Since I'm using HandBrake (x264 encoder) I'm using the variable frame rate (VFR) setting. My sources are almost always constant frame rate (CFR) and I never had any playback problems, so I really didn't gave it much thought. I read the Wiki/Docs about frame rates and stuff but I'm still not quite sure what the VFR setting really does:
In my understanding so far, VFR does only make a difference if I have a VFR source with mixed frame rates (maybe 24 fps for 20 minutes, and then 10 minutes 30 fps). So by implication if I have a purely CFR source the VFR setting would change absolutely nothing. This "theory" would be backed by my observation, that every CFR source I encode with VFR set to on still produces CFR target videos (at least that's what Mediainfo tells me, which could be wrong, of course):
Code: Select all
Frame rate mode : Constant
But more importantly: What is true for the VFR setting in handbrake? If I choose VFR will the x264 encoder really try to save space by dynamically adjusting the frame rate for each individual scene - even if I provide a CFR source? Or will it really just switch between different frame rate "modes" - if they exist in the source (i.e.: 24 fps --> 30 fps --> 24 fps)?