iMovie seems to lose video quality. Help?

[audiokeeffe]

I took a 3 minute video with my camera phone and imported it into imovie to detach the sound. In iMovie the quality looked good, but when I went to export it and save, the quality of the video that was exported has reduced and is all grainy looking!! Why did this happen and can I avoid this in the future? (I'm using iMovie '09)

 

[Laurencia7]

How did you export it?
with "share>export movie"? or etc?
It determines what bit rate your video is set on.
Select the medium to hd options, this will increase your pixel/bit rate.