color seperation

I do not know what it is called. Rings around the light. I see it in major movie animations. I can’t have it here in this shot or I need it reduced till it is not obvious. I have rendered a PNG sequence in xvid, Theora,Mpeg and all have this.
How can I reduce this? It looks bad in the video.


One more it is almost the same thing. First few frames sometimes looks like crap, more of what you see above, sometimes really bad. Its like it takes blender 3 to 5 frames to start working/rendering right.

It’s called banding and dithering is used to get rid of it. https://www.youtube.com/watch?v=YwrTaXXSZsY
Perhaps use those terms to search for more detailed information of why it happens and what dithering does. Video encoding can introduce it too so have to be careful that you’re not removing it from the sequence and still have it in the video, in which case it could be a problem in the codec or encoding settings.

Thanks I will need to re render to change color depth.
It is all in the video compression.