rc: set pbFactor to default with cutree

--HG--
branch : stable
rc: use actual bits to update vbv buffer

--HG--
branch : stable
extra : amend_source : 641274167691f037c955ab0145822db961fb1bb9
rc: fixes to improve quality in vbv

--HG--
branch : stable
combine NAL output semantics into one clean(er) interface

--HG--
extra : amend_source : fb7e506db684d852cc0da1b770b9c8c23d5346ff
Merge with stable
ratecontrol: change type of m_bframeBits to int64_t