[FFmpeg-user] Two-pass versus CRF: a curiosity question

[Fred M. Sloniker]

I'm given to understand that, under the hood, two-pass and CRF are the 
same thing, just that two-pass calculates the necessary CRF to get the 
desired filesize. Is this correct? And if so, is it possible to see what 
CRF was selected in the two-pass encoding? I'm experimenting with 
encoding two versions of a video, one at a higher resolution than the 
other, and I'm curious if I could encode the high-res one with two-pass, 
then somehow encode the low-res one with the same CRF. (I already 
figured out that naively dividing the filesize by some amount for a 
second two-pass encode isn't going to work.)