IOS - Metadata of images that are not displayed on the PC, visible in the online parser

Question

I am trying to add metadata to a jpeg image, not using the metadata dictionary clause in iOS, but using some kind of tool that adds metadata as a header to the jpeg file.

Some problems: "Make" and "Artist" are not displayed on Mac / Windows if the length of the value is less than 5 characters. The height reference does not appear on Mac. The User Comment field does not appear on the Mac, but appears on Windows.

The problem is that all of these values ​​are displayed if I check the online parser (regex.info/exif.cgi)

The question is, what does iOS expect Exif information to be in a specific format? If so, what is it?

Edit: Even the altitude and longitude values ​​are incorrect. Lat comes as 0 0 '0 ", and longitude is x 0' 0", where x is the value for the clock I set.
If I use the ususal method to save metadata in iOS, I pass the decimal value for lat and long, but in this tool I go through several minutes and seconds separately.

Answer 1

Yes, there is a certain format for storing "Make", "Artist", GPS information and user comments, they must be encoded in ASCII and in HEX tags (from 13B to 10E). Custom comments may be Unicode, however, not many metadata readers support this.

On page 15 of the EXIF ​​2.2 specification , a list of metadata attributes and a description of each attribute follow the table.

As a third-party note, make sure you use the correct EXIF ​​metadata reader, usually products skip reading metadata if they counteract any error reading it (for example, a window viewer)