Connecting my Wii via official component cable to OSSC 1.6 I get green (instead of grey/black) when games switch screens and when it goes to power down screen saver mode. In that case all screen turns into dark green instead of black/dark. For better describing my issue the lower the brightness on OSSC the more green image it becomes.
Connecting my Wii via RGB has much better and vibrant colors and works as normal. My component cable is ok as I test it to a crt Sony BVM. I don’t have another console to output component in order to compare.
The reason “5” looks wrong is because of the difference in how video is transmitted with YPbPr versus RGB.
Simply put, with YPbPr, a black and white image is sent on the green line (Y, luminance), and the other two lines contain minimal color data (the difference between luma and blue, Pb; and the difference luma and red, Pr); and RGB sends red, green, and blue color data on separate lines; essentially red, green, and blue images that get combined into a full-color image.
So, when your Wii is outputting YPbPr, and the OSSC is interpreting it as RGB (RGsB specifically), it looks all-green, because almost all of the image data is being sent on the green line.