ID3 Comment/Description tag?

[SenorSmartyPants]

I'm in the process of using beets-audible to clean up my library and embed metadata. I've hit a snag with mp3s. ABS doesn't seem to pick up the book description that I'm embedding. Here's an ffprobe output, but the description in ABS is empty.

Input #0, mp3, from '00 Dark Matter - Blake Crouch.mp3':
  Metadata:
    title           : 00 Dark Matter
    artist          : Blake Crouch
    track           : 1/17
    album           : Dark Matter
    disc            : 1/1
    date            : 2016-07-26
    genre           : Mystery, Thriller & Suspense/Thriller & Suspense
    compilation     : 0
    TIT3            : A Novel
    comment         : test
    TIPL            : arranger
    TDOR            : 2016-07-26
    album_artist    : Blake Crouch
    composer        : Jon Lindstrom
    ASIN            : B01CUKULGA
    COMM            : CoMM
    publisher       : Random House Audio
    album-sort      : Dark Matter - A Novel
    CATALOGNUMBER   : B01CUKULGA
    MusicBrainz Album Type: audiobook
    XXX             : ***"Are you happy with your life?"***
                    :
                    : Those are the last words Jason Dessen hears before the masked abductor knocks him unconscious.
                    :
                    : Before he awakens to find himself strapped to a gurney, surrounded by strangers in hazmat suits.
                    :
                    : Before a man Jason's never met smiles down at him and says, "Welcome back, my friend."
                    :
                    : In this world he's woken up to, Jason's life is not the one he knows. His wife is not his wife. His son was never born. And Jason is not an ordinary college physics professor but a celebrated genius who has achieved something remarkable. Something impossi
                    :
                    : Is it this world or the other that's the dream? And even if the home he remembers is real, how can Jason possibly make it back to the family he loves? The answers lie in a journey more wondrous and horrifying than anything he could've imagined - one that
                    :
                    : From the author of the best-selling Wayward Pines trilogy, *Dark Matter* is a brilliantly plotted tale that is at once sweeping and intimate, mind-bendingly strange and profoundly human - a relentlessly surprising science-fiction thriller about choices, p

XXX is listed as Comment [XXX] in picard. I added the COMM and comment fields manually using picard. Am I using the wrong fields?

M4B embedded descriptions are picked up.

[advplyr]

Currently abs is using the meta tag description or desc. I've never seen the XXX meta tag before. I've considered adding the comment tag as a fallback for description.

[siddhartas]

I have the same problem. I use Mp3tag to edit my audiobooks metadata and my DESCRIPTION (Mp3tag uses upper-case for their tags - does that matter?) tag is not picked up by ABS.
The comment tag would be great as a fallback.

Thank you for ABS - it's great!

[SenorSmartyPants]

According to this https://github.com/seanap/Plex-Audiobook-Guide#tags-that-are-being-set it seems like desc is only supported for M4B, not MP3 files.

[SenorSmartyPants]

I think the XXX represents the language code for the comment. When viewed in Picard it is labeled as Comment [XXX] . Comments support multiple language versions apparently.