[0:v][1:v]xfade=transition=fade:duration=0.7:offset=2.8[x1];
[x1][2:v]xfade=transition=fade:duration=0.7:offset=5.6[x2];
[x2][3:v]xfade=transition=fade:duration=0.7:offset=8.4[x3];
[x3][4:v]xfade=transition=fade:duration=0.7:offset=11.2[x4];
[x4][5:v]xfade=transition=fade:duration=0.7:offset=14.0[x5];
[x5]fade=t=in:st=0:d=0.5,fade=t=out:st=17.0:d=0.5,format=yuv420p[vout]