Hi,
We suggest try this setup:
Random blockiness in the picture RTSP server-client -Jetson TX2 - #5 by DaneLLL
Generally IDR/I frames have larger size. Setting virtual buffer size can reduce some gap between IDR/I and P frames.
And can enable this property and try:
EnableTwopassCBR : Enable two pass CBR while encoding
flags: readable, writable, changeable only in NULL or READY state
Boolean. Default: false