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>
96 lines
2.6 KiB
Python
96 lines
2.6 KiB
Python
# /// script
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# requires-python = ">=3.10"
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# dependencies = ["numpy"]
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# ///
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"""
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@effect trails
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@version 1.0.0
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@author artdag
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@description
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Trails effect. Creates persistent motion trails by blending current
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frame with previous frames. Like echo but with configurable blend.
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@param persistence float
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@range 0 0.99
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@default 0.8
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How much of previous frame remains (0 = none, 0.99 = very long trails).
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@param blend_mode string
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@enum blend add screen lighten darken
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@default blend
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How to combine frames.
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@param fade_color list
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@default [0, 0, 0]
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Color to fade toward.
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@state trail_buffer ndarray
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Accumulated trail buffer.
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@example
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(effect trails :persistence 0.85)
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@example
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;; Long bright trails
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(effect trails :persistence 0.9 :blend_mode "add")
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"""
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import numpy as np
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def process_frame(frame: np.ndarray, params: dict, state: dict) -> tuple:
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"""
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Apply trails effect to a video frame.
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Args:
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frame: Input frame as numpy array (H, W, 3) RGB uint8
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params: Effect parameters
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- persistence: trail length 0-0.99 (default 0.8)
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- blend_mode: how to combine (default blend)
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- fade_color: color to fade to (default black)
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state: Persistent state dict
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Returns:
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Tuple of (processed_frame, new_state)
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"""
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persistence = max(0, min(params.get("persistence", 0.8), 0.99))
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blend_mode = params.get("blend_mode", "blend")
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fade_color = params.get("fade_color", [0, 0, 0])
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if state is None:
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state = {}
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# Initialize trail buffer
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if "trail_buffer" not in state or state["trail_buffer"].shape != frame.shape:
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state["trail_buffer"] = frame.astype(np.float32)
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buffer = state["trail_buffer"]
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current = frame.astype(np.float32)
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# Get fade color
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if isinstance(fade_color, (list, tuple)) and len(fade_color) >= 3:
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fade = np.array(fade_color[:3], dtype=np.float32)
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else:
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fade = np.array([0, 0, 0], dtype=np.float32)
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# Blend buffer toward fade color
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faded_buffer = buffer * persistence + fade * (1 - persistence)
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# Combine with current frame based on blend mode
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if blend_mode == "add":
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result = faded_buffer + current
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elif blend_mode == "screen":
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result = 255 - ((255 - faded_buffer) * (255 - current) / 255)
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elif blend_mode == "lighten":
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result = np.maximum(faded_buffer, current)
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elif blend_mode == "darken":
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result = np.minimum(faded_buffer, current)
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else: # blend
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result = faded_buffer + current * (1 - persistence)
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# Update buffer
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state["trail_buffer"] = np.clip(result, 0, 255)
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return np.clip(result, 0, 255).astype(np.uint8), state
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