On Fri, Aug 24, 2018 at 12:08:06PM +1000, Trent W. Buck via luv-talk wrote:
1. that specific DVD disc has <4.7GiB of actual raw bytes on it, i.e. if you did
cp /dev/sr0 my-dvd.udf # or dd if=/dev/sr0 of=my-dvd.udf
the resulting file would be normal DVD-size.
I assume so, I haven't used optical media for almost 10 years :-)
2. inside the ordinary UDF filesystem might be (say) three different versions of the movie, which are 95% identical, but just have 5% different scenes --- e.g. the original theatrical version, the director's cut (5% extra content) and the pre-watershed TV broadcast version (5% less content - no sexy bits). (...) So when Rohan ripped the DVD into some conventional format, he ended up with (say) (...) which "adds up" to more than the DVD can logically hold.
That's how I understand it.
3. this is similar to hard links (or btrfs/ZFS shared reflinks), and removing them due to incautious copying. Example: (...)
Probably an apt analogy, since the VOB files in the directory structure are able to reference the same VOBs (or subsets thereof) on disc, albeit it gets more complicated than that, i.e. the DVD-Video format includes it's own machine-language and VM. ~J
Joel W. Shea via luv-talk wrote:
3. this is similar to hard links (or btrfs/ZFS shared reflinks), and removing them due to incautious copying. Example: (...)
Probably an apt analogy, since the VOB files in the directory structure are able to reference the same VOBs (or subsets thereof) on disc, albeit it gets more complicated than that, i.e. the DVD-Video format includes it's own machine-language and VM.
I thought the *whole point* of DVDs was that they threw away most of Red Book and made everything ALWAYS packet-based and ALWAYS UDF, and the "movies" were done at a higher layer (i.e. they're just files on the UDF, laid out in a certain way). Am I wrong? A glance at Wikipedia's DVD Video article doesn't turn up any glaring contradiction.
participants (2)
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Joel W. Shea -
Trent W. Buck