mp4 → mp3
Keep the audio from an MP4 and drop the rest
For the recordings where the picture was never the point — a lecture, a call, a set filmed on someone's phone. What comes back is a tenth of the size and plays in anything.
Processed on your own hardware · never transmitted, never stored
What happens when you drop a file in
The file stays put. Your browser opens it the same way an image viewer would. There is no transfer, which is why there is no upload bar to watch.
An encoder arrives once. The first job on this site pulls down a compiled build of FFmpeg, roughly 30 MB. It is kept afterwards, so every job after the first starts immediately.
Your own hardware does the job. The work happens in this tab, on your processor. A laptop from the last few years handles short clips in well under real time.
The result lands in Downloads. Assembled in memory and handed straight to your browser. Close the tab and every trace of it is gone.
The picture is usually dead weight
A large share of the video people record is not watched, it is listened to. Conference sessions, interviews, rehearsals, a talk someone filmed from the back of a room. The frames take up almost all the file and contribute almost nothing.
The arithmetic is stark. An hour of 1080p sits at a couple of gigabytes; the same hour at 192 kbps is around 85 megabytes. That is the difference between a file you shuffle between drives and one you keep on your phone without thinking.
It also unlocks tools that refuse video outright. Transcription services, dictation apps, podcast hosts and most audio editors want an audio file and will not accept anything else.
Picking a bitrate without overthinking it
Speech is forgiving — 128 kbps is transparent for a lecture or an interview and keeps files comfortably small. Music is not: compression artefacts surface first in cymbals, reverb tails and sustained high notes, so go to 320 kbps if there is any music you care about. When a recording holds both, 192 kbps is the setting nobody complains about.
Common questions
Does a low-resolution video mean bad audio?
No. The soundtrack sits in the file independently of the picture, so a grainy recording can carry perfectly clean sound.
Will it take formats other than MP4?
Yes — MOV, M4V and most variants work. It reads whatever audio track it finds.
How much quality do I lose?
A little, since the audio is decoded and compressed again. From 192 kbps upward the difference is inaudible on ordinary equipment.
Where does my file go?
Nowhere. It is opened locally and processed in this tab.