Chapters (Audiobooks, Mixes & Long Files)

New in v22.1

BTR AMP can now read the chapters inside a single long audio file — audiobooks, DJ mixes, live sets, concert recordings, single-file album rips — and let you see where you are, browse the full chapter list, and jump straight to any chapter. Chapters are available to everyone; no purchase is required.

Chapters work with any file format, because BTR AMP reads chapter information from three different places (see Where chapters come from below). Nothing needs to be re-scanned or re-imported: chapters are detected automatically the moment a chaptered file starts playing.

What you’ll see

When the current song has chapters, the player adapts across every surface:

Player screen

• The big title shows the current chapter. Instead of the file name, the headline reads the chapter title with its position — for example “The Vanishing (4/12)”. The line beneath still shows the artist and album (for an audiobook, typically the author and book title), so nothing is lost. When a chapter has no title of its own, BTR AMP shows “Chapter 4” style names instead.
• The seek bar covers the current chapter, not the whole file. On an 11-hour audiobook, a full-width drag of a whole-file seek bar would fling you hours away — so while a chaptered file plays, the scrubber is scoped to the current chapter and dragging it moves you precisely within that chapter. To move between chapters, use the chapter list (below).
• Two progress readings at once. Directly under the seek bar sits a thin, read-only second bar. The convention is the same everywhere in the app: the primary bar shows chapter progress, and the thin bar shows overall file progress — your at-a-glance “how far into the book am I” reading. The time labels match: the left label shows your position within the current chapter, the right label shows your position within the whole file (both respect your existing elapsed/remaining time preference).

The chapter list

Open the Queue panel while a chaptered file is playing and it opens directly in a new Chapters view:

• A Queue ⇄ Chapters toggle at the top switches between the chapter list and the regular play queue.
• Each row shows the chapter number, title, and start time (e.g. 4 The Vanishing 1:02:35).
• The current chapter is highlighted with a playing indicator and the list auto-scrolls to follow along as playback advances (pausing politely if you’re scrolling it yourself).
• Tap any chapter to jump straight to it. If playback was paused, tapping a chapter seeks there and starts playing.

When a file has no chapters, the panel is simply the normal play queue — nothing changes.

Mini players

The compact player in the tab bar and the now-playing row at the top of the queue use the same dual-bar convention: primary bar = chapter progress, thin bar = file progress. Wherever you glance, the two bars always mean the same thing.

Previous / Next and your listening position

The transport buttons keep their meaning: Previous and Next always move between files (in the app, on the lock screen, from headphones, and in CarPlay). Chapter jumping happens through the chapter list.

But chaptered files get an important safety behavior: when you skip away from a chaptered file, BTR AMP bookmarks your exact position first, and pressing Previous never restarts a chaptered file from the beginning — it always moves to the previous item in the queue. When you come back to the file later, playback resumes right where you left off. Hours of progress in an audiobook can’t be wiped out by an accidental button press.

Sleep timer: End of Chapter

The sleep timer gains a new End of Chapter mode, shown alongside End of Song and End of Album whenever the current file has chapters. It gently fades playback out at the boundary of the chapter that was playing when you set the timer — perfect for “just one more chapter” listening. If the file ends before that chapter boundary is reached, playback fades out at the end of the file as you’d expect.

Metadata editor protection

Editing the tags of an m4b/m4a/mp4 file requires rewriting the file, and that rewrite cannot currently preserve an embedded chapter track. To make sure you never lose chapters by surprise, BTR AMP now warns you before saving tag edits to a file that contains embedded chapters, with the choice to cancel or save anyway. (Chapters that come from a .cue sidecar file or from the comments tag are not affected by tag edits, so no warning appears for those.)

Where chapters come from

BTR AMP checks three sources, in order, and uses the first one that produces a valid chapter list:

1. A .cue sidecar file (any format)

Place a standard cue sheet next to the audio file, with the same base name:

Live Set 2024.flac
Live Set 2024.cue

Each track entry in the cue sheet becomes a chapter. This is the classic way to keep a single-file album rip, DJ mix, or concert recording intact while still being able to navigate it. The cue sheet must describe that one audio file (a cue sheet spanning multiple files is ignored). Common text encodings (UTF-8, Latin-1, Windows-1252) are all handled.

Because the sidecar is checked first, you can also use it to override bad embedded chapters in a file — just drop a corrected .cue next to it, no re-tagging needed.

2. Embedded chapters (m4b / m4a / mp4)

Files with a QuickTime-style chapter track — the standard used by audiobooks and by tools like ffmpeg, Libation, m4b-tool, and Audiobook Builder — are read directly. This is the canonical audiobook path: any properly authored .m4b just works, including titles and files with hundreds of chapters.

3. A tracklist in the Comments tag (any format)

Unique to BTR AMP: if a file’s Comments tag contains a timestamped tracklist — the kind commonly pasted under DJ mixes and live sets — BTR AMP parses it into chapters. All of these line styles work:

0:00 Intro
03:45 Second Track
1. Opening Theme 0:00
[1:02:03] The Long Middle Part
Encore - 1:45:30

To be accepted as chapters (and never produce bogus chapters from a comment that merely mentions a time), the tracklist must have:

• at least 3 timestamped lines,
• timestamps in increasing order,
• a first timestamp at or near the very start (within the first 5 seconds),
• a last timestamp that falls within the file’s duration.

Blank lines and un-timestamped header lines in between are fine. If the list doesn’t meet the rules, BTR AMP simply shows no chapters — it never guesses.

Since the Comments tag is already in your library database, this source even works for iTunes-library items whose files BTR AMP can’t open directly.

A nicety for downloaded mixes: when chapter titles arrive with their own numbering baked in (“3). Track Title”), BTR AMP strips the redundant numbering — the chapter list already shows the number — while leaving titles that genuinely start with a number (“99 Problems”) untouched.

Adding chapters to your own files

• Audiobooks: most audiobook tools (Libation, m4b-tool, Audiobook Builder, ffmpeg) write standard m4b chapters that BTR AMP reads as-is.
• Album rips / mixes / recordings: write (or download) a .cue sheet and place it next to the file with the same base name.
• Quick and tag-only: paste a timestamped tracklist into the file’s Comments tag — you can do this right in BTR AMP’s metadata editor. Follow the format rules above (start at 0:00, at least 3 lines, ascending times).

Not yet supported (planned for a future release)

Chapters in v22.1 is a complete, polished first version, but some sources and surfaces are deliberately saved for future updates: more chapter sources, more surfaces, and chapter editing.

Related, but separate: splitting a file + cue into individual library tracks. Today a .cue sidecar presents as chapters of one library item. A future feature under consideration would optionally split such rips into real, individually browsable tracks — with audiobook-style files always staying whole. Cue-as-chapters will remain the default for files you don’t want split.

One note on design intent rather than roadmap: the Previous/Next buttons will continue to mean previous/next file everywhere. Chapter navigation lives in the chapter list, which keeps transport behavior predictable across music and audiobooks alike.