iPhoto not importing videos; "The following file could not be imported...."
iPhoto '11 isn't importing certain of my videos; they are a combination of .mov and .mp4s. Other of the same file types are imported without trouble. I get the error "Unreadable Files: # The following file could not be imported. The file is an unrecognized format" and then a list of the files. I'm on a current generation iMac with up-to-date OS.
The files open fine in Quicktime with a double click. I used HandBrake to convert the files (into all .mp4s) and have the same importing problem, even though the files continue to open when clicked.
FWIW, I'm copying the items into the iPhoto library (i.e., that box is checked in preferences), based on the advice of this site. However, when I previously did not do that (i.e., when I had a referenced library) I didn't have this problem.
Any help? Thanks.
iPhoto '11, OS X Mavericks (10.9.1)