[Easytag-mailing] Problems with empty tag fields in ogg files

[Thorsten Gunkel <tgunkel_lists gmx de>]

Easytag seems to dislike tagfields in ogg files that are mentioned in
the header but have no value. This is a problem for me because oggenc
creates such entries if you have something like oggenc --album "$album"
and "$album" is an empty string. I don't know if easytag needs to be
fixed to be able to deal with such entries or if oggenc shouldn't add
entries with no value (or if I have to check that I only use oggenc
options I have values for).

This is how I can trigger problems:
1. Create 3 wave files
2. oggenc -q 5 --output="$ofilename"
     --tracknum "$trcknr" 
     --title "$title" 
     --album "$album" 
     --artist "$artist" 
     "$ifilename"
   With "$ofilename" is the destination, "$ifilename" the source and
   everything else but "$title" is empty.
3. ogginfo on one of the files
,----[$ogginfo a.ogg]
| filename=a.ogg
| 
| serial=1850893416
| header_integrity=pass
| title=a
| artist=
| album=
| tracknumber=
| vendor=Xiphophorus libVorbis I 20011231
| version=0
| channels=2
| rate=44100
| bitrate_upper=none
| bitrate_nominal=160032
| bitrate_lower=none
| stream_integrity=pass
| bitrate_average=169908
| length=10.953651
| playtime=0:10
| stream_truncated=false
| 
| total_length=10.953651
| total_playtime=0:10
`----
4. run easytag
- Enter something in the artist field. Switch to another file and back
  to the changed one: The field is blank.
- Reenter something and apply the value to all files: None has been
  changed.
- Reenter something and save the file: Change is not saved.
- Change the title and save the file: All empty fields are removed and
  from now on all changes seem to work.
,----[ $ogginfo a.ogg ]
| ogginfo a.ogg
| filename=a.ogg
| 
| serial=1850893416
| header_integrity=pass
| title=aa
| tracknumber=00
| vendor=Xiphophorus libVorbis I 20011231
| version=0
| channels=2
| rate=44100
| bitrate_upper=none
| bitrate_nominal=160032
| bitrate_lower=none
| stream_integrity=pass
| bitrate_average=169895
| length=10.953651
| playtime=0:10
| stream_truncated=false
| 
| total_length=10.953651
| total_playtime=0:10
`----

regards
 Thorsten
-- 
There's a door
Where does it go?
It stays where it is, I think.
(Terry Pratchett, Eric)