[FFmpeg-trac] #8728(undetermined:new): Misplaced chapters for mp3 files (ID3v2 Chapter Frame Addendum)

[FFmpeg]

#8728: Misplaced chapters for mp3 files (ID3v2 Chapter Frame Addendum)
-------------------------------------+-------------------------------------
             Reporter:  sandreas     |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:  chapters,    |               Blocked By:
  mp3, misplaced                     |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 When i use ffmpeg to export ffmetadata of an mp3 file with chapter and
 then reimport the same ffmetadata, the chapters timestamps are different.

 1. download the media file
 https://send.firefox.com/download/efb4d882f95b99bd/#gbNb7ZUVFxrVWDSobvZvYg

 2. create a file ffmeta.txt with the following contents:
 {{{
 ;FFMETADATA1
 title=01 - Preface.

 album=History of a Six Weeks' Tour

 genre=Speech

 artist=Percy Bysshe Shelley

 track=1

 encoder=Lavf58.29.100

 [CHAPTER]
 TIMEBASE=1/1000
 START=0
 END=196437
 title=01 - Preface.
 [CHAPTER]
 TIMEBASE=1/1000
 START=196437
 END=381591
 title=02 - Author's Introduction.
 [CHAPTER]
 TIMEBASE=1/1000
 START=381591
 END=1712027
 title=03 - France.
 [CHAPTER]
 TIMEBASE=1/1000
 START=1712027
 END=2653177
 title=04 - Switzerland.
 [CHAPTER]
 TIMEBASE=1/1000
 START=2653177
 END=3279154
 title=05 - Germany.
 [CHAPTER]
 TIMEBASE=1/1000
 START=3279154
 END=3640978
 title=06 - Holland.
 [CHAPTER]
 TIMEBASE=1/1000
 START=3640978
 END=4214143
 title=07 - Letters Written During a
 [CHAPTER]
 TIMEBASE=1/1000
 START=4214143
 END=4657969
 title=08 - Letters Written During a
 [CHAPTER]
 TIMEBASE=1/1000
 START=4657969
 END=6200600
 title=09 - Letters Written During a
 [CHAPTER]
 TIMEBASE=1/1000
 START=6200600
 END=7782426
 title=10 - Letters Written During a
 [CHAPTER]
 TIMEBASE=1/1000
 START=7782426
 END=8352603
 title=11 - Mont Blanc. Lines Written
 }}}

 3. import the ffmeta.txt chapters by:
 {{{
 'ffmpeg' '-hide_banner' '-i' 'merged.mp3' '-i' 'ffmeta.txt'
 '-map_metadata' '1' 'merged.new.mp3'
 }}}

 4. export a new ffmeta-after-import.txt from the file just imported:
 {{{
 'ffmpeg' '-hide_banner' '-i' 'merged.new.mp3' '-f' 'ffmetadata' 'ffmeta-
 after-import.txt'
 }}}

 5. diff ffmeta.txt and ffmeta-after-import.txt


 Because the chapters did not change between import and export, i would
 expect, that the chapters are at the same time, but the times are
 different. ffmpeg seems to change something here while importing chapters,
 whatever the reason is...

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8728>
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