For some reason, using MFX_SCENARIO_GAME_STREAMING causes the keyframe
quants to be higher than other frames, which is not desirable. In turn,
this causes bitrate to be higher than the target bitrate for a sustained
period of time after each keyframe.
Not setting the scenario removes this behavior and returns CBR to
somewhat reasonable levels of consistency.
Co-authored by: Chris (Flaeri) <flaeri@otterbro.com>
03b70f0672