Hey and Welcome!
most "key" metadata fields (tags) do write to the file by default. This can depend on a few things though - file container (extended tags in a FLAC file might not be able to be written to an mp3 file or a wav file for example); type of field (a calculated field generally can't be written to the file) to name a couple off the top of my head. Make sure that the tags you want written to the file are configured to do so.
Options=>Library&Fields=>Manage Library Fields Make sure that the option Save in file tags when possible is checked. If for some reason a field was unchecked and you check this option you can then run Library Tools=>Update Tags from Library after selecting the tracks in question which will force a re-write to the file containers themselves.
Now it is possible that your AK
47120 (haha, had to look your nice portable player up on google
) only can read ID3v2 tags, but if an iphone can handle what JRiver throws at it I'm sure your's can. However maybe you are converting flacs to mp3s for the player ... might need to remap a field or two, sort of doubt, but depedns on the fields you use and if have have created custom ones.
I'd do a tag dump (either in JRiver or in an external program) to see what has actually been written to the file. It will indicate the tag info and the Field Name it was written to.
(google the forum+tag dump) sorry my train just pulled in if you don't know how)
