In this tutorial, we learn how to export in HD in iMovie '09. First, open up your iMovie, then go into "share", then "YouTube". If the HD is not checked, you will need to check it and then click "next" and "publish". That is the quickest way to export to YouTube. To do this from iDVD, click on the "share", then "iDVD" and then it will go to iDVD and you can export it in HD. You can do this for any of your movies by simply clicking on the share menu, and making sure your settings are changed to HD. After this, you will have movies in the quality you prefer and you're finished!
Have an iPhone? Check out all 200+ new features coming in iOS 13.