anchor.diff:  
   (defun get-mode-extension-string (channel-mode layer mode-extension)
     (declare #.utils:*standard-optimize-settings*)
  +  (declare (fixnum channel-mode layer mode-extension))
   
     (if (not (= channel-mode +channel-mode-joint+))
         ""
  
positive.code: 
    (defun valid-bit-rate-index (br-index)
      (declare #.utils:*standard-optimize-settings*)
  
      (and (> (the fixnum br-index) 0) (< (the fixnum br-index) 15)))
  
    (defun get-bit-rate (version layer bit-rate-index)
      (declare #.utils:*standard-optimize-settings*)
  
negative.code: 
  (defun get-side-info-size (version channel-mode)
    (declare #.utils:*standard-optimize-settings*)
    (declare (fixnum version channel-mode))
  
    (if (= version +mpeg-1+)
        (if (= channel-mode +channel-mode-mono+)
            17
            32)
        (if (= channel-mode +channel-mode-mono+)
            9
            17)))
  
  (defmethod check-vbr ((me frame))
    (declare #.utils:*standard-optimize-settings*)
  
    (with-frame-slots (me)
      (let ((i (get-side-info-size version channel-mode)))
        (declare (fixnum i))
        (when (>= i (length payload))
          (return-from check-vbr nil))
        (when (or (and (= (aref payload (+ i 0)) (char-code #\X))
                       (= (aref payload (+ i 1)) (char-code #\i))
                       (= (aref payload (+ i 2)) (char-code #\n))
  