Remove noise from video

Before you try it: which video files this opens, how large they can be, and which browsers and phones it runs on. Once you know it works on your file, cleaning the audio on a video covers the actual workflow.

Only the audio track is touched

Your browser opens the file where it sits and reads the sound out of it. The video track is never decoded, never modified and never uploaded — and neither is the audio, because there is no upload step in this at all. Your original file is opened read-only and left exactly as it was; what you get back is a separate audio file.

Which video files work

We do not go by the extension. We read the first bytes of the file, work out what it actually is, and then take the cheapest route that will open it:

• mp4-family files have an index we can read, so we look up where the audio for the stretch we want lives and read only those bytes.
• Anything else the browser can decode — webm and friends — is decoded in full instead. Slower and hungrier, but it works.
• If the cheap route fails on a file that looked like it should work, we fall back to decoding the whole thing rather than giving up. You only see an error when both have failed, and it says so plainly, with the fix: convert to mp3 or wav first, which almost always works. The missing piece in those cases is a container unpacker, not the noise removal.

So the honest answer to "does it support my format" is that dropping the file in is faster than us guessing. It costs you nothing and the answer arrives immediately.

Big files and long files

Size is mostly not the problem. Because mp4-family files are read through their index, we measured about 103 times less memory than decoding the whole file — a couple of gigabytes on disk does not become a couple of gigabytes in your browser.

Length is the thing to watch, and only on the files that have to be decoded in full. A very long recording on that route can run your browser out of memory. If that happens, an mp4 of the same material takes the cheap path.

Phones and browsers

We test in Chrome and Safari, including Safari on iPhone, where a 30 second preview takes a few seconds. Other Chromium browsers such as Edge use the same engine as Chrome. We have not tested Firefox yet.

The engine is about 9 MB of WebAssembly, fetched once after you pick a file — landing on this page does not download it. On a phone that is a real download, so it is worth being on wifi the first time.

What comes back

A 16-bit mono WAV at 48 kHz, audio only, about 2.9 MB for the 30 seconds. It is not level-matched to your original — we do no loudness normalisation, and the cleaned version measured about 2 LU quieter on our own sample. Getting it back against the picture, including the ffmpeg command, is on the video audio page.