Release 2.2.0 — qualities 10..18 K = q - 2 measured contiguously from quality 4 to 18 by solving for the shift from the reference encoder's own quantized coefficients. Decode and encode both cover 0..18; 54/54 agreement with the reference encoder and decoder at 10..18. Quality 19+ stays refused: the shift stops being observable below an 8192x8192 probe, not because the format stops there.