;; Contrast effect - adjust image contrast
;; Usage: python3 plan.py effects/contrast.sexp -p amount=1.5 | python3 execute.py - -d . -o output.mp4
;;
;; Parameters:
;;   amount: contrast multiplier (0.0 to 3.0, default: 1.5)
;;           <1 = less contrast, >1 = more contrast

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

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

  ;; Default parameter (overridden by -p amount=N)
  (def amount 1.5)

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