Remove metadata from a video
A video from a phone knows where it was shot. That lives in a small piece of the
MP4 file called udta — user data. It comes out here, and the footage itself is
untouched.
The udta box
| Tag | Usually holds |
|---|---|
| ©xyz | Latitude and longitude, written by the phone at record time. On Android this is near-universal; on iPhone it appears depending on the app and settings. |
| ©mak / ©mod | Camera make and model. |
| ©swr | The app that recorded or exported it — camera app, editor, or a social platform's export pipeline. |
| ©nam / ©des / ©cmt | Title, description, comment — free text, sometimes filled in automatically. |
| ©day | Creation date. |
Video files also carry a creation timestamp in the container header itself. That one is structural — removing it would require re-encoding, so it stays.
An MP4 keeps an index of where every frame lives
An MP4 is a set of nested boxes, and inside the moov box there is a table
— stco — that records the absolute byte offset of every chunk of video
data.
So if you delete the metadata box and it happens to sit before the video data, everything behind it moves earlier — and the index now points into the wrong place. Some tools will produce a file that opens fine and then plays garbage.
What this tool does: it checks where moov sits relative to
mdat. If removing the metadata would shift the video data, it rewrites the
offset table to match. If it can't find that table, it refuses rather than guessing.
A file that plays correctly is the only acceptable output. A smaller file that might not is not an improvement.
Honest limits
- It does not re-encode. The video and audio streams are copied byte for byte — that is why the output plays identically and the file is only marginally smaller.
- Thumbnail and timecode tracks stay. Some editors embed a frame grab or a burned-in timecode. Those are part of the structure, not the metadata box.
- It cannot undo what a platform already did. If a service re-encoded and logged your upload, the copy on their server still has whatever it has.