This problem is related to my previous problem about pdf trimming.
Here is the minimal code:
\documentclass{article}
\usepackage{pdfpages}
\usepackage[paperwidth=6.38in,paperheight=4.025in,margin=0mm]{geometry}
\newlength{\mylength}
\setlength{\mylength}{0.7in}
\usepackage{multido}
\begin{document}
\multido{\i=50+1}{10}%
{%
\ifthenelse{\isodd{\i}}%
{%
\includepdf[pages=\i,trim=\mylength 4.325in 0.3in 0.9in,clip]{MVC}%
\pagebreak
\includepdf[pages=\i,trim=0.7in 0.4in 0.3in 4.825in,clip]{MVC}%
}%
{%
\includepdf[pages=\i,trim=0.3in 4.325in 0.7in 0.9in,clip]{MVC}%
\pagebreak
\includepdf[pages=\i,trim=0.3in 0.4in 0.7in 4.825in,clip]{MVC}%
}%
}%
\end{document}
The pdf file to be trimmed is available here. I rename the pdf as MVC.pdf and save it in the same directory in which the tex input file above is saved.
I compiled and got blank pages.