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>
91 lines
2.3 KiB
Python
91 lines
2.3 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 strobe
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@version 1.0.0
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@author artdag
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@description
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Strobe / Posterize Time effect. Locks video to a reduced frame rate,
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creating a choppy, stop-motion look. Also known as frame hold.
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@param frame_rate float
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@range 1 60
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@default 12
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Target frame rate in fps. Lower = choppier.
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@param sync_to_beat bool
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@default false
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If true, hold frames until next beat (overrides frame_rate).
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@param beat_divisor int
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@range 1 8
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@default 1
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Hold for 1/N beats when sync_to_beat is true.
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@state held_frame ndarray
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Currently held frame.
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@state held_until float
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Time until which to hold the frame.
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@example
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(effect strobe :frame_rate 8)
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@example
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;; Very choppy at 4 fps
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(effect strobe :frame_rate 4)
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@example
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;; Beat-synced frame hold
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(effect strobe :sync_to_beat true :beat_divisor 2)
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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 strobe/posterize time 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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- frame_rate: target fps 1-60 (default 12)
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- sync_to_beat: use beat timing (default False)
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- beat_divisor: beat fraction (default 1)
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state: Persistent state dict
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- held_frame: currently held frame
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- held_until: hold expiry time
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Returns:
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Tuple of (processed_frame, new_state)
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"""
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target_fps = max(1, min(params.get("frame_rate", 12), 60))
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sync_to_beat = params.get("sync_to_beat", False)
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beat_divisor = max(1, int(params.get("beat_divisor", 1)))
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# Get current time from params (executor should provide this)
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t = params.get("_time", 0)
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if state is None:
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state = {}
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# Initialize state
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if "held_frame" not in state:
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state["held_frame"] = None
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state["held_until"] = 0.0
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state["last_beat"] = -1
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# Frame rate based hold
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frame_duration = 1.0 / target_fps
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if t >= state["held_until"]:
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# Time for new frame
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state["held_frame"] = frame.copy()
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state["held_until"] = t + frame_duration
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return state["held_frame"] if state["held_frame"] is not None else frame, state
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