I found a similar thread concerning PD9 but there was no resolution and nothing that helped me.

I have a number of generated Timelapse clips:

H.264 AVC
12.09 Mbps
1920x1080
30 fps
16:9
Baseline
Progressive

My project is 16:9. I can play these perfectly in any player I choose. When I import them to PD10 (the latest upgraded version) they are pixelated in places. Not all clips (although they were generated at the same time and have the same specs).
Furthermore, the play back resolution (which I understand) did what I expected, in that at lower resolutions it showed no degradation but the produced movie, at whatever resolution, MP4 full HD, .wmv HD shows the problem.

Then it gets weird:
Playing the compiled clips with preview screen resolution at "High preview" and "HD Preview it is fine". Then when I go to "Full HD preview" it is also fine. It was not fine when I started. It is not fine on the clips alone. After I produce it and go back the preview is crap again without me changing anything.

I can't be the first one to see this can I?

I appreciate any help and will fill in blanks in my explanation as best I can. cheers,
Bob