Write back updated info in both, XMP file and JPG

[Cobblestone-TLT]

Hello! I use XMP sidecar files for all my JPG files, and I need that xmp-info in both of theem was identical after saving (writing back).
I tryed any different combinations of settings in "Metadata 2" section of Preferences, tryed to configure JPG file format there and changed "Use XMP sidecar file" option, but when I write back, updated information (keywords) was saved in JPG file, OR in XMP, but NOT in both.

As I wrote earlier in another topic, in addition to iMatch, for tagging (keywording) files I use different application on my smartphone which can writeback keywords in XMP files. That another application is set to read meta info only from XMP and it's not allowed to writeback info in original image (JPG file). So on smartphone I create/edit/update XMP files only, then I syncrhonizing them with my photo DB on PC, and I need to get info from updated/new XMP files and write it back in JPG. If I update meta info of files in iMatch, I need that information was written in image file (JPG) and in XMP file, to synchronize with smartphone again. If I can do so, I'll get my main photo archive on PC with actual info in JPG files, and possibility to easy and fast sync my photo tags with smartphone and back without moving entire massive archive of JPG files there and back... (and sync JPG manually if image changed, but not only meta info).

So how in iMatch write back meta info in both, sidecar file and source?)

Thanks!

[Mario]

Looking at the XMP specification and supported by the rules and recommendations of the Metadata Working Group, JPEG files (and TIFF, PNG, PSD, DNG,...) always use embedded XMP data. And optionally embedded EXIF, legacy IPTC and GPS metadata.
Using external XMP files for file formats for which the standard requires embedded metadata is not recommended and may cause issues with other applications, now or in the future.

If you copy an XMP file from your smart phone to a folder containing JPEG files, this XMP file "belongs" to all files with the same file name.

But now you have two XMP records for each of your files, which is always bad.
Because, who can tell which bit of data from which XMP record is more current?

Maybe the external XMP record is incomplete, having less data than the XMP record embedded in the image. Or it has contradictory data for some tags...?

For example, does your smartphone app look at the embedded metadata in the JPEG and then writes the sidecar file from the data found in the JPEG, updating the required digests (checksums) and adding whatever data it has to add? As required by the XMP standard and the Metadata Working Group.

Does your smart phone synchronize existing EXIF/GPS/IPTC data from the JPEG file into the XMP sidecar file it creates?

Or does it perhaps just write "some" XMP data in the sidecar file?

Support for reading/writing files on smart phones is severely limited. And when I recall correctly, XMP support is blotchy and greatly depends on the the version of Android/iOS in use.

You can force IMatch to "favor" the data in the XMP sidecar file over the XMP data embedded in the XMP via Edit > Preferences > Metadata 2: File Formats. But that can have sever impacts, may cause data loss etc. Not recommended.

See https://www.photools.com/help/imatch/#rmh_config_metadata2.htm?dl=h-9 for more information.

[Cobblestone-TLT]

I already tryed any possible combinations of settings in "Metadata 2:File formats" section in Preferences. When "Favor" or "Force" option for XMP sidecar file is selected iMatch writeback meta info only in sidecar file, when "Default" - writeback only in source JPG file, I can't now remember fourth option, but it's also let iMatch writeback only in one of them,  XMP sidecar OR source. I just ask is there an option to write back current info from iMatch database to sidecar file AND in source file at the same time?

[Mario]

IMatch always writes one XMP record. Not two.
There is no option to make it write XMP into the JPEG as well as into an external sidecar file. Something like that is never needed. Except perhaps for your very peculiar workflow.
Consider using ExifTool to extract the XMP data from the JPEG into a separate sidecar file if you really have to.

Again, the default and recommended storage location for XMP is embedded in the JPEG. Maybe you should use another app on your smart phone, which can update XMP in JPEG files and does not force you to use such a cumbersome workflow.

[Cobblestone-TLT]

Ok! I understand that, thanks!