The file claw_pix_example02_movie.mp4 is an MPEG-4 animation created by QuickTime Pro out of PNG files which were created by the MATLAB script CLAW_PIX from solution data generated by CLAWPACK.
In this animation, the 1D acoustics equation
Pt + K * Ux = 0
rho * Ut + Px = 0
is being solved at successive time steps. There are 400
spatial cells involved, and 30 time steps are taken.
The boundary condition at the left is solid reflecting wall,
and the boundary condition at the right is 0-order extrapolation,
that is, the data is simply copied to the
ghost cells.