anchor.diff:  	 (read-sequence (extra-bytes rec) is)))
          (return)))
   
  -(defmethod decode-media-stream ((rec audio-stream-record) fsize input-stream)
  +(defmethod decode-media-stream ((rec wav-stream-record) fsize input-stream)
     (let* ((chunk (pop (wcursor rec)))
   	 (cur-lock (vacancy-lock chunk))
   	 (new-chunk (car (wcursor rec))))
  
positive.code:   (loop for chunk = (riff:read-riff-chunk stream)
       with rec = (make-instance 'wav-stream-record :container wav)
       when (string-equal (riff:riff-chunk-id chunk) "strh") do
         (flexi-streams:with-input-from-sequence (is (riff:riff-chunk-data chunk))
  	 (setf (fcc-type rec) (riff::read-fourcc is)
  	       (fcc-handler rec) (riff::read-fourcc is)
  	       (flags rec) (riff:read-u4 is)
  	       (priority rec) (riff:read-u2 is)
  	       (language rec) (riff:read-u2 is)
  	       (initial-frames rec) (riff:read-u4 is)
  	       (scale rec) (riff:read-u4 is)
  	       (rate rec) (riff:read-u4 is)
  	       (start rec) (riff:read-u4 is)
  	       (stream-length rec) (riff:read-u4 is)
  	       (suggested-buffer-size rec) (riff:read-u4 is)
  	       (quality rec) (riff:read-u4 is)
  	       (sample-size rec) (riff:read-u4 is)
  	       (frame rec) (list (riff:read-u2 is) (riff:read-u2 is) (riff:read-u2 is) (riff:read-u2 is))))
         (when (and (string-equal (fcc-type rec) "vids") (not (member (fcc-handler rec) '("mjpg") :test #'string-equal)))
  	 (error 'unsupported-wav-file-format))
         (cond ((and (string-equal (fcc-type rec) "vids") (string-equal (fcc-handler rec) "mjpg"))
  	      (change-class rec 'mjpeg-stream-record) (setf (frame-delay rec) (/ (scale rec) (rate rec))))
  	     ((string-equal (fcc-type rec) "auds")
  	      (change-class rec 'audio-stream-record) (read-audio-stream-header rec stream) (setf (frame-delay rec) (/ (scale rec) (rate rec)))))
         (return-from read-wav-stream-info rec))
    (error 'malformed-wav-file-format))
  
  
negative.code: 	   (fourcc (getf chunk :file-type)))
        (unless (string-equal id "riff")
  	(error 'unrecognized-file-format))
        (cond ((string-equal fourcc "wave") (read-wav-header wav stream))
  	    (t (error 'unsupported-wav-file-format))))
      (when (player-callback wav)
        (funcall (player-callback wav) wav))
  