why does iphoto not play my movies

I have a macbook pro. I have transferred photos and movies from SD cards that are otherwise part of my Nikon D 5100 and Panasonic TZ 40. After initially loading the photos and movies, all movies were playing as expected. However, somewhere after updating to OX 10.9.4 they have stopped playing. The icon for the movie still shows, but the time of the movie appears as ZERO. When I click to play, the movie loads begins to play but ends almost immediately.

Currently the movies are not playing.