[FFmpeg-user] [offtopic] expansion of video content

[Ted Park]

> You must understand that the ISO9660 file system is an *additional*
> abstraction on the DVD. A real DVD video player does not know how to
> read a file system, but rather uses other raw information to access its
> tracks (or whatever you want to call them) correctly. On copy-protected
> (video) disks, the ISO9660 file system is a big fake to fool programs
> which mount the file system. Files may appear much larger than they
> should be, stuff may be hidden, sectors with I/O erros may be included,
> and so on.
> 
> IMO, you need to copy your images with something which operates on the
> raw device, not on the file system.
> 
> Anyone: please correct me if I'm wrong. My experience with DVDs is a
> bit aged. ;-)

I know it is possible to have no iso9660 filesystem on a dvd at all, which might be the reason behind the lack of any info from isoinfo. Also, I agree that working on the raw device is the ideal approach to take, but in theory only. After all, OP ended up where we are now after dd copied 20+ GB’s from /dev/sr0.

DVD is proprietary and licensed in a way that drive manufacturers have to implement scrambling. It’s been broken for a while now, but if you don’t do anything to work around it, the actual block device will lie to you when asked to read from a copy protected disc.