Overlay 위치
overlay=x:y. 흔한 위치 expression:
overlay=10:10— top-left, 10px in.overlay=W-w-10:10— top-right (W = main width, w = overlay width).overlay=W-w-10:H-h-10— bottom-right.overlay=(W-w)/2:(H-h)/2— centered.
Time-aware overlay
enable='between(t,2,5)' — t=2s 와 t=5s 사이만 overlay. Sponsor logo, lower-third 등에 유용.