out=299 \
-transition \
composite a_track=0 b_track=1 out=299 distort=1 \
-start=0,70%:100%x64:100 \
+start=0/70%:100%x64:100 \
-transition \
composite a_track=0 b_track=2 out=299 titles=1 \
-start=100%,70%:999%x20% \
-end=-299%,70%:999%x20% \
+start=100%/70%:999%x20% \
+end=-299%/70%:999%x20% \
$*