History. I keep losing my place on books with random touches, and I dislike the process of finding it again through sampling. Spoilers! The history feature fixes that.

And the built in equalizer. And the speed shifting. And the file management. It's just a great app.

Thanks. Also how do you get books onto your phone for Smart Audiobook Player in the first place?

I used to use Syncthing with a custom .stignore to exclude all but the books I want to listen to offline.

Samba.

Does SAP integrate with samba or do you have to download files manually?

You get history in the ABP android app.

One thing LLM's could do for me is a "recap" feature. I sometimes completely forget listening to books when I'm halfway through. So I'm either having to Google for synopsis per chapter or just start over. Mostly i just pick something else to listen. If it could recap up until where I'm at that'd be pretty neat.

Honestly, for me it's kinda minimal, simple and ergonomic UI is the point. It has some more sophisticated features, but they don't distract me, nor I actually need them. For instance:

- bookmarks (I tried to use them, but it's too much work, if I really need to take a note, I better do it in written form)

- UI to write down characters (same: I used it a couple of times, just because it's there, but it's not worth it, use normal note-taking app for note-taking)

- equalizer (I'm sure somebody uses it, but I never truly needed it for audio-books)

And many more.

What actually matters are small details:

- Granular playback speed control. ABS seems to have it done right too, but some players have like 1-1.25-1.5-..., which is not granular enough to get normal conversational talking speed out of somebody way too slow.

- It is possible to enable ID3, but it doesn't force it either.

- It recognizes chapters in whatever I have. m4b, mp3, cue, many files in a single folder, many nested folders, whatever. If it gets things wrong, it is possible to merge books in the library. I guess, the worst case is if I am overzealous with chapters (like marking chapters in a youtube podcastwhich has a mark like every 2 minutes), but then again, it only means "stop at the end of the chapter" becomes not feasible, but otherwise it's fine.

- I guess, every audio-book player does, but still: it does remember positions in multiple books, so I can switch between lectures and fictions and get back to where I stopped.

- It takes into account the current playback speed when estimating how much time is left.

- It is possible to remove buttons you don't need, it's possible to choose an action at the end of the book, it's possible to choose a lot, but defaults are really just fine for me.

- I never used it, but thinking about your question I just found out it has "Skip start/end" functionality. This is just great, I'm excited to try it out ASAP.

Anyway, I probably forget some small details, so you better take a look yourself. It's not perfect, but good enough to study when building something similar. I can also suggest 1 thing that is not in SABP, and, again, it's important to not overload the UI, but I sometimes wished it was there. In SABP it's only possible to either stop after X minutes (with sleep-suggestive volume fade), or at the end of a chapter (without fade). Sometimes I wish I could tell it to stop at the end of a chapter approximately after X minutes (like, if it has a chapter every 7-15 minutes, and you are planning to listen for about 30-40 minutes more, but you don't want it to fade volume an to stop in the middle of a chapter overall). So it's either "approx X minutes" or simply "N more chapters". Neither is possible in SABP.

Also, I don't know it I actually want it, but it seemed nice listening to podcats in NewPipe (SABP doesn't have it). There is an option to skip silence in NewPipe. I didn't actually use it too much, and the last time was a while ago (I pretty much stopped to listen podcasts on it), but I seem to recall it worked nicely.

Thanks!