mov → mp4
MOV to MP4, and usually nothing gets re-encoded
iPhone and QuickTime footage, turned into something Windows and Android will open without complaint. Most files finish in seconds because the picture never has to be decoded at all.
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.
These two formats are closer than they look
MOV and MP4 are built on the same underlying specification, and both routinely carry H.264 video. The difference is largely the label on the box. When that is the case, the video stream can be lifted out and placed in an MP4 without being touched.
That is what happens first here. Nothing is decoded, nothing is recompressed, and the picture that comes out is identical to the picture that went in — at a fraction of the time a real conversion would take.
Some MOV files hold ProRes instead, common from professional cameras and certain Mac exports. MP4 cannot carry it, so those get a full re-encode automatically. You are not asked to know which case you have.
Where all these MOV files come from
iPhones record MOV by default. So does QuickTime Player, so do most Mac screen recorders, and so do a good number of DSLRs. The format is flawless inside the Apple world and creates friction almost everywhere outside it, which is why this particular conversion is among the most searched of any.
Common questions
Will the quality drop?
Usually not at all, because the video is copied rather than converted. If your file needs the fallback path, the loss is not visible in normal viewing.
Mine took much longer than seconds.
It held a codec MP4 cannot store, almost certainly ProRes, so it was re-encoded. The result is still correct.
What about HEVC from an iPhone?
It works, though HEVC files usually take the slower path since most players expect H.264 inside an MP4.
Does the file get uploaded?
No. Your browser opens it locally and it stays there.