I have a pretty simple home theater set-up and have continuous dropouts. At first it was audio AND video dropouts, then I made some adjustments.
I had an HDMI cable connected from the STB to the receiver. From there, the HDMI went from the receiver to the TV (HDMI 3).
I had frequent (twice per hour) audio and video dropouts occurring.
I then made a change and connected the HDMI cable from the STB directly to the TV (HDMI 4) and used RCA for audio from the STB to the receiver.
Now, I have Video ONLY dropouts.
I have swapped the STB from Verizon and changed the HDMI input from 3 to 4. Audio is absolutely fine. When I play Bluray, there are no video dropouts. Video dropouts occur during live TV and DVR playback.