Scenario.
There is a number of videos embedded in resources (QRC). Playing the first movie works fine. Switching to the next movie causes a crash. From the crash report you can see this is after trying to access a method of QResource. Having investigated the issue, it turned out that in the sources of the qt7 plugin the 'resource' object is deleted, by the pointer is not reset to 0.

Resetting the pointer to 0 helped to solve the crash. However switching to the next movie causes the application to 'freeze'. Having it run in gdb, you can see that there is a dead lock. Investigating the issue and using google led me to the 'setMovie: nil' message. Calling this in certain places might cause problems like the one described. Commenting out the line with this message solves the problem.

A patch is attached.