[mythtv-users] DVD Playback crashing in 0.24-fixes -- workaround

[Mark Lord]

On 12-04-01 01:57 PM, John Pilkington wrote:
> On 01/04/12 17:41, Mark Lord wrote:
>> Ever since I upgraded to 0.24-fixes (over a year ago),
>> the built-in DVD playback stuff has been unusable.
>>
>> It *always* crashes, often on beginning DVD playback,
>> or often on the first press of the MENU button while playing.
>>
>> Sometimes a new, never-seen-before, DVD will play okay for longer,
>> but on reinsertion things always crash again.
>> This is on multiple installations.  The bug in somewhere in Mythtv.
> 
> < patch etc snipped >
> 
> My 0.24-fixes box spends a lot of its time authoring DVDs and I occasionally use it to play them. 
> Playback is usually OK but menu handling often leaves something to be desired. vlc usually handles
> menus better. I have often felt that the internal Myth player has been much influenced by the desire
> to play commercial disks with copy-frustrating features, to the detriment of its ability to play the
> products of MythArchive, but I don't recognise your problem as one that I have seen.  Maybe others
> will.  In case it's relevant, I don't use VDPAU.


The crashes happen with/without VDPAU, and there have been many tickets
(from others) reporting the issue, but no resolution.

I suspect a race between MythDVDPlayer::GetBookmark() and other parts of the player.
Saving bookmarks doesn't seem to cause trouble, just retrieving the first one
on resume of playback.  This leads to internal heap corruption in libc++,
and then subsequent crashes in unrelated sections of code.

The code there does seem simple enough.  Some experienced C++ eyeballs
ought to be able to spot the bug.

Cheers