Self-scrolling formulas and text in Beamer?

Synposis:

%put a longer paragraph of text in a box
newsaveboxlipsumbox
begin{lrbox}{lipsumbox}%
  begin{minipage}{textwidth}%
    strut
    lipsum
    strut
  end{minipage}
end{lrbox}

%scroll the box content within a viewport of limited height
smoothscroll[autoplay]{lipsumbox}{0.93textheight}{400}{25}

Usage:

smoothscroll[autoplay]
  {<box number>}       %filled box
  {<viewport height>}
  {<steps>}            %increase to enhance smoothness
  {<steps per sec>}    %adjust scrolling speed (not more than 25)

Complete example:

documentclass[a5paper]{scrartcl}
usepackage{lipsum}
usepackage{animate}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
usepackage{xsavebox}
newcommandsmoothscroll[5][]{%
  % [#1] autoplay
  % #2 <boxnum>
  % #3 <viewport height>
  % #4 <steps>
  % #5 <steps per sec>
  edefmywd{thewd#2}%
  edefmyht{theht#2}%
  edefmytht{thedimexprht#2+dp#2relax}%
  xsavebox{scrollbox}{usebox{#2}}% make re-usable PDF XObject
  edefportht{thedimexpr#3relax}%
  begin{animateinline}[#1,width=mywd,height=portht,loop]{#5}
    multiframe{#4}{dRaiseLen=-myht+dimexpr(mytht+portht)/#4relax}{%
      begin{minipage}[b][#3][b]{mywd}%
        raisebox{dRaiseLen}[0pt][0pt]{thescrollbox}%
      end{minipage}%
    }%
  end{animateinline}%
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

begin{document}huge
newsaveboxlipsumbox
begin{lrbox}{lipsumbox}%
  begin{minipage}{textwidth}
    strut Lipsum:

    lipsum[1]
    begin{equation}
      E=mc^2
    end{equation}
    centerline{* * *}strut
  end{minipage}
end{lrbox}

noindent Read this if you can:[1ex]
smoothscroll[autoplay]{lipsumbox}{0.93textheight}{400}{25}
end{document}