+All alternatives must
+have the same amount of inputs, with an exception for IdentityEffect, which can
+coexist with an effect requiring any amount of inputs (if selected, the IdentityEffect
+just passes its first input unchanged). Similarly, if you set a parameter with
+set_int() or similar, it must be valid for all alternatives (again excepting
+IdentityEffect); if there is one that can only be used on a certain alternative,
+you must set it directly on the effect::
+
+ local resample_effect = ResampleEffect.new()
+ resample_effect:set_float("zoom_x", 1.0001) -- Not valid for ResizeEffect.
+
+ local input0_scaled = scene:add_effect({resample_effect, ResizeEffect.new()})
+ input0_scaled:set_int("width", 1280) -- Set on both alternatives.
+ input0_scaled:set_int("height", 720)
+