Files
test/sexp_effects/effects/blend.sexp
gilesb d241e2a663 Add streaming video compositor with sexp interpreter
- New streaming/ module for real-time video processing:
  - compositor.py: Main streaming compositor with cycle-crossfade
  - sexp_executor.py: Executes compiled sexp recipes in real-time
  - sexp_interp.py: Full S-expression interpreter for SLICE_ON Lambda
  - recipe_adapter.py: Bridges recipes to streaming compositor
  - sources.py: Video source with ffmpeg streaming
  - audio.py: Real-time audio analysis (energy, beats)
  - output.py: Preview (mpv) and file output with audio muxing

- New templates/:
  - cycle-crossfade.sexp: Smooth zoom-based video cycling
  - process-pair.sexp: Dual-clip processing with effects

- Key features:
  - Videos cycle in input-videos order (not definition order)
  - Cumulative whole-spin rotation
  - Zero-weight sources skip processing
  - Live audio-reactive effects

- New effects: blend_multi for weighted layer compositing
- Updated primitives and interpreter for streaming compatibility

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
2026-01-29 01:27:39 +00:00

57 lines
2.2 KiB
Common Lisp

;; Blend effect - combines two video streams
;; Multi-input effect: uses frame-a and frame-b
;; Params:
;; mode - blend mode (add, multiply, screen, overlay, difference, lighten, darken, alpha)
;; opacity - blend amount (0-1)
;; resize_mode - how to resize frame-b to match frame-a (fit, crop, stretch)
;; priority - which dimension takes priority (width, height)
;; pad_color - color for padding in fit mode [r g b]
(require-primitives "image" "blending")
(define-effect blend
:params (
(mode :type string :default "overlay")
(opacity :type float :default 0.5)
(resize_mode :type string :default "fit")
(priority :type string :default "width")
(pad_color :type list :default (quote [0 0 0]))
)
(let [a frame-a
a-w (width a)
a-h (height a)
b-raw frame-b
b-w (width b-raw)
b-h (height b-raw)
;; Calculate scale based on resize mode and priority
scale-w (/ a-w b-w)
scale-h (/ a-h b-h)
scale (if (= resize_mode "stretch")
1 ;; Will use explicit dimensions
(if (= resize_mode "crop")
(max scale-w scale-h) ;; Scale to cover, then crop
(if (= priority "width")
scale-w
scale-h)))
;; For stretch, use target dimensions directly
new-w (if (= resize_mode "stretch") a-w (round (* b-w scale)))
new-h (if (= resize_mode "stretch") a-h (round (* b-h scale)))
;; Resize b
b-resized (resize b-raw new-w new-h "linear")
;; Handle fit (pad) or crop to exact size
b (if (= resize_mode "crop")
;; Crop to center
(let [cx (/ (- new-w a-w) 2)
cy (/ (- new-h a-h) 2)]
(crop b-resized cx cy a-w a-h))
(if (and (= resize_mode "fit") (or (!= new-w a-w) (!= new-h a-h)))
;; Pad to center
(let [pad-x (/ (- a-w new-w) 2)
pad-y (/ (- a-h new-h) 2)
canvas (make-image a-w a-h pad_color)]
(paste canvas b-resized pad-x pad-y))
b-resized))]
(if (= mode "alpha")
(blend-images a b opacity)
(blend-images a (blend-mode a b mode) opacity))))