&rfx_sendmsg (
  qq{
    (begin
      (when (= $start $frame)
        (define color-match-image (car (gimp-file-load RUN-NONINTERACTIVE "$in2" "$in2")))
        (gimp-image-undo-disable color-match-image)
        (gimp-image-scale-full color-match-image $width $height INTERPOLATION-CUBIC)
        (gimp-convert-indexed color-match-image NO-DITHER MAKE-PALETTE 256 FALSE TRUE "") )
        
      (let* ((input-file (string-append "$curtmpdir" DIR-SEPARATOR "$in"))
             (image (car (gimp-file-load RUN-NONINTERACTIVE input-file input-file)))
             (layer (car (gimp-image-get-active-layer image)))
             (decomp-mode "LAB") 
               ; (decomp-mode "YCbCr_ITU_R709")
               ; (decomp-mode "YCbCr_ITU_R470")
             (cb-image (car (gimp-image-duplicate color-match-image)))
             (decomp-layer 0)
             (y-images '())
             (uv-images '()) )
        (gimp-image-undo-disable image)
        (gimp-image-undo-disable cb-image)
        (set! decomp-layer (car (gimp-layer-new-from-drawable layer cb-image)))
        (gimp-image-add-layer cb-image decomp-layer 0)
        (gimp-convert-rgb cb-image)
        (let ((y-images (plug-in-decompose RUN-NONINTERACTIVE 
                                           image 
                                           layer
                                           decomp-mode 
                                           FALSE ))
              (uv-images (plug-in-decompose RUN-NONINTERACTIVE 
                                            cb-image 
                                            decomp-layer
                                            decomp-mode 
                                            FALSE )) )
          (gimp-image-delete cb-image)
          (set! cb-image (car (plug-in-compose RUN-NONINTERACTIVE
                                               (car y-images)
                                               0
                                               (cadr uv-images)
                                               (caddr uv-images)
                                               (cadddr y-images)
                                               decomp-mode  )))
          (map (lambda (x) (unless (< x 1) (gimp-image-delete x))) y-images)
          (map (lambda (x) (unless (< x 1) (gimp-image-delete x))) uv-images) )
        (gimp-image-delete image)

        (gimp-image-merge-visible-layers cb-image CLIP-TO-IMAGE)
        (rfx-save-frame cb-image "$out") 
        )
      )
    }
  );
