Function held_refresh_quality 

pub fn held_refresh_quality(
    settings: &RustCaptureSettings,
    encoder: EncoderQuality,
) -> u32

The quality index a held refresh (a predicted frame) is coded at: the paint-over one, or, where a constant rate last coded far coarser, as much finer than that as HELD_KEY_BUDGET_S of the target allows at six steps a doubling, since a refresh of a whole screen at the paint-over quantizer after heavy motion at a low rate would cost many frames of budget at once.