this is the part of the code that uses MPEG4

set source [$ns node]
set udp0 [new Agent/UDP]
$ns attach-agent $source $udp0
set vdo [new Application/Traffic/MPEG4]
$vdo set initialSeed_ 0.4
$vdo set rateFactor_ 5
$vdo attach-agent $udp0

$ns at 1.8 "$vdo start"