[0:v]split=2[c0v][c1v];[0:a]asplit=2[c0a][c1a];[c0v] trim=start=0:end=21,setpts=PTS-STARTPTS,fps=24,settb=AVTB [t0v]; [c0a] atrim=start=0:end=20.5,asetpts=PTS-STARTPTS [t0a]; [c1v] trim=start=28.579999999999927:end=44.66999999999993,setpts=PTS-STARTPTS,fps=24,settb=AVTB [t1v]; [c1a] atrim=start=28.579999999999927:end=44.66999999999993,asetpts=PTS-STARTPTS [t1a]; [t0v][t1v]xfade=transition=fade:duration=0.5:offset=20.5[outv];[t0a][t1a]concat=n=2:v=0:a=1[outa];