A trak may hold at most one tref. setQtChapters() appended a second one for
the chap reference instead of joining the atom already present, which happens
whenever the audio track references another track -- a timecode track, as in
camera recordings.
Parsers differ on the result: the lenient keep reading the track, the strict
discard it entirely. A file written this way therefore still reads correctly
in TagLib while presenting as having no audio elsewhere, and anything that
remuxes it from a stricter parser's track list writes an audioless copy back
to disk.
Removal follows the same rule inverted: only the chap box is taken out when
the tref is shared, and the tref itself goes only when chap was its sole
child. It also now looks for the tref that actually contains chap rather than
the first one on the track, so a file already carrying two is repaired rather
than stripped of the wrong reference.
Ryan FrancesconiandGitHub
e37ee8498f