Re: [MLUG - DISCUSSION] dvd db

[Mark Rages <EMAIL:PROTECTED>]

On Mon, Jun 09, 2003 at 07:00:25PM -0500, Michael wrote:
> Anyone feel like helping me out? I'm trying to improve my DVD detection
> routine. Instead of checksumming the entire disc I am trying to checksum
> just the first lil bit of the disc. It's much MUCH quicker. I'm just
> trying to get an idea of how uniq this method is and how reliable it is.
> 
> I use this so that my ripping/playing software can detect the proper name
> of the DVD without needing to be entered by the user. Pretty much works
> like cddb does for cd's. Probably is some standard way of doing this but
> I've yet to find it so I make up my own method.
> 
> If you're using Linux the easiest way to checksum a disc is to put it in
> the drive and then do 'head /dev/dvd | md5sum -'. Here is a tab delimited
> list of a few movies I had sitting on my desk. Checksum, title, length,
> and rating. Does anyone have the same discs and get the same checksum or
> have a different disc that returns the same checksum?
> 

The first part of a DVD contains things like navigation data, so most 
likely that's what you're checksumming, not movie data.  I can imagine 
a case where the movie files differ, but the nav information is exactly 
the same. Imagine something with simple menus like from a set-top DVD-R 
recorder. at default settings.  Movie information would surely be 
"uniq" but you'd probably need to mount the DVD (or use libdvdread) to 
read it.

You may want to check out MPUcoder's site:
http://mpucoder.kewlhair.com/DVD/ There's space in the spec for textual
data, but I don't know how often it's used.  There's a DVD-navigation
library, which I think is now part of libdvdread, whose source code may
be interesting to you.

Regards,
Mark
EMAIL:PROTECTED

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