[MacDV] QuickTime to iMovie 6.0.4 introduces artifacts

[Derek Roff]

I've made a composite of two video frames into a single frame, using 
Final Cut Pro 6.0.5.  This will all the eventual viewer to watch two 
different sign language interpreters simultaneously, in sync with each 
other.  Where the corners of the frames overlap, I created a black and 
white mask in a graphics program to control which part of each frame 
will show.  Basically, I rounded off one corner of the lower right 
frame, where it overlaps the upper left frame.

After rendering, the overlay looks perfect in Final Cut Pro.  I 
exported to a self-contained QuickTime .mov file.  This QuickTime movie 
looks perfect.  I imported this QuickTime movie into iMovie 6.0.4, 
running on an Intel iMac, Leopard 10.5.5.  In iMovie, the video shows a 
horizontal line artifact, along the bottom edge of the overlap area. 
What I seem to be seeing is the lower video layer bleeding through 
along a thin line, where it should have been masked out.  It looks as 
though the mask wasn't properly sized/positioned.  What doesn't make 
sense to me is how this artifact could show up in iMovie, when it 
doesn't appear in Final Cut or QuickTime.  The QuickTime movie that I 
imported has no mask and no overlay.  It is just a series of video 
frames that historically came from a composited image.  How could the 
overlay line suddenly appear?

Any ideas?

Derek

Derek Roff
Language Learning Center
Ortega Hall 129, MSC03-2100
University of New Mexico
Albuquerque, NM 87131-0001
505/277-7368, fax 505/277-3885
Internet: derek at unm.edu