anchor.diff:  
   (defmethod stream-playback-start ((rec wav-stream-record))
     (call-next-method))
  -
  -(define-constant +frame-duration-seconds+ 5)
  -(define-constant +chunk-granularity-scale+ 10) ;10 per second
   
   (defmethod shared-initialize :after ((rec wav-stream-record) slots &key &allow-other-keys)
     (declare (ignorable slots))
  
positive.code: (in-package :cl-video)
  
  (define-constant  +pcmi-uncompressed+ 1)
  
  (define-condition unsupported-wav-file-format (media-decoder-error)
    ()
  
negative.code:     (bt:release-lock cur-lock)))
  
  (defclass wav-container (av-container)
    (chunk-decoder :accessor chunk-decoder))
  
  (defmethod initialize-instance :after ((s wav-container) &key &allow-other-keys)
    (setf (chunk-decoder s) #'(lambda (stream id size)
  			      (decode-media-stream (car (stream-records s)) size stream))))
  
  (defmethod read-wav-stream-info ((wav wav-container) stream)
    (loop for chunk = (riff:read-riff-chunk stream)
  