I fear these problems are something we will have to learn to live with as our lives become more and more "digital". All these devices depend on interpretation of data streams where one single bit misinterpreted can make nonsense of an entire block of data, hence the freezing or pixellating, among other things. With analogue TV you just got a slightly less than perfect picture which was usually still watchable, even through the "snowstorm" in the worst cases, but with digital it is a case of "all or nothing", hence the picture freezing or pixellating as blocks of data are lost.
One of my favourite digital quirks is the delay of the Greenwich time signal on DAB radio so it is broadcast about 2 seconds late . . .

We had a slightly different problem after analogue switch off a few weeks ago. The TV picture was very grainy, even watching a DVD . . . I finally found it was caused by the TV aerial still being plugged in to the TV as well as the SCART connection to the set top box. Once I pulled the aerial out the picture was much improved. Yes, we still have a CRT TV, and have no intention of changing it 'til it gives up the ghost.
Mike.