Sergey Sharybin
fb1265c5cf
The issue was caused by the prefetch code having LOCK_MOVIECLIP lock acquired while reading frames from the movie files. The need of the lock was coming from the fact that `clip->anim` can not be accessed from multiple threads, so that was guarded by a lock. The side effect of this lock was that the main thread (from which drawing is happening) did not have any chance passing through it in the cache code because the prefetch happens so quickly. The solution is to create a local copy of the clip with its own anim handler, so that read can happen without such lock. The prefetch is slower by an absolute number in seconds (within 10% in tests here), but it is interactive now.