White Blocks Of Noise
 

:newbie:
I'm getting small white blocks in the lighter parts of the encoded movie.
These appear only briefly, and are quite small, but in quite a number - it's really noticeable.
It doesn't matter which template I use it still happens.
The original is of high quality so the noise isn't coming from there.
I've tried going through the forums looking for an answer to this question for the last hour or two, but I can't find one.
Any ideas?

A snapshot maybe ?

Use www.imageshack.us to post it for free.