Is there a standard defining the black level of component video signals ( YPrPb, YCrCb )?
Should it be 0V for each three of them or 1-2 V is also acceptable?
SDTV Cr=0.713(R-Y), Cb= .564(B-Y) For black, grey or white both signals are +350 mV For the strongest colours a maximum of 350 mV will be added or subtracted depending on the colour.
HDTV Pr=.6349(R-Y), Pb=.5389(B-Y) For black, grey or white both signals are +350 mV For the strongest colours a maximum of 350 mV will be added or subtracted depending on the colour.
Generally this level does not matter, since most video inputs are AC coupled, followed by a DC restoration circuit. So under these circumstances, even with 1-2VDC measured at the video output, things should be OK.