Add no-op guard

rei_toolbox/dubstrip.py

@@ -23,6 +23,15 @@ def has_audio_in_lang(meta: Dict[str, Any], lang: str) -> bool:
     return False
 
 
+def has_audio_not_in_lang(meta: Dict[str, Any], lang: str) -> bool:
+    for stream in meta["streams"]:
+        if stream["codec_type"] == "audio":
+            if stream.get("tags", {}).get("language") != lang:
+                return True
+
+    return False
+
+
 def make_dubstrip_command(
     file: Path, outfile: Path, meta: Dict[str, Any], keep_lang: str
 ) -> List[Union[str, Path]]:
@@ -55,6 +64,10 @@ def main() -> None:
             print(f"no audio in {args.keep}: leaving untouched.")
             continue
 
+        if not has_audio_not_in_lang(meta, args.keep):
+            print(f"no audio not in {args.keep}: nothing to do.")
+            continue
+
         outfile = file.parent.joinpath("dubstriptmp-" + file.name)
 
         cmd = make_dubstrip_command(file, outfile, meta, args.keep)