Change the date of a video
Set a new recording date on an MP4 or MOV, or move a whole shoot by a few hours when the camera clock was wrong — without re-encoding a single frame.
Drop videos to change their recording date
The date is rewritten in the file header. Nothing is re-encoded and nothing is uploaded.
A video keeps its date in two places
The first is structural: the movie and track headers each store a creation and modification time as a count of seconds since 1904. This is what file browsers, editing software and media servers sort by.
The second is a text tag. QuickTime files carry a ©day field, and iPhone footage adds com.apple.quicktime.creationdate, which uniquely records the time zone the camera was standing in. Apple software reads that one in preference to the header.
Change one and not the other and the file starts contradicting itself, sorted under the new date in a folder but still labelled with the old one in Photos. Both are rewritten here, and where a text tag cannot hold the new value in the space it occupies, it is cleared rather than left to disagree.
Why the file size never moves
The header contains a table of byte positions pointing into the picture data. Make the header one byte longer and every one of those positions is wrong, which is why so many tools re-encode: it is the easy way to sidestep the problem, at the cost of minutes of processing and a generation of quality.
Nothing here changes length. Each value is written over the bytes the old one occupied, so the offsets stay valid and the footage is copied through as-is. To confirm the result, the tool re-reads the date out of the file it just wrote — and you can check it independently in the video metadata viewer.
When you want the date gone instead
Correcting a date and erasing one are different jobs. If you are publishing footage anonymously, the date should not be edited but removed — along with the location and the device name. Remove video metadata clears all of it in one pass, equally losslessly. The same choice exists for stills, where changing a photo date edits the EXIF timestamp instead.
Frequently asked questions
How do I change the date of a video?
Drop one or more MP4 or MOV files above, pick a new date and time, and apply. The date is rewritten inside the file header and each cleaned copy is offered for download. Nothing is uploaded and the footage is never re-encoded.
My camera clock was wrong by a few hours. Do I have to fix each file?
No — that is what the shift mode is for. Every video keeps its own date and moves by the same number of hours, so the order of a shoot is preserved. It is the right fix for a camera left on the wrong time zone, or one that never had daylight saving applied.
Will the video be re-encoded?
No. Only the header is rewritten, and it is rewritten to exactly the same length, so the picture data is carried through untouched. The output is the same size as the input and every frame is byte-for-byte identical.
Why did the date not change in Apple Photos?
Because a video can carry its date in two separate places: the binary movie header that most software sorts by, and a text tag that Apple software prefers. This tool writes both. A file edited with something that only touches the header will keep showing its old date in Photos.
Can I set a date on a video that has none?
Yes, in the set mode — every loaded file is given the exact date you pick. Shift mode is different: it can only move a date that already exists, so files without one are listed as skipped rather than invented.
Which formats are supported?
MP4, MOV, M4V and 3GP make up the ISO Base Media family that phones, drones, action cameras and dashcams record in. MKV, WebM and AVI store their headers differently and are not supported.