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>
54 lines
2.4 KiB
Common Lisp
54 lines
2.4 KiB
Common Lisp
;; slice-every-n construct - group every N beats into one segment
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;;
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;; Usage:
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;; (construct slice-every-n :path "constructs/slice-every-n.sexp")
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;; (def segments (slice-every-n beats-data 4
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;; :init 0
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;; :reducer (fn [acc i start end]
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;; {:source video-a
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;; :effects (list {:effect invert})
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;; :acc (inc acc)})))
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;;
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;; Groups every N analysis times into one segment, calling reducer once per group
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(define-construct slice-every-n
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"Group every N analysis beats into segments"
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(analysis n)
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;; 'init' and 'reducer' come from keyword args
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;; Reducer receives: (acc, i, start, end) where start/end are audio beat times
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;; Reducer returns: {:source src :effects fx :acc new-acc}
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;; Optionally include :start/:end to override (e.g., for wrapping/randomizing)
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;; :duration is calculated from start/end (use :duration to override)
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;; Return :skip true to skip this segment
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(let [times (get analysis :times)
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;; Group times into chunks of n
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grouped (chunk-every times n)]
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(nth
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(reduce
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(fn [state group]
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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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audio-start (first group)
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audio-end (last group)
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audio-duration (- audio-end audio-start)
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;; Call user's reducer with audio beat times
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result (reducer acc i audio-start audio-end)
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new-acc (get result :acc)]
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;; Skip if reducer returns :skip true
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(if (get result :skip false)
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(list new-acc segments)
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(let [;; Use reducer's start/end/duration if provided, else use audio times
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seg-start (get result :start audio-start)
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seg-end (get result :end audio-end)
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seg-duration (get result :duration (- seg-end seg-start))
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segment (dict :source (get result :source)
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:start seg-start
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:end seg-end
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:duration seg-duration
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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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grouped)
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1)))
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