;; Trails effect - motion blur/persistence
;; Usage: python3 plan.py effects/trails.sexp -p persistence=0.7 | python3 execute.py - -d . -o output.mp4
;;
;; Parameters:
;;   persistence: trail strength (0.3 to 0.95, default: 0.7)
;;                higher = longer trails

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

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

  ;; Default parameter (overridden by -p persistence=N)
  (def persistence 0.7)

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