anchor.diff:  (defun encoding-wrapper (filename image ncomp h w &key (quality 4))
     (case quality
       ;; quite good
  -    (1 (encode-image filename image ncomp h w :q-tabs (vector *q-luminance-hi* *q-chrominance-hi*) :sampling '((1 1)(1 1)(1 1))))
  +    (1 (encode-image filename image ncomp h w
  +                     :q-tabs (vector *q-luminance-hi* *q-chrominance-hi*) :sampling '((1 1)(1 1)(1 1))))
       ;; quite good either
  -    (2 (encode-image filename image ncomp h w :q-tabs (vector *q-luminance-hi* *q-chrominance-hi*) :sampling '((2 2)(1 1)(1 1))))
  +    (2 (encode-image filename image ncomp h w
  +                     :q-tabs (vector *q-luminance-hi* *q-chrominance-hi*) :sampling '((2 2)(1 1)(1 1))))
       ;; satisfactory
  -    (3 (encode-image filename image ncomp h w :q-tabs (vector *q-luminance* *q-chrominance*) :sampling '((1 1)(1 1)(1 1))))
  +    (3 (encode-image filename image ncomp h w
  +                     :q-tabs (vector *q-luminance* *q-chrominance*) :sampling '((1 1)(1 1)(1 1))))
       ;; fair, but slightly worse
  -    (4 (encode-image filename image ncomp h w :q-tabs (vector *q-luminance* *q-chrominance*) :sampling '((2 2)(1 1)(1 1))))
  +    (4 (encode-image filename image ncomp h w
  +                     :q-tabs (vector *q-luminance* *q-chrominance*) :sampling '((2 2)(1 1)(1 1))))
       ;; poor, but tolerable in a case of blurry original, gives a sufficient compression
  -    (5 (encode-image filename image ncomp h w :q-tabs (vector *q-luminance* *q-chrominance*) :sampling '((2 3)(1 1)(1 1))))
  +    (5 (encode-image filename image ncomp h w
  +                     :q-tabs (vector *q-luminance* *q-chrominance*) :sampling '((2 3)(1 1)(1 1))))
       (otherwise (error "Illegal encoding quality number specified (valid 1 till 5)"))))
  
positive.code:                                                                collecting (make-array 8))))))
           (preds (make-array ncomp :initial-element 0))
           (tqv (case ncomp
                  (3 #(0 1 1)) ;q-tables destinations for various component numbers
                  (1 #(0))
                  (2 #(0 1))
                  (4 #(0 1 2 3))
  
negative.code:         and tmp11 fixnum and tmp12 fixnum and tmp13 fixnum
          and z1 fixnum and z2 fixnum and z3 fixnum
          and z4 fixnum and z5 fixnum do
          (loop ; for dptrpos fixnum from 7 downto 0
                ; for dptr = (svref data dptrpos) do
                for dptr across data do   ; iterating over rows
                (setf tmp0 (plus (svref dptr 0) (svref dptr 7)))
                (setf tmp7 (minus (svref dptr 0) (svref dptr 7)))
                (setf tmp1 (plus (svref dptr 1) (svref dptr 6)))
  