Geotag mp4 from gpx?

[Marsu42]

I see that exiftools supports copying a static gps location data from an image file to mp4: https://exiftool.org/forum/index.php?topic=12240

However, if I try to -geotag mp4 from a gpx (which works just fine for image files - thanks!) the output is just "Warning: No writable tags set from file.mp4"

I'm using (latest) exiftool 12.65 on Win64.

The information page https://www.exiftool.org/geotag.html indicates that Keys:GPSCoordinates is not among the supported tags - correct?

If I'm not missing something, I'd like to feature request this. I know video files are a can of works, but you're half way there :-) and it's not a stream tag.

The workaround would probably be to create a .xmp (or dummy image file) with the same datetime, -geotag this, and then manually -tagsfromfile to the mp4 - I didn't try this yet.

[StarGeek]

The xmp sidecar is probably your only option at this point

Phil will have to comment on whether or not to add Keys:GPSCoordinates to the Geotag option, but he is away for a few weeks and will be back mid-September.

[Marsu42]

Phil will have to comment on whether or not to add Keys:GPSCoordinates to the Geotag option

Thanks so far - it's not urgent, my .mp4 or .gpx aren't going anywhere - so I'll wait for an answer if Keys:GPSCoordinates might be added to -geotag or I'll have to use the .xmp workaround.

[StarGeek]

Actually, have you tried writing to a mp4? I haven't tested it, but it should write to the XMP:GPSLatitude and XMP:GPSLongitude tags.  From there, it would be an easy copy in to the Keys:GPSCoordinates tag.
exiftool "-Keys:GPSCoordinates<$XMP:GPSLatitude, $XMP:GPSLongitude" /path/to/files/

You would have to use the -Geotime tag to make sure the correct time is used.  Either
exiftool -GeoTag file.gpx "-Geotime<${CreateDate}+00:00" file.mp4
or
exiftool -api QuickTimeUTC -GeoTag file.gpx "-Geotime<CreateDate" file.mp4

The CreateDate in a video is supposed to be already set to UTC, which is what the GPS track should be set to.  Using +00:00 prevents exiftool from using the local time zone on the file and the -api QuickTimeUTC option tells exiftool to convert the CreateDate to local time, which is then converted back to UTC to match the GPS track.

[Phil Harvey]

Right now I would rather not get into the issue of automatically writing GPSCoordinates.  You mention Keys:GPSCoordinates, but about half of my sample files use UserData:GPSCoordinates where it may be written 2 different ways.  Also, Google Photos writes this in the ItemList metadata.  There seems to be no standardization in video metadata.

I think the best solution for now is the write XMP, then run a second command to copy this to Keys:GPSCoordinates for each file.

- Phil

[Phil Harvey]

ExifTool 12.68 will have the ability to write GPSCoordinates directly with the -geotag feature.  A command would be:

exiftool "-geotag=file.gpx" "-quicktime:geotime<createdate" FILE.mp4

The key here is to specify QuickTime:Geotime as an indication that the QuickTime GPSCoordinates should be written.  By default, this writes ItemList:GPSCoordinates, but you may specify keys:geotime, userdata:geotime or itemlist:geotime instead of quicktime:geotime in the command to write GPSCoordinates wherever you like.

- Phil

[xmnboy]

exiftool "-geotag=file.gpx" "-quicktime:geotime<createdate" FILE.mp4

Google Photos won't read the GPS tags in a video file (MP4) if they exceed five decimal digits. So I modified my geotag log file (GPX) so that the GPS data points in it contain no more than five decimal digits. I used the command-line above to set the truncated GPS tags into the video files. Unfortunately, I didn't think about the interpolation arithmetic resulting in data points with more than five decimal digits.

Is there a way to tell Exiftool to truncate GPS values to five decimal digits after performing the interpolation arithmetic on the geotag data?

Here's an example of what I am seeing:

======== PX9_2643.MP4
[QuickTime:ItemList] GPSCoordinates             : 35.00918 135.674765813333 148.120352016449
[Composite]     GPSAltitude                     : 148.120352016449
[Composite]     GPSAltitudeRef                  : 0
[Composite]     GPSLatitude                     : 35.00918
[Composite]     GPSLongitude                    : 135.674765813333
[Composite]     GPSPosition                     : 35.00918 135.674765813333
======== PX9_2647.MP4
[QuickTime:ItemList] GPSCoordinates             : 35.00918 135.67475 149.363360835592
[Composite]     GPSAltitude                     : 149.363360835592
[Composite]     GPSAltitudeRef                  : 0
[Composite]     GPSLatitude                     : 35.00918
[Composite]     GPSLongitude                    : 135.67475
[Composite]     GPSPosition                     : 35.00918 135.67475
======== PX9_2661.MP4
[QuickTime:ItemList] GPSCoordinates             : 35.0089697133334 135.67483 150.468739340623
[Composite]     GPSAltitude                     : 150.468739340623
[Composite]     GPSAltitudeRef                  : 0
[Composite]     GPSLatitude                     : 35.0089697133334
[Composite]     GPSLongitude                    : 135.67483
[Composite]     GPSPosition                     : 35.0089697133334 135.67483
======== PX9_2668.MP4
[QuickTime:ItemList] GPSCoordinates             : 35.00911 135.674765271667 149.082772843997
[Composite]     GPSAltitude                     : 149.082772843997
[Composite]     GPSAltitudeRef                  : 0
[Composite]     GPSLatitude                     : 35.00911
[Composite]     GPSLongitude                    : 135.674765271667
[Composite]     GPSPosition                     : 35.00911 135.674765271667

[Phil Harvey]

I'm surprised that Google hasn't fixed this after 3 years.  A solution is to do a 2nd pass on the file to reduce the resolution.  See this post for a command to do this.

Someone should report this to Google to see if they can fix the problem.

- Phil

[xmnboy]

Thank you for the reply and solution reference, Phil. I'll post my net results when I get things working correctly, in case it helps others.

[xmnboy]

Ultimately, this is what worked for me to truncate the digits after the decimal point in the geo latitude and longitude values. After geotagging the MP4 files using exiftool and a GPS log file (gpx or kml) on Linux:

Code Select Expand

exiftool -c \"%.5f\" -ext MP4 -TagsFromFile %d%f.%e -quicktime:all %d%f.%e -progress *.mp4
What I ended up with is modeled after this cheat-sheet:

https://github.com/jonkeren/Exiftool-Commands?tab=readme-ov-file#exiftool-write-all-incl-gps-location-tags-from-mp4-files-to-corresponding-xmp-files

Thank you, Phil, for Exiftool.

[xmnboy]

An update regarding using a geo log (gpx file) and Google's weird restrictions regarding the geo numbers (no more than four digits to the right of the decimal point). When applying a log file to videos I am also seeing elevation as one of the geotags getting written into the MP4 by the -geotag operation. The lat/long numbers are shortened by the -c formatting option, but the format option does not truncate the GPSAltitude number.

I suspect the GPSAltitude number may also be subject to the rule, but I can't figure out how to test my theory. I removed the elevation numbers from the gpx log file and that removed them from the written -geotag and narrowed down the possibilities. Google either does not like the altitude number or it wants the number to be truncated, like the lat and long numbers.

Is there a way to force write the altitude value in order to test this theory? I couldn't figure out how to do it.

[wywh]

I tested Google Photos today and the max decimals it reads in Keys:GPSCoordinates is 5 decimals for GPS and 4 decimals for Altitude in .mp4, .m4v and .mov. So Google Photos does not read location after this:

Code Select Expand

exiftool -m -P -overwrite_original -Keys:GPSCoordinates='-36.123456789, -66.123456789, 119.1234' movie.mp4

exiftool -a -G1 -s -n -Keys:GPSCoordinates movie.mp4                                                     
[Keys]          GPSCoordinates                  : -36.123456789 -66.123456789 119.1234
But after truncating GPS to 5 decimals it does read GPS:

Code Select Expand

exiftool -m -P -overwrite_original -ext mp4 -ext m4v -ext mov -c '%.5f' -TagsFromFile @ -Keys:GPSCoordinates movie.mp4

exiftool -a -G1 -s -n -Keys:GPSCoordinates movie.mp4                                                                 
[Keys]          GPSCoordinates                  : -36.12346 -66.12346 119.1234
But this does not work because there are 5 decimals in the Altitude. Why doesn't that command truncate also the altitude to 4 decimals? Or is it possible to truncate GPS to 5 decimals and Altitude to 4 decimals (my DJI P3P movies altitude has only 1 decimal so currently I do not need to do that).

Code Select Expand

exiftool -a -G1 -s -n -Keys:GPSCoordinates movie.mp4                                               
[Keys]          GPSCoordinates                  : -36.12345 -66.12345 119.12345

exiftool -m -P -overwrite_original -ext mp4 -ext m4v -ext mov -c '%.4f' -TagsFromFile @ -Keys:GPSCoordinates movie.mp4

exiftool -a -G1 -s -n -Keys:GPSCoordinates movie.mp4                                                                 
[Keys]          GPSCoordinates                  : -36.1234 -66.1235 119.12345
...It is a pain to copy GPS from Google Maps (ctrl-click a location and copy the coordinates) because there are up to 15 decimals that must then be truncated for movies.

- Matti

[Phil Harvey]

The -c option handles latitude/longitude coordinates, not elevation.  Here is an example of how you could limit them all to 5 decimals:

Code Select Expand

> exiftool a.mov -gpscoordinates#="-36.123456789 -66.123456789 119.123456789"
    1 image files updated
> exiftool a.mov -gpscoordinates#
GPS Coordinates                 : -36.123456789 -66.123456789 119.123456789
> exiftool a.mov '-gpscoordinates#<${gpscoordinates#;my @a=map {sprintf("%.5f",$_)} split " ";$_="@a"}'
    1 image files updated
> exiftool a.mov -gpscoordinates#
GPS Coordinates                 : -36.12346 -66.12346 119.12346
The above quoting is for Mac/Linux.  In Windows CMD the command would look like this:

exiftool a.mov "-gpscoordinates#<${gpscoordinates#;my @a=map {sprintf('%.5f',$_)} split ' ';$_=qq(@a)}"

- Phil

[wywh]

Thanks, this fixes those pesky decimals for Google Photos (none of my apps read ItemList:GPSCoordinates so I explicitly write to Keys):

Code Select Expand

exiftool -m -P -overwrite_original '-Keys:GPSCoordinates#<${GPSCoordinates#;my @a=map {sprintf("%.4f",$_)} split " ";$_="@a"}' .
p.s. I have considered switching from Google Photos to immich which looks promising.

- Matti

[StarGeek]

p.s. I have considered switching from Google Photos to immich which looks promising.

There has been a lot of good buzz about immich. The team behind it appears to have been very responsive.  If I ever figure out how to safely expose my Raspberry Pi to the net (still haven't figured out authentication and fail2ban), I'll be looking into it using a docker.