On Sun, Dec 18, 2022 at 7:18 PM Bill Cunningham <bill.cu1234(a)gmail.com> wrote:
Too answer many people's questions here, as to what I want to
accomplish; is there some way to make these huge 7 GB ISOs smaller?
Converting to an mp4 would be the simple answer, but not a simple task
as I am finding.
Assuming you have a DVD that is not encrypted.....
- mount the DVD
- in the VIDEO_TS folder there will be several files names
VTS_xx_y.VOB, where "xx" and "y" are numbers
- cat all of the VTS_xx_*.VOB files together with something like "cat
VTS_01_*.VOB > title_01.mpg". cat does not care if the files are text
or binary - it just concatenates them together.
- use the video player of your choice to play the *.mpg files and
determine which you wish to keep (I like many others prefer vlc).
- you can also use dvdbackup to extract the title set(s) if you don't
want to deal with the file structure yourself
- if you wish to convert the *.mpg file to mp4, you can use any of
several tools. ffmpeg is one that many people favor. The command
would be something like "ffmpeg -i title_01.mpg title_01.mp4" - note
that you might need to add other options to get a higher compression
rate (with corresponding loss of quality) to significantly reduce the
file size. google "ffmpeg convert DVD to mp4" and you should find
several "cheat sheets".
- alternatively you can use one of the OSS linear video editors to do
the conversion; i.e. if you use KDE you can install kdenlive, import
the *.mpg file, and have it do the conversion.
- note that pretty much all of the tools that can do the conversion
will have a certain amount of "learning curve".
Re: DVD structure - there is an AUDIO_TS directory that has to be
present for the structure to be compliant, but unless the DVD provides
DVD-Audio (basically a super-CD), it will be empty. All of the video
(and associated audio tracks) will be in the VIDEO_TS directory.
The files in the VIDEO_TS directory are broken into "title sets" -
each file is named *_xx_y.*, where "xx" is the title set number.
Each title set will have *.IFO, *.VOB, and *.BUP files. The IFO files
contain information such as chapter times, menu items, etc. *.BUP
files are backup files - I think they protect against disc damage to
the sectors in the corresponding *.IFO files. The VOBs are the actual
"video objects" - i.e. the mpg encoded video. Each VOB is split into
multiple files such that no file is larger than 2GB.
That is my non-expert understanding of DVD structure. I'm sure if I
got anything horribly wrong someone else will correct me. You can
probably also find this info via googling.