iFRAME into iMOVIE - most efficient method for importing?

What would be the most efficient method for importing iFrame movies from a camera into iMovie?

iFrame i suppose to save time and work more efficiently in lue of quality but I don't seem to find I way to import the movies faster than in other formats.

On a second note, inporting in iMovie from DV (tape) cameras dramaticly reduced the image quality. Do we still have the same issue when importing an iFrame movie?

Thank you for your help!