New subject: 61GB DVD ?........oops apologies

24 Aug 2018

Trent W. Buck via luv-talk wrote:
...
  Joel Shea via luv-talk wrote:
  On 22 August 2018 at 23:16, Rohan McLeod via
luv-talk &lt;luv-talk(a)luv.asn.au&gt; 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?  Let me paraphase to check my understanding.

   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.

   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)

         4.0GB   movie-theatrical.mp2
         4.2GB   movie-director.mp2
         3.8GB   movie-tv.mp2

      which "adds up" to more than the DVD can logically hold. 

;Apologies Trent ! further investigation shows only 6Gb on the DVD;
whilst not exactly as above what is being reported is uncompressed size;
mystery solved !

apologies  Rohan McLeod

Re: [luv-talk] 61GB DVD ?........oops apologies