Plappa, an Audibookshelf/Jellyfin/Emby app for iOS
I keep finding new apps, so I'll keep sharing! Tonight's fish on the hook, is an Audiobook client for Jellyfin and AudioBookShelf, written in Swift/SwiftUI.
Apart from playing audiobooks, plappa also syncs playback status via iCloud and allows you to download audiobooks for offline listening. It currently runs on iPhone and iPad, a Mac and Apple TV version are planned - roadmap.
plappa should be able to handle all common audio file formats, but is built for and tested mainly with MP3 and M4B files.
I always test plappa using the most common organization scheme for books, but other folder structures should work fine, plappa just searches for audio files recoursively, grouping by album.
Metadata
Most metadata will be taken from Jellyfin/AudioBookShelf, plappa additionally reads the composer field for the narrator name and (if applicable) chapters from the file metadata.
Roadmap
You can see the full roadmap in the plappa project, the short version is:
There's not much that combines these two apps together like this, but there are separate alternatives. Nova Player for hosted media (I use Plex on my Raspberry Pi), Antennapod is one of many many podcast forks (most open source podcast apps use the same layout).
For listening to android localized audio books, I absolutely love Voice. Voice does have chapters built in as long as your audio books have them. You can pick up Voice and Nova Player for free on F-Droid if you want to try them out. Plex and Pi are a little more involved.
I should look into Jellyfin myself. I really need to introduce myself to containers. It's something I should familiarize myself with as a Linux user, but I just barely got done learning the basics of WINE prefixes.