[mythtv-users] dvd iso playback problem

[Richard]

On 27/06/13 06:22, Dan Littlejohn wrote:
>
> On Tue, Apr 30, 2013 at 11:26 AM, Richard <peper03 at yahoo.com
> <mailto:peper03 at yahoo.com>> wrote:
>
>     Hi Dan,
>
>
>         2013-04-28 13:33:03.765665 E [2698/2894] Decoder
>         DVD/dvdringbuffer.cpp:521 (safe_read) - DVDRB: Failed to read block:
>         Error reading NAV packet.
>
>
>     This error seems to indicate that there was an issue with the data
>     from the image.  The library MythTV uses (libdvdnav) to parse the
>     DVD data is reporting that a data structure it was expecting wasn't
>     found (or was corrupt).  One reason for this could be using
>     encrypted ISOs in storage groups across the network, but you said
>     your images were all decrypted so unless one has slipped through the
>     net, it shouldn't be that.
>
>     If the data has been corrupted, it poses the question why the image
>     plays in other applications (to my knowledge, most use the same
>     library, although possibly with their own modifications).  One
>     reason may be that some applications attempt to skip the menu and
>     jump straight to the main feature.  That could well mean that
>     they're not seeing the corrupted data if it's part of the menu.
>
>     You could try starting the frontend with '-v playback
>     --loglevel=debug'.  That will certainly give more data (although not
>     from libdvdnav).
>
>     Are you getting the same problem from the other images that won't play?
>
>     Richard.
>
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>
>
> For anyone else having tthe problem of some dvd ISOs not playing in
> myth, but working in other players I was able to fix it and keep the iso
> format.  What I finally figured out is that you can use the program
> "dvd-shrink" to re-author the disk (non-compressed) to create a new iso
> container.  All the movies I was having problems with were fixed by
> doing this.  Just thought I would pass that along as keeping a single
> iso file for a movie is really convenient and I like the myth interface
> better than the other players I am using.

I'm glad you've found a solution but it would be interesting to know 
exactly why those images didn't play.  Did you remove anything (menus, 
streams etc.) when you ran the images through dvdshrink?

If you still have an original image, I'd be interested to see the 
results of running mythfrontend with the parameters I mentioned before. 
  If you run it from a command-line, there may be some additional 
messages from libdvdnav that don't get routed into the normal MythTV 
logging.

Richard.