Does editing MP4 metadata re-encode the video?
No. For MP4, MOV, M4V and 3GP only the metadata boxes are rewritten; the media data is copied byte for byte. That is also why it takes seconds even for a file of several gigabytes.
Free · runs in your browser
MP4 metadata editor for tags, dates and artwork
Change the atoms and QuickTime keys inside an MP4, MOV or M4V file and save a copy in moments, with the video and audio left exactly as they were.
An MP4 metadata editor changes the tags an MP4 file carries, such as its title (stored in an atom called ©nam), recording date, GPS location (©xyz), comment, artist and cover art, without touching the compressed video. Here you open the file, edit the fields under Edit & clean and press Download new file; only the metadata boxes are rewritten, so even a large file saves almost at once.
MP4 is a family rather than one format. MOV from iPhones and Apple software, M4V from iTunes-style libraries and 3GP from older phones all share the same box structure, and this editor treats them the same way. It shows the raw atom names in Report if you want them, and plain labels everywhere else.
Everything happens in your browser: no upload, no account, no watermark. For the general picture across formats, see the video metadata editor; this page is about what is special to MP4 and MOV.
How to edit MP4 metadata
Open the MP4 or MOV file
Press Open a file (Ctrl/Cmd+O) or drop it on the page. On a phone, pick it from your photo library or Files.
See the current tags
Overview summarises the file; Report has the full MP4/MOV box tree if you want to see each atom and key as stored.
Edit the fields
Open Edit & clean and change Title, Description, Comment, Artist, Copyright, Keywords, Genre, Recorded or Location. Cover art takes Use current frame or Choose image.
Download and check
Press Download new file (Ctrl/Cmd+S), then open What changed to see each field that was removed, changed or added in the new copy.
Atoms, keys and headers: where MP4 metadata lives
An MP4 file is a tree of boxes (Apple calls them atoms). The video and audio sit in one large box called mdat; everything that describes them sits in moov. Within moov, descriptive metadata turns up in three places, and different software writes to different ones:
- Movie and track headers (
mvhd,tkhd,mdhd) hold creation and modification times, counted in seconds from 1 January 1904. Every MP4 has these. - iTunes-style atoms in
udta›meta›ilst, with four-character names such as©namand©day. Music and video tagging software uses these, and so does Windows. - QuickTime keys in
meta›keys, with reverse-domain names such ascom.apple.quicktime.creationdate. iPhones and Apple apps write these, including the location and the camera model.
| Label here | iTunes-style atom | QuickTime key (com.apple.quicktime.…) | ExifTool tag name |
|---|---|---|---|
| Title | ©nam | title | Title |
| Description | desc (long form ldes) | description | Description |
| Comment | ©cmt | comment | Comment |
| Artist | ©ART | artist | Artist |
| Copyright | cprt | copyright | Copyright |
| Keywords | keyw | keywords | Keyword(s) |
| Genre | ©gen | genre | Genre |
| Recorded | ©day | creationdate | ContentCreateDate, CreationDate |
| Location | ©xyz | location.ISO6709 | GPSCoordinates |
| Make, Model, Software | – | make, model, software | Make, Model, Software |
| Cover art | covr | artwork | CoverArt |
Locations are written as an ISO 6709 string such as +51.4779-000.0015+046.000/: latitude, longitude and optionally altitude, each with its sign. The location page shows how to read one, and the diagram below breaks it down.
Where MP4 tags show up (and why Windows sometimes shows nothing)
Windows File Explorer
Properties › Details lists a handful of MP4 tags: Title, Subtitle, Comments, Contributing artists, Year, Genre and a few more. Tagging communities report that Explorer reads the iTunes-style atoms and ignores many others, including Apple’s QuickTime keys. That is why an iPhone MOV with a camera model, a location and a precise date can look nearly empty in Explorer: the data is there, just in keys Explorer does not display. Our Windows guide covers this in more detail.
Mac
Finder’s Get Info lists technical facts such as dimensions, codecs and duration. QuickTime Player’s movie inspector adds a little more format detail. Neither is a tag editor, which is why people searching for an “mp4 metadata viewer mac” end up with a separate app; this page works in Safari instead.
Players and libraries
- VLC shows title, artist, genre, copyright, description and more in its media information window.
- Plex can use embedded MP4, M4V and MOV titles in some library setups, according to its forums, but normally names items from online data and the file name.
- Apple’s apps read the QuickTime keys: the date, location and camera model in Photos come from them.
- Web players and social apps ignore tags. YouTube, Instagram and TikTok take titles and descriptions from what you type when you post.
MP4, MOV, M4V and 3GP compared
| Format | Usually comes from | Metadata notes |
|---|---|---|
| MP4 | Android phones, cameras, editors, screen recorders | iTunes-style atoms are common; Android adds location as ©xyz |
| MOV | iPhones, Macs, many pro cameras | QuickTime keys for date, location and device; sometimes timed metadata tracks |
| M4V | Apple TV and iTunes-style libraries, HandBrake | The same as MP4; often has cover art and TV fields |
| 3GP | Older phones | Same box structure; often a 3GPP loci location box |
Because all four share one structure, edits work the same way on each. The editor writes your changes in the form that kind of file already uses, and the output keeps the original extension.
There are no fields here for TV show, season and episode (tvsh, tvsn, tves) or album. If you tag a home media library that way, use a dedicated tagger or ExifTool. Most media servers match episodes by file name anyway.
Editing MP4 tags on the command line
For batches, two tools cover almost everything this page does:
exiftool -ItemList:Title="Sea swim" -ItemList:Genre="Holiday" -overwrite_original swim.mp4
ffmpeg -i swim.mp4 -map 0 -c copy -metadata title="Sea swim" -movflags use_metadata_tags tagged.mp4
ExifTool edits in place. FFmpeg builds a new file around the copied streams; -movflags use_metadata_tags makes it keep custom keys it would otherwise leave out. Either way, compare the result in the inspector before you replace the original, and see the ffprobe guide for checking tags from the command line.
MP4 metadata: common questions
What is ©nam in an MP4 file?
It is the iTunes-style atom that stores the title. The © sign is part of the four-character name. Other atoms follow the same pattern: ©day for the date, ©cmt for the comment, ©xyz for the location.
Why is the Details tab empty for my MP4 in Windows?
Explorer shows only some tags, and files from iPhones and many cameras keep their information in QuickTime keys that it does not display. Open the file here to see everything, or add a Title and Comment, which Explorer does show.
Can I add cover art to an MP4?
Yes. Under Cover art, use Use current frame or Choose image. The MP4 thumbnail guide explains where the artwork appears.
Can I edit metadata on a video from my iPhone?
Yes. iPhone videos are MOV (or MP4 when exported), and every field here applies. Editing does not need your browser to play HEVC or Dolby Vision, because the frames are never decoded.
Will the file size change?
Only by the size of the metadata you add or remove, usually a few kilobytes. Adding cover art adds roughly the size of the image.
Can I change the Year field?
The year comes from the recording date. Set Recorded to the right date and time; changing a video’s date covers the details, including time zones.