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

[Michael Herman]

>
> Why would mplayer and VLC beable to play the iso file while mythtv's
> player can't?  I was under the impression that ddrescue is able to overcome
> the errors on the disc.
>



> 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.
>
> Mike
>
>
>
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