Originally Posted by bokes
I read claims that the Pioneer Kuro looks best on RGB.
Confused- but isn't that a setting going out to a PC type screen?
And also, My Kuro accepts 4:4:4 I would think that to be the best signal to send it.
Is it more common to send 4:2:2 regardless?
Learning as I go.
No, although computer screens usually do take RGB, its utility is not limited to computer graphics (or computer games). But RGB comes in two flavors -- OPPO calls them RGB Video Level and RGB PC Level -- and there really is benefit to setting things up to use RGB Video Level if you are going to use RGB video format.
The data on disc is YCbCr. To be precise it is what's called YCbCr 4:2:0. RGB format includes three values for every pixel -- a Red, a Green, and a Blue brightness. YCbCr also uses three values -- a gray scale brightness called Luma (Y) and two "color difference" components (Cb and Cr) which tell how much Blue and Red, respectively, to add or subtract from that gray. If you pull all the Blue and Red from a gray pixel, what's left is a Green pixel. The two formats are essentially interchangeable ways to represent the same image.
So why use the more confusing YCbCr format? Because the eye is less sensitive to fine detail in color than in black and white. The encoding scheme for broadcast video (including cable and satellite) and for video on disc (including SD-DVD and Blu-ray) USES that fact in a cunning scheme to reduce the data rate -- less space on disc, and, equally important, less bit rate to read the data OFF the disc.
YCbCr 4:2:0, you see, means that color information occurs in the image stream only HALF as often horizontally AND vertically as gray scale information! This is a type of in-frame compression that is applied before things like MPEG or VC1 encoding get their hands on the video and try to do additional compression based on the fact that successive frames of video are more similar than different -- so you only need to record the changes.
And that's why YCbCr is used. If you want to record color less frequently than gray scale then you need a format which SEPARATES OUT the color information from the gray scale information!
Of course before the pixels can light up on your display every pixel needs to have its own color value assigned.
That means the YCbCr 4:2:0 on the disc has to be interpolated for color -- assigning the missing color values according to the included color values of adjacent pixels. Think of it as a type of upscaling, just like going from SD to HD resolution -- except in this case it is just happening for color.
There are two pieces to this. The recreation of the missing vertical color values raises YCbCr 4:2:0 to YCbCr 4:2:2. The recreation of the missing color information horizontally across each line of video raises YCbCr 4:2:2 to YCbCr 4:4:4. Both pieces have to happen before the pixels can light up. The player ALWAYS does the first piece (because it can't assume the device downstream can buffer multiple lines of video). But the second piece could be done EITHER in the player or in some subsequent device, like your display. Theoretically the result is identical either way.
But the physical display elements typically need R, G, and B values to drive them. And so another step is converting YCbCr 4:4:4 to RGB. (RGB always has all three components for every pixel, so it is equivalent to YCbCr 4:4:4 in data content.)
If everything is working correctly, it should make NO DIFFERENCE whether the player is set to output YCbCr 4:2:2, YCbCr 4:4:4, or RGB Video Level. They should be interchangeable.
The fact that the Kuro displays seem to work better when fed RGB Video Level thus suggests there is a bug in their internal video processing affecting YCbCr input.