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On Fri, Dec 16, 2011 at 9:53 AM, Michael Mol <mikemol@×××××.com> wrote: |
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> On Fri, Dec 16, 2011 at 12:25 PM, Mark Knecht <markknecht@×××××.com> wrote: |
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>> On Fri, Dec 16, 2011 at 9:06 AM, Michael Mol <mikemol@×××××.com> wrote: |
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>>> No; you'll have to decrypt, or do without the encrypted bits. |
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>>> |
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>>> dvdbackup is probably the closest to what you want. |
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>>> |
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>>> On Dec 16, 2011 11:09 AM, "Mark Knecht" <markknecht@×××××.com> wrote: |
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>>>> |
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>>>> For archive purposes is there a simple way for me to make a |
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>>>> bit-for-bit copy retail DVDs I've purchased? |
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>>>> |
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>>>> Assume that I've got the right sort of DVD drive, I guess something |
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>>>> capable of writing dual-layer DVDs. |
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>>>> |
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>>>> Thanks, |
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>>>> Mark |
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>> |
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>> Interesting. So even something that just copies blocks of data, like |
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>> dd, can't be used for that purpose? |
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>> |
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>> I have no interest in tearing apart the DVD in any way. It was more |
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>> about the idea of a fire causing the loss of maybe $15K-$20K |
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>> investment over the years. I can rip all the CDs, keep the ripped |
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>> version here to watch on the computer, and store the DVDs elsewhere, |
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>> but that elimiates (generally) being able to watch special features |
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>> which my wife and kid enjoy. |
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>> |
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>> Thanks for the info. |
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> |
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> I did exactly the same thing a few years ago, but it's been a long, |
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> long time, so my memory on my process is very fuzzy. (It also involved |
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> my first foray into RAID...I've got a couple hundred DVDs!) Go ahead, |
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> count the number of times I qualify something with "IIRC"... |
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> |
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> dvdbackup can recreate the ISO images, IIRC. |
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> |
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> If you run a simple 'dd' on a DVD with encrypted portions, you'll get |
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> I/O errors when it encounters the encrypted pieces. IIRC, some of the |
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> data required to decrypt those portions is on the disc, but it's in an |
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> out-of-the-way portion that won't show up as part of the block device. |
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> IIRC, dvdbackup makes use of libdvdcss to decrypt the encrypted |
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> portions[1], and writes a decrypted version of the data. *this* is why |
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> you can't make a bit-for-bit copy; the output data would be decrypted. |
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> |
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> There are other, later obstacles, too; once CSS was broken, some |
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> content publishers (Bandai USA, for example) would fudge the ISO spec |
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> and the DVD nav specs in ways that didn't break *most* hardware DVD |
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> players, but did tend to break players which strictly adhered to the |
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> standards, such as ffmpeg, vlc and mplayer. It also broke dvdbackup |
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> for me, IIRC, which is why I had to resort to vobcopy in some cases. I |
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> expect the software angle for handling these things has gotten better, |
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> though. |
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> |
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> [1] I don't know how it does it when dd would have hit an I/O error. |
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> Obviously, my understanding of the workings of dvdbackup, dd, DVDs and |
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> CSS encryption is flawed somehow. |
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> |
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> -- |
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> :wq |
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> |
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|
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Thanks for the info. It makes it a bit clearer as to what's causing |
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the road block vs. the sort of answer Jorg provided this morning which |
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did nothing (as when I asked on the cd-record list a few days ago and |
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the answer there did nothing either) to advance my knowledge on the |
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subject. |
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|
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I appreciate the time it took you to respond. Thanks! |
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|
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Cheers, |
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Mark |