Ben Stull
d2a97823f5
Per sub-project-2 plan Task 5 / spec §5.2. ffmpeg-only dominant color (no image library), opt-in by design; extract_frame for review previews. Runners injectable so the unit suite never shells out. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
59 lines
1.4 KiB
Python
59 lines
1.4 KiB
Python
"""ffmpeg helpers: representative frame; OPTIONAL dominant color. Runner injectable."""
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from __future__ import annotations
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import subprocess
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def _run_bytes(args) -> bytes:
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return subprocess.run(args, capture_output=True, check=True).stdout
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def dominant_color_from_rgb(rgb: bytes) -> str:
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r, g, b = rgb[0], rgb[1], rgb[2]
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return f"#{r:02x}{g:02x}{b:02x}"
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def compute_dominant_color(path, *, midpoint_s=0.0, runner=_run_bytes) -> str:
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"""ffmpeg-only single-color palette of a mid-segment frame -> #rrggbb."""
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args = [
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"ffmpeg",
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"-v",
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"quiet",
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"-ss",
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str(midpoint_s),
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"-i",
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str(path),
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"-vf",
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"thumbnail,palettegen=max_colors=1",
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"-frames:v",
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"1",
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"-f",
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"rawvideo",
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"-pix_fmt",
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"rgb24",
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"-",
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]
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return dominant_color_from_rgb(runner(args))
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def extract_frame(path, dest, *, midpoint_s=0.0, runner=None):
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"""Write one representative frame to dest (PNG) for the review preview."""
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runner = runner or (lambda a: subprocess.run(a, check=True))
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runner(
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[
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"ffmpeg",
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"-v",
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"quiet",
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"-y",
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"-ss",
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str(midpoint_s),
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"-i",
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str(path),
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"-frames:v",
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"1",
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str(dest),
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]
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)
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return dest
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