MP4 · Lossless · No upload
Remove metadata from MP4
See every hidden field in your MP4 video, then strip it — with the frames copied through untouched.
Where MP4 keeps its metadata
MP4 keeps metadata in udta and meta boxes inside moov, alongside creation and modification timestamps in the movie, track and media headers. Phones add a QuickTime location atom holding GPS coordinates.
How we remove it
Chunk offsets in the stco table point into the mdat box, so shrinking moov would break the file. Instead each metadata box is rewritten as a spec-standard free box of identical size and zeroed, and the header timestamps are set to zero in place. Nothing moves and nothing is re-encoded.
Worth knowing about MP4
- No transcoding means no quality loss and no waiting. Tools built on ffmpeg.wasm re-encode the video, which is slow and visibly degrades it.
- The file is never loaded into memory. Only the moov box is read, so multi-gigabyte videos work fine.
- The cleaned file is the same length as the original. The metadata is gone; its former space is now padding.
Other formats
The same engine handles JPG / JPEG, PNG, WebP, HEIC / HEIF, AVIF, GIF, TIFF and MOV.
Questions
Frequently asked questions
Does removing metadata change my MP4 file's quality?
No. Chunk offsets in the stco table point into the mdat box, so shrinking moov would break the file. Instead each metadata box is rewritten as a spec-standard free box of identical size and zeroed, and the header timestamps are set to zero in place. Nothing moves and nothing is re-encoded. After each removal we re-read the finished file and, where the browser can decode both, compare every pixel against the original to prove nothing changed.
Where is metadata stored inside a MP4 file?
MP4 keeps metadata in udta and meta boxes inside moov, alongside creation and modification timestamps in the movie, track and media headers. Phones add a QuickTime location atom holding GPS coordinates.
Is my MP4 file uploaded?
No. The file is parsed and rewritten by JavaScript on your own device. There is no upload endpoint, so there is also no size cap and no queue.
Can I clean several MP4 files at once?
Yes. Drop as many as you like and download them back as a single ZIP. Files are processed one after another, so memory stays flat no matter how big the batch is.