feat: update split script

Author: egvimo

scripts/split.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+
+import json
+import subprocess
+from pathlib import Path
+import re
+
+BITRATE = "48k"
+
+
+def clean_name(name: str) -> str:
+    name = name or "Chapter"
+    # Only safe characters
+    name = re.sub(r"[^a-zA-Z0-9 _-]+", "", name)
+    return name.strip()
+
+
+def run_ffprobe(file_path: Path):
+    cmd = [
+        "ffprobe",
+        "-v", "error",
+        "-print_format", "json",
+        "-show_chapters",
+        str(file_path)
+    ]
+    result = subprocess.run(cmd, capture_output=True, text=True, check=True)
+    return json.loads(result.stdout)
+
+
+def encode_chapter(input_file: Path, out_file: Path, start: float, duration: float):
+    cmd = [
+        "ffmpeg",
+        "-hide_banner",
+        "-loglevel", "error",
+        "-y",
+
+        "-ss", str(start),
+        "-i", str(input_file),
+        "-t", str(duration),
+
+        # Only audio stream
+        "-map", "0:a:0",
+        "-vn",
+
+        "-c:a", "libopus",
+        "-b:a", BITRATE,
+        "-vbr", "on",
+        "-compression_level", "10",
+
+        # No broken metadata
+        "-map_metadata", "-1",
+
+        str(out_file)
+    ]
+
+    subprocess.run(cmd, check=True)
+
+
+def process_file(file_path: Path):
+    print(f"\n==> {file_path.name}")
+
+    data = run_ffprobe(file_path)
+    chapters = data.get("chapters", [])
+
+    if not chapters:
+        print("   ⚠ No chapters found – skipped")
+        return
+
+    out_dir = file_path.with_suffix("")
+    out_dir.mkdir(exist_ok=True)
+
+    for i, ch in enumerate(chapters, start=1):
+        start = float(ch["start_time"])
+        end = float(ch["end_time"])
+        duration = end - start
+
+        title = ch.get("tags", {}).get("title", f"Chapter {i}")
+        title = clean_name(title)
+
+        out_file = out_dir / f"{i:03d}_{title}.opus"
+
+        print(f"   -> {out_file.name}")
+        encode_chapter(file_path, out_file, start, duration)
+
+
+def main():
+    files = sorted(Path(".").glob("*.m4b"))
+
+    if not files:
+        print("No M4B files found.")
+        return
+
+    for f in files:
+        try:
+            process_file(f)
+        except subprocess.CalledProcessError as e:
+            print(f"Error with {f.name}: {e}")
+
+
+if __name__ == "__main__":
+    main()