;; Strobe effect - flashing/blinking
;; Usage: python3 plan.py effects/strobe.sexp -p frequency=4 | python3 execute.py - -d . -o output.mp4
;;
;; Parameters:
;;   frequency: flashes per second (1 to 15, default: 4)
;;              WARNING: high values may cause discomfort

(recipe "strobe"
  :version "1.0"
  :encoding (:codec "libx264" :crf 20 :preset "medium" :audio-codec "aac" :fps 30)

  (effect strobe :path "sexp_effects/effects/strobe.sexp")

  ;; Default parameter (overridden by -p frequency=N)
  (def frequency 4)

  (def video (source :path "monday.webm"))
  (def clip (-> video (segment :start 0 :duration 10)))
  (def result (-> clip (effect strobe :frequency frequency)))
  result)