i do not think fps or bitrate is the problem, i suspect it is the codec or more bugs with multiple videos playing, or both.
my desktop pc is old but it is no slouch, however most animations in this game work fine enough.
there are only a few that have very high cpu usage which ramp up the fans, like:
and a few more that i forgot.
main menu is up there with cpu usage but it does not make it unusable like the ones i listed above.
the pattern seems to be choppyness as more of the animation plays, i think i lean towards bugs, probably caused by newer renpy engine.