Total number of chapters with mediainfo.
mediainfo source/*.opus --Inform="Menu;%Chapters_Pos_End%,%Chapters_Pos_Begin%" | awk -F, '{ $3=" chapters in total\n\n"; print $1-$2 $3}'
96 chapters in total

I won't be using this though as instead just see chapter names and all info instead with
kid3-cli -c "get all" audiobook.opus



  CHAPTER003              01:27:25.022
  CHAPTER003NAME          849 Word Wars & Captive Thoughts, Part 1
  CHAPTER004              02:11:25.688
  CHAPTER004NAME          850 Word Wars & Captive Thoughts, Part 2

kid3-cli -c "get all" *.opus | grep -E "CHAPTER[0-9]+NAME" | wc -l 

Chapter #0:2: start 5245.022000, end 7885.688000
      Metadata:  title           : 849 Word Wars & Captive Thoughts, Part 1
    Chapter #0:3: start 7885.688000, end 10783.869000
      Metadata:    title           : 850 Word Wars & Captive Thoughts, Part 2

ffprobe *.opus 2>&1 | grep -E 'Chapter #' | wc -l

exiftool *.opus | grep -E "Chapter [0-9]+name" | wc -l

total number of chapters with mplayer
player -frames 0 -identify *.opus 2>&1 | grep ID_CHAPTERS

GeekTips

Total number of chapters with mediainfo.
mediainfo source/*.opus --Inform="Menu;%Chapters_Pos_End%,%Chapters_Pos_Begin%" | awk -F, '{ $3=" chapters in total\n\n"; print $1-$2 $3}'
96 chapters in total

I won't be using this though as instead just see chapter names and all info instead with
kid3-cli -c "get all" audiobook.opus



  CHAPTER003              01:27:25.022
  CHAPTER003NAME          849 Word Wars & Captive Thoughts, Part 1
  CHAPTER004              02:11:25.688
  CHAPTER004NAME          850 Word Wars & Captive Thoughts, Part 2

kid3-cli -c "get all" *.opus | grep -E "CHAPTER[0-9]+NAME" | wc -l 

give total number of chapters

ffprobe audiobook.opus works also and has the dimensions of cover image but ultimately not needed as it displays seconds instead of HH:MM:SS timecode. Starts with chapter 0 which is technically correct.

Chapter #0:2: start 5245.022000, end 7885.688000
      Metadata:  title           : 849 Word Wars & Captive Thoughts, Part 1
    Chapter #0:3: start 7885.688000, end 10783.869000
      Metadata:    title           : 850 Word Wars & Captive Thoughts, Part 2

Total number of chapters with ffprobe

ffprobe *.opus 2>&1 | grep -E 'Chapter #' | wc -l

96

total number of chapters with exiftool

exiftool *.opus | grep -E "Chapter [0-9]+name" | wc -l

96

total number of chapters with mplayer
player -frames 0 -identify *.opus 2>&1 | grep ID_CHAPTERS

ID_CHAPTERS=96

hottg.com/geektips/914

68 viewsedited  Sep 12, 2023 at 20:33