dvd with menu (*.vob) and deinterlacing issues, vlc crashes

[rbayer]

hi,

vlc's capabilities to show and interact with dvd-menues have been improved a lot since the very first releases. thanks.

however, i found that, in conjunction with deinterlacing mode, vlc tends to crash when playing dvds - dvd with menu (*.vob files) - after selecting "play movie" (or something like that) in the dvd's main menu.

notes:
(i) deinterlacing method was set to "linear" all the time.
(ii) i copied some commercial dvds with menu onto the hard disk: no copy protection found, no css, checked the ifo-files with ifoedit: no errors.

behavior:

(1) if deinterlacing is preset to "auto" in preferences,
vlc crashes after displaying the main menu and one selects "play disk" on some dvds.
this is esp. true if the warnings/ads at the beginning, the main menu itself and the chapters of the content (in this case: tv session recordings of the 1960s) differ in needing deinterlacing or not.

(2) if deinterlacing ist set to "on",
vlc ignores the "play directly from menu"-option in the "dvd with menu" (settings tab): vlc starts showing the main menu, ads and warning sreens etc. at the beginning are skipped. however, vlc plays the disk and does not crash.

(3) if deinterlacing is set to "off",
vlc plays the disk without crashing, too, but now recognizes the "play directly from menu"-option in the "dvd with menu"-settings.

(4)
using the chapter menu of the dvd FIRST one-time, vlc does NOT crash (regardless of deinterlace settings). it does not crash even if you go back to the main menu then and select NOW "play all".

behavior is reproduceable 100% on some specific dvds.

(5)
i found it difficult to change the deinterlacing settings via the "video"-tab on-the-fly (from "auto" to "off" or "on" to prevent that vlc crashes afterwards) e.g. if the main menu of the dvd is displayed: a black screen is displayed after changing deinterlace-mode, play and pause buttons have no effect. maybe this is because the main menu is a "still picture" (freezed frame).

(6)
so at the moment, i have changed preferences to "deinterlace: off". i am changing deinterlacing mode (using the video-tab) on-the-fly after leaving the main-menu and the disk content is being played (if needed so).

(7)
of course, i tried to play the dvd also directly from the cd/dvd-drive and found same behavior. using a standard stand-alone dvd-player: no probs.

(8)
this happens to some commercial dvds only, others are played without any problems.

(9)
i used vlc's built-in facility to send you a bug-report. maybe the next version of vlc will not crash without telling me what it doesn't like on those dvds...

rb

[Rémi Denis-Courmont]

Incorrect assumptions in libdvdnav are the most common reason why DVD menus crash. Unfortunately, the DVD specification is not compatible with open source development, so libdvdnav is reverse-engineered and buggy. Furthermore, there does not seem to be much activity in that project anymore.

If you are sure it's linked with deinterlacing however, then it is not libdvdnav's fault. You should probably try a nightly build of VLC 1.2.