Rip chapters of a DVD to separate files

To extract the .VOB for Title 2, Chapter 3

Note that '-chapter 3' and '-chapter 3-' will copy from chapter 3 to the end, and if the chapter number you specify is invalid, the option is ignored, and will therefore copy the full title.

# physical DVD
  mplayer dvd://2 -chapter 3-3 -dumpstream -dumpfile ~/3.VOB

# DVD .iso image  
  mplayer dvd://2 -dvd-device "$dvd_iso" -chapter 3-3 -dumpstream -dumpfile ~/3.VOB  

---

You can use lsdvd to list title, chapter, cell, audio, video, etc for a physical DVD.   However, it doesn't seem(?) to have a way to process a .iso.   You could mount a .iso, if need be.

# count Titles, and count Cells per title. 
# eg. ${cell[1]}      is the Count of Cells for the first title
#     ${cell[titles]} is the Count of Cells for the last title

eval $(lsdvd | sed -n 's/Title: \([0-9]\+\), .* Chapters: \([0-9]\+\), Cells: .*/cells[$((10#\1))]=$((10#\2));/p')
titles=${#cells[@]}

title_num=2
from_cell=1
to_cell=${cell[title_num]}

---

dvdxchap, on the other hand, can process a .iso, but it doesn't list title info.   You can, however, specify the title from which you want chapter info.

  title_num=2
  from_cell=1
# physical DVD
  to_cell="$(dvdxchap -t $title_num  /dev/dvd | sed -n 's/^CHAPTER\([0-9]\+\).*/\1/p' | sed -n '$p')"
# DVD .iso image  
  to_cell="$(dvdxchap -t $title_num "$dvd_iso"| sed -n 's/^CHAPTER\([0-9]\+\).*/\1/p' | sed -n '$p')"   

---

When you know the title number you want, and know the number of cells, you can dump them in a loop:

# physical DVD
  for ((c=$from_cell; c<$to_cell; c++)) ;do
    mplayer dvd://$title_num -chapter $c-$c -dumpstream -dumpfile ~/$c.VOB
  done

# DVD .iso image  
  for ((c=$from_cell; c<$to_cell; c++)) ;do
    mplayer dvd://$title_num -dvd-device "$dvd_iso" -chapter $c-$c -dumpstream -dumpfile ~/$c.VOB
  done