Reborn Audiobooks (plan, Beta 8.19+)

Owner request (2026-10-21): audiobooks as a full feature, a Home entry that can be switched on and off, chapters, remembering where the listener stopped, built on Reborn's FFmpeg layer. Y2Player had the feature; it was assessed, not copied.

Owner decisions

• What is a book: a folder named Audiobooks / Hörbücher (any case, anywhere in the path;

  Y2Player's AUDIOBOOKS rule), every .m4b, and files tagged genre Audiobook / Hörbuch.

• Playback speed 0.75–2.0×, per book, in this feature (Y2Linux FFmpeg gains atempo).
• Sleep timer (15/30/45/60 min, end of chapter, fade-out) in this feature; it works for music too.
• Home entry shown automatically once the library holds a book; switched off and on in

  Customize > Home Menu.

What Y2Player had (assessment)

Kept: path identity (book = folder, Disc/CD/Part N folders fold into it, author folders stay), natural chapter order (disc, folder, track only if every file has one, filename), one progress row per book, saves on start/pause/change/tick, nothing saved in the first 10 s or last 5 s of a file, 5 s rewind on resume, books kept out of every music view, Book Options (Chapters, Start from Beginning, Clear Progress), books always in order.

Fixed here: embedded chapters were never read (an M4B was one long item); Next on the last chapter deleted the progress; starting a book turned shuffle and repeat off globally for good; renaming a folder lost the progress; search named books "CD1"; the rewind applied only from the book list; no finished state, no speed, no book-level time left, no settings.

Constraints found in Reborn

• AVFormatContext->chapters is never read; FFmpeg's mov (QuickTime chapter track, Nero chpl),

  mp3 (ID3 CHAP) and ogg (CHAPTERxx) demuxers produce them.

• No atempo in the device FFmpeg; speed touches RbDspConfig (352-byte layout asserts), the

  position maths (playback.rs position, UI extrapolation, crossfade windows, scrobble time).

• Every seek, resume and output change runs a full load() (sink reopen, open + probe).
• Open budget 32 MiB and av_max_alloc(32 MiB): a single-file M4B over roughly 9 h of AAC-LC may

  not open (the mov sample index is one allocation). Non-attached video streams are refused.

• One global position_ms; full Tracks go into the 8 MiB session — chapters stay out of Track.
• Settings root holds 9 rows, the Music page 5; components::time has no hours.

Phase 0 results (2026-10-21, host FFmpeg 9.0.2 = device version)

Fixtures made with the host ffmpeg (sine audio, ffmetadata chapters), run through Reborn's media layer (crates/reborn-media/examples/book_probe.rs: inspect, open, read, seek to 90 %):

Cost of the 10.5-h book with the larger cap: peak RSS 186 MB vs 49 MB for a short book (open 49 ms, seek to 90 % in 1 ms). The player has ≈822 MB available; Reborn's RSS is ≈33 MB.

Phases

1. Risks with real files: fixtures for an M4B with chapters, a >10 h M4B, an M4B with an image

   track, an MP3 folder book, an MP3 with CHAP; scan + open within the budgets; chapters seen.

2. Library: book identity computed from path/extension/genre (no schema or revision bump);

   grouping and order; author from album artist/artist; rb_media_chapters + a chapter cache table keyed by file identity; books removed from Songs/Albums/Artists/Genres/Folders, Cover Flow, counts, Recently added, Shuffle, Last.fm.

3. Progress: additive book_progress table (book key, file, position, chapter, finished,

   updated); found again by file name + size after a rename; saved every 15 s, on pause, chapter change, switching away and shutdown; rewind 5 s (pause < 10 min), 15 s (< 1 day), 30 s (longer); finished instead of deleted.

4. Playback rules: no shuffle/repeat/crossfade for books (music settings untouched); Next/Previous

   = chapter (Previous restarts after 5 s); last chapter never deletes; held seek steps 10 s → 30 s → 60 s; in-file seek without reopening; AVRCP title = chapter, album = book.

5. Menus: Home > Audiobooks (continue first, cover, author, "Chapter 3 of 12 · 45 %",

   Finished), book page (Resume, Start Over, Chapters, Mark as Finished, total/left), Now Playing for books (chapter title and progress, book time left, h:mm:ss), hold menu Chapters / Speed / Sleep.

6. Speed: atempo in Y2Linux FFmpeg and its verify lists, RbDspConfig.speed, scaled times.
7. Sleep timer.
8. Finish: tests, previews, skins, docs, device test with real books, beta.

Status (2026-10-21)

Phases 0–6 are implemented on main (11febec library, faa87fc progress and playback, 56f79ac menus, 6aeec66 speed, b2951f5 sleep timer, f61c7c3 skins); Y2Linux 01d8882 builds FFmpeg with atempo. Code map:

• reborn_core::books: detection (is_book), grouping and order (books, order, natural),

  chapters (ChapterMark, Span, spans), the playing book (Listening: chapter at, next, previous, progress), the shelf (Shelf, Progress, rewind_ms), speeds (SPEEDS, next_speed).

• AppModel.book (session), LibraryState.shelf / .chapters (kept out of action rollback),

  AppModel.sleep_timer (memory only); effects PlayBook, SetBookFinished, ForgetBook, LoadChapters, SetAudiobooksOnHome, SetBookSpeed, SetSleepTimer.

• App: app/reborn/src/books.rs (shelf file state/books.json, chapter reader thread, start,

  chapter steps, finish, rewind), sleep_timer.rs; hooks in main.rs (checkpoint saves the place, queue replacement saves first, Next/Previous, track end, crossfade 0 and speed in load(), book seek steps, rewind in toggle()); playback.rs scales played frames by the job's tempo.

• UI: views_books.rs (list rows, book page, BookNow for Now Playing and skins), Home entry,

  Home Menu toggle, hold menus, search results, components::time with hours.

• Media: rb_media_chapters, admit_streams, av_max_alloc 128 MiB, RbDspConfig.speed

  (360 bytes) with atempo after aformat, heavy_mp4 scan serialisation.

Host evidence: workspace tests (608), clippy, previews b1–b6 in Reborn's look and two skins, GLES comparison 165/165.

Device test (2026-10-21, owner's player, builds 117 and 118 = 1.0.0-beta.8.19, seq 8301/8302)

Test books in Internal Storage/Audiobooks/Reborn Test Books/ (the Phase 0 fixtures: 3-min M4B with 4 chapters, the same as MP3 with ID3 CHAP, an M4B with a cover video track and Nero chapters, a 10.5-h M4B, a 6-file Frank Test/The Folder Book/CD 1|2 book). Buttons by evdev injection, screens by y2-screen-stream.

• Scan: all 10 files, the 10.5-h book with its length; Home shows Audiobooks; the list shows all

  five books with author and length, in progress first, finished last.

• A book's page reads the M4B's chapters in the background (0:45 / 1:05 / 0:40 …).
• Chapter 3 plays from 1:50; Next → chapter 4 (150 s); Previous early → 110 s; Previous after 6 s

  restarts the chapter; Next in the last chapter keeps the place.

• Speed 1.5×: the chain carries atempo=1.50, the position moved 6.4 s in 4 s; kept per book.
• A book played to its end is Finished and starts over; its speed is kept.
• 10.5-h M4B: plays; Reborn RSS 92 MB (peak 155 MB at open), 741 MB still available; a seek to

  9 h 27 min (rebornctl seek) took 2.8 s including a full reopen.

• Sleep timer End of Chapter paused at the next chapter's start; Now Playing said "Sleeps after

  chapter".

• Resume after a Reborn restart: build 117 skipped the rewind (the shutdown checkpoint refreshed

  the last-listened time); fixed in da5b777, build 118 continued 5 s before the pause.

• The cover-track M4B plays.

Not testable by injection: held seek (the button driver reports the key released ~18 ms after an injected press). Not done: in-file seek without a reopen (a chapter jump in a very long single file costs ≈2–3 s); heard by ear: speed quality, the sleep fade.