Yes, definitely - I think you may not have read my post completely. Note, I said either as an embedded id3 tag or a .id3 file
The id3 files (not embedded tags) were introduced for those file formats that were not compatible (or supported in LMCE) with embedded id3 tags, such as flac and avi's etc. That is their entire purpose. UpdateMedia looks for these as well, esp on the first scan - if they already exist, then it simply imports the metadata from them rather than creating new ones (in fact it never creates new id3 files for this type of media on the first scan - as there is no metadata in the database already for the new media file, and there is no id3 file, then there is no metadata so it doesn't bother to create an id3 file)
I have a fairly large collection of MP3 files. I went thru the web admin to tag them properly, and things showed up nicely in LinuxMCE. Unfortunately, upon a reinstall, none of the change stuck.
possy - hmm, interesting, I don't think I have ever tried that. The vast majority of my mp3 files have tags already embedded from the original rip. These get imported by UpdateMedia into the database. Upon rebuild, of course, they get reimported again so appear to be persistent. I have only edited a small number of mp3 tags on the LMCE side, so if these reverted I probably wouldn't have noticed.
I have to say though, I have noticed instances where I have edited mp3 tags in LMCE, and the changes did not appear to be reflected in the embedded id3 tags in the mp3 file when viewed in Windows. But I assumed that was more a Windows problem (particularly to do with NTFS "streams")... perhaps not
But there are definitely instances where the mp3 tags have been updated visibly in Windows... so under some circumstances it does work. Perhaps UpdateMedia can only export to an embedded id3 tag if one already exists? Or perhaps only if one doesn't exist? Either way, if UpdateMedia exports correctly to the id3 embedded tag, then your metadata is definitely persistent, as on rebuild it will import again from this. I really don't know how Windows decides whether to use a "stream" or an embedded tag or both (most likely), and how it coordinates any changes to this, but this could be implicated as well. For mp3s I would recommend editing the embedded tag directly using something like mp3tag as this is reliably imported into LMCE
Note - I did read somewhere on the forums recently that UpdateMedia only imports from embedded tags the "first time". Not sure what was meant by that, but on the face of it, this isn't true. I do single and bulk changes to mp3 tags, and can see updatemedia scanning them in on the next pass without having to do a manual scan. I believe updatemedia is just looking for date stamp changes (or possibly md5?) and rescans fully each file that is different.
But for other media like video, id3 files are immediately created as soon as you tag them. These are always scanned back in on rebuild. And there is less uncertainty on the Windows side because NTFS streams do not apply in this case, of course.