[FFmpeg-trac] #6558(avformat:new): libavformat discards chapters in mp3 files

[FFmpeg]

#6558: libavformat discards chapters in mp3 files
----------------------------------+---------------------------------------
             Reporter:  danimo    |                     Type:  defect
               Status:  new       |                 Priority:  normal
            Component:  avformat  |                  Version:  unspecified
             Keywords:            |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
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 Summary of the bug:
 How to reproduce:
 {{{
 % ffprobe -input http://chaosradio.ccc.de/archive/reproducer/1.mp3
 ffmpeg version 3.3.0
 (reproducable up until master)
 }}}

 Previous ffmpeg versions would display chapter marks (ffprobe) or be able
 to transfer/export them (ffmpeg). Since ffmpeg 3.3.0, this is no longer
 possible.

 I have run a git bisect with the reproducer line above, and ended up
 finding that 65862f57ad2f7f49d715f334a9d892e0b20d42f1 is the culprit.

 "avformat: Ignore ID3v2 tags if other tags are present e.g. vorbis"

 It switches from ff_id3v2_read to ff_id3v2_read_dict. Following the
 description of the functions, this would be the reason why the chapter
 marks went missing:

 {{{
 ff_id3v2_read_dict: Read an ID3v2 tag into specified dictionary and
 retrieve supported extra metadata.
 ff_id3v2_read: Read an ID3v2 tag, including supported extra metadata and
 chapters.
 }}}

 However, I am sure how to proceed from here. Either the chapters really
 discarded, or do they end up in id3v2_extra_meta, being improperly handled
 there.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/6558>
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