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

[JD]

On 9/25/19 8:54 AM, Ted Park wrote:
>> 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.
Thank you Ted for this revelation. I had no idea .....