I've been trying to see if anyone has addressed these, but on G3 platform cameras my testing would show:
True - It's always VBR in H264 or H265 on all of my G3 cameras.
DS-2CD2x87G2 yes. DS-2CD2x47G2 no. I can set the I frame rate and it makes a difference on DS-2CD2x47G2 but my DS-2CD2x87G2s...