Add ascii_dual_blend recipe and fix blend/layer effects

- Add ascii_dual_blend.sexp: blends two ASCII-processed videos synced to audio
- Fix blend.sexp: add require-primitives, fix params syntax
- Fix layer.sexp: add require-primitives
- Use consistent (effect blend ...) syntax instead of special form

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

effects/ascii_dual_blend.sexp

@@ -0,0 +1,101 @@
+;; ASCII Dual Blend
+;;
+;; Applies ASCII alternating rotation effect to two video sources,
+;; blends them together, and muxes with audio.
+;; All synced to the same audio analysis.
+
+(recipe "ascii_dual_blend"
+  :version "1.0"
+  :description "Blend two ASCII-processed videos synced to audio"
+  :minimal-primitives true
+  :encoding (:codec "libx264" :crf 20 :preset "medium" :audio-codec "aac" :fps 30)
+
+  :params (
+    (cols :type int :default 50 :range [20 100]
+      :desc "Number of character columns")
+    (rotation_scale :type float :default 60 :range [0 180]
+      :desc "Max rotation in degrees")
+    (blend_opacity :type float :default 0.5 :range [0 1]
+      :desc "Blend opacity (0=video-a only, 1=video-b only)")
+    (blend_mode :type string :default "overlay"
+      :desc "Blend mode: alpha, add, multiply, screen, overlay, difference")
+    (audio_start :type float :default 60
+      :desc "Start time in audio (seconds)")
+    (duration :type float :default 10
+      :desc "Duration (seconds)")
+  )
+
+  ;; Registry - effects and analyzers
+  (effect ascii_fx_zone :path "../sexp_effects/effects/ascii_fx_zone.sexp")
+  (effect rotate :path "../sexp_effects/effects/rotate.sexp")
+  (effect blend :path "../sexp_effects/effects/blend.sexp")
+  (analyzer energy :path "../../artdag-analyzers/energy/analyzer.py")
+
+  ;; Source files
+  (def video-a (source :path "../monday.webm"))
+  (def video-b (source :path "../new.webm"))
+  (def audio (source :path "../dizzy.mp3"))
+
+  ;; Stage 1: Analysis
+  (stage :analyze
+    :outputs [energy-data]
+    (def audio-clip (-> audio (segment :start audio_start :duration duration)))
+    (def energy-data (-> audio-clip (analyze energy))))
+
+  ;; Stage 2: Process both videos
+  (stage :process
+    :requires [:analyze]
+    :inputs [energy-data]
+    :outputs [blended audio-clip]
+
+    ;; Get audio clip for final mux
+    (def audio-clip (-> audio (segment :start audio_start :duration duration)))
+
+    ;; Process video A with ASCII effect
+    (def clip-a (-> video-a (segment :start 0 :duration duration)))
+    (def ascii-a (-> clip-a
+      (effect ascii_fx_zone
+        :cols cols
+        :char_size (bind energy-data values :range [10 20])
+        :color_mode "color"
+        :background "black"
+        :energy (bind energy-data values :range [0 1])
+        :rotation_scale rotation_scale
+        :cell_effect (lambda [cell zone]
+          (rotate cell
+            (* (if (= (mod (+ (get zone "row") (get zone "col")) 2) 0) 1 -1)
+               (* (get zone "energy")
+                  (get zone "rotation_scale")
+                  (* 1.5 (+ (get zone "col-norm")
+                            (- 1 (get zone "row-norm")))))))))))
+
+    ;; Process video B with ASCII effect
+    (def clip-b (-> video-b (segment :start 0 :duration duration)))
+    (def ascii-b (-> clip-b
+      (effect ascii_fx_zone
+        :cols cols
+        :char_size (bind energy-data values :range [10 20])
+        :color_mode "color"
+        :background "black"
+        :energy (bind energy-data values :range [0 1])
+        :rotation_scale rotation_scale
+        :cell_effect (lambda [cell zone]
+          (rotate cell
+            (* (if (= (mod (+ (get zone "row") (get zone "col")) 2) 0) 1 -1)
+               (* (get zone "energy")
+                  (get zone "rotation_scale")
+                  (* 1.5 (+ (get zone "col-norm")
+                            (- 1 (get zone "row-norm")))))))))))
+
+    ;; Blend the two ASCII videos using consistent effect syntax
+    (def blended (-> ascii-a
+      (effect blend ascii-b
+        :mode blend_mode
+        :opacity blend_opacity
+        :resize_mode "fit"))))
+
+  ;; Stage 3: Output
+  (stage :output
+    :requires [:process]
+    :inputs [blended audio-clip]
+    (mux blended audio-clip)))

sexp_effects/effects/blend.sexp

@@ -3,17 +3,19 @@
 ;; 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)
+;;   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]
+;;   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")
-    (list :type string :default 0 0 0)
-  )
+    (pad_color :type list :default [0 0 0])
   )
   (let [a frame-a
         a-w (width a)
@@ -24,31 +26,31 @@
         ;; 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")
+        scale (if (= resize_mode "stretch")
                 1  ;; Will use explicit dimensions
-                (if (= resize-mode "crop")
+                (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)))
+        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")
+        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)))
+            (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)]
+                    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)))
+      (blend-images a (blend-mode a b mode) opacity))))

sexp_effects/effects/layer.sexp

@@ -2,6 +2,8 @@
 ;; Multi-input effect: uses frame-a (background) and frame-b (overlay)
 ;; Params: x, y (position), opacity (0-1), mode (blend mode)
 
+(require-primitives "image" "blending")
+
 (define-effect layer
   :params (
     (x :type int :default 0)