Better handle date/time changes caused by time zone changes including daylight savings

[Peter Berck]

I put the SD card from the camera in my computer. This starts up RPD. Normally it shows the photo’s on the card, and knows which photo’s are new since the last download. I can then proceed to download just the new images from the card to the computer. It now tells me the timeline is corrupt, and I let it generate a new one, as it suggested. This took a while, and when it was ready RPD told all 2400 images on the card were new (in reality, only about 60).

[Damon Lynch (dlynch3)]

What do you think is the precise explanation for why the time recorded in the EXIF metadata for /run/media/pberck/3031-3130/DCIM/100ND750/DSC_0001.JPG differs from file modification time as recorded on the device file system? That is one example of why the Timeline needed to be rebuilt. There might be others.

If the time does not in fact differ, then that is another question.

[Peter Berck (pberck)]

I was thinking about the change to daylight saving time, which happened between the previous time I downloaded pictures, and the time it wanted to rebuild the timeline... but that shouldn't change recorded times in EXIF (but maybe affects how the device time is returned?).

If I look at the image time stamp ("ls -l") on the SD card, it says 'Dec 3 16:53', but the time recorded in the EXIF is '2019:12:03 17:53:57' according to exiv2.

[Damon Lynch (dlynch3)]

I assume the SD card is formatted using the FAT32 file system. Correct? Or is it exFAT?

[Peter Berck (pberck)]

I have no idea, let me check how I can check. It came with the camera and worked (I might have formatted it in camera, but I don't remember).

[Damon Lynch (dlynch3)]

The problem is that file has time the photo was taken as 4:53 PM, and the file system says something else, 5:53 PM.

Unfortunately both the primary EXIF data and the FAT32 file system ignore time zones, which makes it really difficult to track what time a photo was taken when you move across time zones or daylight savings comes & goes, causing problems of the kind you are seeing.