Initial commit: auto-video-cut project

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

auto_video_cut/cutter.py

@@ -0,0 +1,198 @@
+"""Stille- und Szenen-Erkennung sowie Schnitt-Logik."""
+
+from __future__ import annotations
+
+import re
+import subprocess
+import tempfile
+from dataclasses import dataclass
+from pathlib import Path
+
+
+@dataclass
+class TimeRange:
+    start: float
+    end: float
+
+    @property
+    def duration(self) -> float:
+        return self.end - self.start
+
+
+def _run(cmd: list[str]) -> subprocess.CompletedProcess:
+    return subprocess.run(cmd, capture_output=True, text=True, check=False)
+
+
+# ---------------------------------------------------------------------------
+# Stille-Erkennung
+# ---------------------------------------------------------------------------
+
+def detect_silence(
+    input_path: Path,
+    threshold_db: float = -40,
+    min_duration: float = 0.5,
+) -> list[TimeRange]:
+    """Stille-Abschnitte via ffmpeg silencedetect erkennen."""
+    cmd = [
+        "ffmpeg", "-i", str(input_path),
+        "-af", f"silencedetect=n={threshold_db}dB:d={min_duration}",
+        "-f", "null", "-",
+    ]
+    result = _run(cmd)
+    output = result.stderr
+
+    starts = [float(m) for m in re.findall(r"silence_start: ([\d.]+)", output)]
+    ends = [float(m) for m in re.findall(r"silence_end: ([\d.]+)", output)]
+
+    return [TimeRange(s, e) for s, e in zip(starts, ends)]
+
+
+def _get_duration(input_path: Path) -> float:
+    """Video-Länge in Sekunden ermitteln."""
+    cmd = [
+        "ffprobe", "-v", "error",
+        "-show_entries", "format=duration",
+        "-of", "default=noprint_wrappers=1:nokey=1",
+        str(input_path),
+    ]
+    result = _run(cmd)
+    return float(result.stdout.strip())
+
+
+def invert_ranges(silence_ranges: list[TimeRange], total_duration: float) -> list[TimeRange]:
+    """Stille-Abschnitte umkehren → Abschnitte mit Ton."""
+    speech: list[TimeRange] = []
+    cursor = 0.0
+    for silence in sorted(silence_ranges, key=lambda r: r.start):
+        if silence.start > cursor:
+            speech.append(TimeRange(cursor, silence.start))
+        cursor = silence.end
+    if cursor < total_duration:
+        speech.append(TimeRange(cursor, total_duration))
+    return speech
+
+
+def remove_silence(
+    input_path: Path,
+    output_path: Path,
+    threshold_db: float = -40,
+    min_duration: float = 0.5,
+) -> Path:
+    """Stille aus Video entfernen und Ergebnis speichern."""
+    silence = detect_silence(input_path, threshold_db, min_duration)
+    total = _get_duration(input_path)
+    segments = invert_ranges(silence, total)
+
+    if not segments:
+        raise RuntimeError("Keine Ton-Abschnitte gefunden — Stille-Schwelle zu hoch?")
+
+    output_path.parent.mkdir(parents=True, exist_ok=True)
+
+    with tempfile.TemporaryDirectory() as tmp_dir:
+        tmp = Path(tmp_dir)
+        clip_files: list[Path] = []
+
+        for i, seg in enumerate(segments):
+            clip = tmp / f"seg_{i:04d}.mp4"
+            cmd = [
+                "ffmpeg", "-y",
+                "-ss", str(seg.start),
+                "-to", str(seg.end),
+                "-i", str(input_path),
+                "-c", "copy",
+                str(clip),
+            ]
+            result = _run(cmd)
+            if result.returncode != 0:
+                raise RuntimeError(f"ffmpeg Fehler beim Ausschneiden: {result.stderr}")
+            clip_files.append(clip)
+
+        _concat_clips(clip_files, output_path)
+
+    return output_path
+
+
+# ---------------------------------------------------------------------------
+# Szenen-Erkennung
+# ---------------------------------------------------------------------------
+
+def detect_scenes(input_path: Path, threshold: float = 27.0) -> list[TimeRange]:
+    """Szenen-Grenzen via PySceneDetect erkennen."""
+    try:
+        from scenedetect import VideoManager, SceneManager
+        from scenedetect.detectors import ContentDetector
+    except ImportError:
+        raise ImportError("PySceneDetect nicht installiert: pip install scenedetect[opencv]")
+
+    video_manager = VideoManager([str(input_path)])
+    scene_manager = SceneManager()
+    scene_manager.add_detector(ContentDetector(threshold=threshold))
+
+    video_manager.set_downscale_factor()
+    video_manager.start()
+    scene_manager.detect_scenes(frame_source=video_manager)
+    scene_list = scene_manager.get_scene_list()
+    video_manager.release()
+
+    return [
+        TimeRange(
+            start.get_seconds(),
+            end.get_seconds(),
+        )
+        for start, end in scene_list
+    ]
+
+
+def split_scenes(
+    input_path: Path,
+    output_folder: Path,
+    threshold: float = 27.0,
+) -> list[Path]:
+    """Video an Szenen-Grenzen aufteilen."""
+    scenes = detect_scenes(input_path, threshold)
+    output_folder.mkdir(parents=True, exist_ok=True)
+    clips: list[Path] = []
+
+    for i, scene in enumerate(scenes):
+        out = output_folder / f"scene_{i:04d}.mp4"
+        cmd = [
+            "ffmpeg", "-y",
+            "-ss", str(scene.start),
+            "-to", str(scene.end),
+            "-i", str(input_path),
+            "-c", "copy",
+            str(out),
+        ]
+        result = _run(cmd)
+        if result.returncode != 0:
+            raise RuntimeError(f"ffmpeg Fehler: {result.stderr}")
+        clips.append(out)
+
+    return clips
+
+
+# ---------------------------------------------------------------------------
+# Hilfsfunktion concat
+# ---------------------------------------------------------------------------
+
+def _concat_clips(clips: list[Path], output: Path) -> None:
+    """Clips via ffmpeg concat demuxer zusammenfügen."""
+    output.parent.mkdir(parents=True, exist_ok=True)
+    with tempfile.NamedTemporaryFile(
+        mode="w", suffix=".txt", delete=False, encoding="utf-8"
+    ) as fh:
+        list_file = Path(fh.name)
+        for clip in clips:
+            fh.write(f"file '{clip.resolve()}'\n")
+
+    cmd = [
+        "ffmpeg", "-y",
+        "-f", "concat", "-safe", "0",
+        "-i", str(list_file),
+        "-c", "copy",
+        str(output),
+    ]
+    result = _run(cmd)
+    list_file.unlink(missing_ok=True)
+    if result.returncode != 0:
+        raise RuntimeError(f"ffmpeg concat Fehler: {result.stderr}")