Constant DXVA_MIN_PIXELS

const DXVA_MIN_PIXELS: u64 = _; // 921_600u64

DXVA pays for itself only on big frames: a hardware decode is a GPU round-trip per frame (submit, decode, video-process, sync, copy back), which costs more than just software-decoding anything SD-sized. Attach the D3D manager at 720p and up.