406cc7c0c7
Add S-expression based video effects pipeline with modular effect definitions, constructs, and recipe files. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
46 lines
1.7 KiB
Common Lisp
46 lines
1.7 KiB
Common Lisp
;; slice-on construct - iterate over analysis times with user function
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;;
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;; Usage:
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;; (construct slice-on :path "constructs/slice-on.sexp")
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;; (def segments (slice-on beats-data
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;; :init 0
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;; :reducer (fn [acc i start end]
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;; {:source (nth (list video-a video-b) (mod acc 2))
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;; :effects (list)
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;; :acc (inc acc)})))
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;;
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;; The construct receives:
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;; - First positional arg as 'analysis' (the analysis data with :times)
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;; - :init as 'init' (initial accumulator value)
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;; - :reducer as 'reducer' (the reducer lambda)
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(define-construct slice-on
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"Iterate over analysis times, calling reducer for each slice"
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(analysis)
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;; 'init' and 'reducer' come from keyword args
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;; Get times from analysis data
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(let [times (get analysis :times)
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pairs (zip-pairs (cons 0 times))]
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;; Use nth to get second element of reduce result (the segments list)
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(nth
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(reduce
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(fn [state pair]
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(let [acc (first state)
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segments (nth state 1)
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i (len segments)
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start (first pair)
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end (nth pair 1)
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;; Call user's reducer function
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result (reducer acc i start end)
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;; Extract new acc and build segment
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new-acc (get result :acc)
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segment (dict :source (get result :source)
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:start start
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:end end
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:duration (- end start)
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:effects (get result :effects))]
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(list new-acc (append segments segment))))
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(list init (list))
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pairs)
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1)))
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