I have 1920x1080 files to edit in iMovie to show on large movie screen for charity event what is best frame rate and best save option for quality versus file size?

Question

I shoot a lot of HD video of my kid, and at first I struggled to find a good balance between maintaining the full-resolution original footage and having something a little more reasonable and lightweight to work with. For example, even on my one-year-old iMac, I can't smoothly scrub the full HD video clips in the editor -- but if the clips have been 'optimized' to 960 x 540, they're smooth as butter (and still look good enough for almost every output scenario).
If, when you're importing the original footage, you enable the "Optimize video" checkbox, you'll get the lightweight version in your event library, but you won't get a copy of the orignal footage as well. It'll still be on your camera (or wherever else you put it before heading to iMovie), but that's not very helpful.
If you're using iMovie '09 (v.8) or '11 (v.9), there's a decent way to do this that isn't terribly obvious.
So here's what I do:
When importing the original footage, disable the 'Optimize video' checkbox, and select the 'Move files' radio button. This will move the full HD clip into /[selected volume]/iMovie Events/[event title]. (Or you can use 'Copy files' and get the same end result.)
Select the new event in the Event Library in iMovie, and go to File » Optimize Video » Large -- 960x540 (or 'Full,' which is still going to be more compressed than the original HD, but at the same resolution; I find 'Large' to be just fine for my needs, though).
That second step takes the original HD clip that was in /[selected volume]/iMovie Events/[event title] and moves it into /[selected volume]/iMovie Original Movies/[event title], and then puts the optimized version into /[selected volume]/iMovie Events/[event title].
Now you've got a fully organized directory structure containing all of your original HD footage, sorted by event, plus an Event Library full of nice lightweight versions for quick editing and exporting.

Answer 1

Thanks for that info! Even in my time answering questions on iMovie Discussion Group, I never had a good understanding of when and how Optimize Movie came into play. I always would import as Optimized and Large Size and figured that was good enough. But knowing you got much, much more flexibility doing it the way you describe gives me a much better understanding of the different routes you can take into the Event Library.