Having issues with aliasTags and CUSTOM tags

[simoncn]

Your writeAlltags setting should have created a file named "true" in the MinimServer/appData folder on your Synology NAS.

Using a hex editor to look at tags requires detailed knowledege of the tag metadata file format. For the COMM frame in ID3v2.3, you can find this information in this section.

From this, you can see that the XXX you are seeing in Notepad corresponds to the "Language" field. This field is not used when mapping the COMM frame. The COMM frame is mapped to a tag whose name is the string "COMMENT" followed by a space and the "Short content description" field. In your case, the "Short content description" field has the value "SONGS-DB_CUSTOM4", giving a tag name of "COMMENT SONGS-DB_CUSTOM4".

You can add this tag name to indexTags to verify that this tag is present in your MP3 files or you can look at the output of writeAllTags as suggested by Alandbush.

If you prefer to view this tag name as CUSTOM4 for your MP3 files, you can set the aliasTags property to:

COMMENT SONGS-DB_CUSTOM4:CUSTOM4