I've got some video files from a JVC Everio HDD camcorder which are .mod files. The file info is as follows: Stream: MOV001.MOD Path: /Volumes/UDISK 28X/PRG00A/MOV001.MOD Type: MPEG program stream Duration: 0:00:13 Data Size: 12.29 MB Bit Rate: 7.43 Mbps Video Tracks: 224 MPEG-2, 720 × 576, 16:9, 25 fps, 8.40 Mbps, upper field first Audio Tracks: 128 AC3 2/0, 48 kHz, 384 kbps Stream Files: MOV001.MOD (12.29 MB) The playback on the camcorder and through a TV is excellent. However, you can see on this screenshot the quality when seen on my Mac. Note the horse's legs. This is only evident in shots with appreciable movement, either of the subject, or the camera. I was going to use iMovie9 because I'd read that iMovie9 imports mod files, but it didn't. So I used MPEGStreamclip to try formats that it did, and used mpeg4, but the problem still showed after import into iMovie9. I then decided to try my old favourite iMovieHD. After importing the mpeg4 files the quality was back to normal. So I then tried using the DV option in MPEGStreamclip's export settings, and again, the problem had disappeared. Any ideas why the quality should be different in the two formats?