Assembled Cogniscenti small mystery: I was looking at this DVD "The Lovely Bones" with a view to ; assembling the .vob files into one file to play on my machine. The 'DVD drive is actually a Blu-Ray R/W drive ; which can read and write 100GB M-disks. But I was still astonished when this "DVD", seemed to have 61 GB of files ! At first I thought it was just corrupt and reporting false file sizes; but when I started copying files they all seemed to be correct. Instead of say 4 - 6 .vob files totalling about 4-6 GB ; there were 6 groups of 6 vob files; anyone come across this kind of thing and why does it exist ? regards Rohan McLeod
On 22 August 2018 at 23:16, Rohan McLeod via luv-talk <luv-talk@luv.asn.au> wrote:
I was still astonished when this "DVD", seemed to have 61 GB of files ! ... anyone come across this kind of thing and why does it exist ?
This has to do with the way DVD-Video is "authored", the format's specification is quite complicated[1], so without going too deep; the DVD "filesystem" is just one view of the content—since video, audio, subtitle and navigation streams are _multiplexed_ and stored in the VOB container, you can have multiple titles with their own set of VOB files that reference the same MPEG input streams in different ways, this could be due to multi-angle feature (e.g. for internationalisation, directors cuts, etc) and/or other extra features. It appears you may have a benign "multiple title" DVD-Video, rather than a brain dead copy protection attempt (e.g. obfuscation using 99 titles). How were you copying these files? Perhaps the following command might help grab only the main feature's title set; $ dvdbackup -i /dev/dvd -o ~ -F Failing that, if you already know which title contains the main feature; $ dvdbackup -i /dev/dvd -o ~ -t <title-number> These were taken from https://wiki.archlinux.org/index.php/Dvdbackup As always, YMMV ~ J [1] For reference, see: https://en.wikipedia.org/wiki/DVD-Video https://en.wikibooks.org/wiki/Inside_DVD-Video http://stnsoft.com/DVD/index.html
Joel Shea via luv-talk wrote:
On 22 August 2018 at 23:16, Rohan McLeod via luv-talk <luv-talk@luv.asn.au> wrote:
I was still astonished when this "DVD", seemed to have 61 GB of files ! ... anyone come across this kind of thing and why does it exist ? This has to do with the way DVD-Video is "authored", the format's specification is quite complicated[1], so without going too deep; the DVD "filesystem" is just one view of the content—since video, audio, subtitle and navigation streams are _multiplexed_ and stored in the VOB container, you can have multiple titles with their own set of VOB files that reference the same MPEG input streams in different ways, this could be due to multi-angle feature (e.g. for internationalisation, directors cuts, etc) and/or other extra features.
Thanks for that Joel it goes some way to explaining the ; variable success of concatenating the relevant .vob files. However my question concerned the underlying hardware. which seems to normally limit content size to about 4 - 6GB see for example : http://www.osta.org/technology/dvdqa/dvdqa6.htm Where as this video, without any particular notification on the packet, has verified (ie not just file size corruption) content ; of approx 61GB ! regards Rohan McLeod
On Fri, Aug 24, 2018 at 09:24:16AM +1000, Rohan McLeod via luv-talk wrote:
... However my question concerned the underlying hardware. which seems to normally limit content size to about 4 - 6GB ...
Where as this video, without any particular notification on the packet, has verified (ie not just file size corruption) content ; of approx 61GB !
The physical media only contains 4.7GB (or 8.5GB for dual layer). Keeping in mind, "VOBs have nothing to do with the division into .VOB files in the DVD-Video directory structure"[1], simplistically .IFO files contain pointers to content, so it only appears there's 61GB because your software is probably traversing different paths to the same data. Simply copying VOB files from the directory structure, is likely creating duplicate copies of some subset(s) of data, and DVD ripping is a more complicated process. ~J [1] - https://en.wikibooks.org/wiki/Inside_DVD-Video/IFO_Files
participants (3)
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Joel Shea -
Joel W. Shea
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Rohan McLeod