Hi,
I've had the same problem, using Nactl's Artnet Library, and my take is that the ratio of defined pixels and amount of incoming universes/channels are messing with the original code of the Library.
If you look in the original code, you see a segment:
if ((universe - startUniverse) < maxUniverses)
universesReceived[universe - startUniverse] = 1;
for (int i = 0 ; i < maxUniverses ; i++)
{
if (universesReceived[i] == 0)
{
//Serial.println("Broke");
sendFrame = 0;
break;
}
}
..and I think amount of universes is somehow messing this up so that "sendFrame = 0" all the time. When this happens, further down in the code, you will see that "leds.show()" is never called because of it, and this stops the pixels from being drawn.
My solution was to simply comment out the above code segment, and then it worked! Honestly, I have no idea what this portion of code is actually doing. The only explainer given is: "Store which universe has got in". I haven't tried it in enough cases to see if this code is actually needed or not, but so far so good!