Exampled

rtmp {
    server {
        listen 1935;
        application vod {
            play /var/flvs;
        }
    }
}

rtmp {
    server {
        listen 1935;
        application live {
            live on;
        }
    }
}

rtmp {
    server {
        listen 1935;
        application tv {
            live on;
            pull rtmp://cdn.example.com:443/programs/main pageUrl=http://www.example.com/index.html name=maintv;
        }
    }
}

rtmp {
    server {
        listen 1935;
        application tv {
            live on;
            hls on;
            hls_path /tmp/tv2;
            hls_fragment 15s;

            pull rtmp://tv2.example.com:443/root/new name=tv2;
        }
    }
}
http {
    server {
        listen 80;
        location /tv2 {
            alias /tmp/tv2;
        }
    }
}

$ ffmpeg -f x11grab -follow_mouse centered -r 25 -s cif -i :0.0 -f flv rtmp://localhost/myapp/screen