a=import("C:\path\to\source.avs").subtitle("Source", align=9)
b=ffvideosource("C:\path\to\encode.mkv").subtitle("Encode", align=9)

interleave(a,b)
spline36resize(converttorgb,ffsar>1?round(width*ffsar):width,ffsar<1?round(height/ffsar):height)
ffinfo(framenum=true,frametype=true,cfrtime=false,vfrtime=false)