19/02/08 09:45:34.37 m2RBeXnR0.net
URLﾘﾝｸ(trac.ffmpeg.org)
申し訳ない、ここになにかも書いてありました。
Mapping options from libx264
No CRF-like mode is currently supported. The only constant-quality mode is CQP (constant quantisation parameter), which has no
adaptivity to scene content. It does, however, allow different quality settings for different frame types, to improve compression by
spending fewer bits on unreferenced B-frames - see the (i|b)_q(factor|offset) options. CQP mode cannot be combined with a maximum
bitrate or buffer size.
CRFもないし、maxrateとcqp(qp)値との併用もできないようです。