I've used mp3tag to tag 1000+ .wav files. I've added a unique comment for each individual file through use of a .txt. All of this was done in one go, in the very same manner. In mp3tag, all this data seems to be added correctly and shows up. When I open the tagged files in Wavelab, only half of the files show to have metadata. What could be the cause of this?
If MP3tag shows them as they should be then the tags have been filled the way you wanted.
MP3tag has no database in the background but shows only the data that can currently be found in the files. This may be different to your application.
So find out how that application updates its data.
Also, it could be that your application has some kind of length restriction for some fields ... Anyway: I think it is a problem of the target application.
Thanks for the quick help. I'll go and ask there.