We have RGB outputs working fine with 525 line input YCbCr, pretty much like the table 67 scripts(EAV/SAV timing). These are 1 Volt RGB signals, with 286 mV sync pulses, as per the normal 525 component/composite standard. However SMPTE 253 specifies 1V RGB signal with 300 mV sync pulses.
It seems that the only way I can get 300 mV sync pulse on the outputs is to change register 80 bits 1:0 from NTSC to PAL. But then of course since my input is 525 and has a different number of active pixels, I get some garbage on the edge of the picture.
Is there any other way to get 300 mV sync pulses with 525 line input?