[mythtv-users] DVD iso won't show menus

Michael T. Dean mtdean at thirdcontact.com
Wed Sep 5 12:25:34 UTC 2012

On 09/05/2012 12:37 AM, Nick Rout wrote:
> On Wed, Sep 5, 2012 at 3:33 PM, Michael T. Dean wrote:
>> On 09/04/2012 07:40 PM, Michael Herman wrote:
>>> Hi there,
>>> I am new to this mailing list; although I have used Mythtv for quite
>>> awhile (although I still feel like a beginner at it).  I recently got a
>>> large enough harddrive that I wanted to put my DVD collection on it as .iso
>>> files.  I followed the directions at:
>>> http://www.cmdln.org/2010/01/22/backing-up-disney-dvds/ to create a .iso
>>> file of Hunger Games.  When I play it through the video browser it plays a
>>> bunch of previews at the start of the disk, each of which seems to be a
>>> seperate chapter of the DVD.  But after that it just quits and never shows
>>> the Main Menu.  If I play it outside of Mythtv with VLC or mplayer it goes
>>> stright to the main menu.
>>> I read that mythtv doesn't support menus but it seemed dated and I
>>> couldn't find info for Mythtv .25 which I am using. Is there anything
>>> obvious that I should try?  I could always use an external player but I
>>> wanted to see if mythtv would be fine so I didn't have to mess with the
>>> remote control working in a different application.
>> MythTV supports DVD menus for compliant DVDs.  Disney is notorious for
>> creating non-compliant DVDs using structural protection (i.e. errors on the
>> disc) to prevent copying.  Generally, a player (hardware or software) will
>> play a DVD with structural protection without problems because the
>> navigation information keeps the player from reading the "broken" data.
>> Ripping the disc, however, entails copying all the data on the disc--which
>> means you'd attempt to read the broken data and get an error.  This is why
>> you had to use the hack you referenced to attempt to rip the disc.  However,
>> I wouldn't be surprised to learn that the rip of such a CD is unplayable by
>> MythTV (we have no code, whatsoever, to try to work around
>> copyright-protection mechanisms--including structural protection--even
>> though many (most?) other DVD player packages do).
>> So, I'd recommend sticking the actual disc in the drive and attempting to
>> play it with MythTV.  If it works, that means that the approach you had to
>> use to rip the broken DVD gave you an even-more-broken rip.  You can then
>> take the disc back to the store and tell them you're returning it because
>> it's not compliant with the DVD specification, so it can't be played on your
>> player.  If playback of the original disc doesn't work, it may or may not be
>> the structural protections causing problems in MythTV--you'd probably have
>> to dig deep into the code and the actual disc/playback to find out what's
>> happening and whether it's a MythTV bug or a non-compliant disc that's
>> causing the failure.  (And remember that other DVD playback software does
>> try to incorporate workarounds for protected discs--so just because it works
>> in<insert DVD player name>, doesn't mean that it's not the structural
>> protection or that it's a compliant disc.)
> All of what you say is clearly correct, but what I have never been
> able to work out is how even quite old STB DVD players cope with all
> these broken disney (and other manufacturer) disks (assuming they do,
> mine has been sitting in the garage for a while now).

Because a) the navigation information in the disc prevents the player 
from ever attempting to read the errored parts on the disc (as mentioned 
above) and b) most non-computer DVD players do not return errors that 
cause failure when they do stumble across an error on a disc (they were 
designed this way to help them be more resilient to scratched discs, 
causing just playback glitches rather than failures).  Computer drives, 
however, are designed to get exact information from discs and keep 
retrying when they see errors and report errors when they eventually 
decide they can't read a portion.  (Also note that generally the 
cheapest DVD player hardware tends to be the most resilient--to allow 
the manufacturer to create a product that's most likely to work without 
having to test as extensively for compliance--so quality of the DVD 
player may not affect results in the way one would think.)

See also http://en.wikipedia.org/wiki/ARccOS_Protection for more info on 
one such implementation of structural protection.

That's why I'm guessing that playing the actual disc will work and it's 
just the "even-more-errored-than-the-(broken-by-design)-disc" rip that's 
likely causing problems.


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