3- In EXIF, how to make sure we are compliant with the specification when adding some tag? For example, we are not considerinb what are mandatory (or optional) IFDs for tags.
4- Add GST_TYPE_FRACTION support for GStreamer TAGS
5- currently, in JPEG files, if there is a Photoshop segment, everything inside it but IPTC will be lost. From the point of view of implementation it is easy, but I still don't now how to solve from the point of view of "designing". Anyway I think it is not so important.
6- language is not considered in XMP (How to do it with GStreamer?)