[Enhancement]: Allow Explicit and Abridged be set from the audio file meta tags

Type of Enhancement

Server Backend; Audio file metadata tag parser

Describe the Feature/Enhancement

After checking through what tags ABS parses from the audio files I've noticed that abridged and explicit cannot be set. And I would like to suggest that tags are added to the list it is looking at, and that the parser can set them accordingly.

Explicit: Pretty straightforward as there is a standard M4B tag for this;

• Standard Rating tag (atom: rtng)

Usage: Uses 1 for explicit, 2 for clean, 0 for unrated (for ABS 2 and 0 should map to False for Explicit). (not sure if this is equal to ITUNESADVISORY but otherwise it can be used as alternative)

• Custom freeform tag: EXPLICIT

Usage: This should allow [1 | True | Yes] for explicit content and [0 | False | No] for clean content. If only a single type of value would be used, use 1 and 0 for easy of use and consistency. This more directly maps to the boolean of is_adult_product or isAdult keys from the used APIs.

Abridged: There is no standard tag used but we can find some common freeform tags used;

• Custom freeform tag: ABRIDGED

Usage: This should allow [1 | True | Yes] for abridged and [0 | False | No] for unabridged. If only a single type of value would be used, use 1 and 0 for easy of use and consistency.

• Custom freeform tag: FORMAT

Usage: This should be human readable values Abridged for abridged and Unabridged for unabridged audiobooks. This directly maps to format_type key from api.audible.com or formatType key from api.audnex.us Furthermore FORMAT is show on the Audible website when viewing the audiobook's information.

Why would this be helpful?

Having rating and the format/abridged set in the audiobook metadata that then could be read and used by AudioBookShelf directly without users having to fetch upstream metadata.

Future Implementation (Screenshot)

Audiobookshelf Server Version

2.36.0

Current Implementation (Screenshot)

The details tab when editing an audiobook metadata. I've been writing custom script to properly tag all my audiobooks.