Currently Being ModeratedMar 30, 2013 7:42 AM (in response to herraduraman)
Not much to go on. Please tell us the following:
Sequence settings & clip properties. Control-click your sequence in the FCE Browser. Select Item Properties. Tell us what it says for Vid Rate, Frame Size and Compressor. Do the same with one or more of your clips.
Did you Render All > Both before exporting your video?
What version of OS X and QuickTime are on your Mac?