Hi there!
Back in 2004/5 I build my first momo light controller and it was fun, playing with 3 30cm RGB strips 
Now I'm revisiting the whole ambilight scene and wow a lot of progress is made!
I have 170 WS2812B leds around my tv and it is somewhat working, small things like the location is a little off and the leds are somewhat dim. But that just needs tinkering.
Playback of 720p material is mostly fine, some minor auto dropouts, playback of anything 1080p and I get black screens with flashes of movie in between. If I look at the cpu usages in 720 is about 5% in 1080 a little more but nothing to bad.
Something however is very wrong and I don't know what. I found someone with the same issue on a dutch forum but it seems it never got solved.
I could not find any information about how many led's a PI3 could handle. Is 170 to much? it is running out of cpu time or memory bandwidth?
Hope someone can help.
Kodi --> Arduino nano --> ws2812B
Arduino and ws2812B powered by a 5v 8 amp PSU
Raspberry PI3 powered by a 5v 5 amp PSU
Kodi version : 17.6 compiled April 13-2018
hypercon version : 1.03.3
Ambilight version 1.03.4
Hyperion log
Arduino code
Youtube video showing the problem
Youtube Video showing 720 low bitrate