Add skip-audio mode and resilient merge handling

src/merge_audio_video.py

@@ -6,10 +6,11 @@ from __future__ import annotations
 import argparse
 import logging
 import re
+import shutil
 import subprocess
 from pathlib import Path
 
-from logging_config import configure_logging, debug_log_lifecycle
+from logging_config import configure_logging
 
 
 SCRIPT_DIR = Path(__file__).resolve().parent
@@ -32,14 +33,14 @@ def parse_args() -> argparse.Namespace:
     parser.add_argument("--audios-dir", type=Path, default=DEFAULT_AUDIOS_DIR)
     parser.add_argument("--output-dir", type=Path, default=DEFAULT_OUTPUT_DIR)
     parser.add_argument(
-        "--log-level",
-        default=None,
-        help="Logging level (overrides LOG_LEVEL env var)",
+        "--allow-missing-audio",
+        action="store_true",
+        help="If set, create merged output from video only when audio is missing.",
     )
+    parser.add_argument("--log-level", default="INFO")
     return parser.parse_args()
 
 
-@debug_log_lifecycle
 def main() -> int:
     args = parse_args()
     configure_logging(args.log_level)
@@ -55,14 +56,24 @@ def main() -> int:
         audio = args.audios_dir / f"output_{num}.mp3"
         output = args.output_dir / f"merged_{num}.mp4"
 
-        if not audio.exists():
-            LOGGER.warning("No audio found for shot %s (%s); skipped", num, audio)
-            continue
-
         if output.exists():
             LOGGER.info("Already exists; skipped shot %s", num)
             continue
 
+        if not audio.exists():
+            if args.allow_missing_audio:
+                LOGGER.warning(
+                    "No audio found for shot %s (%s); using video-only output",
+                    num,
+                    audio,
+                )
+                shutil.copy2(video, output)
+                LOGGER.info("Done (video-only): %s", output)
+                continue
+
+            LOGGER.warning("No audio found for shot %s (%s); skipped", num, audio)
+            continue
+
         LOGGER.info("Merging shot %s: %s + %s -> %s", num, video, audio, output)
         subprocess.run(
             [