I'm experiencing problems when exporting a 16:9 widescreen project to a 4:3 formatted .MP4 file for uploading to youtube. I set the options to "crop" to preserve aspect ratio in the export menu.
The exported .MP4 file is correctly sized at 320x240, but the video appears to be both cropped and then squished to fit the frame (very strange looking), not simply cropped as I selected.
I am able to get around this problem by exporting the project to a .dv stream and then converting that .dv stream to a .MP4 file in QTPro. I can either export as a 16:9 .dv stream and crop it in QTPro, or export a cropped 4:3 .dv stream. Both give the correct and expected formatting in the .dv stream.
The strange part that I don't understand is that the exact same cropping settings in the export menu produce different results depending on if you select .MP4 or .dv as the export format.
Mac Mini (Core Duo 1.8GHz), Mac OS X (10.4.10), iMovie 6 HD, QTPro 7