My HD signal gets pixel-y and blocky on darker red areas, especially in motion. Normal or not?

Question

Is it a problem with the signal? The box? The cable? Or is this just a drawback to HD?

Answer 1

It's not a drawback to HD, it's just your cable/satellite company being cheap. The TV stations are being broadcast digitally and highly compressed to save bandwidth.

The cable company can choose the level of compression. Usually they select a very high level, that way they can cram more channels into the same bandwidth. High compression leads to visible compression artifacts. The most noticable form of compression artifact is known by the scientific name "blockyness" :)

If your cable company weren't so cheap they would get more bandwidth to allow for lower compression, and thus get better image quality!

The human eye is very good at picking up nuances of red, so you pick up compression artifacts in red areas more easily. Compression artifacts are usually most visible in high-motion scenes.