[Liverpool] Backing up video DVD's

[Stephen Watkin]

The last time I was tasked with backing up a DVD, it turned out the disc 
in question was purposefully corrupted in places to throw off 
straight-forward attempts at duplication. It was quite a while ago, but 
I remember the solution involved downloading some file containing an 
index of all the broken sectors to avoid that was specifically for that 
disc, then feed it to some (windows) program that copied the disc in 
such a way as to avoid those sectors.

As it happens it wasn't even for my own selfish gain that time. It was a 
friend's Barney The Dinosaur DVD that he bought to replace the one his 
kid scratched to bits. He wanted a copy so he could keep the original 
safe. I don't even know if we're even legally allowed to make backups in 
this country.

Ste


On 03/06/11 10:16, Sebastian Arcus wrote:
> Following on from the conversation the other night regarding backing 
> up video dvd's, I went back and did more experiments.
>
> 1. cp and dd will work on dvd's without copy protection.
> 2. dd will work on some copy protected dvd's - if used with "bs=1024" 
> as an option.
> 3. However, both cp and dd will fail (sometimes after about apparently 
> random amounts of data - on some dvd's as much as 298MB) on dvd's with 
> certain copy protection systems. The failure is different from film to 
> film, but the amount of data copied before failure is always the same 
> on different tries for the same disc. In my case only about 25% of dvd 
> discs I tried could be copied with dd or cp.
> 4. vobcopy will manage most copy protection systems - but I still have 
> about 1% of my brand new dvd's which have played just fine on the same 
> computer - but vobcopy hasn't managed to copy. I've seen other reports 
> on the internet that there are several copy protection types which 
> give problems even to vobcopy. Maybe it will be fixed in a future 
> version. The symptom seems to be caused by a trick in the layout, 
> where the drive is stuck in what sounds like repeated seek action on 
> the disc - in a permanent limbo - while copying under vobcopy.
>
> I'm using vobcopy 1.2.0. I'm not sure how would one find out which 
> copy protection system a particular dvd is using. I've seen talk on 
> the Internet about several different types - but nobody mentioned how 
> to find out what is used on a particular disc.
>
> I would be curious if others have found otherwise on their machines or 
> their dvd's
>
> Sebastian
>
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