In updated versions of FFmpeg (5.1.x) and SVT-AV1 (1.2.0/1.3.0), the
rate contol mode selection mechanism has changed, causing CBR to throw
an "Invalid Parameter" error and the encoder will fail to start. This
appears to be caused by us specifying rc_max_rate, which will also fail
on FFmpeg CLI. Adjust how we manage rate control methods, appropriately
version-gated, to work with both our current dependency versions and the
versions that we'd like to use.
46e17a1160