Artifacts during night scenes

Hi, we had our U-verse installed yesterday. Overall our experience has been good, but we're seeing pretty noticeable artifacts during night scenes. The black background of the scenes has a ton of blocking / artifacts in it. We have a 55" TV and do not see the artifacts on BluRay. I know U-verse uses a lot of signal compression, so I'm wondering if that's the cause, and it's something we'll have to live with, or if something's actually wrong with my signal. I don't see the artifacts really except on black backgrounds. I'd appreciate any thoughts or experiences you guys can share.

Thanks!

Mark