mlt_fade_in_and_out

melt \
clip1.dv out=74 -blank 99 clip3.dv in=25 \
-track \
-blank 49 clip2.mpeg out=149 \
-transition luma in=50 out=74 a_track=0 b_track=1 \
-transition luma in=175 out=199 a_track=0 b_track=1 reverse=1 \
-transition mix:-1 in=50 out=74 a_track=0 b_track=1 \
-transition mix:-1 in=175 out=199 a_track=0 b_track=1 reverse=1 \
$*