I didn't use ConvertToRGB24, only ConvertToRGB32.....as even if I do RGB24 in AVS, then I will need to do convert to 32 again....which will mean more CPU time required
I've just tried again with
ConvertToRGB24(matrix="rec709") + RGB24>RGB32 conversion in ffdshow(as neither VMR9/EVR or HR will accept RGB24 input) and I still get pixelated red.....are you sure you got this output from ConvertToRGB24 ?!
maybe it's ffdshow messing the whole stuff up, then ? even tho I kinda doubt it