UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Video "quantizing" effect through modulator

Argus25 · 28th May 2018, 2:54 pm

Basically what you are seeing is called a "paint by numbers effect" with sudden obvious jumps in the luminance level. Mostly, this is a common effect seen in the low lights of digital TV, its less commonly seen on the high lights but it is the same problem.

It is a digital effect, meaning the difference between the white level on the face and the grey level next to it, represents a change of one count or one bit, suggesting the resolution (number of bits) feeding the D to A converter is far too low. When you say the signal is from a PC source, is it a composite signal from a connector on your video card ? Can you adjust the resolution of the video card in the computer's settings ?

28th May 2018, 2:54 pm	#2
Argus25 No Longer a Member Join Date: Oct 2016 Location: Maroochydore, Queensland, Australia. Posts: 2,679	Re: Video "quantizing" effect through modulator Basically what you are seeing is called a "paint by numbers effect" with sudden obvious jumps in the luminance level. Mostly, this is a common effect seen in the low lights of digital TV, its less commonly seen on the high lights but it is the same problem. It is a digital effect, meaning the difference between the white level on the face and the grey level next to it, represents a change of one count or one bit, suggesting the resolution (number of bits) feeding the D to A converter is far too low. When you say the signal is from a PC source, is it a composite signal from a connector on your video card ? Can you adjust the resolution of the video card in the computer's settings ?