melt \
clip3.dv \
-filter \
watermark:clip1.dv \
composite.start=10%/10%:20%x20% \
composite.key[33]=30%/70%:25%x25% \
composite.key[66]=70%/30%:15%x15% \
composite.end=70%/70%:20%x20% \
composite.out=100 \
$*