feat: 新增文件

engine/video_editor.py

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+from __future__ import annotations
+
+from dataclasses import dataclass
+from pathlib import Path
+
+from moviepy import AudioFileClip, CompositeVideoClip, TextClip, VideoFileClip, concatenate_videoclips, vfx
+
+from .config import AppConfig
+
+
+@dataclass(frozen=True)
+class Segment:
+    video_path: Path
+    audio_path: Path
+    narration: str
+
+
+def _fit_video_to_audio(video: VideoFileClip, audio: AudioFileClip) -> VideoFileClip:
+    if audio.duration is None or video.duration is None:
+        return video.with_audio(audio)
+    if audio.duration > video.duration:
+        video = video.with_effects([vfx.Loop(duration=audio.duration)])
+    elif video.duration > audio.duration:
+        video = video.subclipped(0, audio.duration)
+    return video.with_audio(audio)
+
+
+def _subtitle_clip(text: str, size: tuple[int, int], duration: float) -> TextClip:
+    # MoviePy 2 uses Pillow for text rendering by default on most setups.
+    return (
+        TextClip(
+            text=text,
+            font_size=44,
+            color="white",
+            stroke_color="black",
+            stroke_width=2,
+            size=(int(size[0] * 0.92), None),
+            method="caption",
+        )
+        .with_position(("center", "bottom"))
+        .with_duration(duration)
+        .with_opacity(0.95)
+    )
+
+
+def render_final(segments: list[Segment], cfg: AppConfig, output_path: str | Path | None = None) -> Path:
+    transition_s = float(cfg.get("video.transition_seconds", 0.25))
+    out = Path(output_path or str(cfg.get("video.final_output", "./final_poc.mp4")))
+    out.parent.mkdir(parents=True, exist_ok=True)
+
+    clips = []
+    for seg in segments:
+        v = VideoFileClip(str(seg.video_path))
+        a = AudioFileClip(str(seg.audio_path))
+        v2 = _fit_video_to_audio(v, a)
+
+        w, h = v2.size
+        sub = _subtitle_clip(seg.narration, (w, h), v2.duration or a.duration or 0)
+        comp = CompositeVideoClip([v2, sub])
+        if transition_s > 0:
+            comp = comp.with_effects([vfx.FadeIn(transition_s), vfx.FadeOut(transition_s)])
+        clips.append(comp)
+
+    final = concatenate_videoclips(clips, method="compose")
+    try:
+        final.write_videofile(
+            str(out),
+            codec="libx264",
+            audio_codec="aac",
+            fps=clips[0].fps if clips and clips[0].fps else int(cfg.get("video.mock_fps", 24)),
+            threads=4,
+            preset="medium",
+        )
+    finally:
+        final.close()
+        for c in clips:
+            c.close()
+    return out