Users of PLASMA television are reporting high levels of 'artifacting' on DIRECT TV's HD Channel lineup. For those that don't have a degree in digital television, "artifacting" is when large blocks of fuzzy picture appear. You may notice this effect during TV scenes involving FIRE or WATER. Both of those scenarios require high amounts of data to properly render a sharp picture. Reason? The DELTA, or change in, location from one pixel to the next is so intense, that the data requirements increase beyond the capabilities of the delivery medium, in this case satellite to terrestrial MULTICAST.
If you're trying to smooth out the picture after it has been decoded by using your television controls, this can be very effective on smaller screens .  However for the larger plasma and LCD displays, artifact ING and data-errors are one of the most egregious problems occurring while video decompression is taking place.  
Interlacing is another misconception of four signal quality.  What this means is you look at the screen and it looks to you as if there are horizontal lines .  What you are really seeing is a step down conversion from a four to 80 interlaced to 1080 interlaced or perhaps 720 progressive.