HDMI cables are subject to misbehaving. The longer the run, the bigger the chance that the desired "I" signal pattern is turned into something that looks more like the oscilloscope sine wave that opens classic episodes of "Outer Limits." But you can control the vertical and horizontal, so to speak, with some HDMI extenders. There are several kinds available, from inexpensive inline devices like the UltraLink that worked for Tom (but not for me) and there are more heavily engineered solutions like the Etheral Restorer.