IMAG LED walls not always in sync
I work at a venue with two LED IMAG walls. Sometimes the walls appear perfectly in sync with camera cuts, and sometimes one wall appears to switch 1/2 to one frame before the other.
Each wall has its own separate Novapro UHD Jr processor. The processors are fed from the same source, either directly from a Blackmagic ATEM Constellation, or sometimes from a visiting fly pack.
Signal is SDI out of switcher directly to SDI inputs on each processor. No conversion in line. There is no scaling happening at either processor.
The two LED processors are not tied together in any way as far as genlock or network connections.
Why would the screens sometimes appear perfectly in sync, and sometimes the left screen appears to be a half to one frame “faster” than the other?