Do the transcoding quality settings actually work?

[gnattu]

In my experience, those encode settings only apply to CPU transcoding.

Yes. These settings only applies to CPU encoders.

These CRF settings typically have no effect on hardware encoders because:

• The hardware vendor's own metrics, such as "CQ," have different interpretations across vendors, and they differ from the CRF used in software encoders.
  
• Most of the time, we will have a bitrate limit that overrides the constant quality setting on hardware encoders. The actual override policy is vendor-specific.
  

If you want to trade off quality for speed, you can select an Encoding Preset. We have some internal mappings from these presets to hardware vendor-defined quality levels.