[DVDnav-discuss] Invalid IFO for title XX (VTS_XX_0.IFO)

[Loïc Minier]

        Hey

 I'm creating ISOs of my DVDs, but I'm getting errors with some of them.
 I suspect it's a copy protection scheme.

 When playing the DVD directly, e.g. "vlc /dev/dvd", things "just work".
 With some DVDs, "dd if=/dev/dvd of=foo.iso && vlc foo.iso" works
 equally well (I need to run "vlc /dev/dvd" to CSS-unlock the data).

 But with some DVDs which don't seem particularly scratched, I'll
 receive exactly one read error during the dd (I'm passing
 "conv=noerror" to dd to circumvent that); the resulting .iso file is
 then unusable and shows various errors:
 libdvdnav: Using dvdnav version 4.1.3
 libdvdread: Using libdvdcss version 1.2.10 for DVD access
 libdvdnav: DVD Title: TMS0EUW1
 libdvdnav: DVD Serial Number: 3a8e11db
 [...]
 libdvdread: Get key for /VIDEO_TS/VTS_15_0.VOB at 0x002f01a5
 libdvdread: Elapsed time 0
 libdvdread: Get key for /VIDEO_TS/VTS_15_1.VOB at 0x002f0258
 libdvdread: Elapsed time 0
 libdvdread: Get key for /VIDEO_TS/VTS_16_0.VOB at 0x002f8be7
 libdvdread: Elapsed time 0
 libdvdread: Get key for /VIDEO_TS/VTS_16_1.VOB at 0x002f8c9a
 libdvdread: Elapsed time 0
 libdvdread: Get key for /VIDEO_TS/VTS_17_0.VOB at 0x00344d9e
 libdvdread: Error cracking CSS key for /VIDEO_TS/VTS_17_0.VOB
 (0x00344d9e)
 libdvdread: Elapsed time 0
 libdvdread: Get key for /VIDEO_TS/VTS_17_1.VOB at 0x00344dae
 libdvdread: Error cracking CSS key for /VIDEO_TS/VTS_17_1.VOB
 (0x00344dae)!!
 libdvdread: Elapsed time 0
 libdvdread: Found 17 VTS's
 libdvdread: Elapsed time 0
 Warning: call to srand(309709)
 libdvdread: Invalid IFO for title 17 (VTS_17_0.IFO).
 libdvdnav: ifoOpenVTSI failed
 vlc: /build/buildd/libdvdnav-4.1.3/src/vm/vm.c:1485: process_command:
 Assertion `0' failed.

 I'm using Ubuntu 10.10's libdvdnav, libdvdread, and vlc with a
 self-built libdvdcss.  I checked that Ubuntu's libdvdnav doesn't have
 an embedded libdvdread, and neither does vlc.

 I cherry-picked SVN r1215 from svn://svn.mplayerhq.hu/dvdnav/trunk into
 libdvdread, but this didn't help.  I also took SVN r237 from
 svn://svn.videolan.org/libdvdcss/trunk into libdvdcss just in case it
 was the explanation for the CSS key issues.


 There seem to be three issues at various levels:
 - dd fails to read some bytes from /dev/dvd.  I'm thinking that this is
   caused by the copy-protection scheme at the disc mastering level, and
   that it's an intentional error; maybe this triggers some fallback
   code pathes in commercial DVD playing software which are not
   triggered when using a .iso file which has no error
 - libdvdcss reports that the last title's key can't be cracked when
   using the .iso file, but it works when using /dev/dvd (almost all the
   time, albeit there was one case where it didn't work)
 - libdvdread/libdvdnav are extremely unhappy with ifoOpenVTSI() failing


 The error seemed similar to the one fixed by the addition of .BUP file
 support, unfortunately this didn't help.


 This happens on a range of Walt Disney DVDs


 Is there some information I can provide on the failure to help track it
 down?  I'm afraid I'm not familiar with the DVD specs.

   Cheers,
-- 
Loïc Minier