MiniMax-H3: _decode_video_file turns ±90° display-rotated videos upside down #14985

turns = round(rotation / 90.0) % 4
if turns:
    frames = np.ascontiguousarray(np.rot90(frames, k=-turns, axes=(1, 2)))

import subprocess
import sys
import tempfile
from pathlib import Path

import av
import numpy as np


def run(*args: str) -> bytes:
    return subprocess.run(["ffmpeg", "-v", "error", "-y", *args], check=True, capture_output=True).stdout


def ffmpeg_upright(path: Path, width: int, height: int) -> np.ndarray:
    raw = run("-i", str(path), "-frames:v", "1", "-f", "rawvideo", "-pix_fmt", "rgb24", "-")
    return np.frombuffer(raw, np.uint8).reshape(height, width, 3)


def main() -> int:
    tmp = Path(tempfile.mkdtemp())
    base = tmp / "base.mp4"
    # 320x192 landscape, grey, a red 96x64 block in the top-left corner.
    run("-f", "lavfi", "-i", "color=c=gray:s=320x192:d=1:r=24", "-vf",
        "drawbox=x=0:y=0:w=96:h=64:color=red:t=fill", "-c:v", "libx264", "-pix_fmt", "yuv420p", str(base))
    failures = 0
    for display_rotation in (90, -90, 180):
        tagged = tmp / f"rot{display_rotation}.mp4"
        run("-display_rotation", str(display_rotation), "-i", str(base), "-c", "copy", str(tagged))
        with av.open(str(tagged)) as container:
            frame = next(container.decode(container.streams.video[0]))
            rotation = frame.rotation
            frames = np.stack([frame.to_ndarray(format="rgb24")])
        turns = round(rotation / 90.0) % 4
        diffusers = np.rot90(frames, k=-turns, axes=(1, 2))[0]
        opposite = np.rot90(frames, k=+turns, axes=(1, 2))[0]
        height, width = diffusers.shape[:2]
        truth = ffmpeg_upright(tagged, width, height)
        err_diffusers = float(np.abs(diffusers.astype(int) - truth.astype(int)).mean())
        err_opposite = float(np.abs(opposite.astype(int) - truth.astype(int)).mean())
        # Codec noise is ~2; a frame turned the wrong way is an order of magnitude more.
        ok = err_diffusers <= err_opposite + 1.0
        failures += not ok
        print(f"-display_rotation {display_rotation:>4}: frame.rotation={rotation:>6} turns={turns} "
              f"mean|diff| vs ffmpeg: k=-turns {err_diffusers:6.2f} · k=+turns {err_opposite:6.2f} "
              f"→ {'k=-turns matches ffmpeg' if ok else 'k=-turns is upside down vs ffmpeg'}")
    print(f"av {av.__version__}, numpy {np.__version__}, "
          + subprocess.run(["ffmpeg", "-version"], capture_output=True, text=True).stdout.split("\n")[0])
    return failures


if __name__ == "__main__":
    sys.exit(main())