35 lines
1.8 KiB
Python
35 lines
1.8 KiB
Python
"""FFmpeg encoding; this module also works outside Unreal."""
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from pathlib import Path
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import subprocess
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from .paths import executable
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def encode(frames, fps, output=None, ffmpeg=None, expected_frames=None, audio=None):
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"""Encode PNG frames to MP4. Audio is cut to the film; shorter audio ends in silence."""
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frames = Path(frames).resolve()
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if fps <= 0:
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raise ValueError("FPS musi byc dodatni.")
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images = sorted(frames.glob("frame_*.png"))
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count = len(images)
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if not count or any(p.name != f"frame_{i:04d}.png" for i, p in enumerate(images)):
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raise RuntimeError(f"Brak kompletnej numeracji frame_0000.png, frame_0001.png... w {frames}")
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if expected_frames is not None and count != expected_frames:
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raise RuntimeError(f"Render zapisal {count} klatek zamiast {expected_frames}.")
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output = Path(output) if output else frames.parent / "film.mp4"
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output.parent.mkdir(parents=True, exist_ok=True)
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audio_input, audio_output = [], []
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if audio is not None:
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if not Path(audio).is_file():
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raise FileNotFoundError(audio)
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audio_input = ["-i", str(audio)]
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audio_output = ["-map", "0:v:0", "-map", "1:a:0", "-c:a", "aac", "-b:a", "192k", "-t", str(count / fps)]
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command = [executable("ffmpeg", ffmpeg), "-hide_banner", "-loglevel", "error", "-y",
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"-framerate", str(fps), "-start_number", "0", "-i", str(frames / "frame_%04d.png"), *audio_input,
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"-frames:v", str(count), "-c:v", "libx264", "-crf", "20", "-pix_fmt", "yuv420p",
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"-vf", "pad=ceil(iw/2)*2:ceil(ih/2)*2", *audio_output, "-movflags", "+faststart", str(output)]
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result = subprocess.run(command, capture_output=True, text=True)
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if result.returncode:
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raise RuntimeError("FFmpeg: " + result.stderr[-4000:])
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return output.resolve()
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