I'm not sure if I understand certain options correctly.
Can you tell me if I'm right or totally wrong?

How do the -crf and -qp options within x264 determine what bitrate
to use for your video?

1. Does -crf option determine the bitrate by a "quality-value" that you entered (ie. -crf 21),
And translate that to something like --> user wants approx. 85% Q per frame ???
Wich then let's the encoder determine wich bitrate will best match 85% quality on a per frame basis?

confusing sometimes.

2. And will setting up the -qp option let x264 behave more like "Constant Bitrate" with MP3 does?
When each frame was given a pre-determined amount of bits to use/frame-period.
Regardless if it could maintain transparancy or not.

Thanks for any useful info.
It gets confusing sometimes.