[0:v] trim=start=0:end=0.83,fps=25,settb=AVTB [t0v]; [0:a] atrim=start=0:end=0.83 [t0a]; [1:v] trim=start=0:end=64.38,fps=25,settb=AVTB [t1v]; [1:a] atrim=start=0:end=64.38 [t1a]; [t0v][t1v]concat=n=2:v=1:a=0[outv]; [t0a][t1a]concat=n=2:v=0:a=1[outa];