Update tagging extension documentation

docs/extensions/tagging.md

@@ -2,16 +2,49 @@
 title: Tag downloaded files using Mutagen
 ---
 
-Add episode and podcast titles to MP3/OGG tags
+Add episode and podcast titles to MP3/OGG tags.
+
+By default, this extension will:
+   - Remove existing tags
+   - Write the Title tag, stripping the album from the beginning of the Title if necessary
+   - Write the Album tag
+   - Write the Artist tag (with the same string as the Album tag)
+   - Write the Genre (to "Podcast", configurable)
+   - Write the publish date
+
+Also available are writing the Subtitle tag and the Comments tag (both with the
+subtitle field), but the subtitle is often so long that it may cause problems with
+certain audio players, such as Rockbox players. These are disabled by default.
+
+This extension can optionally embed coverart - note that the coverart will not be
+standardized in any way, so Rockbox users be wary. This is disabled by default.
+
+This extension can optionally remove all tags instead of doing any of the above.
+This is disabled by default.
+
+## Dependencies
+
+This extension requires python module `mutagen`.
 
 | setting                                      | value      | description                                                                               | version           |
 |----------------------------------------------|------------|-------------------------------------------------------------------------------------------|-------------------|
-| extensions.tagging.always\_remove\_tags      | true/false | true = extension removes all tags instead of creating/adding tag information              | 3.5.0             |
-| extensions.tagging.auto\_embed\_coverart     | true/false | true = extension adds existing coverart after download                                    | git master branch |
-| extensions.tagging.genre\_tag                | Genre      | with this setting you can define the genre tag. Default = Podcast                         | all               |
-| extensions.tagging.strip\_album\_from\_title | true/false | true = removes the album name from the episode if the episode begins with the album title | all               |
+| extensions.tagging.strip\_album\_from\_title | **true**/false | Remove the Album tag from the Title tag if the Title begins with the same string as the Album tag | all |
+| extensions.tagging.genre\_tag                | Podcast    | Value for the Genre tag | all |
+| extensions.tagging.always\_remove\_tags      | true/**false** | Remove all tags instead of creating/adding tag information              | 3.5.0 and newer             |
+| extensions.tagging.auto\_embed\_coverart     | true/**false** | Embed channel cover art in file | git master branch |
+| extensions.tagging.set\_artist\_to\_album    | **True**/False | Set the Artist tag to the same as the existing Album tag | git master branch |
+| extensions.tagging.set\_version              | 4              | Sets the id3 version which will be written | git master branch |
+| extensions.tagging.modify\_tags              | **True**/False | Allow tags to be modified rather than simply added. If set to False, remove\_before\_modify has no effect | git master branch |
+| extensions.tagging.remove\_before\_modify    | **True**/False | Delete all existing tags prior to writing new tags | git master branch |
+| extensions.tagging.write\_title              | **True**/False | Write the title field | git master branch |
+| extensions.tagging.write\_album              | **True**/False | Write the album field | git master branch |
+| extensions.tagging.write\_subtitle           | True/**False** | Write the subtitle field | git master branch |
+| extensions.tagging.write\_comments           | True/**False** | Write the comments field (with the subtitle) | git master branch |
+| extensions.tagging.write\_genre              | **True**/False | Write the genre with the genre\_tag setting | git master branch |
+| extensions.tagging.write\_pubdate            | **True**/False | Write the published date | git master branch |
+
+
 
 Links:
 
 -   [Extension Source](https://github.com/gpodder/gpodder/blob/master/share/gpodder/extensions/tagging.py)
--   [Flattr the Extension](https://flattr.com/thing/1203533/gPodder-Tagging-Extension)