Im trying to parse JPEG EXIF data on my own.
How should I handle with tags that share the same tag ID (like tag ID 0001 that can be for GPSLatitudeRef and for InteropIndex)?
for now just found only GPS tags that share same ID with other tags.
also, how should I recognize which IFD im parsing (aka IFD0 / IFD1 etc..), I saw also that I have some tags that tagged as IFD on Phil's table, which also appears in IFD1 and associated with the thumbnail image.
any help?
Not my area of knowledge, but I believe location in the structure matters. For example, using the command in FAQ #3 (https://exiftool.org/faq.html#Q3), you will see that InteropIndex appears in the InteropIFD section, which, in the jpg I was looking at, is a sub-directory of the ExifIFD.
The exiftool source code is open, so you might look over the Exif.pm (https://github.com/exiftool/exiftool/blob/master/lib/Image/ExifTool/Exif.pm) code. And you can look over the EXIF standard (link (http://url=https://web.archive.org/web/20190624045241if_/http://www.cipa.jp:80/std/documents/e/DC-008-Translation-2019-E.pdf) to 2.32 via archive.org) (link (https://www.cipa.jp/e/std/std-sec.html) to 3.00 via cipa.jp).