Video Meta Data: DJI Drones, (Sun, Jun 16th)

[ixsky]

Video Meta Data: DJI Drones, (Sun, Jun 16th)

Many years ago, I wrote about the EXIF data in pictures taken with Smartphones. Smartphones often record extensive meta data including GPS and accelerometer data.

So I wondered how much similar data can be found in footage collected with a drone. As an example, I am using a DJI Mini Pro 4 drone. This is a very common and popular drone, and I just happened to have footage available.

The drone has the ability to record video as well as still photos. For the still photos, typically saves in JPG format, the data looks a bit like what you expect from a smartphone. It includes camera parameters, date, time, and GPS coordinates (oddly, the height was VERY wrong in my sample if I used the "exists" tools, but inspecting it with a homemade tool, it looks better. Likely just an encoding issue)

Here is the complete EXIF data from a sample image


   
      
         Tag
         Value
      
   
   
      
         exiftags
         invalid field offset (Make)
      
      
         exiftags
         maker note not supported
      
      
         Camera-Specific Properties
          
      
      
         Camera Model
         FC8482
      
      
         Camera Software
         10.08.04.08
      
      
         Maximum Lens Aperture
         f/1.7
      
      
         Focal Length (35mm Equiv)
         24 mm
      
      
         Image-Specific Properties
          
      
      
         Image Orientation
         Top, Left-Hand
      
      
         Horizontal Resolution
         72 dpi
      
      
         Vertical Resolution
         72 dpi
      
      
         Image Created
         2024:03:20 11:43:03
      
      
         Exposure Time
         1/2500 sec
      
      
         F-Number
         f/1.7
      
      
         Exposure Program
         Normal Program
      
      
         ISO Speed Rating
         100
      
      
         Lens Aperture
         f/1.7
      
      
         Exposure Bias
         0 EV
      
      
         Subject Distance
         0.00 m
      
      
         Metering Mode
         Average
      
      
         Light Source
         Daylight
      
      
         Flash
         No Flash
      
      
         Focal Length
         6.72 mm
      
      
         Color Space Information
         sRGB
      
      
         Image Width
         4032
      
      
         Image Height
         2268
      
      
         Rendering
         Normal
      
      
         Exposure Mode
         Auto
      
      
         White Balance
         Auto
      
      
         Scene Capture Type
         Standard
      
      
         Gain Control
         None
      
      
         Contrast
         Normal
      
      
         Saturation
         Normal
      
      
         Sharpness
         Normal
      
      
         Latitude
         N [redacted]
      
      
         Longitude
         W [redcated]
      
      
         Altitude
         4294927.26 m 
      
      
         GPS Status
         Measurement In Progress
      
      
         Geodetic Survey Data
         WGS-84
      
   


The coordinates are the coordinates of the drone, not the coordinates of the operator. The serial number of the drone is not displayed. Note that the serial number uses an "Unknown" exif tag and is only displayed with the -u option in exiftags

"Unkown Tags"


   
      
         Attribute
         Value
      
   
   
      
         Title
         default
      
      
         GPS Info IFD Pointer
         746
      
      
         Unknown
         972
      
      
         Unknown
         1100
      
      
         Unknown
         2
      
      
         Manufacturer Notes
         890
      
      
         Supported FlashPix Version
         808464688
      
      
         Interoperability IFD Pointer
         860
      
      
         Device Settings
         0
      
      
         Unknown
         6TVQL[redacted serial number]
      
      
         Unknown
         24
      
      
         Unknown
         DJI FC8482
      
      
         Unknown
         R98
      
      
         Unknown
         808464688
      
   


Some of the "Unknown" data may be sensitive, but I have not redacted it so far. Let me know if I should

The video data is a bit more complex. DJI saves 3 different files:


   MP4 File: This is the main, full resolution video file
   LRF File: Lower resolution video file
   SRT File: A file with GPS coordinates in "Subtitle" format (more below)


Users sharing a file are most likely going to share the MP4 file. Like the JPEG, some metadata is embedded in the MP4 data stream. It is less verbose than the JPEG data, but it does include the drone's serial number. I did not find GPS data in the MP4 metadata. Just information about the camera and firmware.



The SRT file contains some basic GPS data for each "time slice". In this format, it can easily be overlayed to the video file.


00:00:00,033 --> 00:00:00,066
<font size="28">FrameCnt: 2, DiffTime: 33ms
2024-03-20 12:59:17.852
[iso: 400] [shutter: 1/320.0] [fnum: 1.7] [ev: 2.0] [color_md: default] [focal_len: 36.30] [latitude: 30.xxxxxx] [longitude: -81.xxxxxx] [rel_alt: 6.500 abs_\
alt: -32.309] [ct: 5695] </font>


Again, only the drone's GPS data is saved, not the operator's location. It has been well documented that DJI includes the operator (or better controller) location in the datastream sent to the drone, in part to comply with regulations in some locales [1]. An image file doesn't necessarily give it away.

[1] https://www.wired.com/story/dji-droneid-operator-location-hacker-tool/

 

 

---
Johannes B. Ullrich, Ph.D. , Dean of Research, SANS.edu
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 (c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.

Source: Video Meta Data: DJI Drones, (Sun, Jun 16th)