if you take movies with your iOS device (or other camera) that need to be trimmed, you may have encountered the following. If you do not trim the movie on the device, but do it later on your Mac using QuickTime, the file’s date will change to the date you trimmed it, resulting in an incorrect sort order in iPhoto.
Terminal and touch come to the rescue:
First check the original file’s date and time in the Finder by selecting it and pressing Command-I.
Then, in Terminal, use touch to change the date and time. Here’s an example:
touch -t 201208191230 /Users/myname/Desktop/trimmed_movie.movThis will change the file's modification date to August 19, 2012 at 12:30. Doing this before importing the trimmed video will keep an appropriate sort order in iPhoto.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20120821134116586