27 lines
712 B
Python
27 lines
712 B
Python
"""LTX-2 frame-count math. Legal F satisfy F % 8 == 1 (8x temporal + 1)."""
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def is_legal_frames(f: int) -> bool:
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return f >= 9 and f % 8 == 1
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def legal_frames(min_f: int = 9, max_f: int = 1000) -> list[int]:
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start = max(9, min_f + ((1 - min_f) % 8)) # first 8k+1 >= min_f
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return list(range(start, max_f + 1, 8))
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def nearest_legal_frames(f: int) -> int:
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if f <= 9:
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return 9
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low = ((f - 1) // 8) * 8 + 1
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high = low + 8
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return low if (f - low) <= (high - f) else high
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def duration_for_frames(frames: int, fps: float) -> float:
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return frames / fps
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def frames_for_duration(duration: float, fps: float) -> int:
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return nearest_legal_frames(round(duration * fps))
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