?
Either the file genuinely has no audio track — screen recordings made without a microphone often do not — or its codec is not one your browser can decode. The tool names both possibilities rather than guessing.
How large a file can it handle?
The whole track is held in memory while converting, so very long recordings can exhaust a tab. 16 kHz mono needs about a sixth of the memory of CD-quality stereo, which is usually the fix.
Part of nine free KaiOrb instruments — all in-browser, none of them upload your files.