Your videos carry a GPS track
A photo stores one location. An action camera or drone stores a continuous telemetry track: position, altitude, speed and motion sampled many times per second for the entire clip. That is not "where I filmed", it is the route you took, how fast, and where you started and stopped.
Where the data lives
MP4 and MOV files are containers built from nested boxes. Metadata sits in a handful of well-known places:
udta, the user-data box, which is where most per-device tags land.metaboxes carrying key/value pairs, anduuidboxes carrying vendor-specific or standardized payloads such as content credentials.mvhdandtkhdheaders, which hold creation and modification timestamps for the movie and each track.- A dedicated timed metadata track, alongside the video and audio tracks, for cameras that record telemetry.
That last one is the difference between a photo and a video.
What each camera writes
iPhone. A single location fix in udta, stored as com.apple.quicktime.location.ISO6709: latitude, longitude and altitude for where the recording began, plus make, model and the iOS version. One point, but a precise one.
GoPro. A gpmd track containing GPMF telemetry, sampled around eighteen times a second on common models. GPS position, ground speed, altitude, accelerometer and gyroscope. At that rate a ten-minute ride is roughly ten thousand position samples: the full route, drawn.
DJI and other drones. Flight telemetry in the file, and frequently a second leak that survives cleaning the video entirely. Many DJI modes write a companion .SRT subtitle file next to the clip containing per-frame coordinates, altitude and camera settings in plain text. Clean the .MP4, upload the folder, and the sidecar still has the flight path.
Everything encoded on a computer. The x264 and x265 encoders embed an options string in the video stream itself, in an SEI block. It records the encoder version and every setting used, which fingerprints the software and the workflow, not the location.
Why a track is different from a point
A single coordinate on a holiday video is a disclosure. A track is a pattern. It shows the route home, the speed you travelled, the place you paused, and where the clip you trimmed out actually started, because trimming the visible video does not necessarily trim the telemetry that spans it.
Combine that with the capture timestamps in mvhd and you have a movement log with times attached, which is a category of data most people would never post deliberately.
How to check on a Mac
| Method | What you get |
|---|---|
mdls clip.mov | kMDItemLatitude and kMDItemLongitude if a location tag is present, plus codecs and dates. |
| Finder, then Cmd-I | Dimensions, codecs and the "Where from" line for downloads. |
| Look next to the file | A matching .SRT, .LRV or .THM from a drone or action camera. Open the SRT in TextEdit and read the coordinates. |
The sidecar check is the one people skip, and it is the one that most often makes cleaning the video pointless.
Before you upload
Assume the file knows more than the frames show. Strip the container metadata and the telemetry track, look for companion files in the same folder, and remember that trimming and re-exporting in a video editor usually writes fresh metadata of its own rather than removing the old.
File cleaning is coming next to tdy.
tdy is a Mac menu-bar app that already tidies every link you copy. Stripping location, telemetry and device tags out of video before you share it is on the way. One email when it ships, nothing else.
Join the launch list