Extracts the audio track from a video and writes it as MP3, whatever the container. Drop an MP4, MOV, MKV, WebM or M4V — the format is detected from the file itself rather than from its extension.
The video is never decoded
The practical consequence: it works on files this browser could not play. An iPhone recording is HEVC and a ProRes export from Final Cut is not decodable in any browser, and both give up their audio without complaint.
Which containers are read
The format is identified from the file's own bytes, so a mislabelled extension does not matter. If the container genuinely is not supported you are told which one it is.
Formats a browser genuinely cannot read
WMA (Windows Media Audio), AC-3 and DTS (cinema surround tracks), AMR (old phone voice recordings) and RealAudio are not decodable by any browser. If your file uses one you are told which, rather than being left with a failure that says nothing.
HEVC video cannot be decoded either — but that does not matter here. Extracting audio discards the video track before anything tries to decode it, so an iPhone recording converts perfectly well even though the browser could not play its picture.
How MP3 encoding works without a server
It is the same encoder desktop software has used for twenty years, producing standard files that play everywhere. Because it is fetched on demand, pages that convert to WAV or M4A never download it.
Other names for this
Also searched as “extract audio from video”, “convert video to audio”, “rip audio from video”.
Questions
- Which video formats work?
- MP4, MOV, M4V, MKV, WebM, Ogg and MPEG-TS, plus most AVI files. The container is detected from the file rather than the extension.
- Does the video codec matter?
- No. It is discarded before decoding, so HEVC and ProRes files work even though the browser cannot play them.
- Can I convert a whole folder?
- Yes. Drop the folder and every video in it is processed, keeping its name.
- Why does my purchased file fail?
- If it is DRM-protected — an Apple Music download, an Audible book, a rented film — it cannot be converted. That is what the protection is for, and no converter can or should get around it.
- Is my file uploaded?
- No. The demuxing, decoding and encoding all happen in this tab using the browser’s own media stack plus a WebAssembly encoder. A recording can be an interview, a lecture, a private call — none of it is transmitted. Turn your Wi-Fi off after the page loads and it still works.
- How large a file can I convert?
- There is no imposed limit, only your device’s memory — around 2 GB in a desktop browser and 400 MB on a phone, since the file is held in memory while it converts. A two-hour video converts in well under a minute on a laptop.