chendelian
089f00c3ff
Adds tools/screencast/ — a reusable screen-recording pipeline for skill demo videos. Wraps a pytest desktop E2E run with: - ScreenRecorder: mss-based full-screen frame capture (background thread) - SubtitleEngine: stdout keyword → timestamped SRT generation - compose_video: FFmpeg filter_complex merge (video + subtitles + BGM) - run_screencast: main orchestrator wiring all three layers Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
72 lines
2.2 KiB
Python
72 lines
2.2 KiB
Python
"""FFmpeg 合成：帧序列 + SRT 字幕 + 背景音乐 → MP4。"""
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from __future__ import annotations
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import random
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import subprocess
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import sys
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from pathlib import Path
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def compose_video(
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frames_dir: str,
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fps: int,
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subtitle_path: str,
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music_dir: str,
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output_path: str,
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music_volume: float = 0.15,
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) -> str:
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frames_dir = Path(frames_dir)
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subtitle_path = Path(subtitle_path)
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output_path = Path(output_path)
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output_path.parent.mkdir(parents=True, exist_ok=True)
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# 随机选一首背景音乐
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music_files = list(Path(music_dir).rglob("*.mp3"))
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if not music_files:
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raise FileNotFoundError(f"music_dir 下没有找到 MP3 文件: {music_dir}")
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music_file = random.choice(music_files)
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print(f"[screencast] 背景音乐: {music_file.name}")
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# FFmpeg 字幕路径在 Windows 下需要转义冒号（subtitles 滤镜内部语法）
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srt_path_str = str(subtitle_path).replace("\\", "/").replace(":", "\\:")
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subtitle_filter = (
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f"subtitles='{srt_path_str}'"
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":force_style='FontName=Arial,FontSize=28,"
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"PrimaryColour=&H00FFFFFF,OutlineColour=&H00000000,"
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"Outline=2,Shadow=1,Alignment=2'"
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)
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# 视频和音频都放进 filter_complex，避免 -vf 与 -filter_complex 混用报错
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filter_complex = (
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f"[0:v]{subtitle_filter}[vout];"
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f"[1:a]volume={music_volume},apad[aout]"
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)
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cmd = [
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"ffmpeg", "-y",
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"-framerate", str(fps),
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"-i", str(frames_dir / "frame_%06d.png"),
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"-i", str(music_file),
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"-filter_complex", filter_complex,
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"-map", "[vout]",
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"-map", "[aout]",
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"-c:v", "libx264",
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"-preset", "fast",
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"-crf", "23",
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"-c:a", "aac",
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"-b:a", "128k",
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"-shortest",
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"-pix_fmt", "yuv420p",
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str(output_path),
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]
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print(f"[screencast] 运行 FFmpeg 合成...")
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result = subprocess.run(cmd, capture_output=True, text=True, encoding="utf-8", errors="replace")
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if result.returncode != 0:
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print(result.stderr, file=sys.stderr)
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raise RuntimeError(f"FFmpeg 合成失败，退出码 {result.returncode}")
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print(f"[screencast] 输出: {output_path}")
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return str(output_path)
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