+\subsection{How to Build OpenCV Plugins}%
+\label{sub:how_build_opencv_plugins}
+
+For users who do their own build or for administrators who want to create a System build that
+includes OpenCV, here are some notes to facilitate doing so. Building findobject will configure
+and build OpenCV into the thirdparty library build area if needed (it does not rebuild if done
+previously). Network access is required to obtain the OpenCV source, at least once. You will
+need a minimum of $4\, GB$ in the thirdparty build directory and more time to compile.
+
+\subsubsection*{Build using stable tarballs}%
+\label{ssub:stable_tars}
+
+Instead of using the latest git version, there is a custom archive source tarball on the
+website already created to build and test OpenCV versions. The reason for this is that OpenCV
+is quite volatile, and may or may not work on any given day so this is an already tested version
+that is considered to be more stable. A build using the tarball requires that your
+system have \textit{wget} already installed to initially download the prepared source tar.
+There are currently 2 tarballs of stable versions on the website used for user builds.
+The 20180401 version:\newline
+{\small \url{ https://cinelerra-gg.org/download/opencv/opencv-20180401.tgz}}\newline
+works with older version of cmake, and 20200308 is the current 4.2 release:\newline
+{\small \url{https://cinelerra-gg.org/download/opencv/opencv-20200306.tgz}}
+
+To build using the tarballs on the website, use this bld.sh procedure (you may want to run "make
+clean" first):
+\begin{lstlisting}[style=sh]
+#!/bin/bash
+( ./autogen.sh
+ ./configure --with-single-user --with-booby \
+ --with-opencv=sta,tar=http://cinelerra-gg.org/download/opencv/opencv-20200306.tgz
+ make && make install ) 2>&1 | tee log
+mv Makefile Makefile.cfg
+cp Makefile.devel Makefile
+\end{lstlisting}
+
+\subsubsection*{Build using current git version}%
+\label{ssub:current_git}
+
+To build findobject and the other plugins using OpenCV, access the src using git:
+
+\begin{lstlisting}[style=sh]
+git clone -depth 1 "git://git.cinelerra-gg.org/goodguy/cinelerra.git" cinelerra5
+\end{lstlisting}
+To use the latest version, the method for creating a tarball is:
+
+\begin{enumerate}
+ \item download both opencv and opencv\_contrib source tarballs from the web:
+ {\small \url{https://sourceforge.net/projects/opencvlibrary/files/4.2.0/}}
+ {\small \url{https://github.com/opencv/opencv\_contrib/archive/4.2.0.tar.gz}}
+ \item create a temporary directory opencv\_src and unpack the tarballs into the src directory
+ \item rename these sources to opencv and opencv\_contrib
+ \item run a test build, using opencv\_build for config:
+\end{enumerate}