MOV to MP4
An iPhone records .mov. Most upload forms want .mp4. Nearly always the video inside is already exactly what the .mp4 needs — only the wrapper differs. This swaps the wrapper and copies the video across untouched, so nothing is re-encoded and no quality is lost.
Nothing is uploaded. Open your browser’s Network tab while you convert — you will see the file go nowhere.
Why this is instant, when other converters are not
A video file has two parts: the compressed picture and sound, and the container that wraps them with timing information. .mov and .mp4 are two containers that hold the same kinds of video. An iPhone clip is H.264 or HEVC inside a QuickTime wrapper; an .mp4 is usually the very same H.264 or HEVC inside an MP4 wrapper.
So converting the picture does not require decoding a single frame: the compressed video is copied across byte for byte and a new wrapper is written around it. That is why this finishes in about the time it takes to read the file, and why the result is not one pixel different from the original.
The sound is a different story, and we would rather say so than let you assume otherwise. It is decoded and re-encoded as AAC, because that is what plays everywhere an .mp4 is expected. Speech and music come through fine, but unlike the picture it is not bit-for-bit identical. Every finished file is re-opened and checked before it is handed to you, and what it actually contains is listed with the result.
Converters that upload your file are doing the same trivial job on a server, after making you send several hundred megabytes to reach it.
When it cannot just copy
If a track uses something an MP4 cannot hold, it has to be re-encoded, and that does cost quality and time. This tool works out which case you are in and tells you before it writes anything, including if something would be dropped. A converter that hands back a video with no sound and calls it done is worse than one that refuses.
What happens to the location tag
An iPhone writes the coordinates of the spot you were standing into the
video file, under com.apple.quicktime.location.ISO6709, alongside
the phone’s model and the moment you pressed record. Most people have no
idea it is in there, and every video they post carries it.
The MP4 this writes does not carry any of it across. A new container is written
from scratch around the compressed picture, and the QuickTime metadata is simply
not copied into it — not the coordinates in the old ©xyz
atom, not the newer Apple keys, not the original recording time. We checked this
rather than assumed it: the automated test builds a file carrying a location in
both formats, runs it through this tool, and then looks for the coordinates twice
— once with a proper parser and once by searching the raw bytes of the
result, because a leak that hides from one can still be found by the other.
Being exact about the limits: the finished file does carry the time you converted it, because the writer stamps one. That says when you used this page, which you already know; it does not say where you were or what recorded it. And this is about metadata, not about the picture — if a street sign is visible in the frame, no tool can help with that.
Common questions
Will this reduce the quality?
Not the picture. The video is copied across already-compressed, so it is identical to the original — and the finished file is checked afterwards to confirm the same video stream came through. The sound is re-encoded as AAC, which is a small quality cost and is stated in the table before you convert rather than buried here.
Is there a file size limit?
No limit is imposed. The practical ceiling is your device’s memory, since the finished file is assembled there. Phones give up sooner than laptops.
Does my video get uploaded?
No. All of the work happens in this page. The site’s privacy page explains how the browser is prevented from sending it anywhere, and you can watch the Network tab to confirm it.
Why did it say it would drop the audio?
Because that browser could not carry that particular audio format into an MP4. It is usually a browser limitation rather than a problem with your file — the same video often converts with sound intact in Safari on an iPhone. You are told before it happens rather than after.
All 39 HermitFile tools
Every one of them runs in your browser. Nothing you open is uploaded, and nothing is stored.