seek, name=First-forward-seek, playback_time="min(5.0, (duration/8))", start="min(10, 2*(duration/8))" seek, name=Second-forward-seek, playback_time="min(15.0, 3*(duration/8))", start="min(20, 4*(duration/8))" seek, name=Third-forward-seek-with-stop-value-1-sec, playback_time="min(25, 5*(duration/8))", start="min(30.0, 6*(duration/8))", stop="min(35.0, 8*(duration/8))"