mlt_squeeze_box

melt \
clip1.dv out=124 clip2.dv out=149 clip3.dv in=75 out=224 clip1.dv \
-track \
-blank 99 colour:black out=49 -blank 99 colour:black out=49 -blank 99 colour:black out=49 \
-group progressive=1 \
-transition composite:"0=0%/0%:100%x100%; 25=50%/0%:5%x100%; -1=0%/0%:100%x100%" a_track=1 b_track=0 in=100 out=149 sliced_composite=1 \
-transition composite:"0=0%/0%:100%x100%; 25=0%/50%:100%x5%; -1=0%/0%:100%x100%" a_track=1 b_track=0 in=250 out=299 sliced_composite=1 \
-transition composite:"0=0%/0%:100%x100%; 25=100%/0%:5%x100%; -1=0%/0%:100%x100%" a_track=1 b_track=0 in=400 out=449 sliced_composite=1 \
$*