Does it happen on more than 1 box?
Any issues with any of the regular channels?
Have you tried resetting router and stb?
I’m a physicist with long experience in electronics and optics, and I have solved this problem on two set-top boxes in my house. I removed the coax cable between the wall jack and the set-top box and replaced it with one that was 3” shorter. End of problem. What?? Why should something so silly actually do anything? Well, here’s what I think is going on: The RF radiation that enters that cable can be weakly reflected from its ends. If the wavelength of the particular channel has the correct relationship to the cable length, a resonance can be set up, just like blowing into a flute creates distinct tones. This resonance can cause problems. Changing the length of the cable by a quarter of a wavelength shifts it out of resonance. The channels I had problems with use frequencies 727 MHz and 636 MHz. (You can find this using Menu/Settings/System Information/Info in FiOS). The formula for the wavelength in this kind of coax cable is: wavelength in inches = 7793 / frequency in MHz. This gave 7793/727 = 10.7 inches and 7793/636 =12.3 inches. A quarter of those lengths is 3 to 4 inches. I had a cable lying around that was about the right length – being off by an inch or two wouldn’t matter. I got lucky the first time. If this had not worked, I would have tried some other lengths within a wavelength of the original cable length.
I just experienced the same issue of "On Demand" shows seen in HD having Pixelation. I have an older STB which is a Motorola HD QIP 7100 1 STB. A few years ago, I experienced the same issue renting a movie and watching in HD. I stopped renting On Demand movies after spending so much time with a Verizon FIOS rep telling me to restart my STB, running a test, disconnect cables and reconnect, make sure all cables are tightened, etc. and having the same issue. Very frustrating. FIOS just offered me a free On Demand movie rental. I watched a movie last night in HD and had the same issue again.
I have friends who are new to FIOS TV and their STB boxes are black in color and much smaller than what I have. Could the STB be the issue? All of us pay good money to Verizon Fios for a clear picture and having this issue is frustrating to say the least. I do not experience any issues watching regular TV channels in HD. This only appears watching On Demand shows and movies in HD. Any suggestions would be appreciated. My friends have no issues with their black colored FIOS STB's. Thanks
Do you have more than 1 STB?
If so, does it happen on all?
Have you checked coax connections?
Start at ONT and make sure all connections are tight.