ExifTool Forum

Hello there,

I am not too sure if this is the right section for my question so if it's not, please let me know and I will be happy to move my post.

For the past a few days I am trying to get my head around how can I modify DJI MOV/MP4 video footage and photos so they can be "swallowed" by the GoPro app "Quik".
So far I am only happy with my progress on the videos, my tiny script can convert, map streams add Geo-data as well as other metadata in a way that "Quik" sees these files as GoPro video file. Unfortunately, I am not getting along with modifying DJI photos to meet the same requirements. I have been trying all sorts of methods to either create, copy GoPro/App6 Tag to my file and then update them to reflect an actual camera setting or even been thinking if it's possible to copy raw photo over to the file with GPMF Tags and then modify all other writable tags to meet minimum requirements for "Quik". All my attempts with using https://exiftool.org/sample_images.html (https://exiftool.org/sample_images.html) sample images, different tools also failed however more and more frequently I have been seeing that this Tag group is not writable (like here https://exiftool.org/TagNames/GoPro.html (https://exiftool.org/TagNames/GoPro.html)) which really made me puzzled as without deeper knowledge I am struggling to understand how that is even possible... I've found a lot of practical examples how to extract meta-data from i.e photo galleries but read-only tags remain as a mystery to me :) Eventually, I've found this project https://github.com/gopro/gpmf-write (https://github.com/gopro/gpmf-write), I compiled source code and hit another wall as it's not as trivial to use as I was hoping. That is actually the reason why I thought about asking question here as its quite possible that I am still missing something in the entire process which does not allow to achieve even with the tool what I am looking to do. Could you please enlighten me and maybe point me in the right direction? I must admit meta-data was well underestimated by me until now...

Hi Tom,

From this table (https://exiftool.org/#JPEG), you can see that ExifTool doesn't have the ability to edit APP6 GoPro information, so it can't help you in this regard.

But the ExifTool -htmldump feature may be a useful tool for if you are trying to understand the structure of a JPEG file and want to see how all of the various metadata written by the GoPro is stored.

- Phil

Quote from: azgooon on September 14, 2020, 06:02:50 PMI have been seeing that this Tag group is not writable (like here https://exiftool.org/TagNames/GoPro.html (https://exiftool.org/TagNames/GoPro.html)) which really made me puzzled as without deeper knowledge I am struggling to understand how that is even possible

There's a big difference between reading metadata and writing it in a way that is still compatible.  It takes time to write code and make sure that it won't accidentally destroy the image/video/etc.  There also has to be demand for the feature.  There are a lot of tags where there isn't much demand for the ability to write them or that are handled better by software specific to that filetype.  For example, there are hundreds fo apps to deal with the metadata for mp3s and other sound files.

Additionally, camera makers are not really known for sticking to their own standards.  For example, this thread (https://exiftool.org/forum/index.php?topic=11627.msg62455#msg62455) from a couple days ago where Garmin changed the way they wrote their video files.  And gps tracks in videos are another example.  So far exiftool can decode some 40(?)+ different ways that gps tracks can be embedded in video files.  And that doesn't even take into account proprietary encoding of some data.

Thank you both for your responses.

Now I get that it is not an unwritable tag but currently writing it's not supported. I mean even in my case it's not something I can't live without but more thought that having all media within "easy to use" software like Quik may help me edit them in time effective way (it can be done even on the phone so more opportunities during the day).

I've used -htmldump and even managed to insert APP6 segment through HexEditor into the new file so after that exiftool read and displayed new GoPro tags however then image itself didn't load and GIMP just thrown an error that there is additional content before the image offset and then I thought that for the sake of having a few DJI photos within the GoPro Quik its just not worth the time spent.

Either way at least I know a bit more about the meta-datas then before my attempt :)