Imovie - HELP!

Not a whole lot tbh. Just cutting out the crap, putting a few vid shots into a
sequence and then adding a some music.
I think I may have found the issue. It seems to be compressing the original
files as it puts them into Imovie.

For all those mac users here, has anyone any experience using Imovie?

I'm having a somewhat frustrating issue with the picture quality of the
finished film. The clips I'm putting in are MP4 format and after I'm done
messing about, adding music and whatever the hell else, I'm trying to
save it back as an MP4. Here's the issue, the quality of the finished article
after being save is no where near the quality of the original clips that I'm
putting in.....GRRRR!!

When saving I can choose either "export movie", which gives me a nice
simple selection of file size of which I'm choosing 'Large' which so far is
the best quality. (It saves as an MPEG4)
Or "export using quicktime" which gives me a range of different file
formats to choose (one being MP4) and each format has it's own range of
techy options.

However, after playing about with various options and even resorting to
reading rather vague instructions, I'm still no closer to getting the
finished film to saving at the same quality of the original separate clips.

Why lord oh why?!!

Doug H

Ps, in case you're wondering, yes this is sailing based. They're clips of me
and friends training in radials.