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How do we process video from a DJI drone to bring it into FMV for ArcGIS?

Blog Post created by CBenkelman-esristaff Employee on Sep 9, 2018

For FMV in ArcGIS (ArcGIS Pro 2.2 with Image Analyst Extension, or ArcMap 10.x with the FMV add-in) to display videos and link the footprint into the proper location on the map, the video must include georeferencing metadata multiplexed into the video stream.  The metadata must be in MISB (motion industry standards board) format, originally designed for military systems.  Information is here http://www.gwg.nga.mil/misb/index.html, but drone users do not need to study this specification.  For non-MISB datasets, Esri has created a geoprocessing tool called the “Video Multiplexer” that will process a video file with a separate metadata text file to create a MISB-compatible video.  This is described more completely (e.g. format for the metadata about camera location, orientation, field of view, etc.) in the FMV Manual at http://esriurl.com/FMVmanual.

 

For those with DJI drones, the challenge then becomes “where is the required metadata?”.  DJI drones write a binary formatted metadata file with extension *.dat (or possibly *.srt, depending on drone and firmware) for every flight.  There is a free utility called “DatCon” at this link https://datfile.net/DatCon/downloads.html which will reportedly convert the DJI files to ASCII format. 

 

Key points:

  • Esri has not tested and cannot endorse this free utility. If you choose to use it, as with any download from the internet, you should check it for viruses etc.
  • DJI has changed the format of the metadata in this file on multiple occasions, so depending on your drone and date of its firmware, you will find differences in the metadata content. Esri does not have a specification for this metadata at any version, so cannot advise you what to expect to be included in (or missing from) this file.
  • Another key point is that the DJI *.dat file was created for the purpose of troubleshooting. It was not created with the intent of supporting geospatial professionals seeking a complete metadata record for the drone, gimbal, and camera.  As a result, users will typically find temporal gaps in the metadata.  As a result, processing this metadata through the FMV Multiplexer will likely generate inaccurate results, unless you are willing to apply manual effort (requiring trial and error, and substantial time) to identify the temporal gaps and fill in your own estimated or interpolated values for the missing times and missing fields.
  • IMPORTANT: This blog was written in September 2018, and it is very possible that DJI will make firmware changes in the future to change the readability and completeness of their metadata.

 

There is an alternative to this, but it is not an Esri solution.  CompassDrone, an Esri business partner and DJI authorized distributor, has built a flight planning and flight control application called CIRRUAS using the DJI API.  This application has access to the DJI metadata in flight, and (among other features) is explicitly designed to capture complete metadata as defined by Esri for FMV support.  If you are using the CIRRUAS app, a metadata file will be captured and exported from the drone, and this will feed directly into the FMV multiplexer. 

 

The CIRRUAS app is available here https://compassdrone.com/software/dji2fmv-cirruas-app/.  For further discussion, please refer to the blog on this topic written by CompassDrone:  https://compassdrone.com/dat-srt-vs-cirruas/

 

A few final notes:

  • Our testing of the CIRRUAS app has yielded good results, but Esri does not provide technical support for the app.
  • Note that the CIRRUAS app must be used to plan and fly the mission, and this will initiate the recording of complete metadata. It cannot be applied to video that was previously recorded, since the metadata records will not be complete.
  • It is not known if there are other alternatives which provide a solution for processing video from DJI drones for ArcGIS FMV.

 

Check back in this blog for updates as more capabilities are developed.

#EsriFMVDJI

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