There are posts in many of the forums about this problem. And not just with DirecTV by the way, there are problems with Dish receivers, cable boxes, HDMI switching receivers, upconverting DVD players etc etc The core of the problem is that different HDMI/HDCP implementations that are supposed to work with each other, don't. Often both the manufacturers say they are in specification, the spec seems just to be badly defined.
There are a couple of problems with Samsung and DirecTV receivers. First, many Samsung TVs do not support 480i resolution over HDMI. If you read the "fine print" in the user manual you will find a list of supported resolutions. If 480i is not in the list, you need to go into the H20 setup menu and uncheck 480i as a supported resolution, that way the H20 will not try to send 480i to the TV.
If that works, great.
If your TV does support 480i over HDMI, but you can't get HDMI to work, then there is a compatibility problem between the H20 and your TV. Many Samsung TVs, and a couple of other manufacturers, use a particular HDMI/HDCP chip - not made by Samsung, they buy it from a chip manufacturer - that the H20 HDMI implementation can't communicate with properly. It isn't clear which is at fault - the H20 works fine with many other TVs that don't use this chip, and the Samsung TVs work OK with other (but not all) cable and dish receivers. But whatever the problem, DirecTV is trying to modify the HDMI implementation on the H20 (which is basically in software, not a dedicated chipset) so that it is compatible with as many TVs as possible. They have already made changes to the HR20 software that have resulted in many of the HDMI problems going away. We assume that similar changes will be made to the H20 software, but have no idea when a software update will be available - rumor was it was going to be January but it didn't happen. Meanwhile you should just use component video connections.
Most people find that the picture quality on component is as good as HDMI. Some people report component gives a better picture than HDMI. Any difference between the two is most likely caused by different calibration on the inputs. Although HDMI is a digital connection, all the conversions going on in your receiver and in the TV have far more effect on picture quality than anything introduced by digital to analog conversion, especially with short component cables. And HDMI has its own issues, particularly with longer cables - it is fairly susceptible to interference, and needs equalization over long distances. Its main advantage is that it is a single cable solution. I have both HDMI and component in use on my system, using 6ft cables from monoprice.com (don't pay a lot for cables, it's not worth it) and both give great picture quality
