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

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09-09-2018 07:27 PM
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CodyBenkelman
Esri Regular Contributor
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For FMV in ArcGIS (ArcGIS Pro 2.2 or later 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.  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.

Running the Video Multiplexer is straightforward if you have the required metadata in the proper format, so that is the key challenge. 

Esri has an app available at http://esriurl.com/SSEE that can be used to plan and control drone flights.  This app for iPad is free for users with an ArcGIS Online or Enterprise account, and it will automatically record the metadata required for the Video Multiplexer on any video flight (manual or autonomous).  Drones supported by this app are listed at https://esriurl.com/SiteScanSupportedDrones.    

For users that require Android, Esri business partner CompassDrone has built an application called CIRRUAS that will capture video metadata required for FMV support.  CIRRUAS is available at https://compassdrone.com/cirruas/.

Note that the required metadata must be captured at the time of the drone flight.  If you have videos that were previously captured without using this app, it may be possible to extract the required metadata, but there are limitations and our experience has shown that it is challenging.  Further discussion is included below.

DJI drones write a binary formatted metadata file with extension *.dat or *.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.   That ASCII file could then be manually edited for compatibility with ArcGIS Pro as described below.  If you decide to pursue this editing and reformatting, please see this blog for additional advice: http://esriurl.com/MultiplexerTipsTricks.


Key points:

  • Esri has not tested and cannot endorse the free DatCon 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 the DJI 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 and *.srt files were created for the purpose of troubleshooting; they were NOT designed 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 incomplete and/or inaccurate results, unless you apply manual effort to identify the temporal gaps and fill in your own estimated or interpolated values for the missing times and missing fields.
  • This blog was first 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.

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

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