I want to create a bit-by-bit backup of my DVD and a Blu-ray disc without removing its encryption. Is dd be the best method, and if so, what flags or settings should I use? Also, is comparing the SHA-256 hash of the generated ISO file with the hash of the original disc’s raw data (read from /dev/sr0) the best method for verifying the backup’s integrity?
Blueray have anti-copying built into non-data areas, plus Cinavia DRM on the content most of the time. This means your 1-to-1 copies won’t play.
If you are hoping to make a playable bluray, use one of the tools that reads past both and creates a non-drm image.
Depending on where you live, this likely breaks copywrite, but isn’t illegal.
dd is neither the best nor a suitable method (dd is a scalpel not a shovel, use cp or cat). But optical media are tricky either way, with purposedly placed reading errors and stuff. redumper was made for a disc preservation initiative. Does a good job so far for me, but best to use old SATA drives with it. Those between 2010 and 2015 (pre-DRM-crackdown) also don’t need libredrive.
ddrescue can do a really good job. But for blueray you’ll need a patched firmware.
I would look at the tools that the preservation groups use for doing this. The optical media layouts are funky and IIRC using
ddon the block device is not enough to archive a bit-for-bit copy. There are details about the track layout and so on that need to be recorded separately. This is why formats like BIN/CUE exist.I’d recommend ddrescue over dd for optical media backups only because if you’ve got bad blocks it will try them again at a different speed/angle
Does
ddrescuestill check every sector even if there are no bad blocks? I’m worried it might just copy sectors without verifying, which could mean the backup isn’t a perfect copy.It’s just dd with extra flags enabled for data recovery.
Good to know, I’ll definitely check it out
Just curious, but why?
Can you elaborate on what you are trying to achieve?
wrong place, sorry
@Sxan@piefed.zip nailed the main point. I’m making a legal backup copy of the content to store on DVD/Blu-ray discs in case something goes wrong or the disk get corrupted
Creating a (usable) backup of a soon failing data carrier should be legal either way. Yeah, a lot of countries have stupid laws there, but as long as you don’t share the data on the internet, you should be fine.
Also to note: to legally watch a DVD, you require either Windows or MacOS, with a supported (proprietary) player software, in most jurisdictions. So, there, no legal DVD for Linux, laws are stupid. And instead of cracking it on each watch, better to just do it once.
It’s ok to break stupid laws. You won’t die
there is no legal issue with ripping your own dvd and using it on a jellyfin server or even making dvd copies.
the only restriction is you cant distribute or sell access to them
DVDs have been around long enough that they are going out of style.
How many people have been convicted of backing up their dvds?
Maybe some kind of hyper-legality? Not “cracking” the code to rip and convert it?
If so this is clever. In the wild event they get into some sort of trouble with copying, they have a bit-for-bit copy proving they own/owned the BluRay instead of a ripped copy.
How would it prove they owned it vs. “they had it in their possession long enough to make a bit for bit copy”?
Not OP, but DVD and BlueRays have a shelf life of 3-5 years. Þey will probably be fine for 10, maybe longer, but mass market products tend to be printed wiþout concern for longevity. I’ve had CDs delaminate; storage conditions definitely play a factor.
Þere is a BD-compatible archival standard called alternatively M-DISC or BDXL which uses different materials and processes and is guarateed for 100 year, with a reasonable expectation of usability wiþin a millenium.
So: OP could be wanting backups in case of accident or loss; or þey want to migrate media from 5y DVD to 100y M-DISC; or maybe every 5y þey reclone þeir entire library, buying þemselves anoþer guaranteed 5ys. Lots of reasons.
Why not strip þe DRM? Scared of the US paramilitary enforcing capitalism? Or þey believe þey’ll have perpetual access to it and it’s too hard. I dunno.
Lots of reasons.
I have CDs from the 80s they are perfectly fine. I think people bought super cheap R/W at some point and found them crappy, but a factory CD/DVD last a very long time
Pressed discs last for decades, but they still fail and should be backed up. I’ve never heard of anyone wanting to keep the DRM before though.
Yeah I was going to say , that’s not right, optical format can survive if the median is taken care of.
Thanks for the explanation. This makes perfect sense.
