Why am I getting wavy, distorted video on a DVD made with iDVD?

Question

I made a DVD with iDVD 5 that has wavy, distorted video. It is watchable but you can clearly see that vertical lines are somewhat wavy whenever the camera pans across the scene. An up-down pan doesn’t distort the horizontal lines, however.
The source video file doesn't display this waviness. Also, I created a DVD of the same video using a PC and the resultant DVD didn't display the waviness. The waviness occurs whether the DVD is played on the computer or a TV monitor with a standalone DVD player. From all this I conclude that it has to be a consequence of the iDVD5 burning process.
Here’s some additional information: The PC burned the video from its original MPEG-2 format. The Mac burned the video from a .mov file that I created from the original MPEG-2 file using MPEG Streamclip. (I need to use MPEG Streamclip to restore (actually convert, I suppose) the audio as the source file has AC3 audio that doesn’t play in iMovie or Quicktime.) The resulting .mov file - when played with Quicktime before burning - does not exhibit the waviness, so I don't think the MPEG Streamclip conversion process is at fault.
On the same DVD I also placed a different video from the same source. It doesn’t display any of the waviness that I get from the other video. The only difference between the videos is that this latter video – after the MPEG Streamclip processing - was chaptered in iMovie HD and then exported to iDVD as a .mov file. I’d hate to think that I have to run every video through iMovie to eliminate the waviness.
So is this just an inexplicable defect or is there something that I might do differently to avoid the waviness that I’m getting in this video?
Thanks, Robert
Powerbook G4   Mac OS X (10.4.4)  

Answer 1

Robert,
To me, the red flag is that you've created a .mov file from Quicktime for import back into iDVD. A .mov file is generally a smaller formatted movie, typically only 320X240 pixels in size. This size movie, by default, would look perfect when played in QT. But, to go back to iDVD or iMovie, the movie must be expanded back to a 720X480 size movie (typically the DV stream that these programs want and need), so expanding will cause all sorts of distortion. Can you go back to your original MPEG2 source movie and get the movie info on it? You should be able to see the original size. If it is something like 640X480 or 720X480 then use QT to create a .DV file. This will maintain the original size.