clip1.dv out=74 \
-track \
-blank 49 clip2.mpeg \
--transition composite:57%,10%:33%x33% end=0%,0%:100%x100% progressive=1 distort=true in=50 out=74 a_track=0 b_track=1 \
+-transition composite:57%/10%:33%x33% end=0%/0%:100%x100% progressive=1 distort=true in=50 out=74 a_track=0 b_track=1 \
-transition mix:-1 in=50 out=74 a_track=0 b_track=1 \
$*