DVD backup

Make sure that SCSI drivers are loaded:

sudo modprobe sg

Open the DVD in VLC or similar to "unlock" the disc encryption, you can then rip the videos from the DVD:

makemkvcon mkv disc:0 all .

Extract the subtitles from the ripped MKV:

mkvextract B1_t00.mkv tracks 2:B1_t00.idx

Convert the image-based subtitles into SRT. Tesseracts OCR engine mode 1 gives better results than 0 but does still require editing.

vobsub2srt --tesseract-oem 1 B1_t00

Fix everything that OCR got wrong in the SRT, %s/|/I/g takes care of a lot, but missing spaces, `!` turned into `l`, etc., are common as well.

Create a new MKV from the rip with the subtitles replaced by the SRT:

# either copy.. ffmpeg -i B1_t00.mkv -i B1_t00.srt -c copy -c:s subrip -map 0:v -map 0:a -map 1 -metadata:s:s:0 language=eng -disposition:s:0 default B1_t00-resub.mkv # ..or reencode as h265 (lower -crf is better, slower -preset is better) ffmpeg -i B1_t00.mkv -i B1_t00.srt -c:v libx265 -crf 20 -preset medium -c:s subrip -map 0:v -map 0:a -map 1 -metadata:s:s:0 language=eng -disposition:s:0 default B1_t00-resub.mkv