Not AMF related, haven't tried it there, but this is the closest forum I could find.
I'm writing a movie (4K H.264) using Media Foundation. If I specify a bit rate of over 100Mb/s, the result is equivalent to specifying 10Mb/s.
(Windows 10; Radeon RX 460, RX 480, R9 M390X; Drivers 17.4.4, 17.6.2, 17.7.2)
Retrieving data ...