With most high color, sports, or awards shows, like the Grammy's from a few weeks ago, the pixelization was horrible. The performance of Alice Cooper was simply unwatchable.
I did some research and this is clearly a network or satellite issue. One major US tv carrier representative was very candid on how so few people are bothered by this, or at least never complain about it. If more people did, then something would obviously be done. At one point, that carrier would give their cable subscribers a credit due to the pixelization.
So if you're reading this, it's likely not your TV or cable if it happens intermittently but frequently. It's the signal Shaw is either receiving from it's source or there is a signal (loss) issue between your cable box and Shaw.