[minor] Unrecognized MakerNotes

[glue]

Hello everyone!

Foreword: I'm trying to do something (with my JPEG files from a smartphone) to get ability to work in Lightroom with the GPS date and time that are available via exiftool but not available in Lightroom.

I decided to do the following:

exiftool '-title<DateTimeOriginal' '-DateTimeOriginal<GPSDateTime' "here_s_the_filename.jpg"

(I'm copying DateTimeOriginal to the title because I want to save DateTimeOriginal somewhere before replacing it with GPSDateTime data)

And then exiftool gives me the following warnings:

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Warning: [minor] Unrecognized MakerNotes - %here's_the_file_path%
Warning: [minor] Entries in IFD0 were out of sequence. Fixed. - %here's_the_file_path%

I've read about MakerNotes but didn't fully understand in which cases they are important. In my case, I don't want to touch them at all. All I need is to do the things that I've described above.

So, here's the question: is it possible to say that what I'm doing is safe to the JPEGs from this device?

[Phil Harvey]

Well, the metadata for this file is very poorly written.  But apparently it was written by Microsoft software, so this is to be expected.

ExifTool will fix the out-of-sequence problems and keep the makernote data untouched when updating this file.  The makernote warning is because absolute offsets embedded in the makernotes must be updated if the makernotes are moved, but ExifTool doesn't recognized the format so it has no way to tell if there are any offsets that need updating.  Honestly, I would normally say that the chance of there being any absolute offsets is very low because it is a very stupid design and modern software designers should know better and use relative offsets instead of absolute.  However, this is Microsoft we are talking about, so all bets are off.

If you have any software that displays the proprietary metadata in the maker notes then you can use it to see if it is affected by an ExifTool update.  If you don't have any such software then you won't notice if some of the makernote information is lost anyway.

Note that your file has a trailer of 164 kB of zeros.  This is preserved by ExifTool when writing, but is a complete waste of space.  I recommend adding -trailer:all= to your command to remove this and save some disk space.

- Phil

[glue]

Phil, thanks a lot for the answer!

Unfortunately, I have no idea what MS software can read these maker notes. Maybe to be 100% sure that nothing is damaged it is worth not to change anything? Hm..

But anyway I want to import these files into the Lightroom, for keywording and storing purposes.

According to the things that were said about the maker notes and their probable absolute offset, how do you think, does Lightroom affect maker notes when I save the metadata (using CMD+S)? Of course, Lightroom doesn't show any warnings like Exiftool does. I'm asking because Lightroom doesn't use external .XMP-files for JPEGs, instead of this it rewrites the JPEG file in order to update the metadata in it.

P. S. I know that this forum is not about Lightroom, but I think it could be worth to know the information about this.

[Phil Harvey]

Adobe's usual strategy is to silently delete the makernote information when rewriting a file.  That's one way to be sure the information isn't corrupted:  When in doubt, delete it all!

I can't say for sure if your version of LR does this, but Photoshop certainly does.

Best case is that LR preserves the makernote metadata, but if it does I can almost guarantee it wouldn't properly update any absolute offsets.

- Phil

[Happy Hobo]

Note that your file has a trailer of 164 kB of zeros.  This is preserved by ExifTool when writing, but is a complete waste of space.  I recommend adding -trailer:all= to your command to remove this and save some disk space.

Wouldn't removing the trailer merely change the file size but (usually) still end in the same block of the disk?

[Happy Hobo]

Well, the metadata for this file is very poorly written.  But apparently it was written by Microsoft software, so this is to be expected.

I get the same two messages with files created by Google's Nexus 5 (Android)

[Phil Harvey]

Wouldn't removing the trailer merely change the file size but (usually) still end in the same block of the disk?

This depends entirely on your filesystem.  A block size of 164 kB is pretty big.

I get the same two messages with files created by Google's Nexus 5 (Android)

Can you attach a sample?

- Phil

[Happy Hobo]

I get the same two messages with files created by Google's Nexus 5 (Android)

Can you attach a sample?

I re-processed a whole month's photos, most of them done with the Nexus.  Did not get the "IFD0 were out of sequence" message (probably because earlier runs fixed it.  But lots of the "Unrecognized MakerNotes"  I don't see a way to attach here, so I zipped five files created by the Nexus and uploaded them to https://HappyHobo.net/Nexus.zip; only two of them get that message.  Included the other three for comparison.  Nine other files done that day by the Nexus did not get that message.  That was typical of other days using the Nexus—just a few files of many.

[Phil Harvey]

Google really butchers the metadata.  So many problems.

FAQ 15 discusses makernote warnings.  The last paragraph mentions unrecognized makernotes.

- Phil