Extracting GPS data from MP4 video file

[Manfred Prechtl]

I have a Redtiger F7N dashcam and I have got the folloing output from

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exiftool.exe -ee -gps* [MP4-File]

GPS Date/Time                  : 0022:12:23 10:30:17Z
GPS Latitude                    : 13726 deg 17' 9.95" N
GPS Longitude                  : 10626 deg 11' 58.35" E
GPS Speed                      : 0.104
GPS Track                      : 180
GPS Date/Time                  : 0022:12:23 10:30:18Z
GPS Latitude                    : 13726 deg 17' 9.95" N
GPS Longitude                  : 10626 deg 11' 58.35" E
GPS Speed                      : 0.159
GPS Track                      : 180
GPS Date/Time                  : 0022:12:23 10:30:19Z
GPS Latitude                    : 15203 deg 46' 23.57" N
GPS Longitude                  : 10626 deg 11' 58.35" E
GPS Speed                      : 0.423
GPS Track                      : 180
and so on.

From exiftool.exe -v3 [MP4-File] I got the warning

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"Warning = GPSLatitude/Longitude encryption is not yet known, so these will be wrong"
OK, they are really wrong.

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Type='gps ', Sample 1 of 60 (16384 bytes)
  2e110c: 00 00 40 00 66 72 65 65 47 50 53 20 f0 01 00 00 [..@.freeGPS ....]
  2e111c: 59 4f 55 51 49 4e 47 47 50 53 00 00 20 07 5f 01 [YOUQINGGPS.. ._.]
  2e112c: 00 00 00 00 00 00 00 00 a8 e7 99 45 24 10 97 44 [...........E$..D]
  2e113c: 0a 00 00 00 1e 00 00 00 11 00 00 00 16 00 00 00 [................]
  2e114c: 0c 00 00 00 17 00 00 00 41 4e 45 00 00 00 00 00 [........ANE.....]
    [snip 16304 bytes]
Warning = GPSLatitude/Longitude encryption is not yet known, so these will be wrong
GPSDateTime = 0022:12:23 10:30:17Z
GPSLatitude = 13726.286096
GPSLongitude = 10626.199541
GPSSpeed = 0.104000002145767
GPSTrack = 180
Type='gps ', Sample 2 of 60 (16384 bytes)
  5d8224: 00 00 40 00 66 72 65 65 47 50 53 20 f0 01 00 00 [..@.freeGPS ....]
  5d8234: 59 4f 55 51 49 4e 47 47 50 53 00 00 20 07 5f 01 [YOUQINGGPS.. ._.]
  5d8244: 00 00 00 00 00 00 00 00 a8 e7 99 45 24 10 97 44 [...........E$..D]
  5d8254: 0a 00 00 00 1e 00 00 00 12 00 00 00 16 00 00 00 [................]
  5d8264: 0c 00 00 00 17 00 00 00 41 4e 45 00 00 00 00 00 [........ANE.....]
    [snip 16304 bytes]
GPSDateTime = 0022:12:23 10:30:18Z
GPSLatitude = 13726.286096
GPSLongitude = 10626.199541
GPSSpeed = 0.158999994397163
GPSTrack = 180
Can you help me to got the real values.
Must be somthing like: N:49.4160..  E:12.1417..

Thank you,
Manfred

[StarGeek]

As the warning says, the encryption isn't known, so there's no way to get correct values.

There are a lot of cameras that are obfuscating there data like this for no practical except they want you to only use their software.  Nothing can be done until either someone figures out the encoding or someone talks some sense into the camera's manufacturer. 

[Manfred Prechtl]

Thank you, for your quick resonse.

Is is possible with exiftool, to get only the complete gps chuncks buffers (16384 bytes) out of the mp4 files ?
Maybe I can try to interpret it by my own.

Thank you
Manfred

[StarGeek]

No.  The best exiftool can offer would be to use -v5 (-verbose5) option which will give a hex dump of each of the blocks.
exiftool -G1 -a -s -ee3 -v5 file.mp4

Note that this will result in a lot of output.  My test on a short file gave nearly 232,000 lines of output.