[mythtv] mtd: libdvdread vs libdvdnav

Ed W lists at wildgooses.com
Wed Jul 4 17:07:41 UTC 2007

> Presumably any DVD with "RipGuard" would also have CSS and
> so would probably be illegal to import into MythTV for most
> of the devs on this list. Hence we are unlikely to help you,
> and this does not pertain to MythTV development since it
> is _highly_ unlikely that a DVD copy protection bypass would
> be committed to the MythTV tree.

I don't really see that this follows.  Ripping functionality is in myth 
already - the original poster just asked how to fix some "bugs" in it.

CSS seems irrelevant to the original point since "ripguard" is just a 
silly way to have bad sectors on your disk.  It can be "circumvented" 
simply by playing the disk correctly rather than ripping all the sectors 
of the disk blindly - hence it's arguably no more copy protection than 
it is a test case that your dvd read code is correctly parsing the DVD 

Also, an increasing number of countries seem to no longer have any 
issues with CSS, and even the US seems to be showing signs of cracking.  
IANAL, but given that every (modern) windows player out there now seems 
to correctly bypass CSS and ripguard with zero problems and given that 
Windows appears to be the dominant OS out there then certainly this is 
about the last player out there which still can't read modern DVDs. 

It certainly drives me nuts that having bragged to a bunch of friends 
about linux and Mythtv that they will then bring a DVD round, or I rent 
one from the video shop and quite likely find that it doesn't rip off 
correctly to play...  Inevitably I end up having to drag out the Windows 
laptop and rip it there instead.  FWIW I am in the UK and we appear to 
have adequate fair use protection for making a personal backup of a DVD. 

Myth already has functionality to rip disks correctly.  It's up to the 
user if they wish to bypass CSS or not, outside of the scope of Myth.  
If the original posters question was simply about how to streamline this 
process and avoid ripping unused sectors from the disk and also how to 
streamline the ripper to correctly parse the DVD structures then this 
seems to be completely ontopic?


Ed W

P.S.  Try dumping the output to /dev/null, possibly you are writing the 
output in small chunks and hitting a disk bottleneck.  Possibly also you 
have some magic on your drive to prevent it spinning up in speed - try 
forcing the disk speed higher...?

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