Below snippet is copy-paste that can install 3rd party modules on nginx prebuilt debian package.
Don’t use it if you don’t understand every line it may break stuff. it’s intended for advanced sysadmins
ngx_version=$(nginx -v 2>&1 | cut -s -f2 -d '/')
ngx_config=$(nginx -V 2>&1 | cut -s -f2 -d':' | head -2 | tail -1 | awk -F '\--with-cc-opt' '{print $1}')
sudo apt-get install build-essential libpcre3 libpcre3-dev libssl-dev libzip-dev
sudo mkdir ~/build && cd ~/build
sudo git clone git://github.com/arut/nginx-rtmp-module.git
sudo wget http://nginx.org/download/nginx-$ngx_version.tar.gz
sudo tar xzf nginx-$ngx_version.tar.gz && cd nginx-$ngx_version
sudo ./configure $ngx_config --add-module=../nginx-rtmp-module
sudo make
sudo make install
