This is for curiosity only; I'm not trying to break copyright.
(I own the disc and there's a much better quality version available on YouTube).
I copy one file from the disc, convert it from .vob to .mp4 format and end up with a file that's less than 15% of the size of the original disc.
What exactly gets lost during this process?
$ find /tmp/Name -type f | wc
13 13 405
$ du -s -m /tmp/Name/*
0 /tmp/Name/AUDIO_TS
1 /tmp/Name/AUTORUN.INF
7 /tmp/Name/IVI
192 /tmp/Name/VIDEO_TS
$ ls -l /tmp/Name/VIDEO_TS/
-r--r--r-- 1 ray ray 16384 Jan 10 2003 VIDEO_TS.BUP
-r--r--r-- 1 ray ray 16384 Jan 10 2003 VIDEO_TS.IFO
-r--r--r-- 1 ray ray 116736 Jan 10 2003 VIDEO_TS.VOB
-r--r--r-- 1 ray ray 20480 Jan 10 2003 VTS_01_0.BUP
-r--r--r-- 1 ray ray 20480 Jan 10 2003 VTS_01_0.IFO
-r--r--r-- 1 ray ray 75776 Jan 10 2003 VTS_01_0.VOB
-r--r--r-- 1 ray ray 200710144 Jan 10 2003 VTS_01_1.VOB
$ ffmpeg -i /tmp/Name/VTS_01_1.VOB /tmp/Name/Name.mp4
$ ls -l /data/Music/Download/Hurt.mp4
-rw-rw-r-- 1 ray ray 28439944 Feb 15 15:38 /tmp/Name/Name.mp4
So:
- start with: 13 files, 198 Mb
- select: 1 file, 192 Mb
- convert: 1 file, 28 Mb
What was lost in the other 12 files?
What was lost in the 85% reduction during the conversion?
The video is 720p at 29.97 fps, and I don't see any significant difference between the two versions on a 4K monitor.