doubts about codecs and compressions

Hi everybody,

First of all I am sorry for my english.

I lost a night for this, so I thought to ask to the Cow!

I had to edit a video assembling a lot of different videos, most of all mp4 or mov in h264 codec (not a great quality).
I worked and I've exported to animation to have an intermediate codec.
Then, after some client's correction, I had to compress in the best possible quality for a wall projection from a pc.

I used compressor and I made three videos (1024x576, 10 minutes long) to test:

-mpeg4 at the best
-quicktime h264 at the best
-mpeg2 at vbr average bitrate 18, pick bitrate 30

What I saw is that:
- mpeg4 and h264 degraded a lot the contrast and show a lot of broken pixel, it was really bad.
- mpeg2 (with compressor saying 720 pal 16:9) wasn't 1024x576, but 720x404, it had less details on the graphics, but contrast and colors were good, near to the animation.

So my questions are:

- why compressor makes mpeg2 pal 16:9 so little and not in a standard 1024x576?
- we know that in a lot of case best codec for internet is mp4 or mov h264, but for a presentation or a projection (as in my example) which is the best format and codec?

thanks everyone and sorry if my description was so long!!! ;)