Would a USB to DMX converter and DMX lights be supported?

It is working great!

For me personally another great thing would be an option to say hyperion not to send send artnet data if the ambilight function is not turned on because I am normally controlling all my lights with openhab. So I could use the dmx fixtures independently when hyperion is just in "color-mode" to use them in different light scenes as well.

The only problem that is a little bit complicated to solve is the issue with the blacklevel recognition because the dmx fixtures are always on even if the screen is black. If I tweak the gamma levels to optimal values the lights are out when the screen is black or dark but the maximum brightness is reduced way too much so you couldn't talk about an "ambilight" anymore. But this is not really artnet related.

Excellent !

If you change these options it should only send differences:
Configuration -> LED Hardware -> Refresh time = 0
Configuration -> Image Processing -> Smoothing -> Continuous Output = unitcked

You may need to use the spanner icon in the top right hand corner to set the settings level to "expert"

I've submitted a pull request to get this merged into the main code

https://github.com/hyperion-project/hyperion.ng/pull/440

That's great! Thanks for realizing the artnet support!

no problem - did the config options stop it sending needless updates so you can have openhab work at the sames time?

No, unfortunately it didn't. The light was still on. But I found a way that works for me. I just disabled json-forwarding and now I just set the color of my DMX fixtures to black and then I can fully control them with openhab. And if I want the ambilight back on I just send a clear command with openhab to hyperion and then I have the full ambilight again.

The code you tested is now merged into the master branch of Hyperion.ng