The detailed setting of the movie is given in the paper, Hotta et al, 2012, A&A, 539, A30 (free access) . In the last paragraph of the subsection 3.2, the Reduced Speed of Sound Technique with inhomogeneous xi is investigated. The top, middle, and bottom panels correspond to homogeneous xi(=20), inhomogeneous and conservative form (eq. 34), and non-conservative form (eq. 3), respectively. This result shows that the RSST with inhomogeneaus xi and non-conservative form is valid.