Hi,
It seems as if php has problems with reading EXIF data in certain JPG files. This is seemingly a known issue, but caused me headaches until i determined the root cause. This is just a heads-up to others who may have image sorting issues.
It started when the EXIF sorting in Piwigo seemingly went wonky. And I couldn't figure out why. Long story short, I have configured Piwigo to use DateTimeOriginal as primary Image sort key, but Piwigo is unable to extract that information from certain images. In my particular case the problem was related to a Huawei smartphone. Samsung, Sony and others worked well. So in Albums where several manufacturers were involved, the sorting was completely illogical - until I discovered the reason why.
I have submitted a ticket to the php team here:
https://bugs.php.net/bug.php?id=75785
The simple resolution is to use the EXIF DateTime instead of DateTimeOriginal. However it causes other implications if pictures are post-processed, since I really want to sort the photos when they were taken - not when they were processed.
Until the php issue is resolved, DateTime it is.
Piwigo version: 2.9
PHP version: 7.2.11
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As far as I can tell, there are at least three date fields in EXIF. "Date/Time Original" and "Create Date" are the capture date for digital cameras, and are untouched by software (Lightroom in my case). Software updates the "Modify Date" field.
Another option would be to map one of the IPTC recorded dates.
https://piwigo.org/doc/doku.php?id=user … n:metadata
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