Could you make some process snapshots and send them to us? We should be able to get an idea of where it's freezing from those. Since it's taking a very long time, it might make sense to wait 15 seconds or so between making each snapshot, so we can see if it progresses from one file to another.
Here's how to make them:
With that filter, you may be able to speed things up by reversing the two lines, so it checks the file type group first, then checks the image description second. That would do the fast check first, and avoid trying to calculate the descriptions of any non-image files.